@article{Abellan2017a,
abstract = {During the mature phase of El Ni{\~{n}}o–Southern Oscillation (ENSO) events there is a southward shift of anomalous zonal winds (SWS), which has been suggested to play a role in the seasonal phase locking of ENSO. Motivated by the fact that coupled climate models tend to underestimate this feature, this study examines the representation of the SWS in phase 5 of the Coupled Model Intercomparison Project (CMIP5). It is found that most models successfully reproduce the observed SWS, although the magnitude of the zonal wind stress anomaly is underestimated. Several significant differences between the models with and without the SWS are identified including biases in the magnitude and spatial distribution of precipitation and sea surface temper-ature (SST) anomalies during ENSO. Multiple-linear regression analysis suggests that the climatological meridional SST gradient as well as anomalous ENSO-driven convective activity over the northwest Pacific both might play a role in controlling the SWS. While the models that capture the SWS also simulate many more strong El Ni{\~{n}}o and La Ni{\~{n}}a events peaking at the correct time of year, the overall seasonal synchronization is still underestimated in these models. This is attributed to underestimated changes in warm water volume (WWV) during moderate El Ni{\~{n}}o events so that these events display relatively poor seasonal synchronization. Thus, while the SWS is an important metric, it is ultimately the magnitude and zonal extent of the wind changes that accompany this SWS that drive the changes in WWV and prime the system for termination.},
author = {Abell{\'{a}}n, Esteban and McGregor, Shayne and England, Matthew H.},
doi = {10.1175/JCLI-D-16-0326.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Climate models,ENSO,Model errors,Seasonal cycle,Wind stress},
number = {7},
pages = {2415--2435},
title = {{Analysis of the southward wind shift of ENSO in CMIP5 models}},
volume = {30},
year = {2017}
}
@article{Abraham2013,
abstract = {The evolution of ocean temperature measurement systems is presented with a focus on the development and accuracy of two critical devices in use today (expendable bathythermographs and conductivity-temperature-depth instruments used on Argo floats). A detailed discussion of the accuracy of these devices and a projection of the future of ocean temperature measurements are provided. The accuracy of ocean temperature measurements is discussed in detail in the context of ocean heat content, Earth's energy imbalance, and thermosteric sea level rise. Up-to-date estimates are provided for these three important quantities. The total energy imbalance at the top of atmosphere is best assessed by taking an inventory of changes in energy storage. The main storage is in the ocean, the latest values of which are presented. Furthermore, despite differences in measurement methods and analysis techniques, multiple studies show that there has been a multidecadal increase in the heat content of both the upper and deep ocean regions, which reflects the impact of anthropogenic warming. With respect to sea level rise, mutually reinforcing information from tide gauges and radar altimetry shows that presently, sea level is rising at approximately 3 mm yr−1 with contributions from both thermal expansion and mass accumulation from ice melt. The latest data for thermal expansion sea level rise are included here and analyzed.},
archivePrefix = {arXiv},
arxivId = {8755-1209/13/10.1002/rog.20022},
author = {Abraham, J. P. and Baringer, M. and Bindoff, N. L. and Boyer, T. and Cheng, L. J. and Church, J. A. and Conroy, J. L. and Domingues, C. M. and Fasullo, J. T. and Gilson, J. and Goni, G. and Good, S. A. and Gorman, J. M. and Gouretski, V. and Ishii, M. and Johnson, G. C. and Kizu, S. and Lyman, J. M. and Macdonald, A. M. and Minkowycz, W. J. and Moffitt, S. E. and Palmer, M. D. and Piola, A. R. and Reseghetti, F. and Schuckmann, K. and Trenberth, K. E. and Velicogna, I. and Willis, J. K.},
doi = {10.1002/rog.20022},
eprint = {13/10.1002/rog.20022},
isbn = {87551209},
issn = {87551209},
journal = {Reviews of Geophysics},
keywords = {Argo float,Earth energy balance,expendable bathythermograph,global warming,ocean heat content,thermosteric sea level rise},
month = {sep},
number = {3},
pages = {450--483},
primaryClass = {8755-1209},
publisher = {Wiley-Blackwell},
title = {{A review of global ocean temperature observations: Implications for ocean heat content estimates and climate change}},
url = {http://doi.wiley.com/10.1002/rog.20022},
volume = {51},
year = {2013}
}
@article{ABRAM2013168,
abstract = {Sea ice plays an important role in Earth's climate system. The lack of direct indications of past sea ice coverage, however, means that there is limited knowledge of the sensitivity and rate at which sea ice dynamics are involved in amplifying climate changes. As such, there is a need to develop new proxy records for reconstructing past sea ice conditions. Here we review the advances that have been made in using chemical tracers preserved in ice cores to determine past changes in sea ice cover around Antarctica. Ice core records of sea salt concentration show promise for revealing patterns of sea ice extent particularly over glacial–interglacial time scales. In the coldest climates, however, the sea salt signal appears to lose sensitivity and further work is required to determine how this proxy can be developed into a quantitative sea ice indicator. Methane sulphonic acid (MSA) in near-coastal ice cores has been used to reconstruct quantified changes and interannual variability in sea ice extent over shorter time scales spanning the last ∼160 years, and has potential to be extended to produce records of Antarctic sea ice changes throughout the Holocene. However the MSA ice core proxy also requires careful site assessment and interpretation alongside other palaeoclimate indicators to ensure reconstructions are not biased by non-sea ice factors, and we summarise some recommended strategies for the further development of sea ice histories from ice core MSA. For both proxies the limited information about the production and transfer of chemical markers from the sea ice zone to the Antarctic ice sheets remains an issue that requires further multidisciplinary study. Despite some exploratory and statistical work, the application of either proxy as an indicator of sea ice change in the Arctic also remains largely unknown. As information about these new ice core proxies builds, so too does the potential to develop a more comprehensive understanding of past changes in sea ice and its role in both long and short-term climate changes.},
annote = {Sea Ice in the Paleoclimate System: the Challenge of Reconstructing Sea Ice from Proxies},
author = {Abram, Nerilie J and Wolff, Eric W and Curran, Mark A J},
doi = {10.1016/j.quascirev.2013.01.011},
issn = {0277-3791},
journal = {Quaternary Science Reviews},
keywords = {Ice cores,MSA,Palaeoclimate,Sea ice,Sea salt},
pages = {168--183},
title = {{A review of sea ice proxy information from polar ice cores}},
url = {http://www.sciencedirect.com/science/article/pii/S0277379113000206},
volume = {79},
year = {2013}
}
@article{Abram2014,
abstract = {The Southern Annular Mode (SAM) is the primary pattern of climate variability in the Southern Hemisphere1,2 , influencing latitudinal rainfall distribution and temperatures from the subtropics to Antarctica. The positive summer trend in the SAMover recent decades is widely attributed to stratospheric ozonedepletion2 ;however, the brevity of observational records from Antarctica1 —one of the core zones that defines SAM variability—limits our understanding of long-term SAM be- haviour. Herewe reconstruct annual mean changes in the SAM since AD 1000 using, for the first time, proxy records that encompass the full mid-latitude to polar domain across the Drake Passage sector.We find that the SAM has undergone a progressive shift towards its positive phase since the fifteenth century, causing cooling of the main Antarctic continent at the same time that the Antarctic Peninsula has warmed. The positive trend in the SAM since ∼AD 1940 is reproduced by multimodel climate simulations forced with rising greenhouse gas levels and later ozone depletion, and the long-termaverage SAMindex is nowat its highest level for at least the past 1,000 years.Reconstructed SAMtrends before the twentieth century are more prominent than those in radiative-forcing climate experiments and may be associated with a teleconnected response to tropical Pacific climate. Our findings imply that predictions of further greenhouse-driven increases in the SAM overthecomingcentury3 alsoneedtoaccountforthepossibility of opposing effects from tropical Pacific climate changes},
author = {Abram, Nerilie J and Mulvaney, Robert and Vimeux, Fran{\c{c}}oise and Phipps, Steven J and Turner, John and England, Matthew H},
doi = {10.1038/nclimate2235},
isbn = {1758-678X},
issn = {17586798},
journal = {Nature Climate Change},
keywords = {pages2kpmip3},
month = {may},
number = {7},
pages = {564--569},
pmid = {1651522616},
publisher = {Nature Publishing Group},
title = {{Evolution of the Southern Annular Mode during the past millennium}},
url = {http://dx.doi.org/10.1038/nclimate2235 10.1038/nclimate2235 https://www.nature.com/articles/nclimate2235{\#}supplementary-information},
volume = {4},
year = {2014}
}
@article{Abram2020a,
author = {Abram, Nerilie J. and Wright, Nicky M. and Ellis, Bethany and Dixon, Bronwyn C. and Wurtzel, Jennifer B. and England, Matthew H. and Ummenhofer, Caroline C. and Philibosian, Belle and Cahyarini, Sri Yudawati and Yu, Tsai-Luen and Shen, Chuan-Chou and Cheng, Hai and Edwards, R. Lawrence and Heslop, David},
doi = {10.1038/s41586-020-2084-4},
issn = {0028-0836},
journal = {Nature},
month = {mar},
number = {7799},
pages = {385--392},
title = {{Coupling of Indo-Pacific climate variability over the last millennium}},
url = {http://www.nature.com/articles/s41586-020-2084-4},
volume = {579},
year = {2020}
}
@article{cp-13-1661-2017,
abstract = {Abstract. This study uses the simplified patterns of temperature and effective precipitation approach from the Australian component of the international palaeoclimate synthesis effort (INTegration of Ice core, MArine and TErrestrial records – OZ-INTIMATE) to compare atmosphere–ocean general circulation model (AOGCM) simulations and proxy reconstructions. The approach is used in order to identify important properties (e.g. circulation and precipitation) of past climatic states from the models and proxies, which is a primary objective of the Southern Hemisphere Assessment of PalaeoEnvironment (SHAPE) initiative. The AOGCM data are taken from the Paleoclimate Modelling Intercomparison Project (PMIP) mid-Holocene (ca. 6000 years before present, 6 ka) and pre-industrial control (ca. 1750 CE, 0 ka) experiments. The synthesis presented here shows that the models and proxies agree on the differences in climate state for 6 ka relative to 0 ka, when they are insolation driven. The largest uncertainty between the models and the proxies occurs over the Indo-Pacific Warm Pool (IPWP). The analysis shows that the lower temperatures in the Pacific at around 6 ka in the models may be the result of an enhancement of an existing systematic error. It is therefore difficult to decipher which one of the proxies and/or the models is correct. This study also shows that a reduction in the Equator-to-pole temperature difference in the Southern Hemisphere causes the mid-latitude westerly wind strength to reduce in the models; however, the simulated rainfall actually increases over the southern temperate zone of Australia as a result of higher convective precipitation. Such a mechanism (increased convection) may be useful for resolving disparities between different regional proxy records and model simulations. Finally, after assessing the available datasets (model and proxy), opportunities for better model–proxy integrated research are discussed.},
author = {Ackerley, Duncan and Reeves, Jessica and Barr, Cameron and Bostock, Helen and Fitzsimmons, Kathryn and Fletcher, Michael-Shawn and Gouramanis, Chris and McGregor, Helen and Mooney, Scott and Phipps, Steven J and Tibby, John and Tyler, Jonathan},
doi = {10.5194/cp-13-1661-2017},
issn = {1814-9332},
journal = {Climate of the Past},
month = {nov},
number = {11},
pages = {1661--1684},
title = {{Evaluation of PMIP2 and PMIP3 simulations of mid-Holocene climate in the Indo-Pacific, Australasian and Southern Ocean regions}},
url = {https://www.clim-past.net/13/1661/2017/ https://cp.copernicus.org/articles/13/1661/2017/},
volume = {13},
year = {2017}
}
@article{Adcroft2019,
abstract = {We document the configuration and emergent simulation features from the Geophysical Fluid Dynamics Laboratory (GFDL) OM4.0 ocean/sea ice model. OM4 serves as the ocean/sea ice component for the GFDL climate and Earth system models. It is also used for climate science research and is contributing to the Coupled Model Intercomparison Project version 6 Ocean Model Intercomparison Project. The ocean component of OM4 uses version 6 of the Modular Ocean Model and the sea ice component uses version 2 of the Sea Ice Simulator, which have identical horizontal grid layouts (Arakawa C-grid). We follow the Coordinated Ocean-sea ice Reference Experiments protocol to assess simulation quality across a broad suite of climate-relevant features. We present results from two versions differing by horizontal grid spacing and physical parameterizations: OM4p5 has nominal 0.5° spacing and includes mesoscale eddy parameterizations and OM4p25 has nominal 0.25° spacing with no mesoscale eddy parameterization. Modular Ocean Model version 6 makes use of a vertical Lagrangian-remap algorithm that enables general vertical coordinates. We show that use of a hybrid depth-isopycnal coordinate reduces the middepth ocean warming drift commonly found in pure z* vertical coordinate ocean models. To test the need for the mesoscale eddy parameterization used in OM4p5, we examine the results from a simulation that removes the eddy parameterization. The water mass structure and model drift are physically degraded relative to OM4p5, thus supporting the key role for a mesoscale closure at this resolution.},
author = {Adcroft, Alistair and Anderson, Whit and Balaji, V. and Blanton, Chris and Bushuk, Mitchell and Dufour, Carolina O. and Dunne, John P. and Griffies, Stephen M. and Hallberg, Robert and Harrison, Matthew J. and Held, Isaac M. and Jansen, Malte F. and John, Jasmin G. and Krasting, John P. and Langenhorst, Amy R. and Legg, Sonya and Liang, Zhi and McHugh, Colleen and Radhakrishnan, Aparna and Reichl, Brandon G. and Rosati, Tony and Samuels, Bonita L. and Shao, Andrew and Stouffer, Ronald and Winton, Michael and Wittenberg, Andrew T. and Xiang, Baoqiang and Zadeh, Niki and Zhang, Rong},
doi = {10.1029/2019MS001726},
issn = {19422466},
journal = {Journal of Advances in Modeling Earth Systems},
keywords = {CORE,hybrid coordinates,ocean circulation model},
month = {oct},
publisher = {Blackwell Publishing Ltd},
title = {{The GFDL Global Ocean and Sea Ice Model OM4.0: Model Description and Simulation Features}},
year = {2019}
}
@article{Adler2017b,
abstract = {Global precipitation variations over the satellite era are reviewed using the Global Precipitation Climatology Project (GPCP) monthly, globally complete analyses, which integrate satellite and surface gauge information. Mean planetary values are examined and compared, over ocean, with information from recent satellite programs and related estimates, with generally positive agreements, but with some indication of small underestimates for GPCP over the global ocean. Variations during the satellite era in global precipitation are tied to ENSO events, with small increases during El Ninos, and very noticeable decreases after major volcanic eruptions. No overall significant trend is noted in the global precipitation mean value, unlike that for surface temperature and atmospheric water vapor. However, there is a pattern of positive and negative trends across the planet with increases over tropical oceans and decreases over some middle latitude regions. These observed patterns are a result of a combination of inter-decadal variations and the effect of the global warming during the period. The results reviewed here indicate the value of such analyses as GPCP and the possible improvement in the information as the record lengthens and as new, more sophisticated and more accurate observations are included.},
author = {Adler, Robert F. and Gu, Guojun and Sapiano, Matthew and Wang, Jian-Jian and Huffman, George J.},
doi = {10.1007/s10712-017-9416-4},
issn = {0169-3298},
journal = {Surveys in Geophysics},
month = {jul},
number = {4},
pages = {679--699},
title = {{Global Precipitation: Means, Variations and Trends During the Satellite Era (1979–2014)}},
url = {http://link.springer.com/10.1007/s10712-017-9416-4},
volume = {38},
year = {2017}
}
@article{huffman2013gpcp,
author = {Adler, Robert F. and Huffman, George J and Chang, Alfred and Ferraro, Ralph and Xie, Ping-Ping and Janowiak, John and Rudolf, Bruno and Schneider, Udo and Curtis, Scott and Bolvin, David and Gruber, Arnold and Susskind, Joel and Arkin, Philip and Nelkin, Eric},
doi = {10.1175/1525-7541(2003)004<1147:TVGPCP>2.0.CO;2},
issn = {1525-755X},
journal = {Journal of Hydrometeorology},
month = {dec},
number = {6},
pages = {1147--1167},
title = {{The Version-2 Global Precipitation Climatology Project (GPCP) Monthly Precipitation Analysis (1979–Present)}},
url = {http://journals.ametsoc.org/doi/10.1175/1525-7541(2003)004{\%}3C1147:TVGPCP{\%}3E2.0.CO;2},
volume = {4},
year = {2003}
}
@article{AitBrahim2018,
author = {{Ait Brahim}, Yassine and Wassenburg, Jasper A. and Cruz, Francisco W. and Sifeddine, Abdelfettah and Scholz, Denis and Bouchaou, Lhoussaine and Dassi{\'{e}}, Emilie P. and Jochum, Klaus P. and Edwards, R. Lawrence and Cheng, Hai},
doi = {10.1038/s41598-018-35498-x},
issn = {2045-2322},
journal = {Scientific Reports},
month = {dec},
number = {1},
pages = {17446},
title = {{Multi-decadal to centennial hydro-climate variability and linkage to solar forcing in the Western Mediterranean during the last 1000 years}},
url = {http://www.nature.com/articles/s41598-018-35498-x},
volume = {8},
year = {2018}
}
@article{hess-17-2967-2013,
author = {Alkama, R and Marchand, L and Ribes, A and Decharme, B},
doi = {10.5194/hess-17-2967-2013},
journal = {Hydrology and Earth System Sciences},
number = {7},
pages = {2967--2979},
title = {{Detection of global runoff changes: results from observations and CMIP5 experiments}},
url = {https://www.hydrol-earth-syst-sci.net/17/2967/2013/},
volume = {17},
year = {2013}
}
@article{Allan2014c,
author = {Allan, Richard P.},
doi = {10.1038/ngeo2243},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {oct},
number = {10},
pages = {700--701},
title = {{Dichotomy of drought and deluge}},
url = {http://www.nature.com/articles/ngeo2243},
volume = {7},
year = {2014}
}
@article{Allen2014,
abstract = {The tropical belt has widened by several degrees latitude since 1979, as evidenced by shifts in atmospheric circulation and climate zones1–5 . Global climate models also simulate tropical belt widening, but less so than observed6,7 . Reasons for this discrepancy and the mechanisms driving the expansion are uncertain. Here we analyse multidecadal variability in tropical belt width since 1950 using the Coupled Model Intercomparison Project Phase 5 climate model runs and find that simulated rates of tropical expansion over the past 30 years—particularly in the Northern Hemisphere—are in better agreement with observations than previous models.We find that models driven by observed sea surface temperatures over this interval yield the largest rate of tropical expansion. We link the tropical expansion in the Northern Hemisphere to the leading pattern of sea surface temperature variability in the North Pacific, the Pacific Decadal Oscillation. We also find, both from models and observations, that the tropical belt contracted in the Northern Hemisphere from 1950 to 1979, coincident with the reversal of the Pacific Decadal Oscillation trend. In both time periods, anthropogenic aerosols act to modify thePacific Decadal Oscillation and therefore contribute to the width of the tropical belt. We conclude that tropical expansion and contraction are influenced by multidecadal sea surfacetemperaturevariabilityassociatedwithboththePacific Decadal Oscillation and anthropogenic aerosols. Recent},
annote = {Zonal mean Hadley cell in NH
Meridional streamfunction@500hPa=0, tropospheric jet maximum, peak of subtropical ridge, P–E=0, cloud minimum, and those combined
Reanalyses, GPCP+OAFlux, ISCCP+PATMOS-x
CMIP5 historical+RCP4.5 (8.5 if 4.5 is unavailable), single forcing runs, AMIP
1979-2009

-In historical run, GHG is major driver of widening, with weak contributions from natural, aerosol and ozone forcings
- AMIP produces much stronger widening in NH
- PDO is an important driver for NH Hadley cell expansion
- Due to positive tendency for 1950-1979, NH Hadley cell contracted, in contrast to SH Hadley cell expansion due to GHG and ozone
- For 1979-2009 NH Hadley cell expanded due to negative trend of PDO},
author = {Allen, Robert J. and Norris, Joel R. and Kovilakam, Mahesh},
doi = {10.1038/ngeo2091},
isbn = {1752-0894},
issn = {17520908},
journal = {Nature Geoscience},
number = {4},
pages = {270--274},
title = {{Influence of anthropogenic aerosols and the Pacific Decadal Oscillation on tropical belt width}},
volume = {7},
year = {2014}
}
@article{Allen2017,
abstract = {AbstractObservations show the tropical belt has widened over the past few decades, a phenomenon associated with poleward migration of subtropical dry zones and large-scale atmospheric circulation. Coupled climate models also simulate tropical belt widening, but less so than observed. Reasons for this discrepancy, and the mechanisms driving the expansion remain uncertain. Here, we show the role of unforced, natural climate variability–particularly natural sea surface temperature (SST) variability–in recent tropical widening. Compared to coupled ocean atmosphere models, atmosphere only simulations driven by observed SSTs consistently lead to larger rates of tropical widening, especially in the Northern Hemisphere (NH), highlighting the importance of recent SST evolution. Assuming the ensemble mean SSTs from historical simulations accurately represent the externally forced response, the observed SSTs can be decomposed into a forced and an unforced component. Targeted simulations with the Community Atmosphere...},
annote = {Zonal mean Hadley circuation
- 7 Reanalyses
- CMIP5 historical-RCP4.5, AMIP
- CESM1 LENS historical-RCP8.5, piControl, pacemaker
- CAM5 AMIP historical-RCP4.5, TOGA, AMIP-NOFORC (AMIP-fixed RF), AMIP-NOOZONE (AMIP-fixed Ozone), CAM5 FSST (forced SST), CAM5 UFSST (unforced SST)
- Index: Latitudes of 850-300hPa mean u max (JET), zero meridional streamfunction@500hPa 
-1979-2008 (partly -2014)

- Large uncertainty in observations {\ldots} method and dataset
- Radiative forcing widens the Hadley cell on average, but weaker
- Large ensemble spread in both coupled and AGCM runs
- AMIP captures stronger widening (especially in NH) which is closer to reanalysis
- TOGA and pacemaker consistently show stronger warming, explainng large part of CMIP-AMIP difference
- Important contribution from ENSO/PDO},
author = {Allen, Robert J. and Kovilakam, Mahesh},
doi = {10.1175/JCLI-D-16-0735.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Climate models,Climate variability,Multidecadal variability},
number = {16},
pages = {6329--6350},
title = {{The role of natural climate variability in recent tropical expansion}},
volume = {30},
year = {2017}
}
@article{Allen1999,
abstract = {{\{}$\backslash$enspace{\}}Current approaches to the detection and attribution of an anthropogenic influence on climate involve quantifying the level of agreement between model-predicted patterns of externally forced change and observed changes in the recent climate record. Analyses of uncertainty rely on simulated variability from a climate model. Any numerical representation of the climate is likely to display too little variance on small spatial scales, leading to a risk of spurious detection results. The risk is particularly severe if the detection strategy involves optimisation of signal-to-noise because unrealistic aspects of model variability may automatically be given high weight through the optimisation. The solution is to confine attention to aspects of the model and of the real climate system in which the model simulation of internal climate variability is adequate, or, more accurately, cannot be shown to be deficient. We propose a simple consistency check based on standard linear regression which can be applied to both the space-time and frequency domain approaches to optimal detection and demonstrate the application of this check to the problem of detection and attribution of anthropogenic signals in the radiosonde-based record of recent trends in atmospheric vertical temperature structure. The influence of anthropogenic greenhouse gases can be detected at a high confidence level in this diagnostic, while the combined influence of anthropogenic sulphates and stratospheric ozone depletion is less clearly evident. Assuming the time-scales of the model response are correct, and neglecting the possibility of non-linear feedbacks, the amplitude of the observed signal suggests a climate sensitivity range of 1.2--3.4 K, although the upper end of this range may be underestimated by up to 25{\%} due to uncertainty in model-predicted response patterns.},
author = {Allen, M R and Tett, S F B},
doi = {10.1007/s003820050291},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {6},
pages = {419--434},
title = {{Checking for model consistency in optimal fingerprinting}},
url = {https://doi.org/10.1007/s003820050291},
volume = {15},
year = {1999}
}
@article{Allen2003b,
abstract = {There is increasingly clear evidence that human influence has contributed substantially to the large-scale climatic changes that have occurred over the past few decades. Attention is now turning to the physical implications of the emerging anthropogenic signal. Of particular interest is the question of whether current climate models may be over- or under-estimating the amplitude of the climate system's response to external forcing, including anthropogenic. Evidence of a significant error in a model-simulated response amplitude would indicate the existence of amplifying or damping mechanisms that are inadequately represented in the model. The range of uncertainty in the factor by which we can scale model-simulated changes while remaining consistent with observed change provides an estimate of uncertainty in model-based predictions. With any model that displays a realistic level of internal variability, the problem of estimating this factor is complicated by the fact that it represents a ratio between two incompletely known quantities: both observed and simulated responses are subject to sampling uncertainty, primarily due to internal chaotic variability. Sampling uncertainty in the simulated response can be reduced, but not eliminated, through ensemble simulations. Accurate estimation of these scaling factors requires a modification of the standard ``optimal fingerprinting'' algorithm for climate change detection, drawing on the conventional ``total least squares'' approach discussed in the statistical literature. Code for both variants of optimal fingerprinting can be found on http://www.climateprediction.net/detection.},
author = {Allen, M R and Stott, P A},
doi = {10.1007/s00382-003-0313-9},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {5},
pages = {477--491},
title = {{Estimating signal amplitudes in optimal fingerprinting, part I: theory}},
volume = {21},
year = {2003}
}
@incollection{IPCC2018,
author = {Allen, M.R. and Dube, O.P. and Solecki, W. and Arag{\'{o}}n-Durand, F. and Cramer, W. and Humphreys, S. and Kainuma, M. and Kala, J. and Mahowald, N. and Mulugetta, Y. and Perez, R. and Wairiu, M. and Zickfeld, K.},
booktitle = {Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change,},
chapter = {1},
doi = {https://www.ipcc.ch/sr15/chapter/chapter-1},
editor = {Masson-Delmotte, V. and Zhai, P. and P{\"{o}}rtner, H.-O. and Roberts, D. and Skea, J. and Shukla, P.R. and Pirani, A. and Moufouma-Okia, W. and P{\'{e}}an, C. and Pidcock, R. and Connors, S. and Matthews, J.B.R. and Chen, Y. and Zhou, X. and Gomis, M.I. and Lonnoy, E. and Maycock, T. and Tignor, M. and Waterfield, T.},
pages = {49--92},
publisher = {In Press},
title = {{Framing and Context}},
url = {https://www.ipcc.ch/sr15/chapter/chapter-1},
year = {2018}
}
@article{Amaya2018,
abstract = {The poleward branches of the Hadley Cells and the edge of the tropics show a robust poleward shift during the satellite era, leading to concerns over the possible encroachment of the globe's subtropical dry zones into currently temperate climates. The extent to which this trend is caused by anthropogenic forcing versus internal variability remains the subject of considerable debate. In this study, we use a Joint EOF method to identify two distinct modes of tropical width variability: (1) an anthropogenically-forced mode, which we identify using a 20-member simulation of the historical climate, and (2) an internal mode, which we identify using a 1000-year pre-industrial control simulation. The forced mode is found to be closely related to the top of the atmosphere radiative imbalance and exhibits a long-term trend since 1860, while the internal mode is essentially indistinguishable from the El Ni{\~{n}}o Southern Oscillation. Together these two modes explain an average of 70{\%} of the interannual variability seen in model ``edge indices'' over the historical period. Since 1980, the superposition of forced and internal modes has resulted in a period of accelerated Hadley Cell expansion and decelerated global warming (i.e., the ``hiatus''). A comparison of the change in these modes since 1980 indicates that by 2013 the signal has emerged above the noise of internal variability in the Southern Hemisphere, but not in the Northern Hemisphere, with the latter also exhibiting strong zonal asymmetry, particularly in the North Atlantic. Our results highlight the important interplay of internal and forced modes of tropical width change and improve our understanding of the interannual variability and long-term trend seen in observations.},
annote = {Hadley circulation, zonal mean and regionality
-Joint EOF
-Observations
-CM2.1 piControl, historical

-Historical radiative forcing has acted to expand the Hadley cell
-La Ni{\~{n}}a (El Ni{\~{n}}o) acts to expand (narrow) the Hadley cell
-{\textgreater} Accelerated Hadley cell expansion since 1980s},
author = {Amaya, Dillon J. and Siler, Nicholas and Xie, Shang-Ping and Miller, Arthur J},
doi = {10.1007/s00382-017-3921-5},
journal = {Climate Dynamics},
month = {jul},
number = {1},
pages = {305--319},
title = {{The interplay of internal and forced modes of Hadley Cell expansion: lessons from the global warming hiatus}},
url = {https://doi.org/10.1007/s00382-017-3921-5},
volume = {51},
year = {2018}
}
@article{Amaya2017,
abstract = {The Atlantic Meridional Mode (AMM) is the dominant mode of tropical SST/wind coupled variability. Modeling studies have implicated wind-evaporation-SST (WES) feedback as the primary driver of the AMM's evolution across the Atlantic basin; however, a robust coupling of the SST and winds has not been shown in observations. This study examines observed AMM growth, propagation, and decay as a result of WES interactions. Investigation of an extended maximum covariance analysis shows that boreal wintertime atmospheric forcing generates positive SST anomalies (SSTA) through a reduction of surface evaporative cooling. When the AMM peaks in magnitude during spring and summer, upward latent heat flux anomalies occur over the warmest SSTs and act to dampen the initial forcing. In contrast, on the southwestern edge of the SSTA, SST-forced cross-equatorial flow reduces the strength of the climatological trade winds and provides an anomalous latent heat flux into the ocean, which causes southwestward propagation of the initial atmosphere-forced SSTA through WES dynamics. Additionally, the lead-lag relationship of the ocean and atmosphere indicates a transition from an atmosphere-forcing-ocean regime in the northern subtropics to a highly coupled regime in the northern tropics that is not observed in the southern hemisphere. CMIP5 models poorly simulate the latitudinal transition from a one-way interaction to a two-way feedback, which may explain why they also struggle to reproduce spatially coherent interactions between tropical Atlantic SST and winds. This analysis provides valuable insight on how meridional modes act as links between extratropical and tropical variability and focuses future research aimed at improving climate model simulations.},
author = {Amaya, Dillon J and DeFlorio, Michael J and Miller, Arthur J and Xie, Shang-Ping},
doi = {10.1007/s00382-016-3411-1},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {5},
pages = {1665--1679},
title = {{WES feedback and the Atlantic Meridional Mode: observations and CMIP5 comparisons}},
url = {https://doi.org/10.1007/s00382-016-3411-1},
volume = {49},
year = {2017}
}
@article{Amiri-Farahani2019,
abstract = {To date, very few studies have focused on dust and sea salt cloud interactions, particularly the semidirect effect (SDE) that results from changes in column temperature and moisture. Here, we isolate the SDE using several climate models driven by semiempirical dust and sea salt direct radiative effects. The global annual mean SDE varies from 0.01 to 0.10 W/m2, with the bulk of the signal coming from an increase in shortwave radiation. This is consistent with decreases in low cloud over ocean due to cloud burn-off and reductions in midlevel cloud over land due to atmospheric stabilization and decreased convection. Overall, longwave effects weaken the positive SDE but with opposing effects over land and sea. High cloud is reduced over land but enhanced over sea. We conclude that dust and sea salt likely exert a global mean warming effect through cloud rapid adjustments.},
author = {Amiri-Farahani, Anahita and Allen, Robert J. and Li, King Fai and Chu, Jung Eun},
doi = {10.1029/2019GL084590},
issn = {19448007},
journal = {Geophysical Research Letters},
keywords = {aerosol,clouds,dust,rapid adjustment,sea salt,semidirect effect},
month = {sep},
number = {17-18},
pages = {10512--10521},
title = {{The Semidirect Effect of Combined Dust and Sea Salt Aerosols in a Multimodel Analysis}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019GL084590},
volume = {46},
year = {2019}
}
@article{AmiriFarahani2020,
abstract = {The climate response to atmospheric aerosols, including their effects on dominant modes of climate variability like El Ni{\~{n}}o–Southern Oscillation (ENSO), remains highly uncertain. This is due to several sources of uncertainty, including aerosol emission, transport, removal, vertical distribution, and radiative properties. Here, we conduct coupled ocean-atmosphere simulations with two versions of the Community Earth System Model (CESM) driven by semiempirical fine-mode aerosol direct radiative effects without dust and sea salt. Aerosol atmospheric heating off the west coast of Africa—most of which is due to biomass burning—leads to a significant atmospheric dynamical response, including localized ascent and upper-level divergence. Coupled Model Intercomparison Project version 6 (CMIP6) biomass burning simulations support this response. Moreover, CESM shows that the anomalous aerosol heating in the Atlantic triggers an atmospheric teleconnection to the tropical Pacific, including strengthening of the Walker circulation. The easterly trade winds accelerate, and through coupled ocean-atmosphere processes and the Bjerknes feedback, a La Ni{\~{n}}a-like response develops. Observations also support a relationship between south African biomass burning emissions and ENSO, with La Ni{\~{n}}a events preceding strong south African biomass burning in boreal fall. Our simulations suggest a possible two-way feedback between ENSO and south African biomass burning, with La Ni{\~{n}}a promoting more biomass burning emissions, which may then strengthen the developing La Ni{\~{n}}a.},
author = {Amiri-Farahani, Anahita and Allen, Robert J. and Li, King Fai and Nabat, Pierre and Westervelt, Daniel M.},
doi = {10.1029/2019JD031832},
issn = {21698996},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {Africa,La Nina,aerosol,biomass,climate model,teleconnection},
month = {mar},
number = {6},
title = {{A La Ni{\~{n}}a-Like Climate Response to South African Biomass Burning Aerosol in CESM Simulations}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JD031832},
volume = {125},
year = {2020}
}
@article{Anchukaitis2019,
author = {Anchukaitis, Kevin J. and Cook, Edward R. and Cook, Benjamin I. and Pearl, Jessie and D'Arrigo, Rosanne and Wilson, Rob},
doi = {10.1029/2019GL084350},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {nov},
number = {21},
pages = {12417--12426},
title = {{Coupled Modes of North Atlantic Ocean‐Atmosphere Variability and the Onset of the Little Ice Age}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019GL084350},
volume = {46},
year = {2019}
}
@article{Andrews,
abstract = {We describe and evaluate historical simulations which use the third Hadley Centre Global Environment Model in the Global Coupled configuration 3.1 (HadGEM3-GC3.1) model and which form part of the UK's contribution to the sixth Coupled Model Intercomparison Project, CMIP6. These simulations, run at two resolutions, respond to historically evolving forcings such as greenhouse gases, aerosols, solar irradiance, volcanic aerosols, land use, and ozone concentrations. We assess the response of the simulations to these historical forcings and compare against the observational record. This includes the evolution of global mean surface temperature, ocean heat content, sea ice extent, ice sheet mass balance, permafrost extent, snow cover, North Atlantic sea surface temperature and circulation, and decadal precipitation. We find that the simulated time evolution of global mean surface temperature broadly follows the observed record but with important quantitative differences which we find are most likely attributable to strong effective radiative forcing from anthropogenic aerosols and a weak pattern of sea surface temperature response in the low to middle latitudes to volcanic eruptions. We also find evidence that anthropogenic aerosol forcings play a role in driving the Atlantic Multidecadal Variability and the Atlantic Meridional Overturning Circulation, which are key features of the North Atlantic ocean. Overall, the model historical simulations show many features in common with the observed record over the period 1850–2014 and so provide a basis for future in-depth study of recent climate change.},
author = {Andrews, Martin B. and Ridley, Jeff K. and Wood, Richard A. and Andrews, Timothy and Blockley, Edward W. and Booth, Ben and Burke, Eleanor and Dittus, Andrea J. and Florek, Piotr and Gray, Lesley J. and Haddad, Stephen and Hardiman, Steven C. and Hermanson, Leon and Hodson, Dan and Hogan, Emma and Jones, Gareth S. and Knight, Jeff R. and Kuhlbrodt, Till and Misios, Stergios and Mizielinski, Matthew S. and Ringer, Mark A. and Robson, Jon and Sutton, Rowan T.},
doi = {10.1029/2019MS001995},
issn = {19422466},
journal = {Journal of Advances in Modeling Earth Systems},
keywords = {AOGCM,CMIP6,HadGEM3-GC3.1,historical simulations},
number = {6},
pages = {e2019MS001995},
title = {{Historical Simulations With HadGEM3-GC3.1 for CMIP6}},
volume = {12},
year = {2020}
}
@article{Andrews2015,
author = {Andrews, M B and Knight, J R and Gray, L J},
doi = {10.1088/1748-9326/10/5/054022},
issn = {1748-9326},
journal = {Environmental Research Letters},
month = {may},
number = {5},
pages = {054022},
title = {{A simulated lagged response of the North Atlantic Oscillation to the solar cycle over the period 1960–2009}},
url = {http://stacks.iop.org/1748-9326/10/i=5/a=054022?key=crossref.bc725ec9e7b6631f308445d2f4070f67},
volume = {10},
year = {2015}
}
@article{andrews2019forcings,
author = {Andrews, Timothy and Andrews, Martin B and Bodas‐Salcedo, Alejandro and Jones, Gareth S and Kuhlbrodt, Till and Manners, James and Menary, Matthew B and Ridley, Jeff and Ringer, Mark A and Sellar, Alistair A and Senior, Catherine A. and Tang, Yongming},
doi = {10.1029/2019MS001866},
issn = {1942-2466},
journal = {Journal of Advances in Modeling Earth Systems},
month = {dec},
number = {12},
pages = {4377--4394},
publisher = {Wiley Online Library},
title = {{Forcings, Feedbacks, and Climate Sensitivity in HadGEM3‐GC3.1 and UKESM1}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019MS001866},
volume = {11},
year = {2019}
}
@article{Andrews2018,
abstract = {Eight atmospheric general circulation models (AGCMs) are forced with observed historical (1871–2010) monthly sea surface temperature and sea ice variations using the Atmospheric Model Intercomparison Project II data set. The AGCMs therefore have a similar temperature pattern and trend to that of observed historical climate change. The AGCMs simulate a spread in climate feedback similar to that seen in coupled simulations of the response to CO2 quadrupling. However, the feedbacks are robustly more stabilizing and the effective climate sensitivity (EffCS) smaller. This is due to a pattern effect, whereby the pattern of observed historical sea surface temperature change gives rise to more negative cloud and longwave clear-sky feedbacks. Assuming the patterns of long-term temperature change simulated by models, and the radiative response to them, are credible; this implies that existing constraints on EffCS from historical energy budget variations give values that are too low and overly constrained, particularly at the upper end. For example, the pattern effect increases the long-term Otto et al. (2013, https://doi.org/10.1038/ngeo1836) EffCS median and 5–95{\%} confidence interval from 1.9 K (0.9–5.0 K) to 3.2 K (1.5–8.1 K).},
author = {Andrews, Timothy and Gregory, Jonathan M. and Paynter, David and Silvers, Levi G. and Zhou, Chen and Mauritsen, Thorsten and Webb, Mark J. and Armour, Kyle C. and Forster, Piers M. and Titchner, Holly},
doi = {10.1029/2018GL078887},
issn = {19448007},
journal = {Geophysical Research Letters},
number = {16},
title = {{Accounting for Changing Temperature Patterns Increases Historical Estimates of Climate Sensitivity}},
volume = {45},
year = {2018}
}
@article{doi:10.1175/2011JCLI3873.1,
abstract = { AbstractThe Coupled Model Intercomparison Project phase 3 (CMIP3) multimodel ensemble has been widely utilized for climate research and prediction, but the properties and behavior of the ensemble are not yet fully understood. Here, some investigations are undertaken into various aspects of the ensemble's behavior, in particular focusing on the performance of the multimodel mean. This study presents an explanation of this phenomenon in the context of the statistically indistinguishable paradigm and also provides a quantitative analysis of the main factors that control how likely the mean is to outperform the models in the ensemble, both individually and collectively. The analyses lend further support to the usage of the paradigm of a statistically indistinguishable ensemble and indicate that the current ensemble size is too small to adequately sample the space from which the models are drawn. },
author = {Annan, J D and Hargreaves, J C},
doi = {10.1175/2011JCLI3873.1},
journal = {Journal of Climate},
number = {16},
pages = {4529--4538},
title = {{Understanding the CMIP3 Multimodel Ensemble}},
url = {https://doi.org/10.1175/2011JCLI3873.1},
volume = {24},
year = {2011}
}
@article{doi:10.1002/jgrd.50231,
abstract = {Blocking of the tropospheric jet stream during Northern Hemisphere winter (December-January-February) is examined in a multi-model ensemble of coupled atmosphere-ocean general circulation models (GCMs) obtained from the Coupled Model Intercomparison Project Phase 5 (CMIP5). The CMIP5 models exhibit large biases in blocking frequency and related biases in tropospheric jet latitude, similar to earlier generations of GCMs. Underestimated blocking at high latitudes, especially over Europe, is common. In general, model biases decrease as model resolution increases. Increased blocking frequency at high latitudes in both the Atlantic and Pacific basins, as well as more realistic variability of Atlantic jet latitude, are associated with increased vertical resolution in the mid-troposphere to lowermost stratosphere. Finer horizontal resolution is associated with higher blocking frequency at all latitudes in the Atlantic basin but appears to have no systematic impact on blocking near Greenland or in the Pacific basin. Results from the CMIP5 analysis are corroborated by additional controlled experiments using selected GCMs.},
author = {Anstey, James A and Davini, Paolo and Gray, Lesley J and Woollings, Tim J and Butchart, Neal and Cagnazzo, Chiara and Christiansen, Bo and Hardiman, Steven C and Osprey, Scott M and Yang, Shuting},
doi = {10.1002/jgrd.50231},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {blocking,jet,stratosphere},
number = {10},
pages = {3956--3971},
title = {{Multi-model analysis of Northern Hemisphere winter blocking: Model biases and the role of resolution}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/jgrd.50231},
volume = {118},
year = {2013}
}
@article{Aquila2016,
abstract = {{\textcopyright} 2016. American Geophysical Union. All Rights Reserved. Satellite instruments show a cooling of global stratospheric temperatures over the whole data record (1979-2014). This cooling is not linear and includes two descending steps in the early 1980s and mid-1990s. The 1979-1995 period is characterized by increasing concentrations of ozone-depleting substances (ODSs) and by the two major volcanic eruptions of El Chich{\'{o}}n (1982) and Mount Pinatubo (1991). The 1995-present period is characterized by decreasing ODS concentrations and by the absence of major volcanic eruptions. Greenhouse gas (GHG) concentrations increase over the whole time period. In order to isolate the roles of different forcing agents in the global stratospheric temperature changes, we performed a set of simulations using the NASA Goddard Earth Observing System Chemistry-Climate Model with prescribed sea surface temperatures. We find that in our model simulations the cooling of the stratosphere from 1979 to present is mostly driven by changes in GHG concentrations in the middle and upper stratosphere and by GHG and ODS changes in the lower stratosphere. While the cooling trend caused by increasing GHGs is roughly constant over the satellite era, changing ODS concentrations cause a significant stratospheric cooling only up to the mid-1990s, when they start to decrease because of the implementation of the Montreal Protocol. Sporadic volcanic events and the solar cycle have a distinct signature in the time series of stratospheric temperature anomalies but do not play a statistically significant role in the long-term trends from 1979 to 2014. Several factors combine to produce the step-like behavior in the stratospheric temperatures: in the lower stratosphere, the flattening starting in the mid-1990s is due to the decrease in ozone-depleting substances; Mount Pinatubo and the solar cycle cause the abrupt steps through the aerosol-associated warming and the volcanically induced ozone depletion. In the middle and upper stratosphere, changes in solar irradiance are largely responsible for the step-like behavior of global temperature anomalies, together with volcanically induced ozone depletion and water vapor increases in the post-Pinatubo years.},
author = {Aquila, V. and Swartz, W.H. and Waugh, D.W. and Colarco, P.R. and Pawson, S. and Polvani, L.M. and Stolarski, R.S.},
doi = {10.1002/2015JD023841},
journal = {Journal of Geophysical Research: Atmospheres},
number = {13},
pages = {8067--8082},
title = {{Isolating the roles of different forcing agents in global stratospheric temperature changes using model integrations with incrementally added single forcings}},
volume = {121},
year = {2016}
}
@article{Arora2020a,
abstract = {Results from the fully and biogeochemically coupled simulations in which CO2 increases at a rate of 1{\%}yr-1 (1pctCO2) from its preindustrial value are analyzed to quantify the magnitude of carbon-concentration and carbon-climate feedback parameters which measure the response of ocean and terrestrial carbon pools to changes in atmospheric CO2 concentration and the resulting change in global climate, respectively. The results are based on 11 comprehensive Earth system models from the most recent uncertain over land than over ocean as has been seen in existing studies. These values and their spread from 11 CMIP6 models have not changed significantly compared to CMIP5 models. The absolute values of feedback parameters are lower for land with models that include a representation of nitrogen cycle. The transient climate response to cumulative emissions (TCRE) from the 11 CMIP6 models considered here is 1.77±0.37 ° C EgC-1 and is similar to that found in CMIP5 models (1.63±0.48 °C EgC-1) but with somewhat reduced model spread. The expressions for feedback parameters based on the fully and biogeochemically coupled configurations of the 1pctCO2 simulation are simplified when the small temperature change in the biogeochemically coupled simulation is ignored. Decomposition of the terms of these simplified expressions for the feedback parameters is used to gain insight into the reasons for differing responses among ocean and land carbon cycle models.},
author = {Arora, Vivek K. and Katavouta, Anna and Williams, Richard G. and Jones, Chris D. and Brovkin, Victor and Friedlingstein, Pierre and Schwinger, J{\"{o}}rg and Bopp, Laurent and Boucher, Olivier and Cadule, Patricia and Chamberlain, Matthew A. and Christian, James R. and Delire, Christine and Fisher, A. Rosie A. and Hajima, Tomohiro and Ilyina, Tatiana and Joetzjer, Emilie and Kawamiya, Michio and Koven, Charles D. and Krasting, John P. and Law, Rachel M. and Lawrence, David M. and Lenton, Andrew and Lindsay, Keith and Pongratz, Julia and Raddatz, Thomas and S{\'{e}}f{\'{e}}rian, Roland and Tachiiri, Kaoru and Tjiputra, Jerry F. and Wiltshire, Andy and Wu, Tongwen and Ziehn, Tilo},
doi = {10.5194/bg-17-4173-2020},
issn = {17264189},
journal = {Biogeosciences},
number = {16},
pages = {4173--4222},
title = {{Carbon-concentration and carbon-climate feedbacks in CMIP6 models and their comparison to CMIP5 models}},
volume = {17},
year = {2020}
}
@article{Ashok2007a,
abstract = {Using observed data sets mainly for the period 1979–2005, we find that anomalous warming events different from conventional El Nin ˜o events occur in the central equatorial Pacific. This unique warming in the central equatorial Pacific associated with a horseshoe pattern is flanked by a colder sea surface temperature anomaly (SSTA) on both sides along the equator. empirical orthogonal function (EOF) analysis of monthly tropical Pacific SSTA shows that these events are represented by the second mode that explains 12{\%} of the variance. Since a majority of such events are not part of El Nin ˜o evolution, the phenomenon is named as El Nin ˜o Modoki (pseudo-El Nin ˜o) (‘‘Modoki'' is a classical Japanese word, which means ‘‘a similar but different thing''). The El Nin ˜o Modoki involves ocean-atmosphere coupled processes which include a unique tripolar sea level pressure pattern during the evolution, analogous to the Southern Oscillation in the case of El Nin ˜o. Hence the total entity is named as El Nin ˜o–Southern Oscillation (ENSO) Modoki. The ENSO Modoki events significantly influence the temperature and precipitation over many parts of the globe. Depending on the season, the impacts over regions such as the Far East including Japan, New Zealand, western coast of United States, etc., are opposite to those of the conventional ENSO. The difference maps between the two periods of 1979–2004 and 1958–1978 for various oceanic/atmospheric variables suggest that the recent weakening of equatorial easterlies related to weakened zonal sea surface temperature gradient led to more flattening of the thermocline. This appears to be a cause of more frequent and persistent occurrence of the ENSO Modoki event during recent decades.},
author = {Ashok, Karumuri and Behera, Swadhin K. and Rao, Suryachandra A. and Weng, Hengyi and Yamagata, Toshio},
doi = {10.1029/2006JC003798},
isbn = {0148-0227},
issn = {21699291},
journal = {Journal of Geophysical Research: Oceans},
number = {11},
pages = {1--27},
pmid = {16862108},
title = {{El Ni{\~{n}}o Modoki and its possible teleconnection}},
volume = {112},
year = {2007}
}
@article{Ault2012,
author = {Ault, T. R. and Cole, J. E. and {St George}, S.},
doi = {10.1029/2012GL053424},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {nov},
number = {21},
pages = {L21705},
title = {{The amplitude of decadal to multidecadal variability in precipitation simulated by state-of-the-art climate models}},
url = {http://doi.wiley.com/10.1029/2012GL053424},
volume = {39},
year = {2012}
}
@article{acp-2018-296,
author = {Ayarzag{\"{u}}ena, Blanca and Polvani, Lorenzo M and Langematz, Ulrike and Akiyoshi, Hideharu and Bekki, Slimane and Butchart, Neal and Dameris, Martin and Deushi, Makoto and Hardiman, Steven C and J{\"{o}}ckel, Patrick and Klekociuk, Andrew and Marchand, Marion and Michou, Martine and Morgenstern, Olaf and O'Connor, Fiona M and Oman, Luke D and Plummer, David A and Revell, Laura and Rozanov, Eugene and Saint-Martin, David and Scinocca, John and Stenke, Andrea and Stone, Kane and Yamashita, Yousuke and Yoshida, Kohei and Zeng, Guang},
doi = {10.5194/acp-18-11277-2018},
issn = {1680-7324},
journal = {Atmospheric Chemistry and Physics},
month = {aug},
number = {15},
pages = {11277--11287},
title = {{No robust evidence of future changes in major stratospheric sudden warmings: a multi-model assessment from CCMI}},
url = {https://acp.copernicus.org/articles/18/11277/2018/},
volume = {18},
year = {2018}
}
@article{Ayash2008,
abstract = {{\textless}p{\textgreater} Sea salt aerosols play a dual role in affecting the atmospheric radiative balance. Directly, sea salt particles scatter the incoming solar radiation and absorb the outgoing terrestrial radiation. By acting as cloud condensation nuclei, sea salt aerosols indirectly modulate the atmospheric radiative budget through their effective contribution to cloud formation. Using the Canadian Aerosol Module (CAM)–Canadian Centre for Climate Modelling and Analysis (CCCma) GCM, version 3 (GCM3) framework, the direct as well as the indirect shortwave (SW) radiative effects of sea salt aerosols are simulated. The model results herein suggest that sea salt aerosols exert a significant direct radiative effect over oceanic regions, with seasonal means in the range from −2 to −3 W m {\textless}sup{\textgreater}−2{\textless}/sup{\textgreater} over the Southern Ocean. Globally, sea salt's SW indirect effect (annual mean −0.38 W m {\textless}sup{\textgreater}−2{\textless}/sup{\textgreater} ) is found to be less than its direct effect (annual mean −0.65 W m {\textless}sup{\textgreater}−2{\textless}/sup{\textgreater} ). However, sea salt's indirect effect is found to be far stronger over the Southern Hemisphere than over the Northern Hemisphere, especially over the Southern Ocean with seasonal means around −4 W m {\textless}sup{\textgreater}−2{\textless}/sup{\textgreater} , which exceed its direct effect. The model results herein suggest that sea salt aerosols significantly modulate the atmospheric radiation budget over oceanic regions and need to be accounted for in global climate models. {\textless}/p{\textgreater}},
author = {Ayash, Tarek and Gong, Sunling and Jia, Charles Q.},
doi = {10.1175/2007JCLI2063.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jul},
number = {13},
pages = {3207--3220},
title = {{Direct and Indirect Shortwave Radiative Effects of Sea Salt Aerosols}},
url = {http://journals.ametsoc.org/doi/10.1175/2007JCLI2063.1},
volume = {21},
year = {2008}
}
@article{Ayers2012,
author = {Ayers, Jennifer M. and Lozier, M. Susan},
doi = {10.1029/2011JC007368},
issn = {01480227},
journal = {Journal of Geophysical Research: Oceans},
keywords = {Kuroshio extension,North Pacific,air‐sea CO2 flux,carbon sink,geostrophic divergence of DIC,transition zone},
month = {jan},
number = {C1},
pages = {C01017},
publisher = {Wiley-Blackwell},
title = {{Unraveling dynamical controls on the North Pacific carbon sink}},
url = {http://doi.wiley.com/10.1029/2011JC007368},
volume = {117},
year = {2012}
}
@article{Buntgen2020,
abstract = {Climate reconstructions for the Common Era are compromised by the paucity of annually-resolved and absolutely-dated proxy records prior to medieval times. Where reconstructions are based on combinations of different climate archive types (of varying spatiotemporal resolution, dating uncertainty, record length and predictive skill), it is challenging to estimate past amplitude ranges, disentangle the relative roles of natural and anthropogenic forcing, or probe deeper interrelationships between climate variability and human history. Here, we compile and analyse updated versions of all the existing summer temperature sensitive tree-ring width chronologies from the Northern Hemisphere that span the entire Common Era. We apply a novel ensemble approach to reconstruct extra-tropical summer temperatures from 1 to 2010 CE, and calculate uncertainties at continental to hemispheric scales. Peak warming in the 280s, 990s and 1020s, when volcanic forcing was low, was comparable to modern conditions until 2010 CE. The lowest June–August temperature anomaly in 536 not only marks the beginning of the coldest decade, but also defines the onset of the Late Antique Little Ice Age (LALIA). While prolonged warmth during Roman and medieval times roughly coincides with the tendency towards societal prosperity across much of the North Atlantic/European sector and East Asia, major episodes of volcanically-forced summer cooling often presaged widespread famines, plague outbreaks and political upheavals. Our study reveals a larger amplitude of spatially synchronized summer temperature variation during the first millennium of the Common Era than previously recognised.},
author = {B{\"{u}}ntgen, Ulf and Arseneault, Dominique and Boucher, {\'{E}}tienne and {Churakova (Sidorova)}, Olga V and Gennaretti, Fabio and Crivellaro, Alan and Hughes, Malcolm K and Kirdyanov, Alexander V and Klippel, Lara and Krusic, Paul J and Linderholm, Hans W and Ljungqvist, Fredrik C and Ludescher, Josef and McCormick, Michael and Myglan, Vladimir S and Nicolussi, Kurt and Piermattei, Alma and Oppenheimer, Clive and Reinig, Frederick and Sigl, Michael and Vaganov, Eugene A and Esper, Jan},
doi = {10.1016/j.dendro.2020.125757},
issn = {1125-7865},
journal = {Dendrochronologia},
keywords = {Climate reconstruction,Dendroclimatology,Human history,Northern Hemisphere,Tree-ring width,Volcanic eruptions},
pages = {125757},
title = {{Prominent role of volcanism in Common Era climate variability and human history}},
url = {https://www.sciencedirect.com/science/article/pii/S1125786520300965},
volume = {64},
year = {2020}
}
@article{Baccini2017,
abstract = {The carbon balance of tropical ecosystems remains uncertain, with top-down atmospheric studies suggesting an overall sink and bottom-up ecological approaches indicating a modest net source. Here we use 12 years (2003 to 2014) of MODIS pantropical satellite data to quantify net annual changes in the aboveground carbon density of tropical woody live vegetation, providing direct, measurement-based evidence that the world's tropical forests are a net carbon source of 425.2 ± 92.0 teragrams of carbon per year (Tg C year–1). This net release of carbon consists of losses of 861.7 ± 80.2 Tg C year–1 and gains of 436.5 ± 31.0 Tg C year–1. Gains result from forest growth; losses result from deforestation and from reductions in carbon density within standing forests (degradation or disturbance), with the latter accounting for 68.9{\%} of overall losses.},
author = {Baccini, A. and Walker, W. and Carvalho, L. and Farina, M. and Sulla-Menashe, D. and Houghton, R. A.},
doi = {10.1126/science.aam5962},
issn = {0036-8075},
journal = {Science},
month = {oct},
number = {6360},
pages = {230--234},
title = {{Tropical forests are a net carbon source based on aboveground measurements of gain and loss}},
url = {https://www.science.org/doi/10.1126/science.aam5962},
volume = {358},
year = {2017}
}
@article{Baker2019,
author = {Baker, Hugh S. and Woollings, Tim and Forest, Chris E. and Allen, Myles R.},
doi = {10.1175/JCLI-D-19-0038.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {oct},
number = {19},
pages = {6491--6511},
title = {{The Linear Sensitivity of the North Atlantic Oscillation and Eddy-Driven Jet to SSTs}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-19-0038.1},
volume = {32},
year = {2019}
}
@article{Baker2017,
author = {Baker, Hugh S. and Woollings, Tim and Mbengue, Cheikh},
doi = {10.1175/JCLI-D-16-0864.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {aug},
number = {16},
pages = {6413--6431},
title = {{Eddy-Driven Jet Sensitivity to Diabatic Heating in an Idealized GCM}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-16-0864.1},
volume = {30},
year = {2017}
}
@article{Balaguru2016,
abstract = {Super typhoons (STYs), intense tropical cyclones of the western North Pacific, rank among the most destructive natural hazards globally. The violent winds of these storms induce deep mixing of the upper ocean, resulting in strong sea surface cooling and making STYs highly sensitive to ocean density stratification. Although a few studies examined the potential impacts of changes in ocean thermal structure on future tropical cyclones, they did not take into account changes in near-surface salinity. Here, using a combination of observations and coupled climate model simulations, we show that freshening of the upper ocean, caused by greater rainfall in places where typhoons form, tends to intensify STYs by reducing their ability to cool the upper ocean. We further demonstrate that the strengthening effect of this freshening over the period 1961-2008 is ∼53{\%} stronger than the suppressive effect of temperature, whereas under twenty-first century projections, the positive effect of salinity is about half of the negative effect of ocean temperature changes.},
author = {Balaguru, Karthik and Foltz, Gregory R. and Leung, L. Ruby and Emanuel, Kerry A.},
doi = {10.1038/ncomms13670},
issn = {2041-1723},
journal = {Nature Communications},
month = {dec},
number = {1},
pages = {13670},
publisher = {Nature Publishing Group},
title = {{Global warming-induced upper-ocean freshening and the intensification of super typhoons}},
url = {http://www.nature.com/articles/ncomms13670},
volume = {7},
year = {2016}
}
@article{Balaguru2012,
abstract = {Improving a tropical cyclone's forecast and mitigating its destructive potential requires knowledge of various environmental factors that influence the cyclone's path and intensity. Herein, using a combination of observations and model simulations, we systematically demonstrate that tropical cyclone intensification is significantly affected by salinity-induced barrier layers, which are "quasi-permanent"features in the upper tropical oceans. When tropical cyclones pass over regions with barrier layers, the increased stratification and stability within the layer reduce storm-induced vertical mixing and sea surface temperature cooling. This causes an increase in enthalpy flux from the ocean to the atmosphere and, consequently, an intensification of tropical cyclones. On average, the tropical cyclone intensification rate is nearly 50{\%} higher over regions with barrier layers, compared to regions without. Our finding, which underscores the importance of observing not only the upper-ocean thermal structure but also the salinity structure in deep tropical barrier layer regions, may be a key to more skillful predictions of tropical cyclone intensities through improved ocean state estimates and simulations of barrier layer processes. As the hydrological cycle responds to global warming, any associated changes in the barrier layer distribution must be considered in projecting future tropical cyclone activity.},
author = {Balaguru, Karthik and Chang, Ping and Saravanan, R. and Leung, L. Ruby and Xu, Zhao and Li, Mingkui and Hsieh, Jen Shan},
doi = {10.1073/pnas.1201364109},
issn = {00278424},
journal = {Proceedings of the National Academy of Sciences},
month = {sep},
number = {36},
pages = {14343--14347},
title = {{Ocean barrier layers' effect on tropical cyclone intensification}},
volume = {109},
year = {2012}
}
@article{https://doi.org/10.1029/2020RG000708,
abstract = {Abstract Sudden stratospheric warmings (SSWs) are impressive fluid dynamical events in which large and rapid temperature increases in the winter polar stratosphere (∼10–50 km) are associated with a complete reversal of the climatological wintertime westerly winds. SSWs are caused by the breaking of planetary-scale waves that propagate upwards from the troposphere. During an SSW, the polar vortex breaks down, accompanied by rapid descent and warming of air in polar latitudes, mirrored by ascent and cooling above the warming. The rapid warming and descent of the polar air column affect tropospheric weather, shifting jet streams, storm tracks, and the Northern Annular Mode, making cold air outbreaks over North America and Eurasia more likely. SSWs affect the atmosphere above the stratosphere, producing widespread effects on atmospheric chemistry, temperatures, winds, neutral (nonionized) particles and electron densities, and electric fields. These effects span both hemispheres. Given their crucial role in the whole atmosphere, SSWs are also seen as a key process to analyze in climate change studies and subseasonal to seasonal prediction. This work reviews the current knowledge on the most important aspects of SSWs, from the historical background to dynamical processes, modeling, chemistry, and impact on other atmospheric layers.},
annote = {e2020RG000708 10.1029/2020RG000708},
author = {Baldwin, Mark P and Ayarzag{\"{u}}ena, Blanca and Birner, Thomas and Butchart, Neal and Butler, Amy H and Charlton-Perez, Andrew J and Domeisen, Daniela I V and Garfinkel, Chaim I and Garny, Hella and Gerber, Edwin P and Hegglin, Michaela I and Langematz, Ulrike and Pedatella, Nicholas M},
doi = {https://doi.org/10.1029/2020RG000708},
journal = {Reviews of Geophysics},
keywords = {QBO,middle atmosphere,stratosphere,upper atmosphere,weather forecasts},
number = {1},
pages = {e2020RG000708},
title = {{Sudden Stratospheric Warmings}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020RG000708},
volume = {59},
year = {2021}
}
@article{Balmaseda2013,
author = {Balmaseda, Magdalena A. and Trenberth, Kevin E. and K{\"{a}}ll{\'{e}}n, Erland},
doi = {10.1002/grl.50382},
issn = {00948276},
journal = {Geophysical Research Letters},
keywords = {ENSO,climate trends,climate variability,global warming,ocean heat content,ocean reanalyses},
month = {may},
number = {9},
pages = {1754--1759},
publisher = {Wiley-Blackwell},
title = {{Distinctive climate signals in reanalysis of global ocean heat content}},
url = {http://doi.wiley.com/10.1002/grl.50382},
volume = {40},
year = {2013}
}
@article{Bamber2018a,
abstract = {Since 1992, there has been a revolution in our ability to quantify the land ice contribution to sea level rise using a variety of satellite missions and technologies. Each mission has provided unique, but sometimes conflicting, insights into the mass trends of land ice. Over the last decade, over fifty estimates of land ice trends have been published, providing a confusing and often inconsistent picture. The IPCC Fifth Assessment Report (AR5) attempted to synthesise estimates published up to early 2013. Since then, considerable advances have been made in understanding the origin of the inconsistencies, reducing uncertainties in estimates and extending time series. We assess and synthesise results published, primarily, since the AR5, to produce a consistent estimate of land ice mass trends during the satellite era (1992-2016). We combine observations from multiple missions and approaches including sea level budget analyses. Our resulting synthesis is both consistent and rigorous, drawing on (i) the published literature, (ii) expert assessment of that literature, and (iii) a new analysis of Arctic glacier and ice cap trends combined with statistical modelling. We present annual and pentad (five-year mean) time series for the East, West Antarctic and Greenland Ice Sheets and glaciers separately and combined. When averaged over pentads, covering the entire period considered, we obtain a monotonic trend in mass contribution to the oceans, increasing from 0.31 ± 0.35 mm of sea level equivalent for 1992-1996 to 1.85 ± 0.13 for 2012-2016. Our integrated land ice trend is lower than many estimates of GRACE-derived ocean mass change for the same periods. This is due, in part, to a smaller estimate for glacier and ice cap mass trends compared to previous assessments. We discuss this, and other likely reasons, for the difference between GRACE ocean mass and land ice trends.},
author = {Bamber, Jonathan L. and Westaway, Richard Martin and Marzeion, Ben and Wouters, Bert},
doi = {10.1088/1748-9326/aac2f0},
issn = {1748-9326},
journal = {Environmental Research Letters},
keywords = {land ice,satellite remote sensing,sea level budget,sea level rise},
month = {jun},
number = {6},
pages = {063008},
title = {{The land ice contribution to sea level during the satellite era}},
url = {https://iopscience.iop.org/article/10.1088/1748-9326/aac2f0},
volume = {13},
year = {2018}
}
@article{Bamber2019a,
abstract = {Despite considerable advances in process understanding, numerical modeling, and the observational record of ice sheet contributions to global mean sea-level rise (SLR) since the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change, severe limitations remain in the predictive capability of ice sheet models. As a consequence, the potential contributions of ice sheets remain the largest source of uncertainty in projecting future SLR. Here, we report the findings of a structured expert judgement study, using unique techniques for modeling correlations between inter- and intra-ice sheet processes and their tail dependences. We find that since the AR5, expert uncertainty has grown, in particular because of uncertain ice dynamic effects. For a +2 °C temperature scenario consistent with the Paris Agreement, we obtain a median estimate of a 26 cm SLR contribution by 2100, with a 95th percentile value of 81 cm. For a +5 °C temperature scenario more consistent with unchecked emissions growth, the corresponding values are 51 and 178 cm, respectively. Inclusion of thermal expansion and glacier contributions results in a global total SLR estimate that exceeds 2 m at the 95th percentile. Our findings support the use of scenarios of 21st century global total SLR exceeding 2 m for planning purposes. Beyond 2100, uncertainty and projected SLR increase rapidly. The 95th percentile ice sheet contribution by 2200, for the +5 °C scenario, is 7.5 m as a result of instabilities coming into play in both West and East Antarctica. Introducing process correlations and tail dependences increases estimates by roughly 15{\%}.},
author = {Bamber, Jonathan L. and Oppenheimer, Michael and Kopp, Robert E. and Aspinall, Willy P. and Cooke, Roger M.},
doi = {10.1073/pnas.1817205116},
issn = {0027-8424},
journal = {Proceedings of the National Academy of Sciences},
month = {jun},
number = {23},
pages = {11195--11200},
pmid = {31110015},
title = {{Ice sheet contributions to future sea-level rise from structured expert judgment}},
url = {http://www.pnas.org/lookup/doi/10.1073/pnas.1817205116},
volume = {116},
year = {2019}
}
@article{Banerjee2020,
abstract = {Observations show robust near-surface trends in the Southern Hemisphere tropospheric circulation towards the end of the 20th century, including a poleward shift in the midlatitude jet, a positive trend in the Southern Annular Mode, and an expansion of the Hadley cell. It is established that these trends have been driven by ozone depletion in the Antarctic stratosphere due to emissions of ozone-depleting substances. Here we show that these widely reported circulation trends have, in fact, paused, or slightly reversed, around the year 2000. Using a pattern-based detection and attribution analysis of atmospheric zonal wind, we show that the pause in circulation trends is forced by human activities, and has not occurred simply due to internal or natural variability of the climate system. Further, we demonstrate the essential role of stratospheric ozone recovery as a result of the Montreal Protocol in driving the pause. Since the pre-2000 circulation trends have impacted precipitation, and potentially, the ocean circulation and salinity, we anticipate that a pause in these trends will have wider impacts on the Earth system. Signatures of the Montreal Protocol and the associated stratospheric ozone recovery might therefore manifest, or might have already manifested, in other aspects of the Earth system.},
author = {Banerjee, Antara and Fyfe, John C. and Polvani, Lorenzo M. and Waugh, Darryn and Chang, Kai-Lan},
doi = {10.1038/s41586-020-2120-4},
issn = {0028-0836},
journal = {Nature},
month = {mar},
number = {7800},
pages = {544--548},
title = {{A pause in Southern Hemisphere circulation trends due to the Montreal Protocol}},
url = {http://www.nature.com/articles/s41586-020-2120-4},
volume = {579},
year = {2020}
}
@article{Barichivich2013b,
abstract = {Abstract We combine satellite and ground observations during 1950?2011 to study the long-term links between multiple climate (air temperature and cryospheric dynamics) and vegetation (greenness and atmospheric CO2 concentrations) indicators of the growing season of northern ecosystems ({\textgreater}45°N) and their connection with the carbon cycle. During the last three decades, the thermal potential growing season has lengthened by about 10.5 days (P {\textless} 0.01, 1982?2011), which is unprecedented in the context of the past 60 years. The overall lengthening has been stronger and more significant in Eurasia (12.6 days, P {\textless} 0.01) than North America (6.2 days, P {\textgreater} 0.05). The photosynthetic growing season has closely tracked the pace of warming and extension of the potential growing season in spring, but not in autumn when factors such as light and moisture limitation may constrain photosynthesis. The autumnal extension of the photosynthetic growing season since 1982 appears to be about half that of the thermal potential growing season, yielding a smaller lengthening of the photosynthetic growing season (6.7 days at the circumpolar scale, P {\textless} 0.01). Nevertheless, when integrated over the growing season, photosynthetic activity has closely followed the interannual variations and warming trend in cumulative growing season temperatures. This lengthening and intensification of the photosynthetic growing season, manifested principally over Eurasia rather than North America, is associated with a long-term increase (22.2{\%} since 1972, P {\textless} 0.01) in the amplitude of the CO2 annual cycle at northern latitudes. The springtime extension of the photosynthetic and potential growing seasons has apparently stimulated earlier and stronger net CO2 uptake by northern ecosystems, while the autumnal extension is associated with an earlier net release of CO2 to the atmosphere. These contrasting responses may be critical in determining the impact of continued warming on northern terrestrial ecosystems and the carbon cycle.},
author = {Barichivich, Jonathan and Briffa, Keith R and Myneni, Ranga B and Osborn, Timothy J and Melvin, Thomas M and Ciais, Philippe and Piao, Shilong and Tucker, Compton},
doi = {10.1111/gcb.12283},
issn = {13541013},
journal = {Global Change Biology},
month = {oct},
number = {10},
pages = {3167--3183},
title = {{Large-scale variations in the vegetation growing season and annual cycle of atmospheric CO2 at high northern latitudes from 1950 to 2011}},
url = {http://doi.wiley.com/10.1111/gcb.12283},
volume = {19},
year = {2013}
}
@article{Barthel2020a,
abstract = {Abstract. The ice sheet model intercomparison project for CMIP6 (ISMIP6) effort brings together the ice sheet and climate modeling communities to gain understanding of the ice sheet contribution to sea level rise. ISMIP6 conducts stand-alone ice sheet experiments that use space- and time-varying forcing derived from atmosphere–ocean coupled global climate models (AOGCMs) to reflect plausible trajectories for climate projections. The goal of this study is to recommend a subset of CMIP5 AOGCMs (three core and three targeted) to produce forcing for ISMIP6 stand-alone ice sheet simulations, based on (i) their representation of current climate near Antarctica and Greenland relative to observations and (ii) their ability to sample a diversity of projected atmosphere and ocean changes over the 21st century. The selection is performed separately for Greenland and Antarctica. Model evaluation over the historical period focuses on variables used to generate ice sheet forcing. For stage (i), we combine metrics of atmosphere and surface ocean state (annual- and seasonal-mean variables over large spatial domains) with metrics of time-mean subsurface ocean temperature biases averaged over sectors of the continental shelf. For stage (ii), we maximize the diversity of climate projections among the best-performing models. Model selection is also constrained by technical limitations, such as availability of required data from RCP2.6 and RCP8.5 projections. The selected top three CMIP5 climate models are CCSM4, MIROC-ESM-CHEM, and NorESM1-M for Antarctica and HadGEM2-ES, MIROC5, and NorESM1-M for Greenland. This model selection was designed specifically for ISMIP6 but can be adapted for other applications.},
author = {Barthel, Alice and Agosta, C{\'{e}}cile and Little, Christopher M. and Hattermann, Tore and Jourdain, Nicolas C. and Goelzer, Heiko and Nowicki, Sophie and Seroussi, Helene and Straneo, Fiammetta and Bracegirdle, Thomas J.},
doi = {10.5194/tc-14-855-2020},
issn = {1994-0424},
journal = {The Cryosphere},
month = {mar},
number = {3},
pages = {855--879},
title = {{CMIP5 model selection for ISMIP6 ice sheet model forcing: Greenland and Antarctica}},
url = {https://tc.copernicus.org/articles/14/855/2020/},
volume = {14},
year = {2020}
}
@article{Bartlein2011a,
annote = {Cited By :233

Export Date: 8 March 2019},
author = {Bartlein, P J and Harrison, S P and Brewer, S and Connor, S and Davis, B A S and Gajewski, K and Guiot, J and Harrison-Prentice, T I and Henderson, A and Peyron, O and Prentice, I C and Scholze, M and Sepp{\"{a}}, H and Shuman, B and Sugita, S and Thompson, R S and Viau, A E and Williams, J and Wu, H},
doi = {10.1007/s00382-010-0904-1},
journal = {Climate Dynamics},
number = {3},
pages = {775--802},
title = {{Pollen-based continental climate reconstructions at 6 and 21 ka: A global synthesis}},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79959908208{\&}doi=10.1007{\%}2Fs00382-010-0904-1{\&}partnerID=40{\&}md5=fb8df37117a7e2510eb5d2b4f73c9677},
volume = {37},
year = {2011}
}
@article{Bartlein2017a,
author = {Bartlein, Patrick J and Harrison, Sandy P and Izumi, K.},
doi = {10.1002/2017GL074476},
journal = {Geophysical Research Letters},
number = {17},
pages = {9020--9028},
title = {{Underlying causes of Eurasian midcontinental aridity in simulations of mid‐Holocene climate}},
volume = {44},
year = {2017}
}
@article{Bastos2019,
abstract = {Abstract. Continuous atmospheric CO2 monitoring data indicate an increase in the amplitude of seasonal CO2-cycle exchange (SCANBP) in northern high latitudes. The major drivers of enhanced SCANBP remain unclear and intensely debated, with land-use change, CO2 fertilization and warming being identified as likely contributors. We integrated CO2-flux data from two atmospheric inversions (consistent with atmospheric records) and from 11 state-of-the-art land-surface models (LSMs) to evaluate the relative importance of individual contributors to trends and drivers of the SCANBP of CO2 fluxes for 1980–2015. The LSMs generally reproduce the latitudinal increase in SCANBP trends within the inversions range. Inversions and LSMs attribute SCANBP increase to boreal Asia and Europe due to enhanced vegetation productivity (in LSMs) and point to contrasting effects of CO2 fertilization (positive) and warming (negative) on SCANBP. Our results do not support land-use change as a key contributor to the increase in SCANBP. The sensitivity of simulated microbial respiration to temperature in LSMs explained biases in SCANBP trends, which suggests that SCANBP could help to constrain model turnover times.},
author = {Bastos, Ana and Ciais, Philippe and Chevallier, Fr{\'{e}}d{\'{e}}ric and R{\"{o}}denbeck, Christian and Ballantyne, Ashley P. and Maignan, Fabienne and Yin, Yi and Fern{\'{a}}ndez-Mart{\'{i}}nez, Marcos and Friedlingstein, Pierre and Pe{\~{n}}uelas, Josep and Piao, Shilong L. and Sitch, Stephen and Smith, William K. and Wang, Xuhui and Zhu, Zaichun and Haverd, Vanessa and Kato, Etsushi and Jain, Atul K. and Lienert, Sebastian and Lombardozzi, Danica and Nabel, Julia E. M. S. and Peylin, Philippe and Poulter, Benjamin and Zhu, Dan},
doi = {10.5194/acp-19-12361-2019},
issn = {1680-7324},
journal = {Atmospheric Chemistry and Physics},
month = {oct},
number = {19},
pages = {12361--12375},
title = {{Contrasting effects of CO2 fertilization, land-use change and warming on seasonal amplitude of Northern Hemisphere CO2 exchange}},
url = {https://acp.copernicus.org/articles/19/12361/2019/},
volume = {19},
year = {2019}
}
@article{Batehup2015,
author = {Batehup, R and McGregor, S and Gallant, A J E},
doi = {10.5194/cp-11-1733-2015},
journal = {Climate of the Past},
number = {12},
pages = {1733--1749},
title = {{The influence of non-stationary teleconnections on palaeoclimate reconstructions of ENSO variance using a pseudoproxy framework}},
volume = {11},
year = {2015}
}
@article{Bayr2019,
abstract = {Common problems in state-of-the-art climate models are a cold sea surface temperature (SST) bias in the equatorial Pacific and the underestimation of the two most important atmospheric feedbacks operating in the El Ni{\~{n}}o/Southern Oscillation (ENSO): the positive, i.e. amplifying wind-SST feedback and the negative, i.e. damping heat flux-SST feedback. To a large extent, the underestimation of those feedbacks can be explained by the cold equatorial SST bias, which shifts the rising branch of the Pacific Walker Circulation (PWC) too far to the west by up to 30°, resulting in an erroneous convective response during ENSO events. Based on simulations from the Kiel Climate Model (KCM) and the 5th phase of Coupled Model Intercomparison Project (CMIP5), we investigate how well ENSO dynamics are simulated in case of underestimated ENSO atmospheric feedbacks (EAF), with a special focus on ocean–atmosphere coupling over the equatorial Pacific. While models featuring realistic atmospheric feedbacks simulate ENSO dynamics close to observations, models with underestimated EAF exhibit fundamental biases in ENSO dynamics. In models with too weak feedbacks, ENSO is not predominantly wind-driven as observed; instead ENSO is driven significantly by a positive shortwave radiation feedback. Thus, although these models simulate ENSO, which in terms of simple indices is consistent with observations, it originates from very different dynamics. A too weak oceanic forcing on the SST via the positive thermocline, the Ekman and the zonal advection feedback is compensated by weaker atmospheric heat flux damping. The latter is mainly caused by a biased shortwave-SST feedback that erroneously is positive in most climate models. In the most biased models, the shortwave-SST feedback contributes to the SST anomaly growth to a similar degree as the ocean circulation. Our results suggest that a broad continuum of ENSO dynamics can exist in climate models and explain why climate models with less than a half of the observed EAF strength can still depict realistic ENSO amplitude.},
author = {Bayr, Tobias and Wengel, Christian and Latif, Mojib and Dommenget, Dietmar and L{\"{u}}bbecke, Joke and Park, Wonsun},
doi = {10.1007/s00382-018-4575-7},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {1},
pages = {155--172},
title = {{Error compensation of ENSO atmospheric feedbacks in climate models and its influence on simulated ENSO dynamics}},
url = {https://doi.org/10.1007/s00382-018-4575-7},
volume = {53},
year = {2019}
}
@article{Beadling2020a,
abstract = {The air-sea exchange of heat and carbon in the Southern Ocean (SO) plays an important role in mediating the climate state. The dominant role the SO plays in storing anthropogenic heat and carbon is a direct consequence of the unique and complex ocean circulation that exists there. Previous generations of climate models have struggled to accurately represent key SO properties and processes that influence the large-scale ocean circulation. This has resulted in low confidence ascribed to twenty-first-century projections of the state of the SO from previous generations of models. This analysis provides a detailed assessment of the ability of models contributed to the sixth phase of the Coupled Model Intercomparison Project (CMIP6) to represent important observationally based SO properties. Additionally, a comprehensive overview of CMIP6 performance relative to CMIP3 and CMIP5 is presented. CMIP6 models show improved performance in the surface wind stress forcing, simulating stronger and less equatorward-biased wind fields, translating into an improved representation of the Ekman upwelling over the Drake Passage latitudes. An increased number of models simulate an Antarctic Circumpolar Current (ACC) transport within observational uncertainty relative to previous generations; however, several models exhibit extremely weak transports. Generally, the upper SO remains biased warm and fresh relative to observations, and Antarctic sea ice extent remains poorly represented. While generational improvement is found in many metrics, persistent systematic biases are highlighted that should be a priority during model development. These biases need to be considered when interpreting projected trends or biogeochemical properties in this region.},
author = {Beadling, R. L. and Russell, J. L. and Stouffer, R. J. and Mazloff, M. and Talley, L. D. and Goodman, P. J. and Salle{\'{e}}, J. B. and Hewitt, H. T. and Hyder, P. and Pandde, Amarjiit},
doi = {10.1175/JCLI-D-19-0970.1},
issn = {08948755},
journal = {Journal of Climate},
month = {aug},
number = {15},
pages = {6555--6581},
publisher = {American Meteorological Society},
title = {{Representation of Southern Ocean Properties across Coupled Model Intercomparison Project Generations: CMIP3 to CMIP6}},
url = {https://journals.ametsoc.org/jcli/article/33/15/6555/347111/Representation-of-Southern-Ocean-Properties-across},
volume = {33},
year = {2020}
}
@article{doi:10.1002/2014GL061027,
abstract = {Abstract Detection and attribution of human influence on sea level rise are important topics that have not yet been explored in depth. We question whether the sea level changes (SLC) over the past century were natural in origin. SLC exhibit power law long-term correlations. By estimating Hurst exponent through Detrended Fluctuation Analysis and by applying statistics of Lennartz and Bunde [2009], we search the lower bounds of statistically significant external sea level trends in longest tidal records worldwide. We provide statistical evidences that the observed SLC, at global and regional scales, is beyond its natural internal variability. The minimum anthropogenic sea level trend (MASLT) contributes to the observed sea level rise more than 50{\%} in New York, Baltimore, San Diego, Marseille, and Mumbai. A MASLT is about 1 mm/yr in global sea level reconstructions that is more than half of the total observed sea level trend during the XXth century.},
author = {Becker, M and Karpytchev, M and Lennartz-Sassinek, S},
doi = {10.1002/2014GL061027},
journal = {Geophysical Research Letters},
keywords = {long-term persistence,sea level change,tide gauge,trend estimation},
number = {15},
pages = {5571--5580},
title = {{Long-term sea level trends: Natural or anthropogenic?}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2014GL061027},
volume = {41},
year = {2014}
}
@article{Bellenger2014,
abstract = {We analyse the ability of CMIP3 and CMIP5 coupled ocean–atmosphere general circulation models (CGCMs) to simulate the tropical Pacific mean state and El Nin ˜o-Southern Oscillation (ENSO). The CMIP5 multi- model ensemble displays an encouraging 30 {\%} reduction of the pervasive cold bias in the western Pacific, but no quantum leap in ENSO performance compared to CMIP3. CMIP3 and CMIP5 can thus be considered as one large ensemble (CMIP3 ? CMIP5) for multi-model ENSO analysis. The too large diversity in CMIP3 ENSO ampli- tude is however reduced by a factor of two in CMIP5 and the ENSO life cycle (location of surface temperature anomalies, seasonal phase locking) is modestly improved. Other fundamental ENSO characteristics such as central Pacific precipitation anomalies however remain poorly represented. The sea surface temperature (SST)-latent heat flux feedback is slightly improved in the CMIP5 ensemble but the wind-SST feedback is still underestimated by 20–50 {\%} and the shortwave-SST feedbacks remain underestimated by a factor of two. The improvement in ENSO amplitudes might therefore result from error com- pensations. The ability of CMIP models to simulate the SST-shortwave feedback, a major source of erroneous ENSO in CGCMs, is further detailed. In observations, this feedback is strongly nonlinear because the real atmosphere switches from subsident (positive feedback) to convective (negative feedback) regimes under the effect of seasonal and interannual variations. Only one-third of CMIP3 ? CMIP5 models reproduce this regime shift, with the other models remaining locked in one of the two regimes. The modelled shortwave feedback nonlinearity increases with ENSO amplitude and the amplitude of this feedback in the spring strongly relates with the models ability to simulate ENSO phase locking. In a final stage, a subset of metrics is proposed in order to synthesize the ability of each CMIP3 and CMIP5 models to simulate ENSO main characteristics and key atmospheric feedbacks. 1},
archivePrefix = {arXiv},
arxivId = {arXiv:1011.1669v3},
author = {Bellenger, H. and Guilyardi, E. and Leloup, J. and Lengaigne, M. and Vialard, J.},
doi = {10.1007/s00382-013-1783-z},
eprint = {arXiv:1011.1669v3},
isbn = {0930-7575},
issn = {14320894},
journal = {Climate Dynamics},
month = {apr},
number = {7-8},
pages = {1999--2018},
pmid = {25246403},
title = {{ENSO representation in climate models: From CMIP3 to CMIP5}},
url = {https://doi.org/10.1007/s00382-013-1783-z},
volume = {42},
year = {2014}
}
@article{Bellomo2018,
abstract = {Previous studies suggest that internal variability, in particular the Atlantic Meridional Overturning Circulation (AMOC), drives the Atlantic Multidecadal Oscillation (AMV), while external radiative forcing only creates a steady increase in sea surface temperature (SST). This view has been recently challenged and new evidence has emerged that aerosols and greenhouse gases could play a role in driving the AMV. Here we examine the drivers of the AMV using the Community Earth System Model (CESM) Large Ensemble and Last Millennium Ensemble. By computing the ensemble mean we isolate the radiatively forced component of the AMV, while we estimate the role of internal variability using the ensemble spread. We find that phase changes of the AMV over the years 1854--2005 can be explained only in the presence of varying historical forcing. Further, we find that internal variability is large in North Atlantic SST at timescales shorter than 10--25 years, but at longer timescales the forced response dominates. Single forcing experiments show that greenhouse gases and tropospheric aerosols are the main drivers of the AMV in the latter part of the twentieth century. Finally, we show that the forced spatial pattern of SST is not distinct from the internal variability pattern, which has implications for detection and attribution.},
author = {Bellomo, Katinka and Murphy, Lisa N and Cane, Mark A and Clement, Amy C and Polvani, Lorenzo M},
doi = {10.1007/s00382-017-3834-3},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {9},
pages = {3687--3698},
title = {{Historical forcings as main drivers of the Atlantic multidecadal variability in the CESM large ensemble}},
url = {https://doi.org/10.1007/s00382-017-3834-3},
volume = {50},
year = {2018}
}
@article{Bellucci2017,
abstract = {AbstractResults from a study inspecting the origins of multidecadal variability in the North Atlantic sea surface temperature (NASST) are presented. The authors target in particular the 1940?75 ?warm-to-cold? transition, an event that is generally framed in the context of the longer-term Atlantic multidecadal variability (AMV) cycle, in turn associated with the Atlantic meridional overturning circulation (AMOC) internal variability. Here the authors examine the ability of uninitialized, historical integrations from the phase 5 of the Coupled Model Intercomparison Project (CMIP5) archive to retrospectively reproduce this specific episode of twentieth-century climatic history, under a hierarchy of forcing conditions. For this purpose, both standard and so-called historical Misc CMIP5 simulations of the historical climate (combining selected natural and anthropogenic forcings) are exploited. Based on this multimodel analysis, evidence is found for a significant influence of anthropogenic agents on multidecadal sea surface temperature (SST) fluctuations across the Atlantic sector, suggesting that anthropogenic aerosols and greenhouse gases might have played a key role in the 1940?75 North Atlantic cooling. However, the diagnosed forced response in CMIP5 models appears to be affected by a large uncertainty, with only a limited subset of models displaying significant skill in reproducing the mid-twentieth-century NASST cooling. Such uncertainty originates from the existence of well-defined behavioral clusters within the analyzed CMIP5 ensembles, with the bulk of the models splitting into two main clusters. Such a strong polarization calls for some caution when using a multimodel ensemble mean in climate model analyses, as averaging across fairly distinct model populations may result, through mutual cancellation, in a rather artificial description of the actual multimodel ensemble behavior.A potentially important role for both anthropogenic aerosols and greenhouse gases with regard to the observed North Atlantic multidecadal variability has clear implications for decadal predictability and predictions. The uncertainty associated with alternative aerosol and greenhouse gas emission scenarios should be duly accounted for in designing a common protocol for coordinated decadal forecast experiments.},
annote = {doi: 10.1175/JCLI-D-16-0301.1},
author = {Bellucci, A and Mariotti, A and Gualdi, S},
doi = {10.1175/JCLI-D-16-0301.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jun},
number = {18},
pages = {7317--7337},
publisher = {American Meteorological Society},
title = {{The Role of Forcings in the Twentieth-Century North Atlantic Multidecadal Variability: The 1940–75 North Atlantic Cooling Case Study}},
url = {https://doi.org/10.1175/JCLI-D-16-0301.1},
volume = {30},
year = {2017}
}
@article{Bellucci2021,
abstract = {A dominant paradigm for mid-latitude air-sea interaction identifies the synoptic-scale atmospheric “noise” as the main driver for the observed ocean surface variability. While this conceptual model successfully holds over most of the mid-latitude ocean surface, its soundness over frontal zones (including western boundary currents; WBC) characterized by intense mesoscale activity, has been questioned in a number of studies suggesting a driving role for the small scale ocean dynamics (mesoscale oceanic eddies) in the modulation of air-sea interaction. In this context, climate models provide a powerful experimental device to inspect the emerging scale-dependent nature of mid-latitude air-sea interaction. This study assesses the impact of model resolution on the representation of air-sea interaction over the Gulf Stream region, in a multi-model ensemble of present-climate simulations performed using a common experimental design. Lead-lag correlation and covariance patterns between sea surface temperature (SST) and turbulent heat flux (THF) are diagnosed to identify the leading regimes of air-sea interaction in a region encompassing both the Gulf Stream system and the North Atlantic subtropical basin. Based on these statistical metrics it is found that coupled models based on “laminar” (eddy-parameterised) and eddy-permitting oceans are able to discriminate between an ocean-driven regime, dominating the region controlled by the Gulf Stream dynamics, and an atmosphere-driven regime, typical of the open ocean regions. However, the increase of model resolution leads to a better representation of SST and THF cross-covariance patterns and functional forms, and the major improvements can be largely ascribed to a refinement of the oceanic model component.},
author = {Bellucci, Alessio and Athanasiadis, P J and Scoccimarro, E and Ruggieri, P and Gualdi, S and Fedele, G and Haarsma, R J and Garcia-Serrano, J and Castrillo, M and Putrahasan, D and Sanchez-Gomez, E and Moine, M.-P. and Roberts, C. D. and Roberts, M J and Seddon, J and Vidale, P L},
doi = {10.1007/s00382-020-05573-z},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {apr},
number = {7-8},
pages = {2093--2111},
title = {{Air-Sea interaction over the Gulf Stream in an ensemble of HighResMIP present climate simulations}},
url = {https://doi.org/10.1007/s00382-020-05573-z https://link.springer.com/10.1007/s00382-020-05573-z},
volume = {56},
year = {2021}
}
@article{doi:10.1002/asl2.412,
abstract = {Abstract An underestimate of atmospheric blocking occurrence is a well-known limitation of many climate models. This article presents an analysis of Northern Hemisphere winter blocking in an atmospheric model with increased horizontal resolution. European blocking frequency increases with model resolution, and this results from an improvement in the atmospheric patterns of variability as well as a simple improvement in the mean state. There is some evidence that the transient eddy momentum forcing of European blocks is increased at high resolution, which could account for this. However, it is also shown that the increase in resolution of the orography is needed to realise the improvement in blocking, consistent with the increase in height of the Rocky Mountains acting to increase the tilt of the Atlantic jet stream and giving higher mean geopotential heights over northern Europe. Blocking frequencies in the Pacific sector are also increased with atmospheric resolution, but in this case the improvement in orography actually leads to a decrease in blocking Copyright {\textcopyright} 2012 Royal Meteorological Society and British Crown copyright, Met Office.},
author = {Berckmans, Julie and Woollings, Tim and Demory, Marie-Estelle and Vidale, Pier-Luigi and Roberts, Malcolm},
doi = {10.1002/asl2.412},
journal = {Atmospheric Science Letters},
keywords = {atmospheric blocking,high resolution,mean state,orography,transient eddies},
number = {1},
pages = {34--40},
title = {{Atmospheric blocking in a high resolution climate model: influences of mean state, orography and eddy forcing}},
url = {https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/asl2.412},
volume = {14},
year = {2013}
}
@article{Bernie2008,
abstract = {Coupled ocean atmosphere general circulation models (GCM) are typically coupled once every 24 h, excluding the diurnal cycle from the upper ocean. Previous studies attempting to examine the role of the diurnal cycle of the upper ocean and particularly of diurnal SST variability have used models unable to resolve the processes of interest. In part 1 of this study a high vertical resolution ocean GCM configuration with modified physics was developed that could resolve the diurnal cycle in the upper ocean. In this study it is coupled every 3 h to atmospheric GCM to examine the sensitivity of the mean climate simulation and aspects of its variability to the inclusion of diurnal ocean-atmosphere coupling. $\backslash$nThe inclusion of the diurnal cycle leads to a tropics wide increase in mean sea surface temperature (SST), with the strongest signal being across the equatorial Pacific where the warming increases from 0.2°C in the central and western Pacific to over 0.3°C in the eastern equatorial Pacific. Much of this warming is shown to be a direct consequence of the rectification of daily mean SST by the diurnal variability of SST. The warming of the equatorial Pacific leads to a redistribution of precipitation from the Inter tropical convergence zone (ITCZ) toward the equator. In the western Pacific there is an increase in precipitation between Papa new guinea and 170°E of up to 1.2 mm/day, improving the simulation compared to climatology. $\backslash$nPacific sub tropical cells are increased in strength by about 10{\%}, in line with results of part 1 of this study, due to the modification of the exchange of momentum between the equatorially divergent Ekman currents and the geostropic convergence at depth, effectively increasing the dynamical response of the tropical Pacific to zonal wind stresses. $\backslash$nDuring the spring relaxation of the Pacific trade winds, a large diurnal cycle of SST increases the seasonal warming of the equatorial Pacific. When the trade winds then re-intensify, the increase in the dynamical response of the ocean leads to a stronger equatorial upwelling. These two processes both lead to stronger seasonal basin scale feedbacks in the coupled system, increasing the strength of the seasonal cycle of the tropical Pacific sector by around 10{\%}. This means that the diurnal cycle in the upper ocean plays a part in the coupled feedbacks between ocean and atmosphere that maintain the basic state and the timing of the seasonal cycle of SST and trade winds in the tropical Pacific. $\backslash$nThe Madden–Julian Oscillation (MJO) is examined by use of a large scale MJO index, lag correlations and composites of events. The inclusion of the diurnal cycle leads to a reduction in overall MJO activity. Precipitation composites show that the MJO is stronger and more coherent when the diurnal cycle of coupling is resolved, with the propagation and different phases being far more distinct both locally and to larger lead times across the tropical Indo-Pacific. Part one of this study showed that that diurnal variability of SST is modulated by the MJO and therefore increases the intraseasonal SST response to the different phases of the MJO. Precipitation-based composites of SST variability confirm this increase in the coupled simulations. It is argued that including this has increased the thermodynamical coupling of the ocean and atmosphere on the timescale of the MJO (20–100 days), accounting for the improvement in the MJO strength and coherency seen in composites of precipitation and SST. $\backslash$nThese results show that the diurnal cycle of ocean–atmosphere interaction has profound impact on a range of up-scale variability in the tropical climate and as such, it is an important feature of the modelled climate system which is currently either neglected or poorly resolved in state of the art coupled models.},
author = {Bernie, Dan J. and Guilyardi, E. and Madec, G. and Slingo, J. M. and Woolnough, S. J. and Cole, J.},
doi = {10.1007/s00382-008-0429-z},
isbn = {0930-7575$\backslash$r1432-0894},
issn = {09307575},
journal = {Climate Dynamics},
month = {dec},
number = {7-8},
pages = {909--925},
pmid = {249403100003},
publisher = {Springer-Verlag},
title = {{Impact of resolving the diurnal cycle in an ocean–atmosphere GCM. Part 2: A diurnally coupled CGCM}},
url = {http://link.springer.com/10.1007/s00382-008-0429-z},
volume = {31},
year = {2008}
}
@article{Bernie2007,
abstract = {The diurnal cycle is a fundamental time scale in the climate system, at which the upper ocean and atmosphere are routinely observed to vary. Current climate models, however, are not configured to resolve the diurnal cycle in the upper ocean or the interaction of the ocean and atmosphere on these time scales. This study examines the diurnal cycle of the tropical upper ocean and its climate impacts. In the present paper, the first of two, a high vertical resolution ocean general circulation model (OGCM), with modified physics, is developed which is able to resolve the diurnal cycle of sea surface temperature (SST) and current variability in the upper ocean. It is then validated against a satellite derived parameterization of diurnal SST variability and in-situ current observations. The model is then used to assess rectification of the intraseasonal SST response to the Madden–Julian oscillation (MJO) by the diurnal cycle of SST. Across the equatorial Indo-Pacific it is found that the diurnal cycle increases the intraseasonal SST response to the MJO by around 20{\%}. In the Pacific, the diurnal cycle also modifies the exchange of momentum between equatorially divergent Ekman currents and the meridionally convergent geostrophic currents beneath, resulting in a 10{\%} increase in the strength of the Ekman cells and equatorial upwelling. How the thermodynamic and dynamical impacts of the diurnal cycle effect the mean state, and variability, of the climate system cannot be fully investigated in the constrained design of ocean-only experiments presented here. The second part of this study, published separately, addresses the climate impacts of the diurnal cycle in the coupled system by coupling the OGCM developed here to an atmosphere general circulation model.},
author = {Bernie, Dan J. and Guilyardi, E. and Madec, G. and Slingo, J. M. and Woolnough, S. J.},
doi = {10.1007/s00382-007-0249-6},
isbn = {0930-7575$\backslash$r1432-0894},
issn = {09307575},
journal = {Climate Dynamics},
month = {sep},
number = {6},
pages = {575--590},
pmid = {249403100003},
publisher = {Springer-Verlag},
title = {{Impact of resolving the diurnal cycle in an ocean–atmosphere GCM. Part 1: A diurnally forced OGCM}},
url = {http://link.springer.com/10.1007/s00382-007-0249-6},
volume = {29},
year = {2007}
}
@article{Bernie2005,
abstract = {Abstract The intraseasonal variability of SST associated with the passage of the Madden–Julian oscillation (MJO) is well documented; yet coupled model integrations generally underpredict the magnitude of this SST variability. Observations from the Improved Meteorological Instrument (IMET) mooring in the western Pacific during the intensive observing period (IOP) of the Tropical Ocean Global Atmosphere Coupled Ocean–Atmosphere Response Experiment (TOGA COARE) showed a large diurnal signal in SST that is modulated by the passage of the MJO. In this study, observations from the IOP of the TOGA COARE and a one-dimensional (1D) ocean mixed layer model incorporating the K-Profile Parameterization (KPP) vertical mixing scheme have been used to investigate the rectification of the intraseasonal variability of SST by the diurnal cycle and the implied impact of the absence of a representation of this process on the modeled intraseasonal variability in coupled GCMs. Analysis of the SST observations has shown that th...},
author = {Bernie, D. J. and Woolnough, S. J. and Slingo, J. M. and Guilyardi, E.},
doi = {10.1175/JCLI3319.1},
issn = {08948755},
journal = {Journal of Climate},
month = {apr},
number = {8},
pages = {1190--1202},
pmid = {228975100005},
title = {{Modeling diurnal and intraseasonal variability of the ocean mixed layer}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/JCLI3319.1},
volume = {18},
year = {2005}
}
@article{Biasutti2018,
author = {Biasutti, Michela and Voigt, Aiko and Boos, William R. and Braconnot, Pascale and Hargreaves, Julia C. and Harrison, Sandy P. and Kang, Sarah M. and Mapes, Brian E. and Scheff, Jacob and Schumacher, Courtney and Sobel, Adam H. and Xie, Shang-Ping},
doi = {10.1038/s41561-018-0137-1},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {jun},
number = {6},
pages = {392--400},
title = {{Global energetics and local physics as drivers of past, present and future monsoons}},
url = {http://www.nature.com/articles/s41561-018-0137-1},
volume = {11},
year = {2018}
}
@article{Bilbao2019,
author = {Bilbao, Roberto A. F. and Gregory, Jonathan M. and Bouttes, Nathaelle and Palmer, Matthew D. and Stott, Peter},
doi = {10.1007/s00382-019-04910-1},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {nov},
number = {9-10},
pages = {5389--5413},
publisher = {Springer Berlin Heidelberg},
title = {{Attribution of ocean temperature change to anthropogenic and natural forcings using the temporal, vertical and geographical structure}},
url = {http://link.springer.com/10.1007/s00382-019-04910-1},
volume = {53},
year = {2019}
}
@article{Bilbao2015,
abstract = {Predictions of twenty-first century sea level change show strong regional variation. Regional sea level change observed by satellite altimetry since 1993 is also not spatially homogenous. By comparison with historical and pre-industrial control simulations using the atmosphere–ocean general circulation models (AOGCMs) of the CMIP5 project, we conclude that the observed pattern is generally dominated by unforced (internal generated) variability, although some regions, especially in the Southern Ocean, may already show an externally forced response. Simulated unforced variability cannot explain the observed trends in the tropical Pacific, but we suggest that this is due to inadequate simulation of variability by CMIP5 AOGCMs, rather than evidence of anthropogenic change. We apply the method of pattern scaling to projections of sea level change and show that it gives accurate estimates of future local sea level change in response to anthropogenic forcing as simulated by the AOGCMs under RCP scenarios, implying that the pattern will remain stable in future decades. We note, however, that use of a single integration to evaluate the performance of the pattern-scaling method tends to exaggerate its accuracy. We find that ocean volume mean temperature is generally a better predictor than global mean surface temperature of the magnitude of sea level change, and that the pattern is very similar under the different RCPs for a given model. We determine that the forced signal will be detectable above the noise of unforced internal variability within the next decade globally and may already be detectable in the tropical Atlantic.},
author = {Bilbao, Roberto A F and Gregory, Jonathan M and Bouttes, Nathaelle},
doi = {10.1007/s00382-015-2499-z},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {9},
pages = {2647--2666},
title = {{Analysis of the regional pattern of sea level change due to ocean dynamics and density change for 1993–2099 in observations and CMIP5 AOGCMs}},
url = {https://doi.org/10.1007/s00382-015-2499-z},
volume = {45},
year = {2015}
}
@incollection{Bindoff2007,
address = {Cambridge, United Kingdom and New York, NY, USA},
author = {Bindoff, N. L. and Willebrand, J. and Artale, V. and Cazenave, A. and Gregory, J. M. and Gulev, S. and Hanawa, K. and {Le Quere}, C. and Levitus, S. and Nojiri, Y. and Shum, C. K. and Talley, L. D. and Unnikrishnan, A. S. and Contributing authors},
booktitle = {Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change},
chapter = {5},
doi = {https://www.ipcc.ch/report/ar4/wg1},
editor = {Solomon, S and Qin, D and Manning, M and Chen, Z and Marquis, M and Averyt, K B and Tignor, M and Miller, H L},
isbn = {9780521880091},
pages = {385--432},
publisher = {Cambridge University Press},
title = {{Observations: Oceanic Climate Change and Sea Level}},
url = {https://www.ipcc.ch/report/ar4/wg1},
year = {2007}
}
@incollection{Bindoff2019,
author = {Bindoff, Nathaniel L. and Cheung, William W. L. and Kairo, James G. and Aristegui, J. and Guinder, V. A. and Hallberg, Robert and Hilmi, N. and Jiao, N. and Karim, M. S. and Levin, L. and O'Donoghue, S. and {Purca Cuicapusa}, S. R. and Rinkevich, B. and Suga, T. and Tagliabue, A. and Williamson, P.},
booktitle = {IPCC Special Report on the Ocean and Cryosphere in a Changing Climate},
chapter = {5},
doi = {https://www.ipcc.ch/srocc/chapter/chapter-5},
editor = {Pörtner, H.-O. and Roberts, D.C. and Masson-Delmotte, V. and Zhai, P. and Tignor, M. and Poloczanska, E. and Mintenbeck, K. and Alegría, A. and Nicolai, M. and Okem, A. and Petzold, J. and Rama, B. and Weyer, N.M.},
pages = {447--588},
publisher = {In Press},
title = {{Changing Ocean, Marine Ecosystems, and Dependent Communities}},
url = {https://www.ipcc.ch/srocc/chapter/chapter-5},
year = {2019}
}
@incollection{Bindoff2013d,
address = {Cambridge University Press, Cambridge, United Kingdom and New York},
author = {Bindoff, N. L. and Stott, P.A. and AchutaRao, K M and Allen, M.R. and Gillett, N.P. and Gutzler, D and Hansingo, K and Hegerl, G.C. and Hu, Yongyun and Jain, S and Mokhov, I I and Overland, J and Perlwitz, J and Sebbari, R and Zhang, Xuebin},
booktitle = {Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change},
chapter = {10},
doi = {10.1017/CBO9781107415324.022},
editor = {Stocker, T.F and Qin, D. and Plattner, G.-K. and Tignor, M. and Allen, S.K. and Boschung, J. and Nauels, A. and Xia, Y. and Bex, V. and Midgley, P.M.},
isbn = {9781107415324},
pages = {867--952},
publisher = {Cambridge University Press},
title = {{Detection and attribution of climate change: From global to regional}},
url = {https://www.ipcc.ch/report/ar5/wg1},
year = {2013}
}
@article{Bintanja2013,
author = {Bintanja, R and van Oldenborgh, G J and Drijfhout, S S and Wouters, B and Katsman, C A},
doi = {10.1038/ngeo1767},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {may},
number = {5},
pages = {376--379},
publisher = {Nature Publishing Group},
title = {{Important role for ocean warming and increased ice-shelf melt in Antarctic sea-ice expansion}},
url = {http://dx.doi.org/10.1038/ngeo1767 http://10.0.4.14/ngeo1767 https://www.nature.com/articles/ngeo1767{\#}supplementary-information http://www.nature.com/articles/ngeo1767},
volume = {6},
year = {2013}
}
@article{Bintanja2015b,
abstract = {Observations show that, in contrast to the Arctic, the area of Antarctic sea ice has increased since 1979. A potential driver of this significant increase relates to the mass loss of the Antarctic ice sheet. Subsurface ocean warming causes basal ice-shelf melt, freshening the surface waters around Antarctica, which leads to increases in sea-ice cover. With climate warming ongoing, future mass-loss rates are projected to accelerate, which has the potential to affect future Antarctic sea-ice trends. Here we investigate to what extent future sea-ice trends are influenced by projected increases in Antarctic freshwater flux due to subsurface melt, using a state-of-the-art global climate model (EC-Earth) in standardized Climate Model Intercomparison Project phase 5 (CMIP5) climate-change simulations. Virtually all CMIP5 models disregard ocean–ice-sheet interactions and project strongly retreating Antarctic sea ice. Applying various freshwater flux scenarios, we find that the additional fresh water significantly offsets the decline in sea-ice area and is even able to reverse the trend in the strongest freshwater forcing scenario that can reasonably be expected, especially in austral winter. The model also simulates decreasing sea surface temperatures (SSTs), with the SST trends exhibiting strong regional variations that largely correspond to regional sea-ice trends.},
author = {Bintanja, R and van Oldenborgh, G J and Katsman, C A},
doi = {DOI: 10.3189/2015AoG69A001},
edition = {2017/07/26},
issn = {0260-3055},
journal = {Annals of Glaciology},
number = {69},
pages = {120--126},
publisher = {Cambridge University Press},
title = {{The effect of increased fresh water from Antarctic ice shelves on future trends in Antarctic sea ice}},
volume = {56},
year = {2015}
}
@article{Birkel2018a,
abstract = {The Atlantic multidecadal oscillation (AMO) is a 60–70 year pattern of sea-surface temperature (SST) variability in the North Atlantic commonly ascribed to internal ocean dynamics and changes in northward heat transport. Recent modeling studies, however, suggest that SSTs fluctuate primarily in response to major volcanic eruptions and changes in atmospheric circulation. Here, we utilize historical SST, atmospheric reanalysis, and stratospheric aerosol optical depth data to examine the basic evidence supporting a volcanic link. We find that cool intervals across the North Atlantic coincide with two distinct episodes of explosive volcanic activity (1880s–1920s and 1960s–1990s), where key eruptions include 1883 Krakatau, 1902 Santa Mar{\'{i}}a, 1912 Novarupta, 1963 Agung, 1982 El Chich{\'{o}}n, and 1991 Pinatubo. Cool SST patterns develop in association with an increased prevalence of North Atlantic Oscillation (NAO)+ atmospheric patterns caused by stratospheric aerosol loading and a steepened poleward temperature gradient. NAO+ patterns promote wind-driven advection, evaporative cooling, and increased albedo from enhanced Saharan dust transport and anthropogenic aerosols. SSTs across the subpolar gyre are regulated by strength of low pressure near Iceland and the associated wind-driven advection of cold surface water from the Labrador Sea. This is contrary to an interpretation that subpolar SSTs are driven by changes in ocean overturning circulation. We also find that North Pacific and global mean SST declines can be readily associated with the same volcanic triggers that affect the North Atlantic. Thus, external forcing from volcanic aerosols appears to underpin multi-decade SST variability observed in the historical record.},
author = {Birkel, Sean D. and Mayewski, Paul A. and Maasch, Kirk A. and Kurbatov, Andrei V. and Lyon, Bradfield},
doi = {10.1038/s41612-018-0036-6},
issn = {2397-3722},
journal = {npj Climate and Atmospheric Science},
month = {dec},
number = {1},
pages = {24},
title = {{Evidence for a volcanic underpinning of the Atlantic multidecadal oscillation}},
url = {http://www.nature.com/articles/s41612-018-0036-6},
volume = {1},
year = {2018}
}
@article{Bittner2016,
author = {Bittner, Matthias and Schmidt, Hauke and Timmreck, Claudia and Sienz, Frank},
doi = {10.1002/2016GL070587},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {sep},
number = {17},
pages = {9324--9332},
title = {{Using a large ensemble of simulations to assess the Northern Hemisphere stratospheric dynamical response to tropical volcanic eruptions and its uncertainty}},
url = {http://doi.wiley.com/10.1002/2016GL070587},
volume = {43},
year = {2016}
}
@incollection{bitz2008some,
address = {Washington, DC, USA},
author = {Bitz, Cecilia M},
booktitle = {Arctic Sea Ice Decline: Observations, Projections, Mechanisms, and Implications},
doi = {10.1029/180GM06},
editor = {DeWeaver, Eric T. and Bitz, Cecilia M. and Tremblay, L.-B.},
isbn = {9781118666470},
month = {mar},
pages = {63--76},
publisher = {American Geophysical Union (AGU)},
title = {{Some Aspects of Uncertainty in Predicting Sea Ice Thinning}},
url = {http://doi.wiley.com/10.1029/180GM06},
year = {2008}
}
@article{Blau2020,
author = {Blau, M. T. and Ha, K.‐J.},
doi = {10.1029/2020JD033121},
issn = {2169-897X},
journal = {Journal of Geophysical Research: Atmospheres},
month = {aug},
number = {16},
pages = {e2020JD033121},
title = {{The Indian Ocean Dipole and its Impact on East African Short Rains in Two CMIP5 Historical Scenarios With and Without Anthropogenic Influence}},
url = {https://onlinelibrary.wiley.com/doi/10.1029/2020JD033121},
volume = {125},
year = {2020}
}
@article{Blazquez2017,
author = {Blazquez, J. and Solman, S.},
doi = {10.1007/s00382-017-3765-z},
journal = {Climate Dynamics},
number = {7-8},
pages = {2705--2717},
title = {{Fronts and precipitation in CMIP5 models for the austral winter of the Southern Hemisphere}},
volume = {50},
year = {2017}
}
@article{Bock2020,
abstract = {More than 40 model groups worldwide are participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6), providing a new and rich source of information to better understand past, present, and future climate change. Here, we use the Earth System Model Evaluation Tool (ESMValTool) to assess the performance of the CMIP6 ensemble compared to the previous generations CMIP3 and CMIP5. While CMIP5 models did not capture the observed pause in the increase in global mean surface temperature between 1998 and 2013, the historical CMIP6 simulations agree well with the observed recent temperature increase, but some models have difficulties in reproducing the observed global mean surface temperature record of the second half of the twentieth century. While systematic biases in annual mean surface temperature and precipitation remain in the CMIP6 multimodel mean, individual models and high-resolution versions of the models show significant reductions in many long-standing biases. Some improvements are also found in the vertical temperature, water vapor, and zonal wind speed distributions, and root-mean-square errors for selected fields are generally smaller with reduced intermodel spread and higher average skill in the correlation patterns relative to observations. An emerging property of the CMIP6 ensemble is a higher effective climate sensitivity with an increased range between 2.3 and 5.6 K. A possible reason for this increase in some models is improvements in cloud representation resulting in stronger shortwave cloud feedbacks than in their predecessor versions.},
author = {Bock, L. and Lauer, A. and Schlund, M. and Barreiro, M. and Bellouin, N. and Jones, C. and Meehl, G. A. and Predoi, V. and Roberts, M. J. and Eyring, V.},
doi = {10.1029/2019JD032321},
issn = {2169-897X},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {CMIP,climate model,evaluation},
month = {nov},
number = {21},
pages = {e2019JD032321},
title = {{Quantifying Progress Across Different CMIP Phases With the ESMValTool}},
url = {https://onlinelibrary.wiley.com/doi/10.1029/2019JD032321},
volume = {125},
year = {2020}
}
@article{Bodart2019a,
abstract = {Interannual variations associated with El Ni{\~{n}}o-Southern Oscillation can alter the surface-pressure distribution and moisture transport over Antarctica, potentially affecting the contribution of the Antarctic ice sheet to sea level. Here, we combine satellite gravimetry with auxiliary atmospheric data sets to investigate interannual ice-mass changes during the extreme 2015–2016 El Ni{\~{n}}o. Enhanced precipitation during this event contributed positively to the mass of the Antarctic Peninsula and West Antarctic ice sheets, with the mass gain on the peninsula being unprecedented within GRACE's observational record. Over the coastal basins of East Antarctica, the precipitation-driven mass loss observed in recent years was arrested, with pronounced accumulation over Terre Ad{\'{e}}lie dominating this response. Little change was observed over Central Antarctica where, after a brief pause, enhanced mass-loss due to weakened precipitation continued. Overall, precipitation changes over this period were sufficient to temporarily offset Antarctica's usual (approximately 0.4 mm yr−1) contribution to global mean sea level rise.},
author = {Bodart, J.A. and Bingham, R.J.},
doi = {10.1029/2019GL084466},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {dec},
number = {23},
pages = {13862--13871},
title = {{The Impact of the Extreme 2015–2016 El Ni{\~{n}}o on the Mass Balance of the Antarctic Ice Sheet}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019GL084466},
volume = {46},
year = {2019}
}
@article{doi:10.1175/JCLI-D-15-0564.1,
abstract = { AbstractThe Southern Ocean is a critical region for global climate, yet large cloud and solar radiation biases over the Southern Ocean are a long-standing problem in climate models and are poorly understood, leading to biases in simulated sea surface temperatures. This study shows that supercooled liquid clouds are central to understanding and simulating the Southern Ocean environment. A combination of satellite observational data and detailed radiative transfer calculations is used to quantify the impact of cloud phase and cloud vertical structure on the reflected solar radiation in the Southern Hemisphere summer. It is found that clouds with supercooled liquid tops dominate the population of liquid clouds. The observations show that clouds with supercooled liquid tops contribute between 27{\%} and 38{\%} to the total reflected solar radiation between 40° and 70°S, and climate models are found to poorly simulate these clouds. The results quantify the importance of supercooled liquid clouds in the Southern Ocean environment and highlight the need to improve understanding of the physical processes that control these clouds in order to improve their simulation in numerical models. This is not only important for improving the simulation of present-day climate and climate variability, but also relevant for increasing confidence in climate feedback processes and future climate projections. },
author = {Bodas-Salcedo, A and Hill, P G and Furtado, K and Williams, K D and Field, P R and Manners, J C and Hyder, P and Kato, S},
doi = {10.1175/JCLI-D-15-0564.1},
journal = {Journal of Climate},
number = {11},
pages = {4213--4228},
title = {{Large Contribution of Supercooled Liquid Clouds to the Solar Radiation Budget of the Southern Ocean}},
url = {https://doi.org/10.1175/JCLI-D-15-0564.1},
volume = {29},
year = {2016}
}
@article{Boisseson2014,
abstract = {AbstractThe persistent strengthening of the trade winds over the Pacific Ocean over the past 20 years has recently been proposed as a driver for the increase of ocean heat uptake linked to the hiatus in surface global warming. Crucial aspects in this argument are the reliability of the wind signal, usually derived from atmospheric reanalyses, and the ability of models to represent it. This study addresses these two aspects by comparing various observations with reanalyses and model integrations from the European Centre for Medium-Range Weather Forecasts system. We show that the strengthening of trades over the Pacific is a robust feature in several observational data sets as well as in the reanalyses based on full and limited sets of observations. The wind trend is also reproduced in an atmospheric model integration forced by sea surface temperature analysis, a result that opens the doors to further investigation on the nature of the changes.},
annote = {doi: 10.1002/2014GL060257},
author = {Boiss{\'{e}}son, E and Balmaseda, M A and Abdalla, S and K{\"{a}}ll{\'{e}}n, E and Janssen, P A E M},
doi = {10.1002/2014GL060257},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {Tropical Pacific,wind variability},
month = {jun},
number = {12},
pages = {4398--4405},
publisher = {Wiley-Blackwell},
title = {{How robust is the recent strengthening of the Tropical Pacific trade winds?}},
url = {https://doi.org/10.1002/2014GL060257},
volume = {41},
year = {2014}
}
@article{Bonfils2011,
author = {Bonfils, C{\'{e}}line J.W. and Santer, Benjamin D.},
doi = {10.1007/s00382-010-0920-1},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {oct},
number = {7-8},
pages = {1457--1468},
title = {{Investigating the possibility of a human component in various pacific decadal oscillation indices}},
url = {http://link.springer.com/10.1007/s00382-010-0920-1},
volume = {37},
year = {2011}
}
@article{Bonfils,
abstract = {Despite the pervasive impact of drought on human and natural systems, the large-scale mechanisms conducive to regional drying remain poorly understood. Here we use a multivariate approach1,2 to identify two distinct externally forced fingerprints from multiple ensembles of Earth system model simulations. The leading fingerprint, FM1(x), is characterized by global warming, intensified wet–dry patterns3 and progressive large-scale continental aridification, largely driven by multidecadal increases in greenhouse gas (GHG) emissions. The second fingerprint, FM2(x), captures a pronounced interhemispheric temperature contrast4,5, associated meridional shifts in the intertropical convergence zone6–9 and correlated anomalies in precipitation and aridity over California10, the Sahel11,12 and India. FM2(x) exhibits nonlinear temporal behaviour: the intertropical convergence zone moves southwards before 1975 in response to increases in hemispherically asymmetric sulfate aerosol emissions, and it shifts northwards after 1975 due to reduced sulfur dioxide emissions and the GHG-induced warming of Northern Hemisphere landmasses. Both fingerprints are statistically identifiable in observations of joint changes in temperature, rainfall and aridity during 1950–2014. We show that the reliable simulation of these changes requires combined forcing by GHGs, direct and indirect effects of aerosols, and large volcanic eruptions. Our results suggest that GHG-induced aridification may be modulated regionally by future reductions in sulfate aerosol emissions.},
author = {Bonfils, C{\'{e}}line J.W. and Santer, Benjamin D. and Fyfe, John C. and Marvel, Kate and Phillips, Thomas J. and Zimmerman, Susan R.H.},
doi = {10.1038/s41558-020-0821-1},
issn = {17586798},
journal = {Nature Climate Change},
number = {8},
pages = {726--731},
title = {{Human influence on joint changes in temperature, rainfall and continental aridity}},
url = {https://doi.org/10.1038/s41558-020-0821-1},
volume = {10},
year = {2020}
}
@article{Boo2015,
author = {Boo, Kyung-On and Booth, Ben B. B. and Byun, Young-Hwa and Lee, Johan and Cho, ChunHo and Shim, Sungbo and Kim, Kyun-Tae},
doi = {10.1002/2014JD021933},
issn = {2169897X},
journal = {Journal of Geophysical Research: Atmospheres},
month = {jan},
number = {2},
pages = {517--531},
title = {{Influence of aerosols in multidecadal SST variability simulations over the North Pacific}},
url = {http://doi.wiley.com/10.1002/2014JD021933},
volume = {120},
year = {2015}
}
@article{Boos2012,
abstract = {AbstractHere it is shown that almost all models participating in the Coupled Model Intercomparison Project (CMIP) exhibit a common bias in the thermodynamic structure of boreal summer monsoons. The strongest bias lies over South Asia, where the upper-tropospheric temperature maximum is too weak, is shifted southeast of its observed location, and does not extend as far west over Africa as it does in observations. Simulated Asian maxima of surface air moist static energy are also too weak and are located over coastal oceans rather than in their observed continental position. The spatial structure of this bias suggests that it is caused by an overly smoothed representation of topography west of the Tibetan Plateau, which allows dry air from the deserts of western Asia to penetrate the monsoon thermal maximum, suppressing moist convection and cooling the upper troposphere. In a climate model with a decent representation of the thermodynamic state of the Asian monsoon, the qualitative characteristics of this bias can be recreated by truncating topography just west of the Tibetan Plateau. This relatively minor topographic modification also produces a negative anomaly of Indian precipitation of similar sign and amplitude to the CMIP continental Indian monsoon precipitation bias. Furthermore, in simulations of next-century climate warming, this topographic modification reduces the amplitude of the increase in Indian monsoon precipitation. These results confirm the importance of topography west of the Tibetan Plateau for South Asian climate and illustrate the need for careful assessments of the thermodynamic state of model monsoons.},
annote = {doi: 10.1175/JCLI-D-12-00493.1},
author = {Boos, William R and Hurley, John V},
doi = {10.1175/JCLI-D-12-00493.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {oct},
number = {7},
pages = {2279--2287},
publisher = {American Meteorological Society},
title = {{Thermodynamic Bias in the Multimodel Mean Boreal Summer Monsoon}},
url = {https://doi.org/10.1175/JCLI-D-12-00493.1},
volume = {26},
year = {2012}
}
@article{Booth2012,
abstract = {Systematic climate shifts have been linked to multidecadal variability in observed sea surface temperatures in the North Atlantic Ocean. These links are extensive, influencing a range of climate processes such as hurricane activity and African Sahel and Amazonian droughts. The variability is distinct from historical global-mean temperature changes and is commonly attributed to natural ocean oscillations. A number of studies have provided evidence that aerosols can influence long-term changes in sea surface temperatures, but climate models have so far failed to reproduce these interactions and the role of aerosols in decadal variability remains unclear. Here we use a state-of-the-art Earth system climate model to show that aerosol emissions and periods of volcanic activity explain 76 per cent of the simulated multidecadal variance in detrended 1860-2005 North Atlantic sea surface temperatures. After 1950, simulated variability is within observational estimates; our estimates for 1910-1940 capture twice the warming of previous generation models but do not explain the entire observed trend. Other processes, such as ocean circulation, may also have contributed to variability in the early twentieth century. Mechanistically, we find that inclusion of aerosol-cloud microphysical effects, which were included in few previous multimodel ensembles, dominates the magnitude (80 per cent) and the spatial pattern of the total surface aerosol forcing in the North Atlantic. Our findings suggest that anthropogenic aerosol emissions influenced a range of societally important historical climate events such as peaks in hurricane activity and Sahel drought. Decadal-scale model predictions of regional Atlantic climate will probably be improved by incorporating aerosol-cloud microphysical interactions and estimates of future concentrations of aerosols, emissions of which are directly addressable by policy actions.},
author = {Booth, Ben B B and Dunstone, Nick J. and Halloran, Paul R. and Andrews, Timothy and Bellouin, Nicolas},
doi = {10.1038/nature10946},
isbn = {0028-0836},
issn = {00280836},
journal = {Nature},
number = {7393},
pages = {228--232},
pmid = {22498628},
publisher = {Nature Publishing Group},
title = {{Aerosols implicated as a prime driver of twentieth-century North Atlantic climate variability}},
url = {http://dx.doi.org/10.1038/nature10946},
volume = {484},
year = {2012}
}
@article{Bopp2013,
abstract = {{\textless}p{\textgreater}{\textless}p{\textgreater}{\textless}strong{\textgreater}Abstract.{\textless}/strong{\textgreater} Ocean ecosystems are increasingly stressed by human-induced changes of their physical, chemical and biological environment. Among these changes, warming, acidification, deoxygenation and changes in primary productivity by marine phytoplankton can be considered as four of the major stressors of open ocean ecosystems. Due to rising atmospheric CO{\textless}sub{\textgreater}2{\textless}/sub{\textgreater} in the coming decades, these changes will be amplified. Here, we use the most recent simulations performed in the framework of the Coupled Model Intercomparison Project 5 to assess how these stressors may evolve over the course of the 21st century. The 10 Earth system models used here project similar trends in ocean warming, acidification, deoxygenation and reduced primary productivity for each of the IPCC's representative concentration pathways (RCPs) over the 21st century. For the "business-as-usual" scenario RCP8.5, the model-mean changes in the 2090s (compared to the 1990s) for sea surface temperature, sea surface pH, global O{\textless}sub{\textgreater}2{\textless}/sub{\textgreater} content and integrated primary productivity amount to {\&}plus;2.73 (±0.72) °C, −0.33 (±0.003) pH unit, −3.45 (±0.44){\%} and −8.6 (±7.9){\%}, respectively. For the high mitigation scenario RCP2.6, corresponding changes are +0.71 (±0.45) °C, −0.07 (±0.001) pH unit, −1.81 (±0.31){\%} and −2.0 (±4.1){\%}, respectively, illustrating the effectiveness of extreme mitigation strategies. Although these stressors operate globally, they display distinct regional patterns and thus do not change coincidentally. Large decreases in O{\textless}sub{\textgreater}2{\textless}/sub{\textgreater} and in pH are simulated in global ocean intermediate and mode waters, whereas large reductions in primary production are simulated in the tropics and in the North Atlantic. Although temperature and pH projections are robust across models, the same does not hold for projections of subsurface O{\textless}sub{\textgreater}2{\textless}/sub{\textgreater} concentrations in the tropics and global and regional changes in net primary productivity. These high uncertainties in projections of primary productivity and subsurface oxygen prompt us to continue inter-model comparisons to understand these model differences, while calling for caution when using the CMIP5 models to force regional impact models.{\textless}/p{\textgreater}{\textless}/p{\textgreater}},
author = {Bopp, L. and Resplandy, L. and Orr, J. C. and Doney, S. C. and Dunne, J. P. and Gehlen, M. and Halloran, P. and Heinze, C. and Ilyina, T. and S{\'{e}}f{\'{e}}rian, R. and Tjiputra, J. and Vichi, M.},
doi = {10.5194/bg-10-6225-2013},
issn = {1726-4189},
journal = {Biogeosciences},
month = {oct},
number = {10},
pages = {6225--6245},
title = {{Multiple stressors of ocean ecosystems in the 21st century: projections with CMIP5 models}},
url = {https://www.biogeosciences.net/10/6225/2013/},
volume = {10},
year = {2013}
}
@article{Boucher2020,
author = {Boucher, Olivier and Servonnat, J{\'{e}}r{\^{o}}me and Albright, Anna Lea and Aumont, Olivier and Balkanski, Yves and Bastrikov, Vladislav and Bekki, Slimane and Bonnet, R{\'{e}}my and Bony, Sandrine and Bopp, Laurent and Braconnot, Pascale and Brockmann, Patrick and Cadule, Patricia and Caubel, Arnaud and Cheruy, Frederique and Codron, Francis and Cozic, Anne and Cugnet, David and D'Andrea, Fabio and Davini, Paolo and Lavergne, Casimir and Denvil, S{\'{e}}bastien and Deshayes, Julie and Devilliers, Marion and Ducharne, Agnes and Dufresne, Jean‐Louis and Dupont, Eliott and {\'{E}}th{\'{e}}, Christian and Fairhead, Laurent and Falletti, Lola and Flavoni, Simona and Foujols, Marie‐Alice and Gardoll, S{\'{e}}bastien and Gastineau, Guillaume and Ghattas, Josefine and Grandpeix, Jean‐Yves and Guenet, Bertrand and {Guez, Lionel}, E. and Guilyardi, Eric and Guimberteau, Matthieu and Hauglustaine, Didier and Hourdin, Fr{\'{e}}d{\'{e}}ric and Idelkadi, Abderrahmane and Joussaume, Sylvie and Kageyama, Masa and Khodri, Myriam and Krinner, Gerhard and Lebas, Nicolas and Levavasseur, Guillaume and L{\'{e}}vy, Claire and Li, Laurent and Lott, Fran{\c{c}}ois and Lurton, Thibaut and Luyssaert, Sebastiaan and Madec, Gurvan and Madeleine, Jean‐Baptiste and Maignan, Fabienne and Marchand, Marion and Marti, Olivier and Mellul, Lidia and Meurdesoif, Yann and Mignot, Juliette and Musat, Ionela and Ottl{\'{e}}, Catherine and Peylin, Philippe and Planton, Yann and Polcher, Jan and Rio, Catherine and Rochetin, Nicolas and Rousset, Cl{\'{e}}ment and Sepulchre, Pierre and Sima, Adriana and Swingedouw, Didier and Thi{\'{e}}blemont, R{\'{e}}mi and Traore, Abdoul Khadre and Vancoppenolle, Martin and Vial, Jessica and Vialard, J{\'{e}}r{\^{o}}me and Viovy, Nicolas and Vuichard, Nicolas},
doi = {10.1029/2019MS002010},
issn = {1942-2466},
journal = {Journal of Advances in Modeling Earth Systems},
month = {jul},
number = {7},
pages = {e2019MS002010},
title = {{Presentation and Evaluation of the IPSL‐CM6A‐LR Climate Model}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019MS002010},
volume = {12},
year = {2020}
}
@article{Bova2021,
abstract = {Proxy reconstructions from marine sediment cores indicate peak temperatures in the first half of the last and current interglacial periods (the thermal maxima of the Holocene epoch, 10,000 to 6,000 years ago, and the last interglacial period, 128,000 to 123,000 years ago) that arguably exceed modern warmth1–3. By contrast, climate models simulate monotonic warming throughout both periods4–7. This substantial model–data discrepancy undermines confidence in both proxy reconstructions and climate models, and inhibits a mechanistic understanding of recent climate change. Here we show that previous global reconstructions of temperature in the Holocene1–3 and the last interglacial period8 reflect the evolution of seasonal, rather than annual, temperatures and we develop a method of transforming them to mean annual temperatures. We further demonstrate that global mean annual sea surface temperatures have been steadily increasing since the start of the Holocene (about 12,000 years ago), first in response to retreating ice sheets (12 to 6.5 thousand years ago), and then as a result of rising greenhouse gas concentrations (0.25 ± 0.21 degrees Celsius over the past 6,500 years or so). However, mean annual temperatures during the last interglacial period were stable and warmer than estimates of temperatures during the Holocene, and we attribute this to the near-constant greenhouse gas levels and the reduced extent of ice sheets. We therefore argue that the climate of the Holocene differed from that of the last interglacial period in two ways: first, larger remnant glacial ice sheets acted to cool the early Holocene, and second, rising greenhouse gas levels in the late Holocene warmed the planet. Furthermore, our reconstructions demonstrate that the modern global temperature has exceeded annual levels over the past 12,000 years and probably approaches the warmth of the last interglacial period (128,000 to 115,000 years ago).},
author = {Bova, Samantha and Rosenthal, Yair and Liu, Zhengyu and Godad, Shital P and Yan, Mi},
doi = {10.1038/s41586-020-03155-x},
issn = {1476-4687},
journal = {Nature},
number = {7843},
pages = {548--553},
title = {{Seasonal origin of the thermal maxima at the Holocene and the last interglacial}},
url = {https://doi.org/10.1038/s41586-020-03155-x},
volume = {589},
year = {2021}
}
@article{Bracegirdle2018,
author = {Bracegirdle, Thomas J. and Lu, Hua and Eade, Rosie and Woollings, Tim},
doi = {10.1029/2018GL078965},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {jul},
number = {14},
pages = {7204--7212},
title = {{Do CMIP5 Models Reproduce Observed Low‐Frequency North Atlantic Jet Variability?}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GL078965},
volume = {45},
year = {2018}
}
@article{doi:10.1029/2019EA001065,
abstract = {Abstract One of the major globally relevant systematic biases in previous generations of climate models has been an equatorward bias in the latitude of the Southern Hemisphere (SH) mid-latitude tropospheric eddy driven westerly jet. The far-reaching implications of this for Southern Ocean heat and carbon uptake and Antarctic land and sea ice are key reasons why addressing this bias is a high priority. It is therefore of primary importance to evaluate the representation of the SH westerly jet in the latest generation of global climate and earth system models that comprise the Coupled Model Intercomparison Project Phase 6 (CMIP6). In this paper we assess the representation of major indices of SH extratropical atmospheric circulation in CMIP6 by comparison against both observations and the previous generation of CMIP5 models. Indices assessed are the latitude and speed of the westerly jet, variability of the Southern Annular Mode (SAM), and representation of the Amundsen Sea Low (ASL). These are calculated from the historical forcing simulations of both CMIP5 and CMIP6 for time periods matching available observational and reanalysis data sets. From the 39 CMIP6 models available at the time of writing there is an overall reduction in the equatorward bias of the annual mean westerly jet from 1.9° in CMIP5 to 0.4° in CMIP6 and from a seasonal perspective the reduction is clearest in austral spring and summer. This is accompanied by a halving of the bias of SAM decorrelation timescales compared to CMIP5. However, no such overall improvements are evident for the ASL.},
annote = {e2019EA001065 2019EA001065},
author = {Bracegirdle, T J and Holmes, C R and Hosking, J S and Marshall, G J and Osman, M and Patterson, M and Rackow, T},
doi = {10.1029/2019EA001065},
journal = {Earth and Space Science},
keywords = {Amundsen Sea Low,Antarctic,CMIP5,CMIP6,Southern Ocean,westerly jet},
number = {6},
pages = {e2019EA001065},
title = {{Improvements in Circumpolar Southern Hemisphere Extratropical Atmospheric Circulation in CMIP6 Compared to CMIP5}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019EA001065},
volume = {7},
year = {2020}
}
@article{Breeden2016,
abstract = {Abstract. The North Atlantic is the most intense region of ocean CO2 uptake in term of units per area. Here, we investigate multidecadal timescale variability of the partial pressure of CO2 (pCO2) that is due to the natural carbon cycle, using a regional model forced with realistic climate and preindustrial atmospheric pCO2 for 1948–2009. Large-scale patterns of natural pCO2 variability are primarily associated with basin-averaged sea surface temperature (SST) that, in turn, is composed of two parts: the Atlantic Multidecadal Oscillation (AMO) and a long-term positive SST trend. The North Atlantic Oscillation (NAO) drives a secondary mode of variability. For the primary mode, positive AMO and the SST trend modify pCO2 with different mechanisms and spatial patterns. Positive AMO is also associated with a significant reduction in dissolved inorganic carbon (DIC) in the subpolar gyre, due primarily to reduced vertical mixing; the net impact of positive AMO is to reduce pCO2 in the subpolar gyre. Through direct impacts on SST, the net effect of positive AMO is to increase pCO2 in the subtropical gyre. From 1980 to present, long-term SST warming has amplified AMO impacts on pCO2.},
author = {Breeden, Melissa L. and McKinley, Galen A.},
doi = {10.5194/bg-13-3387-2016},
issn = {1726-4189},
journal = {Biogeosciences},
month = {jun},
number = {11},
pages = {3387--3396},
title = {{Climate impacts on multidecadal pCO2 variability in the North Atlantic: 1948–2009}},
url = {https://www.biogeosciences.net/13/3387/2016/},
volume = {13},
year = {2016}
}
@article{Breitburg2018,
abstract = {Oxygen is fundamental to life. Not only is it essential for the survival of individual animals, but it regulates global cycles of major nutrients and carbon. The oxygen content of the open ocean and coastal waters has been declining for at least the past half-century, largely because of human activities that have increased global temperatures and nutrients discharged to coastal waters. These changes have accelerated consumption of oxygen by microbial respiration, reduced solubility of oxygen in water, and reduced the rate of oxygen resupply from the atmosphere to the ocean interior, with a wide range of biological and ecological consequences. Further research is needed to understand and predict long-term, global- and regional-scale oxygen changes and their effects on marine and estuarine fisheries and ecosystems.},
author = {Breitburg, Denise and Levin, Lisa A and Oschlies, Andreas and Gr{\'{e}}goire, Marilaure and Chavez, Francisco P and Conley, Daniel J and Gar{\c{c}}on, V{\'{e}}ronique and Gilbert, Denis and Guti{\'{e}}rrez, Dimitri and Isensee, Kirsten and Jacinto, Gil S and Limburg, Karin E and Montes, Ivonne and Naqvi, S W A and Pitcher, Grant C and Rabalais, Nancy N and Roman, Michael R and Rose, Kenneth A and Seibel, Brad A and Telszewski, Maciej and Yasuhara, Moriaki and Zhang, Jing},
doi = {10.1126/science.aam7240},
issn = {1095-9203},
journal = {Science},
month = {jan},
number = {6371},
pages = {eaam7240},
pmid = {29301986},
publisher = {American Association for the Advancement of Science},
title = {{Declining oxygen in the global ocean and coastal waters.}},
url = {http://www.ncbi.nlm.nih.gov/pubmed/29301986},
volume = {359},
year = {2018}
}
@article{Brierley2020,
abstract = {Abstract. The mid-Holocene (6000 years ago) is a standard time period for the evaluation of the simulated response of global climate models using palaeoclimate reconstructions. The latest mid-Holocene simulations are a palaeoclimate entry card for the Palaeoclimate Model Intercomparison Project (PMIP4) component of the current phase of the Coupled Model Intercomparison Project (CMIP6) – hereafter referred to as PMIP4-CMIP6. Here we provide an initial analysis and evaluation of the results of the experiment for the mid-Holocene. We show that state-of-the-art models produce climate changes that are broadly consistent with theory and observations, including increased summer warming of the Northern Hemisphere and associated shifts in tropical rainfall. Many features of the PMIP4-CMIP6 simulations were present in the previous generation (PMIP3-CMIP5) of simulations. The PMIP4-CMIP6 ensemble for the mid-Holocene has a global mean temperature change of −0.3 K, which is −0.2 K cooler than the PMIP3-CMIP5 simulations predominantly as a result of the prescription of realistic greenhouse gas concentrations in PMIP4-CMIP6. Biases in the magnitude and the sign of regional responses identified in PMIP3-CMIP5, such as the amplification of the northern African monsoon, precipitation changes over Europe, and simulated aridity in mid-Eurasia, are still present in the PMIP4-CMIP6 simulations. Despite these issues, PMIP4-CMIP6 and the mid-Holocene provide an opportunity both for quantitative evaluation and derivation of emergent constraints on the hydrological cycle, feedback strength, and potentially climate sensitivity.},
author = {Brierley, Chris M and Zhao, Anni and Harrison, Sandy P. and Braconnot, Pascale and Williams, Charles J. R. and Thornalley, David J R and Shi, Xiaoxu and Peterschmitt, Jean-Yves and Ohgaito, Rumi and Kaufman, Darrell S. and Kageyama, Masa and Hargreaves, Julia C. and Erb, Michael P and Emile-Geay, Julien and D'Agostino, Roberta and Chandan, Deepak and Carr{\'{e}}, Matthieu and Bartlein, Partrick J and Zheng, Weipeng and Zhang, Zhongshi and Zhang, Qiong and Yang, Hu and Volodin, Evgeny M. and Tomas, Robert A. and Routson, Cody and Peltier, W. Richard and Otto-Bliesner, Bette and Morozova, Polina A and McKay, Nicholas P. and Lohmann, Gerrit and Legrande, Allegra N. and Guo, Chuncheng and Cao, Jian and Brady, Esther and Annan, James D. and Abe-Ouchi, Ayako},
doi = {10.5194/cp-16-1847-2020},
issn = {1814-9332},
journal = {Climate of the Past},
month = {oct},
number = {5},
pages = {1847--1872},
title = {{Large-scale features and evaluation of the PMIP4-CMIP6 midHolocene simulations}},
url = {https://cp.copernicus.org/articles/16/1847/2020/},
volume = {16},
year = {2020}
}
@article{cp-2017-145,
author = {Brierley, Chris M. and Wainer, Ilana},
doi = {10.5194/cp-14-1377-2018},
issn = {1814-9332},
journal = {Climate of the Past},
month = {oct},
number = {10},
pages = {1377--1390},
title = {{Inter-annual variability in the tropical Atlantic from the Last Glacial Maximum into future climate projections simulated by CMIP5/PMIP3}},
url = {https://cp.copernicus.org/articles/14/1377/2018/},
volume = {14},
year = {2018}
}
@article{Bronselaer2018,
abstract = {Meltwater from the Antarctic Ice Sheet is projected to cause up to one metre of sea-level rise by 2100 under the highest greenhouse gas concentration trajectory (RCP8.5) considered by the Intergovernmental Panel on Climate Change (IPCC). However, the effects of meltwater from the ice sheets and ice shelves of Antarctica are not included in the widely used CMIP5 climate models, which introduces bias into IPCC climate projections. Here we assess a large ensemble simulation of the CMIP5 model ‘GFDL ESM2M' that accounts for RCP8.5-projected Antarctic Ice Sheet meltwater. We find that, relative to the standard RCP8.5 scenario, accounting for meltwater delays the exceedance of the maximum global-mean atmospheric warming targets of 1.5 and 2 degrees Celsius by more than a decade, enhances drying of the Southern Hemisphere and reduces drying of the Northern Hemisphere, increases the formation of Antarctic sea ice (consistent with recent observations of increasing Antarctic sea-ice area) and warms the subsurface ocean around the Antarctic coast. Moreover, the meltwater-induced subsurface ocean warming could lead to further ice-sheet and ice-shelf melting through a positive feedback mechanism, highlighting the importance of including meltwater effects in simulations of future climate.},
author = {Bronselaer, Ben and Winton, Michael and Griffies, Stephen M and Hurlin, William J and Rodgers, Keith B and Sergienko, Olga V and Stouffer, Ronald J and Russell, Joellen L},
doi = {10.1038/s41586-018-0712-z},
issn = {1476-4687},
journal = {Nature},
number = {7734},
pages = {53--58},
title = {{Change in future climate due to Antarctic meltwater}},
volume = {564},
year = {2018}
}
@article{Brown2016a,
abstract = {{\textcopyright}2016. American Geophysical Union. All Rights Reserved. Unforced variability in global mean surface air temperature can obscure or exaggerate global warming on interdecadal time scales; thus, understanding both the magnitude and generating mechanisms of such variability is of critical importance for both attribution studies as well as decadal climate prediction. Coupled atmosphere-ocean general circulation models (climate models) simulate a wide range of magnitudes of unforced interdecadal variability in global mean surface air temperature (UITglobal), hampering efforts to quantify the influence of UITglobalon contemporary global temperature trends. Recently, a preliminary consensus has emerged that unforced interdecadal variability in local surface temperatures (UITlocal) over the tropical Pacific Ocean is particularly influential on UITglobal. Therefore, a reasonable hypothesis might be that the large spread in the magnitude of UITglobalacross climate models can be explained by the spread in the magnitude of simulated tropical Pacific UITlocal. Here we show that this hypothesis is mostly false. Instead, the spread in the magnitude of UITglobalis linked much more strongly to the spread in the magnitude of UITlocalover high-latitude regions characterized by significant variability in oceanic convection, sea ice concentration, and energy flux at both the surface and the top of the atmosphere. Thus, efforts to constrain the climate model produced range of UITglobalmagnitude would be best served by focusing on the simulation of air-sea interaction at high latitudes.},
author = {Brown, P.T. and Li, W. and Jiang, J.H. and Su, H.},
doi = {10.1002/2016GL071442},
journal = {Geophysical Research Letters},
number = {24},
pages = {12,543--12,549},
title = {{Spread in the magnitude of climate model interdecadal global temperature variability traced to disagreements over high-latitude oceans}},
volume = {43},
year = {2016}
}
@article{Brown2016,
author = {Brown, Patrick T. and Lozier, M. Susan and Zhang, Rong and Li, Wenhong},
doi = {10.1002/2016GL068303},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {apr},
number = {8},
pages = {3955--3963},
title = {{The necessity of cloud feedback for a basin-scale Atlantic Multidecadal Oscillation}},
url = {http://doi.wiley.com/10.1002/2016GL068303},
volume = {43},
year = {2016}
}
@article{Brown2015,
author = {Brown, Patrick T. and Li, Wenhong and Xie, Shang-Ping},
doi = {10.1002/2014JD022576},
issn = {2169897X},
journal = {Journal of Geophysical Research: Atmospheres},
month = {jan},
number = {2},
pages = {480--494},
title = {{Regions of significant influence on unforced global mean surface air temperature variability in climate models}},
url = {http://doi.wiley.com/10.1002/2014JD022576},
volume = {120},
year = {2015}
}
@article{cp-16-1777-2020,
author = {Brown, J R and Brierley, C M and An, S.-I. and Guarino, M.-V. and Stevenson, S and Williams, C J R and Zhang, Q and Zhao, A and Abe-Ouchi, A and Braconnot, P and Brady, E C and Chandan, D and D'Agostino, R and Guo, C and LeGrande, A N and Lohmann, G and Morozova, P A and Ohgaito, R and O'ishi, R and Otto-Bliesner, B L and Peltier, W R and Shi, X and Sime, L and Volodin, E M and Zhang, Z and Zheng, W},
doi = {10.5194/cp-16-1777-2020},
journal = {Climate of the Past},
number = {5},
pages = {1777--1805},
title = {{Comparison of past and future simulations of ENSO in CMIP5/PMIP3 and CMIP6/PMIP4 models}},
url = {https://cp.copernicus.org/articles/16/1777/2020/},
volume = {16},
year = {2020}
}
@article{Brown2017f,
abstract = {Natural unforced variability in global mean surface air temperature (GMST) can mask or exaggerate human-caused global warming, and thus a complete understanding of this variability is highly desirable. Significant progress has been made in elucidating the magnitude and physical origins of present-day unforced GMST variability, but it has remained unclear how such variability may change as the climate warms. Here we present modelling evidence that indicates that the magnitude of low-frequency GMST variability is likely to decline in a warmer climate and that its generating mechanisms may be fundamentally altered. In particular, a warmer climate results in lower albedo at high latitudes, which yields a weaker albedo feedback on unforced GMST variability. These results imply that unforced GMST variability is dependent on the background climatological conditions, and thus climate model control simulations run under perpetual pre-industrial conditions may have only limited relevance for understanding the unforced GMST variability of the future.},
author = {Brown, Patrick T. and Ming, Yi and Li, Wenhong and Hill, Spencer A.},
doi = {10.1038/nclimate3381},
issn = {17586798},
journal = {Nature Climate Change},
number = {10},
title = {{Change in the magnitude and mechanisms of global temperature variability with warming}},
volume = {7},
year = {2017}
}
@article{Brutel-Vuilmet2013,
abstract = {Abstract. The 20th century seasonal Northern Hemisphere (NH) land snow cover as simulated by available CMIP5 model output is compared to observations. On average, the models reproduce the observed snow cover extent very well, but the significant trend towards a reduced spring snow cover extent over the 1979–2005 period is underestimated (observed: (−3.4 {\&}pm; 1.1){\%} per decade; simulated: (−1.0 {\&}pm; 0.3){\%} per decade). We show that this is linked to the simulated Northern Hemisphere extratropical spring land warming trend over the same period, which is also underestimated, although the models, on average, correctly capture the observed global warming trend. There is a good linear correlation between the extent of hemispheric seasonal spring snow cover and boreal large-scale spring surface air temperature in the models, supported by available observations. This relationship also persists in the future and is independent of the particular anthropogenic climate forcing scenario. Similarly, the simulated linear relationship between the hemispheric seasonal spring snow cover extent and global mean annual mean surface air temperature is stable in time. However, the slope of this relationship is underestimated at present (observed: (−11.8 {\&}pm; 2.7){\%} °C−1; simulated: (−5.1 {\&}pm; 3.0){\%} °C−1) because the trend towards lower snow cover extent is underestimated, while the recent global warming trend is correctly represented.},
address = {BAHNHOFSALLEE 1E},
author = {Brutel-Vuilmet, C and M{\'{e}}n{\'{e}}goz, M. and Krinner, G},
doi = {10.5194/tc-7-67-2013},
issn = {1994-0424},
journal = {The Cryosphere},
month = {jan},
number = {1},
pages = {67--80},
publisher = {COPERNICUS GESELLSCHAFT MBH},
title = {{An analysis of present and future seasonal Northern Hemisphere land snow cover simulated by CMIP5 coupled climate models}},
url = {https://tc.copernicus.org/articles/7/67/2013/},
volume = {7},
year = {2013}
}
@article{Bryden2020,
abstract = {Northward ocean heat transport at 268N in the Atlantic Ocean has been measured since 2004. The ocean heat transport is large—approximately 1.25 PW, and on interannual time scales it exhibits surprisingly large temporal variability. There has been a long-term reduction in ocean heat transport of 0.17 PW from 1.32 PW before 2009 to 1.15 PW after 2009 (2009–16) on an annual average basis associated with a 2.5-Sv (1 Sv [ 106 m3 s21) drop in the Atlantic meridional overturning circulation (AMOC). The reduction in the AMOC has cooled and freshened the upper ocean north of 268N over an area following the offshore edge of the Gulf Stream/North Atlantic Current from the Bahamas to Iceland. Cooling peaks south of Iceland where surface temperatures are as much as 28C cooler in 2016 than they were in 2008. Heat uptake by the atmosphere appears to have been affected particularly along the path of the North Atlantic Current. For the reduction in ocean heat transport, changes in ocean heat content account for about one-quarter of the long-term reduction in ocean heat transport while reduced heat uptake by the atmosphere appears to account for the remainder of the change in ocean heat transport.},
address = {Boston MA, USA},
author = {Bryden, Harry L. and Johns, William E. and King, Brian A. and McCarthy, Gerard and McDonagh, Elaine L. and Moat, Ben I. and Smeed, David A.},
doi = {10.1175/JCLI-D-19-0323.1},
issn = {08948755},
journal = {Journal of Climate},
language = {English},
number = {5},
pages = {1677--1689},
publisher = {American Meteorological Society},
title = {{Reduction in ocean heat transport at 26°N since 2008 cools the eastern subpolar gyre of the North Atlantic Ocean}},
url = {https://journals.ametsoc.org/view/journals/clim/33/5/jcli-d-19-0323.1.xml},
volume = {33},
year = {2020}
}
@article{Buckley2016,
abstract = {Abstract This is a review about the Atlantic Meridional Overturning Circulation (AMOC), its mean structure, temporal variability, controlling mechanisms, and role in the coupled climate system. The AMOC plays a central role in climate through its heat and freshwater transports. Northward ocean heat transport achieved by the AMOC is responsible for the relative warmth of the Northern Hemisphere compared to the Southern Hemisphere and is thought to play a role in setting the mean position of the Intertropical Convergence Zone north of the equator. The AMOC is a key means by which heat anomalies are sequestered into the ocean's interior and thus modulates the trajectory of climate change. Fluctuations in the AMOC have been linked to low-frequency variability of Atlantic sea surface temperatures with a host of implications for climate variability over surrounding landmasses. On intra-annual timescales, variability in AMOC is large and primarily reflects the response to local wind forcing; meridional coherence of anomalies is limited to that of the wind field. On interannual to decadal timescales, AMOC changes are primarily geostrophic and related to buoyancy anomalies on the western boundary. A pacemaker region for decadal AMOC changes is located in a western ?transition zone? along the boundary between the subtropical and subpolar gyres. Decadal AMOC anomalies are communicated meridionally from this region. AMOC observations, as well as the expanded ocean observational network provided by the Argo array and satellite altimetry, are inspiring efforts to develop decadal predictability systems using coupled atmosphere-ocean models initialized by ocean data.},
annote = {doi: 10.1002/2015RG000493},
author = {Buckley, Martha W and Marshall, John},
doi = {10.1002/2015RG000493},
issn = {8755-1209},
journal = {Reviews of Geophysics},
keywords = {Atlantic Meridional Overturning Circulation,climate variability},
month = {mar},
number = {1},
pages = {5--63},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Observations, inferences, and mechanisms of the Atlantic Meridional Overturning Circulation: A review}},
url = {https://doi.org/10.1002/2015RG000493},
volume = {54},
year = {2016}
}
@article{Buermann2018,
abstract = {Climate change is shifting the phenological cycles of plants1, thereby altering the functioning of ecosystems, which in turn induces feedbacks to the climate system2. In northern (north of 30° N) ecosystems, warmer springs lead generally to an earlier onset of the growing season3,4 and increased ecosystem productivity early in the season5. In situ6 and regional7–9 studies also provide evidence for lagged effects of spring warmth on plant productivity during the subsequent summer and autumn. However, our current understanding of these lagged effects, including their direction (beneficial or adverse) and geographic distribution, is still very limited. Here we analyse satellite, field-based and modelled data for the period 1982–2011 and show that there are widespread and contrasting lagged productivity responses to spring warmth across northern ecosystems. On the basis of the observational data, we find that roughly 15 per cent of the total study area of about 41 million square kilometres exhibits adverse lagged effects and that roughly 5 per cent of the total study area exhibits beneficial lagged effects. By contrast, current-generation terrestrial carbon-cycle models predict much lower areal fractions of adverse lagged effects (ranging from 1 to 14 per cent) and much higher areal fractions of beneficial lagged effects (ranging from 9 to 54 per cent). We find that elevation and seasonal precipitation patterns largely dictate the geographic pattern and direction of the lagged effects. Inadequate consideration in current models of the effects of the seasonal build-up of water stress on seasonal vegetation growth may therefore be able to explain the differences that we found between our observation-constrained estimates and the model-constrained estimates of lagged effects associated with spring warming. Overall, our results suggest that for many northern ecosystems the benefits of warmer springs on growing-season ecosystem productivity are effectively compensated for by the accumulation of seasonal water deficits, despite the fact that northern ecosystems are thought to be largely temperature- and radiation-limited10.},
author = {Buermann, Wolfgang and Forkel, Matthias and O'Sullivan, Michael and Sitch, Stephen and Friedlingstein, Pierre and Haverd, Vanessa and Jain, Atul K. and Kato, Etsushi and Kautz, Markus and Lienert, Sebastian and Lombardozzi, Danica and Nabel, Julia E.M.S. and Tian, Hanqin and Wiltshire, Andrew J. and Zhu, Dan and Smith, William K. and Richardson, Andrew D.},
doi = {10.1038/s41586-018-0555-7},
issn = {14764687},
journal = {Nature},
number = {7725},
pages = {110--114},
title = {{Widespread seasonal compensation effects of spring warming on northern plant productivity}},
volume = {562},
year = {2018}
}
@article{butler2015defining,
abstract = {Sudden stratospheric warmings (SSWs) are large, rapid temperature rises in the winter polar stratosphere, occurring predominantly in the Northern Hemisphere. Major SSWs are also associated with a reversal of the climatological westerly zonal-mean zonal winds. Circulation anomalies associated with SSWs can descend into the troposphere with substantial surface weather impacts, such as wintertime extreme cold air outbreaks. After their discovery in 1952, SSWs were classified by the World Meteorological Organization. An examination of literature suggests that a single, original reference for an exact definition of SSWs is elusive, but in many references a definition involves the reversal of the meridional temperature gradient and, for major warmings, the reversal of the zonal circulation poleward of 60° latitude at 10 hPa.},
author = {Butler, Amy H and Seidel, Dian J and Hardiman, Steven C and Butchart, Neal and Birner, Thomas and Match, Aaron},
doi = {10.1175/BAMS-D-13-00173.1},
issn = {0003-0007},
journal = {Bulletin of the American Meteorological Society},
month = {nov},
number = {11},
pages = {1913--1928},
title = {{Defining Sudden Stratospheric Warmings}},
url = {https://journals.ametsoc.org/doi/10.1175/BAMS-D-13-00173.1},
volume = {96},
year = {2015}
}
@article{Butler2016,
author = {Butler, Amy H. and Arribas, Alberto and Athanassiadou, Maria and Baehr, Johanna and Calvo, Natalia and Charlton-Perez, Andrew and D{\'{e}}qu{\'{e}}, Michel and Domeisen, Daniela I. V. and Fr{\"{o}}hlich, Kristina and Hendon, Harry and Imada, Yukiko and Ishii, Masayoshi and Iza, Maddalen and Karpechko, Alexey Yu. and Kumar, Arun and MacLachlan, Craig and Merryfield, William J. and M{\"{u}}ller, Wolfgang A. and O'Neill, Alan and Scaife, Adam A. and Scinocca, John and Sigmond, Michael and Stockdale, Timothy N. and Yasuda, Tamaki},
doi = {10.1002/qj.2743},
issn = {00359009},
journal = {Quarterly Journal of the Royal Meteorological Society},
month = {apr},
number = {696},
pages = {1413--1427},
title = {{The Climate-system Historical Forecast Project: do stratosphere-resolving models make better seasonal climate predictions in boreal winter?}},
url = {http://doi.wiley.com/10.1002/qj.2743},
volume = {142},
year = {2016}
}
@article{Byrne2018c,
abstract = {In recent decades, the land surface has warmed substantially more than the ocean surface, and relative humidity has fallen over land. Amplified warming and declining relative humidity over land are also dominant features of future climate projections, with implications for climate-change impacts. An emerging body of research has shown how constraints from atmospheric dynamics and moisture budgets are important for projected future land–ocean contrasts, but these ideas have not been used to investigate temperature and humidity records over recent decades. Here we show how both the temperature and humidity changes observed over land between 1979 and 2016 are linked to warming over neighboring oceans. A simple analytical theory, based on atmospheric dynamics and moisture transport, predicts equal changes in moist static energy over land and ocean and equal fractional changes in specific humidity over land and ocean. The theory is shown to be consistent with the observed trends in land temperature and humidity given the warming over ocean. Amplified land warming is needed for the increase in moist static energy over drier land to match that over ocean, and land relative humidity decreases because land specific humidity is linked via moisture transport to the weaker warming over ocean. However, there is considerable variability about the best-fit trend in land relative humidity that requires further investigation and which may be related to factors such as changes in atmospheric circulations and land-surface properties.},
author = {Byrne, Michael P. and O'Gorman, Paul A.},
doi = {10.1073/pnas.1722312115},
issn = {0027-8424},
journal = {Proceedings of the National Academy of Sciences},
month = {may},
number = {19},
pages = {4863--4868},
title = {{Trends in continental temperature and humidity directly linked to ocean warming}},
url = {http://www.pnas.org/lookup/doi/10.1073/pnas.1722312115},
volume = {115},
year = {2018}
}
@article{Cabre2015,
abstract = {{\textless}p{\textgreater}{\textless}p{\textgreater}{\textless}strong{\textgreater}Abstract.{\textless}/strong{\textgreater} We analyse simulations of the Pacific Ocean oxygen minimum zones (OMZs) from 11 Earth system model contributions to the Coupled Model Intercomparison Project Phase 5, focusing on the mean state and climate change projections. The simulations tend to overestimate the volume of the OMZs, especially in the tropics and Southern Hemisphere. Compared to observations, five models introduce incorrect meridional asymmetries in the distribution of oxygen including larger southern OMZ and weaker northern OMZ, due to interhemispheric biases in intermediate water mass ventilation. Seven models show too deep an extent of the tropical hypoxia compared to observations, stemming from a deficient equatorial ventilation in the upper ocean, combined with too large a biologically driven downward flux of particulate organic carbon at depth, caused by particle export from the euphotic layer that is too high and remineralization in the upper ocean that is too weak. {\textless}br{\textgreater}{\textless}br{\textgreater} At interannual timescales, the dynamics of oxygen in the eastern tropical Pacific OMZ is dominated by biological consumption and linked to natural variability in the Walker circulation. However, under the climate change scenario RCP8.5, all simulations yield small and discrepant changes in oxygen concentration at mid depths in the tropical Pacific by the end of the 21st century due to an almost perfect compensation between warming-related decrease in oxygen saturation and decrease in biological oxygen utilization. Climate change projections are at odds with recent observations that show decreasing oxygen levels at mid depths in the tropical Pacific. {\textless}br{\textgreater}{\textless}br{\textgreater} Out of the OMZs, all the CMIP5 models predict a decrease of oxygen over most of the surface and deep ocean at low latitudes and over all depths at high latitudes due to an overall slow-down of ventilation and increased temperature.{\textless}/p{\textgreater}{\textless}/p{\textgreater}},
author = {Cabr{\'{e}}, A. and Marinov, I. and Bernardello, R. and Bianchi, D.},
doi = {10.5194/bg-12-5429-2015},
issn = {1726-4189},
journal = {Biogeosciences},
month = {sep},
number = {18},
pages = {5429--5454},
title = {{Oxygen minimum zones in the tropical Pacific across CMIP5 models: mean state differences and climate change trends}},
url = {https://www.biogeosciences.net/12/5429/2015/},
volume = {12},
year = {2015}
}
@article{Caesar2018,
abstract = {The Atlantic meridional overturning circulation (AMOC)—a system of ocean currents in the North Atlantic—has a major impact on climate, yet its evolution during the industrial era is poorly known owing to a lack of direct current measurements. Here we provide evidence for a weakening of the AMOC by about 3 ± 1 sverdrups (around 15 per cent) since the mid-twentieth century. This weakening is revealed by a characteristic spatial and seasonal sea-surface temperature ‘fingerprint'—consisting of a pattern of cooling in the subpolar Atlantic Ocean and warming in the Gulf Stream region—and is calibrated through an ensemble of model simulations from the CMIP5 project. We find this fingerprint both in a high-resolution climate model in response to increasing atmospheric carbon dioxide concentrations, and in the temperature trends observed since the late nineteenth century. The pattern can be explained by a slowdown in the AMOC and reduced northward heat transport, as well as an associated northward shift of the Gulf Stream. Comparisons with recent direct measurements from the RAPID project and several other studies provide a consistent depiction of record-low AMOC values in recent years.},
author = {Caesar, L and Rahmstorf, S and Robinson, A and Feulner, G and Saba, V},
doi = {10.1038/s41586-018-0006-5},
issn = {1476-4687},
journal = {Nature},
number = {7700},
pages = {191--196},
title = {{Observed fingerprint of a weakening Atlantic Ocean overturning circulation}},
url = {https://doi.org/10.1038/s41586-018-0006-5},
volume = {556},
year = {2018}
}
@article{Cai2013,
author = {Cai, Wenju and Zheng, Xiao-Tong and Weller, Evan and Collins, Mat and Cowan, Tim and Lengaigne, Matthieu and Yu, Weidong and Yamagata, Toshio},
doi = {10.1038/ngeo2009},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {dec},
number = {12},
pages = {999--1007},
publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.},
title = {{Projected response of the Indian Ocean Dipole to greenhouse warming}},
url = {http://10.0.4.14/ngeo2009 http://www.nature.com/articles/ngeo2009},
volume = {6},
year = {2013}
}
@article{Cai2014,
annote = {Increase of extreme positive IOD (pIOD) events under global warming
- Obs
- CMIP5 historical-RCP8.5, 1900-2099

- SON precip EOF -{\textgreater} extreme pIOD events are represented as a combination of EOF1 and EOF2
- The extreme events occur through the nonlinear effect of zonal temperature advection in the ocean
- Frequency of extreme events increases significantly under global warming
- Likely due to shallower eastern Eq IO thermocline},
author = {Cai, Wenju and Santoso, Agus and Wang, Guojian and Weller, Evan and Wu, Lixin and Ashok, Karumuri and Masumoto, Yukio and Yamagata, Toshio},
doi = {10.1038/nature13327},
issn = {0028-0836},
journal = {Nature},
month = {jun},
number = {7504},
pages = {254--258},
publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.},
title = {{Increased frequency of extreme Indian Ocean Dipole events due to greenhouse warming}},
url = {http://dx.doi.org/10.1038/nature13327 http://10.0.4.14/nature13327 https://www.nature.com/articles/nature13327{\#}supplementary-information http://www.nature.com/articles/nature13327},
volume = {510},
year = {2014}
}
@article{Cai2019a,
abstract = {The El Ni{\~{n}}o-Southern Oscillation (ENSO), which originates in the Pacific, is the strongest and most well-known mode of tropical climate variability. Its reach is global, and it can force climate variations of the tropical Atlantic and Indian Oceans by perturbing the global atmospheric circulation. Less appreciated is how the tropical Atlantic and Indian Oceans affect the Pacific. Especially noteworthy is the multidecadal Atlantic warming that began in the late 1990s, because recent research suggests that it has influenced Indo-Pacific climate, the character of the ENSO cycle, and the hiatus in global surface warming. Discovery of these pantropical interactions provides a pathway forward for improving predictions of climate variability in the current climate and for refining projections of future climate under different anthropogenic forcing scenarios.},
author = {Cai, Wenju and Wu, Lixin and Lengaigne, Matthieu and Li, Tim and McGregor, Shayne and Kug, Jong Seong and Yu, Jin Yi and Stuecker, Malte F. and Santoso, Agus and Li, Xichen and Ham, Yoo Geun and Chikamoto, Yoshimitsu and Ng, Benjamin and McPhaden, Michael J. and Du, Yan and Dommenget, Dietmar and Jia, Fan and Kajtar, Jules B. and Keenlyside, Noel and Lin, Xiaopei and Luo, Jing Jia and Mart{\'{i}}n-Rey, Marta and Ruprich-Robert, Yohan and Wang, Guojian and Xie, Shang Ping and Yang, Yun and Kang, Sarah M. and Choi, Jun Young and Gan, Bolan and Kim, Geon Il and Kim, Chang Eun and Kim, Sunyoung and Kim, Jeong Hwan and Chang, Ping},
doi = {10.1126/science.aav4236},
issn = {10959203},
journal = {Science},
month = {mar},
number = {6430},
pages = {eaav4236},
pmid = {30819937},
title = {{Pantropical climate interactions}},
url = {http://www.sciencemag.org/lookup/doi/10.1126/science.aav4236},
volume = {363},
year = {2019}
}
@article{doi:10.1029/2019MS001870,
abstract = {Abstract This study provides an overview of the coupled high-resolution Version 1 of the Energy Exascale Earth System Model (E3SMv1) and documents the characteristics of a 50-year-long high-resolution control simulation with time-invariant 1950 forcings following the HighResMIP protocol. In terms of global root-mean-squared error metrics, this high-resolution simulation is generally superior to results from the low-resolution configuration of E3SMv1 (due to resolution, tuning changes, and possibly initialization procedure) and compares favorably to models in the CMIP5 ensemble. Ocean and sea ice simulation is particularly improved, due to better resolution of bathymetry, the ability to capture more variability and extremes in winds and currents, and the ability to resolve mesoscale ocean eddies. The largest improvement in this regard is an ice-free Labrador Sea, which is a major problem at low resolution. Interestingly, several features found to improve with resolution in previous studies are insensitive to resolution or even degrade in E3SMv1. Most notable in this regard are warm bias and associated stratocumulus deficiency in eastern subtropical oceans and lack of improvement in El Ni{\~{n}}o. Another major finding of this study is that resolution increase had negligible impact on climate sensitivity (measured by net feedback determined through uniform +4K prescribed sea surface temperature increase) and aerosol sensitivity. Cloud response to resolution increase consisted of very minor decrease at all levels. Large-scale patterns of precipitation bias were also relatively unaffected by grid spacing.},
author = {Caldwell, Peter M and Mametjanov, Azamat and Tang, Qi and {Van Roekel}, Luke P and Golaz, Jean-Christophe and Lin, Wuyin and Bader, David C and Keen, Noel D and Feng, Yan and Jacob, Robert and Maltrud, Mathew E and Roberts, Andrew F and Taylor, Mark A and Veneziani, Milena and Wang, Hailong and Wolfe, Jonathan D and Balaguru, Karthik and Cameron‐Smith, Philip and Dong, Lu and Klein, Stephen A and Leung, L Ruby and Li, Hong‐Yi and Li, Qing and Liu, Xiaohong and Neale, Richard B and Pinheiro, Marielle and Qian, Yun and Ullrich, Paul A and Xie, Shaocheng and Yang, Yang and Zhang, Yuying and Zhang, Kai and Zhou, Tian},
doi = {10.1029/2019MS001870},
issn = {1942-2466},
journal = {Journal of Advances in Modeling Earth Systems},
month = {dec},
number = {12},
pages = {4095--4146},
title = {{The DOE E3SM Coupled Model Version 1: Description and Results at High Resolution}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019MS001870 https://onlinelibrary.wiley.com/doi/10.1029/2019MS001870},
volume = {11},
year = {2019}
}
@article{angeo-32-793-2014,
author = {Calisto, M and Folini, D and Wild, M and Bengtsson, L},
doi = {10.5194/angeo-32-793-2014},
journal = {Annales Geophysicae},
number = {7},
pages = {793--807},
title = {{Cloud radiative forcing intercomparison between fully coupled CMIP5 models and CERES satellite data}},
url = {https://angeo.copernicus.org/articles/32/793/2014/},
volume = {32},
year = {2014}
}
@article{Calvo2015a,
abstract = {A comprehensive stratosphere-resolving atmospheric model, with interactive stratospheric ozone chemistry, coupled to ocean, sea ice and land components is used to explore the tropospheric and surface impacts of large springtime ozone anomalies in the Arctic stratosphere. Coupling between the Antarctic ozone hole and Southern Hemisphere climate has been identified in numerous studies, but connections of Arctic ozone loss to surface climate have been more difficult to elucidate. Analyzing an ensemble of historical integrations with all known natural and anthropogenic forcings specified over the period 1955-2005, we find that extremely low stratospheric ozone changes are able to produce large and robust anomalies in tropospheric wind, temperature and precipitation in April and May over large portions of the Northern Hemisphere (most notably over the North Atlantic and Eurasia). Further, these ozone-induced surface anomalies are obtained only in the last two decades of the 20th century, when high concentrations of ozone depleting substances generate sufficiently strong stratospheric temperature anomalies to impact the surface climate. Our findings suggest that coupling between chemistry and dynamics is essential for a complete representation of surface climate variability and climate change not only in Antarctica but also in the Arctic.},
address = {TEMPLE CIRCUS},
author = {Calvo, N and Polvani, L M and Solomon, S},
doi = {10.1088/1748-9326/10/9/094003},
issn = {1748-9326},
journal = {Environmental Research Letters},
month = {sep},
number = {9},
pages = {094003},
publisher = {IOP PUBLISHING LTD},
title = {{On the surface impact of Arctic stratospheric ozone extremes}},
url = {https://iopscience.iop.org/article/10.1088/1748-9326/10/9/094003},
volume = {10},
year = {2015}
}
@article{Cane2017,
author = {Cane, Mark A. and Clement, Amy C. and Murphy, Lisa N. and Bellomo, Katinka},
doi = {10.1175/JCLI-D-16-0810.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {sep},
number = {18},
pages = {7529--7553},
title = {{Low-Pass Filtering, Heat Flux, and Atlantic Multidecadal Variability}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-16-0810.1},
volume = {30},
year = {2017}
}
@article{gmd-11-2975-2018,
author = {Cao, Jian and Wang, Bin and Yang, Young-Min and Ma, Libin and Li, Juan and Sun, Bo and Bao, Yan and He, Jie and Zhou, Xiao and Wu, Liguang},
doi = {10.5194/gmd-11-2975-2018},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {jul},
number = {7},
pages = {2975--2993},
title = {{The NUIST Earth System Model (NESM) version 3: description and preliminary evaluation}},
url = {https://gmd.copernicus.org/articles/11/2975/2018/},
volume = {11},
year = {2018}
}
@article{Capotondi2014,
abstract = {AbstractEl Ni{\~{n}}o?Southern Oscillation (ENSO) is a naturally occurring mode of tropical Pacific variability, with global impacts on society and natural ecosystems. While it has long been known that El Ni{\~{n}}o events display a diverse range of amplitudes, triggers, spatial patterns, and life cycles, the realization that ENSO?s impacts can be highly sensitive to this event-to-event diversity is driving a renewed interest in the subject. This paper surveys our current state of knowledge of ENSO diversity, identifies key gaps in understanding, and outlines some promising future research directions.},
annote = {doi: 10.1175/BAMS-D-13-00117.1},
author = {Capotondi, Antonietta and Wittenberg, Andrew T and Newman, Matthew and {Di Lorenzo}, Emanuele and Yu, Jin-Yi and Braconnot, Pascale and Cole, Julia and Dewitte, Boris and Giese, Benjamin and Guilyardi, Eric and Jin, Fei-Fei and Karnauskas, Kristopher and Kirtman, Benjamin and Lee, Tong and Schneider, Niklas and Xue, Yan and Yeh, Sang-Wook},
doi = {10.1175/BAMS-D-13-00117.1},
issn = {0003-0007},
journal = {Bulletin of the American Meteorological Society},
month = {sep},
number = {6},
pages = {921--938},
publisher = {American Meteorological Society},
title = {{Understanding ENSO Diversity}},
url = {https://doi.org/10.1175/BAMS-D-13-00117.1},
volume = {96},
year = {2015}
}
@article{CAPRON2017137,
abstract = {The Last Interglacial (LIG, ∼129-116 thousand years ago, ka) represents an excellent case study to investigate the response of sensitive components of the Earth System and mechanisms of high-latitude amplification to a climate warmer than present-day. The Paleoclimate Model Intercomparison Project (Phase 4, hereafter referred as PMIP4) and the Coupled Model Intercomparison Project (Phase 6, hereafter referred as CMIP6) are coordinating the design of (1) a LIG Tier 1 equilibrium simulation to simulate the climate response at 127 ka, a time interval associated with a strong orbital forcing and greenhouse gas concentrations close to preindustrial levels and (2) associated Tier 2 sensitivity experiments to examine the role of the ocean, vegetation and dust feedbacks in modulating the response to this orbital forcing. Evaluating the capability of the CMIP6/PMIP4 models to reproduce the 127 ka polar and sub-polar climate will require appropriate data-based benchmarks which are currently missing. Based on a recent data synthesis that offers the first spatio-temporal representation of high-latitude (i.e. poleward of 40°N and 40°S) surface temperature evolution during the LIG, we produce a new 126–128 ka time slab, hereafter named 127 ka time slice. This 127 ka time slice represents surface temperature anomalies relative to preindustrial and is associated with quantitative estimates of the uncertainties related to relative dating and surface temperature reconstruction methods. It illustrates warmer-than-preindustrial conditions in the high-latitude regions of both hemispheres. In particular, summer sea surface temperatures (SST) in the North Atlantic region were on average 1.1 °C (with a standard error of the mean of 0.7 °C) warmer relative to preindustrial and 1.8 °C (with a standard error of the mean of 0.8 °C) in the Southern Ocean. In Antarctica, average 127 ka annual surface air temperature was 2.2 °C (with a standard error of the mean of 1.4 °C) warmer compared to preindustrial. We provide a critical evaluation of the latest LIG surface climate compilations that are available for evaluating LIG climate model experiments. We discuss in particular our new 127 ka time-slice in the context of existing LIG surface temperature time-slices. We also compare the 127 ka time slice with the ones published for the 125 and 130 ka time intervals and we discuss the potential and limits of a data-based time slice at 127 ka in the context of the upcoming coordinated modeling exercise. Finally we provide guidance on the use of the available LIG climate compilations for future model-data comparison exercises in the framework of the upcoming CMIP6/PMIP4 127 ka experiments. We do not recommend the use of LIG peak warmth-centered syntheses. Instead we promote the use of the most recent syntheses that are based on coherent chronologies between paleoclimatic records and provide spatio-temporal reconstruction of the LIG climate. In particular, we recommend using our new 127 ka data-based time slice in model-data comparison studies with a focus on the high-latitude climate.},
author = {Capron, E and Govin, A and Feng, R and Otto-Bliesner, B L and Wolff, E W},
doi = {10.1016/j.quascirev.2017.04.019},
issn = {0277-3791},
journal = {Quaternary Science Reviews},
keywords = {127 ka surface temperature time slice,CMIP6/PMIP4 Tier 1 and Tier 2 simulations,Last interglacial,Quantitative uncertainty estimates attached to re},
pages = {137--150},
title = {{Critical evaluation of climate syntheses to benchmark CMIP6/PMIP4 127 ka Last Interglacial simulations in the high-latitude regions}},
url = {http://www.sciencedirect.com/science/article/pii/S0277379117303487},
volume = {168},
year = {2017}
}
@article{Caron2015,
author = {Caron, Louis-Philippe and Hermanson, Leon and Doblas-Reyes, Francisco J.},
doi = {10.1002/2015GL063303},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {apr},
number = {7},
pages = {2417--2425},
title = {{Multiannual forecasts of Atlantic U.S. tropical cyclone wind damage potential}},
url = {http://doi.wiley.com/10.1002/2015GL063303},
volume = {42},
year = {2015}
}
@article{Cassou2018,
abstract = { AbstractThe study of Decadal Climate Variability (DCV) and Predictability is the interdisciplinary endeavor to characterize, understand, attribute, simulate, and predict the slow, multiyear variations of climate at global (e.g., the recent slowdown of global mean temperature rise in the early 2000s) and regional (e.g., decadal modulation of hurricane activity in the Atlantic, ongoing drought in California or in the Sahel in the 1970s–80s, etc.) scales. This study remains very challenging despite decades of research, extensive progress in climate system modeling, and improvements in the availability and coverage of a wide variety of observations. Considerable obstacles in applying this knowledge to actual predictions remain.This short article is a succint review paper about DCV and predictability. Based on listed issues and priorities, it also proposes a unifying theme referred to as “drivers of teleconnectivity” as a backbone to address and structure the core DCV research challenge. This framework goes beyond a preoccupation with changes in the global mean temperature and directly addresses the regional impacts of external (natural and anthropogenic) climate forcing and internal climate interactions; it thus explicitly deals with the societal needs for region-specific climate information. Such a framework also enables the integration of efforts in a large international research community toward advancing the observation, characterization, understanding, and prediction of DCV. Recommendations to make progress are provided as part of the contribution of the CLIVAR “DCVP Research Focus” group. },
author = {Cassou, Christophe and Kushnir, Yochanan and Hawkins, Ed and Pirani, Anna and Kucharski, Fred and Kang, In-Sik and Caltabiano, Nico},
doi = {10.1175/BAMS-D-16-0286.1},
journal = {Bulletin of the American Meteorological Society},
number = {3},
pages = {479--490},
title = {{Decadal Climate Variability and Predictability: Challenges and Opportunities}},
url = {https://doi.org/10.1175/BAMS-D-16-0286.1},
volume = {99},
year = {2018}
}
@article{Cazenave2018a,
abstract = {Global mean sea level is an integral of changes occurring in the climate system in response to unforced climate variability as well as natural and anthropogenic forcing factors. Its temporal evolution allows changes (e.g., acceleration) to be detected in one or more components. Study of the sea-level budget provides constraints on missing or poorly known contributions, such as the unsurveyed deep ocean or the still uncertain land water component. In the context of the World Climate Research Programme Grand Challenge entitled "Regional Sea Level and Coastal Impacts", an international effort involving the sea-level community worldwide has been recently initiated with the objective of assessing the various datasets used to estimate components of the sea-level budget during the altimetry era (1993 to present). These datasets are based on the combination of a broad range of space-based and in situ observations, model estimates, and algorithms. Evaluating their quality, quantifying uncertainties and identifying sources of discrepancies between component estimates is extremely useful for various applications in climate research. This effort involves several tens of scientists from about 50 research teams/institutions worldwide (last access: 22 August 2018). The results presented in this paper are a synthesis of the first assessment performed during 2017-2018. We present estimates of the altimetry-based global mean sea level (average rate of 3.1±0.3mmyr-1 and acceleration of 0.1mmyr-2 over 1993-present), as well as of the different components of the sea-level budget (last access: 22 August 2018). We further examine closure of the sea-level budget, comparing the observed global mean sea level with the sum of components. Ocean thermal expansion, glaciers, Greenland and Antarctica contribute 42{\%}, 21{\%}, 15{\%} and 8{\%} to the global mean sea level over the 1993-present period. We also study the sea-level budget over 2005-present, using GRACE-based ocean mass estimates instead of the sum of individual mass components. Our results demonstrate that the global mean sea level can be closed to within 0.3mmyr-1 (1$\sigma$). Substantial uncertainty remains for the land water storage component, as shown when examining individual mass contributions to sea level.},
author = {Cazenave, Anny and Meyssignac, Benoit and Ablain, Michael and Balmaseda, Magdalena and Bamber, Jonathan and Barletta, Valentina and Beckley, Brian and Benveniste, J{\'{e}}r{\^{o}}me and Berthier, Etienne and Blazquez, Alejandro and Boyer, Tim and Caceres, Denise and Chambers, Don and Champollion, Nicolas and Chao, Ben and Chen, Jianli and Cheng, Lijing and Church, John A. and Chuter, Stephen and Cogley, J. Graham and Dangendorf, Soenke and Desbruy{\`{e}}res, Damien and D{\"{o}}ll, Petra and Domingues, Catia and Falk, Ulrike and Famiglietti, James and Fenoglio-Marc, Luciana and Forsberg, Rene and Galassi, Gaia and Gardner, Alex and Groh, Andreas and Hamlington, Benjamin and Hogg, Anna and Horwath, Martin and Humphrey, Vincent and Husson, Laurent and Ishii, Masayoshi and Jaeggi, Adrian and Jevrejeva, Svetlana and Johnson, Gregory and Kolodziejczyk, Nicolas and Kusche, J{\"{u}}rgen and Lambeck, Kurt and Landerer, Felix and Leclercq, Paul and Legresy, Benoit and Leuliette, Eric and Llovel, William and Longuevergne, Laurent and Loomis, Bryant D. and Luthcke, Scott B. and Marcos, Marta and Marzeion, Ben and Merchant, Chris and Merrifield, Mark and Milne, Glenn and Mitchum, Gary and Mohajerani, Yara and Monier, Maeva and Monselesan, Didier and Nerem, Steve and Palanisamy, Hindumathi and Paul, Frank and Perez, Bego{\~{n}}a and Piecuch, Christopher G. and Ponte, Rui M. and Purkey, Sarah G. and Reager, John T. and Rietbroek, Roelof and Rignot, Eric and Riva, Riccardo and Roemmich, Dean H. and S{\o}rensen, Louise Sandberg and Sasgen, Ingo and Schrama, E. J.O. and Seneviratne, Sonia I. and Shum, C. K. and Spada, Giorgio and Stammer, Detlef and van de Wal, Roderic and Velicogna, Isabella and von Schuckmann, Karina and Wada, Yoshihide and Wang, Yiguo and Watson, Christopher and Wiese, David and Wijffels, Susan and Westaway, Richard and Woppelmann, Guy and Wouters, Bert},
doi = {10.5194/essd-10-1551-2018},
issn = {18663516},
journal = {Earth System Science Data},
number = {3},
pages = {1551--1590},
title = {{Global sea-level budget 1993–present}},
volume = {10},
year = {2018}
}
@article{Cha2018b,
author = {Cha, Sang-Chul and Moon, Jae-Hong and Song, Y. Tony},
doi = {10.1029/2018GL080651},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {nov},
number = {21},
pages = {11885--11894},
title = {{A Recent Shift Toward an El Ni{\~{n}}o-Like Ocean State in the Tropical Pacific and the Resumption of Ocean Warming}},
volume = {45},
year = {2018}
}
@article{Chai2018,
author = {Chai, Jing and Liu, Fei and Liu, Jian and Shen, Xinyong},
doi = {10.3390/atmos9040136},
issn = {2073-4433},
journal = {Atmosphere},
month = {apr},
number = {4},
pages = {136},
title = {{Enhanced Global Monsoon in Present Warm Period Due to Natural and Anthropogenic Forcings}},
url = {http://www.mdpi.com/2073-4433/9/4/136},
volume = {9},
year = {2018}
}
@article{Chan2015a,
abstract = {Attribution studies conclude that it is extremely likely that most observed global- and continental-scale surface air temperature (SAT) warming since 1950 was caused by anthropogenic forcing, but some difficulties and uncertainties remain in attribution of warming in subcontinental regions and at time scales less than 50 years. This study uses global observations and CMIP5 simulations with various forcings, covering 1979-2005, and control runs to develop confidence intervals, to attribute regional trends of SAT and sea surface temperature (SST) to natural and anthropogenic causes. Observations show warming, significantly different from natural variations at the 95{\%} confidence level, over one-third of all grid boxes, and averaged over 15 of 21 subcontinental regions and 6 of 10 ocean basins. Coupled simulations forced with all forcing factors, or greenhouse gases only, reproduce observed SST and SAT patterns. Uncoupled AMIP-like atmosphere-only (prescribed SST and atmospheric radiative forcing) simulations reproduce observed SAT patterns. All of these simulations produce consistent net downward longwave radiation patterns. Simulations with natural-only forcing simulate weak warming. Anthropogenic forcing effects are clearly detectable at the 5{\%} significance level at global, hemispheric, and tropical scales and in nine ocean basins and 15 of 21 subcontinental land regions. Attribution results indicate that ocean warming during 1979-2005 for the globe and individual basins is well represented in the CMIP5 multimodel ensemble mean historical simulations. While land warming may occur as an indirect response to oceanic warming, increasing greenhouse gas concentrations tend to be the ultimate source of land warming in most subcontinental regions during 1979-2005.},
address = {Boston MA, USA},
author = {Chan, Duo and Wu, Qigang},
doi = {10.1175/JCLI-D-14-00253.1},
issn = {08948755},
journal = {Journal of Climate},
language = {English},
number = {8},
pages = {3152--3170},
publisher = {American Meteorological Society},
title = {{Attributing observed SST trends and subcontinental land warming to anthropogenic forcing during 1979–2005}},
url = {https://journals.ametsoc.org/view/journals/clim/28/8/jcli-d-14-00253.1.xml},
volume = {28},
year = {2015}
}
@article{ISI:000373109800051,
abstract = {Extratropical cyclones cause much of the high-impact weather over the midlatitudes. With increasing greenhouse gases, enhanced high-latitude warming will lead to weaker cyclone activity. Here we show that between 1979 and 2014, the number of strong cyclones in Northern Hemisphere in summer has decreased at a rate of 4{\%} per decade, with even larger decrease found near northeastern North America. Climate models project a decrease in summer cyclone activity, but the observed decreasing rate is near the fastest projected. Decrease in summer cyclone activity will lead to decrease in cloud cover, giving rise to higher maximum temperature, potentially enhancing the increase in maximum temperature by 0.5K or more over some regions. We also show that climate models may have biases in simulating the positive relationship between cyclone activity and cloud cover, potentially underestimating the impacts of cyclone decrease on accentuating the future increase in maximum temperature.},
address = {2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA},
annote = {between 1979 and 2014, the number of strong cyclones in Northern Hemisphere in summer has decreased at a rate of 4{\%} per decade, with even larger decrease found near northeastern North America. We also show that climate models may
have biases in simulating the positive relationship between cyclone
activity and cloud cover, potentially underestimating the impacts of
cyclone decrease on accentuating the future increase in maximum
temperature.},
author = {Chang, Edmund K.M. and Ma, Chen-Geng and Zheng, Cheng and Yau, Albert M W},
doi = {10.1002/2016GL068172},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {climate change,extratropical cyclones,maximum te},
month = {mar},
number = {5},
pages = {2200--2208},
publisher = {AMER GEOPHYSICAL UNION},
title = {{Observed and projected decrease in Northern Hemisphere extratropical cyclone activity in summer and its impacts on maximum temperature}},
type = {Article},
volume = {43},
year = {2016}
}
@article{https://doi.org/10.1029/2020MS002298,
abstract = {Abstract We present an unprecedented set of high-resolution climate simulations, consisting of a 500-year pre-industrial control simulation and a 250-year historical and future climate simulation from 1850 to 2100. A high-resolution configuration of the Community Earth System Model version 1.3 (CESM1.3) is used for the simulations with a nominal horizontal resolution of 0.25° for the atmosphere and land models and 0.1° for the ocean and sea-ice models. At these resolutions, the model permits tropical cyclones and ocean mesoscale eddies, allowing interactions between these synoptic and mesoscale phenomena with large-scale circulations. An overview of the results from these simulations is provided with a focus on model drift, mean climate, internal modes of variability, representation of the historical and future climates, and extreme events. Comparisons are made to solutions from an identical set of simulations using the standard resolution (nominal 1°) CESM1.3 and to available observations for the historical period to address some key scientific questions concerning the impact and benefit of increasing model horizontal resolution in climate simulations. An emerging prominent feature of the high-resolution pre-industrial simulation is the intermittent occurrence of polynyas in the Weddell Sea and its interaction with an Interdecadal Pacific Oscillation. Overall, high-resolution simulations show significant improvements in representing global mean temperature changes, seasonal cycle of sea-surface temperature and mixed layer depth, extreme events and in relationships between extreme events and climate modes.},
annote = {e2020MS002298 2020MS002298},
author = {Chang, Ping and Zhang, Shaoqing and Danabasoglu, Gokhan and Yeager, Stephen G and Fu, Haohuan and Wang, Hong and Castruccio, Frederic S and Chen, Yuhu and Edwards, James and Fu, Dan and Jia, Yinglai and Laurindo, Lucas C and Liu, Xue and Rosenbloom, Nan and Small, R Justin and Xu, Gaopeng and Zeng, Yunhui and Zhang, Qiuying and Bacmeister, Julio and Bailey, David A and Duan, Xiaohui and DuVivier, Alice K and Li, Dapeng and Li, Yuxuan and Neale, Richard and St{\"{o}}ssel, Achim and Wang, Li and Zhuang, Yuan and Baker, Allison and Bates, Susan and Dennis, John and Diao, Xiliang and Gan, Bolan and Gopal, Abishek and Jia, Dongning and Jing, Zhao and Ma, Xiaohui and Saravanan, R and Strand, Warren G and Tao, Jian and Yang, Haiyuan and Wang, Xiaoqi and Wei, Zhiqiang and Wu, Lixin},
doi = {10.1029/2020MS002298},
journal = {Journal of Advances in Modeling Earth Systems},
keywords = {Earth system models,climate change,climate variability,high resolution},
number = {12},
pages = {e2020MS002298},
title = {{An Unprecedented Set of High-Resolution Earth System Simulations for Understanding Multiscale Interactions in Climate Variability and Change}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020MS002298},
volume = {12},
year = {2020}
}
@article{doi:10.1002/jgrd.50125,
abstract = {We describe the main differences in simulations of stratospheric climate and variability by models within the fifth Coupled Model Intercomparison Project (CMIP5) that have a model top above the stratopause and relatively fine stratospheric vertical resolution (high-top), and those that have a model top below the stratopause (low-top). Although the simulation of mean stratospheric climate by the two model ensembles is similar, the low-top model ensemble has very weak stratospheric variability on daily and interannual time scales. The frequency of major sudden stratospheric warming events is strongly underestimated by the low-top models with less than half the frequency of events observed in the reanalysis data and high-top models. The lack of stratospheric variability in the low-top models affects their stratosphere-troposphere coupling, resulting in short-lived anomalies in the Northern Annular Mode, which do not produce long-lasting tropospheric impacts, as seen in observations. The lack of stratospheric variability, however, does not appear to have any impact on the ability of the low-top models to reproduce past stratospheric temperature trends. We find little improvement in the simulation of decadal variability for the high-top models compared to the low-top, which is likely related to the fact that neither ensemble produces a realistic dynamical response to volcanic eruptions.},
annote = {- Stratospheric NAM influence on the tropospheric NAM is less persistent in low-top models},
author = {Charlton-Perez, Andrew J and Baldwin, Mark P and Birner, Thomas and Black, Robert X and Butler, Amy H and Calvo, Natalia and Davis, Nicholas A and Gerber, Edwin P and Gillett, Nathan and Hardiman, Steven and Kim, Junsu and Kr{\"{u}}ger, Kirstin and Lee, Yun-Young and Manzini, Elisa and McDaniel, Brent A and Polvani, Lorenzo and Reichler, Thomas and Shaw, Tiffany A and Sigmond, Michael and Son, Seok-Woo and Toohey, Matthew and Wilcox, Laura and Yoden, Shigeo and Christiansen, Bo and Lott, Fran{\c{c}}ois and Shindell, Drew and Yukimoto, Seiji and Watanabe, Shingo},
doi = {10.1002/jgrd.50125},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {CMIP5,Climate,Stratosphere,Validation},
number = {6},
pages = {2494--2505},
title = {{On the lack of stratospheric dynamical variability in low-top versions of the CMIP5 models}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/jgrd.50125},
volume = {118},
year = {2013}
}
@article{Chen897,
abstract = {Global warming seems to have paused over the past 15 years while the deep ocean takes the heat instead. The thermal capacity of the oceans far exceeds that of the atmosphere, so the oceans can store up to 90{\%} of the heat buildup caused by increased concentrations of greenhouse gases such as carbon dioxide. Chen and Tung used observational data to trace the pathways of recent ocean heating. They conclude that the deep Atlantic and Southern Oceans, but not the Pacific, have absorbed the excess heat that would otherwise have fueled continued warming.Science, this issue p. 897 A vacillating global heat sink at intermediate ocean depths is associated with different climate regimes of surface warming under anthropogenic forcing: The latter part of the 20th century saw rapid global warming as more heat stayed near the surface. In the 21st century, surface warming slowed as more heat moved into deeper oceans. In situ and reanalyzed data are used to trace the pathways of ocean heat uptake. In addition to the shallow La Ni{\~{n}}a{\{}$\backslash$textendash{\}}like patterns in the Pacific that were the previous focus, we found that the slowdown is mainly caused by heat transported to deeper layers in the Atlantic and the Southern oceans, initiated by a recurrent salinity anomaly in the subpolar North Atlantic. Cooling periods associated with the latter deeper heat-sequestration mechanism historically lasted 20 to 35 years.},
author = {Chen, Xianyao and Tung, Ka-Kit},
doi = {10.1126/science.1254937},
issn = {0036-8075},
journal = {Science},
number = {6199},
pages = {897--903},
publisher = {American Association for the Advancement of Science},
title = {{Varying planetary heat sink led to global-warming slowdown and acceleration}},
url = {http://science.sciencemag.org/content/345/6199/897},
volume = {345},
year = {2014}
}
@article{Chen2016a,
author = {Chen, Hua and Schneider, Edwin K. and Wu, Zhiwei},
doi = {10.1007/s00382-015-2660-8},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {mar},
number = {5-6},
pages = {1517--1546},
title = {{Mechanisms of internally generated decadal-to-multidecadal variability of SST in the Atlantic Ocean in a coupled GCM}},
url = {http://link.springer.com/10.1007/s00382-015-2660-8},
volume = {46},
year = {2016}
}
@article{Chen2020,
abstract = {The wintertime ENSO teleconnection over the North Pacific region consists of an intensified (weakened) low pressure center during El Ni{\~{n}}o (La Ni{\~{n}}a) events both in observations and in climate models. Here, it is demonstrated that this teleconnection persists too strongly into late winter and spring in the Community Earth System Model (CESM). This discrepancy arises in both fully coupled and atmosphere-only configurations, when observed SSTs are specified, and is shown to be robust when accounting for the sampling uncertainty due to internal variability. Furthermore, a similar problem is found in many other models from piControl simulations of the Coupled Model Intercomparison Project (23 out of 43 in phase 5 and 11 out of 20 in phase 6). The implications of this bias for the simulation of surface climate anomalies over North America are assessed. The overall effect on the ENSO composite field (El Ni{\~{n}}o minus La Ni{\~{n}}a) resembles an overly prolonged influence of ENSO into the spring with anomalously high temperatures over Alaska and western Canada, and wet (dry) biases over California (southwest Canada). Further studies are still needed to disentangle the relative roles played by diabatic heating, background flow, and other possible contributions in determining the overly strong springtime ENSO teleconnection intensity over the North Pacific.},
author = {Chen, Ruyan and Simpson, Isla R. and Deser, Clara and Wang, Bin},
doi = {10.1175/JCLI-D-19-1004.1},
issn = {0894-8755},
journal = {Journal of Climate},
keywords = {Climate models,ENSO,Model errors,Model evaluation/performance,Stationary waves,Teleconnections},
month = {dec},
number = {23},
pages = {9985--10002},
title = {{Model Biases in the Simulation of the Springtime North Pacific ENSO Teleconnection}},
url = {https://journals.ametsoc.org/doi/10.1175/JCLI-D-19-1004.1},
volume = {33},
year = {2020}
}
@article{Chen2019,
abstract = {Satellite data show increasing leaf area of vegetation due to direct factors (human land-use management) and indirect factors (such as climate change, CO2 fertilization, nitrogen deposition and recovery from natural disturbances). Among these, climate change and CO2 fertilization effects seem to be the dominant drivers. However, recent satellite data (2000–2017) reveal a greening pattern that is strikingly prominent in China and India and overlaps with croplands world-wide. China alone accounts for 25{\%} of the global net increase in leaf area with only 6.6{\%} of global vegetated area. The greening in China is from forests (42{\%}) and croplands (32{\%}), but in India is mostly from croplands (82{\%}) with minor contribution from forests (4.4{\%}). China is engineering ambitious programmes to conserve and expand forests with the goal of mitigating land degradation, air pollution and climate change. Food production in China and India has increased by over 35{\%} since 2000 mostly owing to an increase in harvested area through multiple cropping facilitated by fertilizer use and surface- and/or groundwater irrigation. Our results indicate that the direct factor is a key driver of the ‘Greening Earth', accounting for over a third, and probably more, of the observed net increase in green leaf area. They highlight the need for a realistic representation of human land-use practices in Earth system models.},
author = {Chen, Chi and Park, Taejin and Wang, Xuhui and Piao, Shilong and Xu, Baodong and Chaturvedi, Rajiv K. and Fuchs, Richard and Brovkin, Victor and Ciais, Philippe and Fensholt, Rasmus and T{\o}mmervik, Hans and Bala, Govindasamy and Zhu, Zaichun and Nemani, Ramakrishna R. and Myneni, Ranga B.},
doi = {10.1038/s41893-019-0220-7},
issn = {23989629},
journal = {Nature Sustainability},
number = {2},
title = {{China and India lead in greening of the world through land-use management}},
volume = {2},
year = {2019}
}
@article{Cheng2017a,
abstract = {Earth's energy imbalance (EEI) drives the ongoing global warming and can best be assessed across the historical record (that is, since 1960) from ocean heat content (OHC) changes. An accurate assessment of OHC is a challenge, mainly because of insufficient and irregular data coverage. We provide updated OHC estimates with the goal of minimizing associated sampling error. We performed a subsample test, in which subsets of data during the data-rich Argo era are colocated with locations of earlier ocean observations, to quantify this error. Our results provide a new OHC estimate with an unbiased mean sampling error and with variability on decadal and multidecadal time scales (signal) that can be reliably distinguished from sampling error (noise) with signal-to-noise ratios higher than 3. The inferred integrated EEI is greater than that reported in previous assessments and is consistent with a reconstruction of the radiative imbalance at the top of atmosphere starting in 1985. We found that changes in OHC are relatively small before about 1980; since then, OHC has increased fairly steadily and, since 1990, has increasingly involved deeper layers of the ocean. In addition, OHC changes in six major oceans are reliable on decadal time scales. All ocean basins examined have experienced significant warming since 1998, with the greatest warming in the southern oceans, the tropical/subtropical Pacific Ocean, and the tropical/subtropical Atlantic Ocean. This new look at OHC and EEI changes over time provides greater confidence than previously possible, and the data sets produced are a valuable resource for further study.},
author = {Cheng, Lijing and Trenberth, Kevin E. and Fasullo, John and Boyer, Tim and Abraham, John and Zhu, Jiang},
doi = {10.1126/sciadv.1601545},
issn = {2375-2548},
journal = {Science Advances},
month = {mar},
number = {3},
pages = {e1601545},
publisher = {American Association for the Advancement of Science},
title = {{Improved estimates of ocean heat content from 1960 to 2015}},
url = {http://advances.sciencemag.org/lookup/doi/10.1126/sciadv.1601545},
volume = {3},
year = {2017}
}
@article{Cheng2013b,
abstract = {The Atlantic meridional overturning circulation (AMOC) simulated by 10 models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) for the historical (1850–2005) and future climate is ex- amined. The historical simulations of the AMOCmean state are more closely matched to observations than those of phase 3 of the Coupled Model Intercomparison Project (CMIP3). Similarly to CMIP3, all models predict a weakening of the AMOC in the twenty-first century, though the degree of weakening varies con- siderably among the models. Under the representative concentration pathway 4.5 (RCP4.5) scenario, the weakening by year 2100 is 5{\%}–40{\%} of the individual model's historical mean state; under RCP8.5, the weakening increases to 15{\%}–60{\%}over the same period. RCP4.5 leads to the stabilization of the AMOC in the second half of the twenty-first century and a slower (then weakening rate) but steady recovery thereafter, while RCP8.5 gives rise to a continuous weakening of theAMOCthroughout the twenty-first century. In the CMIP5 historical simulations, all but one model exhibit a weak downward trend [ranging from 20.1 to21.8 Sverdrup (Sv) century21;1Sv[106m3 s21] over the twentieth century. Additionally, the multimodel ensemble– mean AMOC exhibits multidecadal variability with a ;60-yr periodicity and a peak-to-peak amplitude of ;1Sv; all individual models project consistently onto this multidecadal mode. This multidecadal variability is significantly correlated with similar variations in the net surface shortwave radiative flux in the North Atlantic and with surface freshwater flux variations in the subpolar latitudes. Potential drivers for the twentieth-century multimodelAMOC variability, including external climate forcing and the North Atlantic Oscillation (NAO), and the implication of these results on the North Atlantic SST variability are discussed.},
author = {Cheng, Wei and Chiang, John C.H. and Zhang, Dongxiao},
doi = {10.1175/JCLI-D-12-00496.1},
isbn = {0894-8755},
issn = {08948755},
journal = {Journal of Climate},
number = {18},
pages = {7187--7197},
title = {{Atlantic meridional overturning circulation (AMOC) in CMIP5 Models: RCP and historical simulations}},
volume = {26},
year = {2013}
}
@misc{Cheng2019,
author = {Cheng, Lijing and Abraham, John and Hausfather, Zeke and Trenberth, Kevin E.},
booktitle = {Science},
doi = {10.1126/science.aav7619},
issn = {10959203},
month = {jan},
number = {6423},
pages = {128--129},
publisher = {American Association for the Advancement of Science},
title = {{How fast are the oceans warming?}},
volume = {363},
year = {2019}
}
@article{Cheng2016a,
abstract = {Greenhouse-gas emissions have created a planetary energy imbalance that is primarily manifested by increasing ocean heat content (OHC). Updated observational estimates of full-depth OHC change since 1970 are presented that account for recent advancements in reducing observation errors and biases. The full-depth OHC has increased by 0.74 [0.68, 0.80]×1022 J yr-1 (0.46Wm-2/ and 1.22 [1.16-1.29] ×1022 J yr-1 (0.75Wm-2/ for 1970-2005 and 1992-2005, respectively, with a 5 to 95{\%} confidence interval of the median. The CMIP5 models show large spread in OHC changes, suggesting that some models are not state-of-the-art and require further improvements. However, the ensemble median has excellent agreement with our observational estimate: 0.68 [0.54-0.82] ×1022 J yr-1 (0.42Wm-2/ from 1970 to 2005 and 1.25 [1.10-1.41] ×1022 J yr-1 (0.77Wm-2/ from 1992 to 2005. These results increase confidence in both the observational and model estimates to quantify and study changes in Earth's energy imbalance over the historical period. We suggest that OHC be a fundamental metric for climate model validation and evaluation, especially for forced changes (decadal timescales).},
author = {Cheng, Lijing and Trenberth, Kevin E. and Palmer, Matthew D. and Zhu, Jiang and Abraham, John P.},
doi = {10.5194/os-12-925-2016},
issn = {18120792},
journal = {Ocean Science},
keywords = {content,heat,model,observed,ocean,simulated},
month = {jul},
number = {4},
pages = {925--935},
title = {{Observed and simulated full-depth ocean heat-content changes for 1970-2005}},
url = {citeulike-article-id:14636611 http://dx.doi.org/10.5194/os-12-925-2016 https://www.ocean-sci.net/12/925/2016/},
volume = {12},
year = {2016}
}
@article{Cheng2020b,
abstract = {Ocean salinity records the hydrological cycle and its changes, but data scarcity and the large changes in sampling make the reconstructions of long-term salinity changes challenging. Here, we present a new observational estimate of changes in ocean salinity since 1960 from the surface to 2000 m. We overcome some of the inconsistencies present in existing salinity reconstructions by using an interpolation technique that uses information on the spatiotemporal covariability of salinity taken from model simulations. The interpolation technique is comprehensively evaluated using recent Argo-dominated observations through subsample tests. The new product strengthens previous findings that ocean surface and subsurface salinity contrasts have increased (i.e., the existing salinity pattern has amplified). We quantify this contrast by assessing the difference between the salinity in regions of high and low salinity averaged over the top 2000 m, a metric we refer to as SC2000. The increase in SC2000 is highly distinguishable from the sampling error and less affected by interannual variability and sampling error than if this metric was computed just for the surface. SC2000 increased by 1.9{\%} 6 0.6{\%} from 1960 to 1990 and by 3.3{\%} 6 0.4{\%} from 1991 to 2017 (5.2{\%} 6 0.4{\%} for 1960–2017), indicating an acceleration of the pattern amplification in recent decades. Combining this estimate with model simulations, we show that the change in SC2000 since 1960 emerges clearly as an anthropogenic signal from the natural variability. Based on the salinity-contrast metrics and model simulations, we find a water cycle amplification of 2.6{\%} 6 4.4{\%} K21 since 1960, with the larger error than salinity metric mainly being due to model uncertainty.},
author = {Cheng, Lijing and Trenberth, Kevin E. and Gruber, Nicolas and Abraham, John P. and Fasullo, John T. and Li, Guancheng and Mann, Michael E. and Zhao, Xuanming and Zhu, Jiang},
doi = {10.1175/JCLI-D-20-0366.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Climate change,Climate records,Salinity,Sampling},
number = {23},
pages = {10357--10381},
title = {{Improved estimates of changes in upper ocean salinity and the hydrological cycle}},
volume = {33},
year = {2020}
}
@article{ISI:000392307300038,
abstract = {We present projected changes in the speed and meridional location of the Subtropical Jet (STJ) during winter using output of the Coupled Model Intercomparison Project Phase 5 (CMIP5) models. We use the ERA-Interim reanalysis dataset to evaluate the historical simulations of the STJ by 18 of the CMIP5 models for the period 1979-2012. Based on the climatology of the STJ from ERA-Interim, we selected the area of study as 70A degrees E-290A degrees E and 20A degrees S-40A degrees S, which is over the Indian and Southern Pacific Oceans, and 300-100 hPa to reduce altitude-related bias. An assessment of the ability of the CMIP5 models in simulating ENSO effects on the jet stream were carried out using standardized zonal wind anomalies at 300-100 hPa. Results show that 47 {\%} of the CMIP5 models used in this study were able to simulate ENSO impacts realistically. In addition, it is more difficult for the models to reproduce the observed intensity of ENSO impacts than the patterns. The historical simulations of the CMIP5 models show a wide range of trends in meridional movement and jet strength, with a multi-model mean of 0.04A degrees A decade(-1) equatorward and 0.42 ms(-1) decade(-1) respectively. In contrast to the ERA-Interim analysis, 94 {\%} of the CMIP5 models show a strengthening of the jet in the historical runs. Variability of the jet strength is significantly (5 {\%}) linked to the sea surface temperature changes over the eastern tropical Pacific. The CMIP5 model projections with Representative Concentration Pathways (RCPs) 4.5 and 8.5 were used for analysis of changes of the STJ for the period 2011-2099. Based on the RCP 4.5 (RCP 8.5) scenario the multi-model mean trend of the 18 CMIP5 models project a statistically significant (5 {\%} level) increase in jet strength by the end of the century of 0.29 ms(-1) decade(-1) (0.60 ms(-1) decade(-1)). Also, the mean meridional location of the jet is projected to shift poleward by 0.006A degrees A decade(-1) (0.042A degrees A decade(-1)) in 2099 during winter, with the only significant (5 {\%}) trend being with RCP 8.5.},
address = {233 SPRING ST, NEW YORK, NY 10013 USA},
annote = {The historical simulations of the CMIP5 models show a wide
range of trends in meridional movement and jet strength, with a
multi-model mean of 0.04A degrees A decade(-1) equatorward and 0.42
ms(-1) decade(-1) respectively. In contrast to the ERA-Interim analysis,
94 {\%} of the CMIP5 models show a strengthening of the jet in the
historical runs. Variability of the jet strength is significantly (5 {\%})
linked to the sea surface temperature changes over the eastern tropical
Pacific.},
author = {Chenoli, Sheeba Nettukandy and Mazuki, Muhammad Yunus Ahmad and Turner, John and {Abu Samah}, Azizan},
doi = {10.1007/s00382-016-3102-y},
issn = {0930-7575},
journal = {Climate Dynamics},
keywords = {CMIP5 models,El Nino Sout,Subtropical Jet Stream},
month = {jan},
number = {1-2},
pages = {661--681},
publisher = {SPRINGER},
title = {{Historical and projected changes in the Southern Hemisphere Sub-tropical Jet during winter from the CMIP5 models}},
type = {Article},
volume = {48},
year = {2017}
}
@article{Cheung2017a,
abstract = {{\textcopyright} 2017 American Meteorological Society. Low-frequency internal climate variability (ICV) plays an important role in modulating global surface temperature, regional climate, and climate extremes. However, it has not been completely characterized in the instrumental record and in the Coupled Model Intercomparison Project phase 5 (CMIP5) model ensemble. In this study, the surface temperature ICV of the North Pacific (NP), North Atlantic (NA), and Northern Hemisphere (NH) in the instrumental record and historical CMIP5 all-forcing simulations is isolated using a semiempirical method wherein the CMIP5 ensemble mean is applied as the external forcing signal and removed from each time series. Comparison of ICV signals derived from this semiempirical method as well as from analysis of ICV in CMIP5 preindustrial control runs reveals disagreement in the spatial pattern and amplitude between models and instrumental data on multidecadal time scales ({\textgreater}20 yr). Analysis of the amplitude of total variability and the ICV in the models and instrumental data indicates that the models underestimate ICV amplitude on low-frequency time scales ({\textgreater}20 yr in the NA; {\textgreater}40 yr in the NP), while agreement is found in the NH variability. A multiple linear regression analysis of ICV in the instrumental record shows that variability in the NP drives decadal-to-interdecadal variability in the NH, whereas the NA drives multidecadal variability in the NH. Analysis of the CMIP5 historical simulations does not reveal such a relationship, indicating model limitations in simulating ICV. These findings demonstrate the need to better characterize low-frequency ICV, which may help improve attribution and decadal prediction.},
author = {Cheung, A.H. and Mann, M.E. and Steinman, B.A. and Frankcombe, L.M. and England, M.H. and Miller, S.K.},
doi = {10.1175/JCLI-D-16-0712.1},
journal = {Journal of Climate},
number = {12},
pages = {4763--4776},
title = {{Comparison of low-frequency internal climate variability in CMIP5 models and observations}},
volume = {30},
year = {2017}
}
@article{doi:10.1002/2016GL069544,
abstract = {Abstract The tropical Pacific cooling from the early 1990s to 2013 has contributed to the slowdown of globally averaged sea surface temperatures (SSTs). The origin of this regional cooling trend still remains elusive. Here we demonstrate that the remote impact of Atlantic SST anomalies, as well as local atmosphere-ocean interactions, contributed to the eastern Pacific cooling during this period. By assimilating observed three-dimensional Atlantic temperature and salinity anomalies into a coupled general circulation model, we are able to qualitatively reproduce the observed Pacific decadal trends of SST and sea level pressure (SLP), albeit with reduced amplitude. Although a major part of the Pacific SLP trend can be explained by equatorial Pacific SST forcing only, the origin of this low-frequency variability can be traced back further to the remote impacts of equatorial Atlantic and South Atlantic SST trends. Atlantic SST impacts on the atmospheric circulation can also be detected for the Northeastern Pacific, thus providing a linkage between Atlantic climate and Western North American drought conditions.},
author = {Chikamoto, Y and Mochizuki, T and Timmermann, A and Kimoto, M and Watanabe, M},
doi = {10.1002/2016GL069544},
journal = {Geophysical Research Letters},
keywords = {atmosphere-ocean interaction,climate change,data assimilation,decadal climate variability,global warming hiatus},
number = {13},
pages = {7143--7151},
title = {{Potential tropical Atlantic impacts on Pacific decadal climate trends}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2016GL069544},
volume = {43},
year = {2016}
}
@article{Chiodo2019a,
author = {Chiodo, Gabriel and Oehrlein, Jessica and Polvani, Lorenzo M. and Fyfe, John C. and Smith, Anne K.},
doi = {10.1038/s41561-018-0293-3},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {feb},
number = {2},
pages = {94--99},
title = {{Insignificant influence of the 11-year solar cycle on the North Atlantic Oscillation}},
url = {http://www.nature.com/articles/s41561-018-0293-3},
volume = {12},
year = {2019}
}
@article{Choi2019,
author = {Choi, Jung and Son, Seok-Woo and Park, Rokjin J.},
doi = {10.1007/s00382-018-4370-5},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {apr},
number = {7-8},
pages = {4127--4142},
title = {{Aerosol versus greenhouse gas impacts on Southern Hemisphere general circulation changes}},
url = {http://link.springer.com/10.1007/s00382-018-4370-5},
volume = {52},
year = {2019}
}
@article{Chiang2013,
author = {Chou, Chia and Chiang, John C. H. and Lan, Chia-Wei and Chung, Chia-Hui and Liao, Yi-Chun and Lee, Chia-Jung},
doi = {10.1038/ngeo1744},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {apr},
number = {4},
pages = {263--267},
title = {{Increase in the range between wet and dry season precipitation}},
url = {http://www.nature.com/articles/ngeo1744},
volume = {6},
year = {2013}
}
@article{Chu2014,
abstract = {The Indian Ocean sea surface temperature (SST) variability has been represented with the two dominant variability modes: the Indian Ocean basin-wide (IOBW) and dipole (IOD) modes. Here we investigate future changes of the two modes together with mean state and El Ni{\~{n}}o and Southern Oscillation (ENSO) relationship under the anthropogenic global warming using 20 coupled models that participated in the phase five of Coupled Model Intercomparison Project by comparing the historical run from 1950 to 2005 and the RCP 4.5 run from 2050 to 2099. The five best models are selected based on the evaluation of the 20 models' performances in simulating the two modes and Indian Ocean basic state for the latest 56 years. They are capable of capturing the IOBW and IOD modes in their spatial distribution, seasonal cycle, major periodicity, and relationship with ENSO to some extent. The five best models project the significant changes in the Indian Ocean mean state and variability including the two dominant modes in the latter part of twenty-first century under the anthropogenic warming scenario. First, the annual mean climatological SST displays an IOD-like pattern change over the Indian Ocean with enhanced warming in the northwestern Indian Ocean and relatively weaker warming off the Sumatra--Java coast. It is also noted that the monthly SST variance is increased over the eastern and southwestern Indian Ocean. Second, the IOBW variability on a quasi-biennial time scale will be enhanced due to the strengthening of the ENSO--IOBW mode relationship although the total variance of the IOBW mode will be significantly reduced particularly during late summer and fall. The enhanced air-sea coupling over the Indian-western Pacific climate in response to El Nino activity in the future projection makes favorable condition for a positive IOD while it tends to derive relatively cold temperature over the eastern Indian Ocean. This positive IOD-like ENSO response weakens the relationship between the eastern Indian Ocean and El Nino while strengthens the relationship with western Indian Ocean. Third, the IOD mode, intrinsic coupled mode of the Indian Ocean may not be changed appreciably under the anthropogenic global warming.},
annote = {IOBM and IOD reproduction and future modulations
- CMIP5 historical vs HadISST, NCEP/NCAR
- 1950-2005

- Monthly EOF -{\textgreater} EOF1 = IOBM, EOF2 = IOD
- Most of models can reproduce the IOBM, with realistic seasonality (max at Feb and min at Sep)
(- Poor simulation in one model is due (at least in part) to failure of ENSO simulation {\ldots} by Du et al (2013)) 
- Majority of models can also reproduce the IOD, most with realistic seasonality (max at Sep-Oct and min at Apr-May), although stonger than obs
- Some models fail in reproducing the pattern

- Future modulations},
author = {Chu, Jung-Eun and Ha, Kyung-Ja and Lee, June-Yi and Wang, Bin and Kim, Byeong-Hee and Chung, Chul Eddy},
doi = {10.1007/s00382-013-2002-7},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {1},
pages = {535--551},
title = {{Future change of the Indian Ocean basin-wide and dipole modes in the CMIP5}},
url = {https://doi.org/10.1007/s00382-013-2002-7},
volume = {43},
year = {2014}
}
@article{Chung2014,
author = {Chung, E.-S. and Soden, B. and Sohn, B. J. and Shi, L.},
doi = {10.1073/pnas.1409659111},
issn = {0027-8424},
journal = {Proceedings of the National Academy of Sciences},
month = {aug},
number = {32},
pages = {11636--11641},
title = {{Upper-tropospheric moistening in response to anthropogenic warming}},
url = {http://www.pnas.org/cgi/doi/10.1073/pnas.1409659111},
volume = {111},
year = {2014}
}
@article{Chung2019,
author = {Chung, Eui-Seok and Timmermann, Axel and Soden, Brian J. and Ha, Kyung-Ja and Shi, Lei and John, Viju O.},
doi = {10.1038/s41558-019-0446-4},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {may},
number = {5},
pages = {405--412},
title = {{Reconciling opposing Walker circulation trends in observations and model projections}},
url = {http://www.nature.com/articles/s41558-019-0446-4},
volume = {9},
year = {2019}
}
@incollection{Church2013,
address = {Cambridge, United Kingdom and New York, NY, USA},
author = {Church, J. A. and Clark, P. U. and Cazenave, A. and Gregory, J. M. and Jevrejeva, S. and Levermann, A. and Merrifield, M. A. and Milne, G. A. and Nerem, R. S. and Nunn, P. D. and Payne, A. J. and Pfeffer, W. T. and Stammer, D. and Unnikrishnan, A. S. and Contributing authors},
booktitle = {Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change},
doi = {10.1017/CBO9781107415324.026},
editor = {Stocker, T F and Qin, D and Plattner, G.-K. and Tignor, M and Allen, S K and Boschung, J and Nauels, A and Xia, Y and Bex, V and Midgley, P M},
isbn = {9781107661820},
pages = {1137--1216},
publisher = {Cambridge University Press},
title = {{Sea Level Change}},
url = {https://www.ipcc.ch/report/ar5/wg1},
year = {2013}
}
@article{Church2013a,
abstract = {We evaluate the ability of process based models to reproduce observed global mean sea-level change. When the models are forced by changes in natural and anthropogenic radiative forcing of the climate system and anthropogenic changes in land-water storage, the average of the modelled sea-level change for the periods 1900–2010, 1961–2010 and 1990–2010 is about 80{\%}, 85{\%} and 90{\%} of the observed rise. The modelled rate of rise is over 1 mm yr−1 prior to 1950, decreases to less than 0.5 mm yr−1 in the 1960s, and increases to 3 mm yr−1 by 2000. When observed regional climate changes are used to drive a glacier model and an allowance is included for an ongoing adjustment of the ice sheets, the modelled sea-level rise is about 2 mm yr−1 prior to 1950, similar to the observations. The model results encompass the observed rise and the model average is within 20{\%} of the observations, about 10{\%} when the observed ice sheet contributions since 1993 are added, increasing confidence in future projections for the 21st century. The increased rate of rise since 1990 is not part of a natural cycle but a direct response to increased radiative forcing (both anthropogenic and natural), which will continue to grow with ongoing greenhouse gas emissions.},
author = {Church, John A and Monselesan, Didier and Gregory, Jonathan M and Marzeion, Ben},
doi = {10.1088/1748-9326/8/1/014051},
isbn = {1748-9326},
issn = {17489326},
journal = {Environmental Research Letters},
keywords = {climate change,projections,sea level},
month = {mar},
number = {1},
pages = {014051},
publisher = {IOP Publishing},
title = {{Evaluating the ability of process based models to project sea-level change}},
url = {http://stacks.iop.org/1748-9326/8/i=1/a=014051?key=crossref.4ce665e68a4f89f38916737e9747559f},
volume = {8},
year = {2013}
}
@article{Chylek2020,
abstract = {We compare projections of the observed hemispherical mean surface temperature (HadCRUT4.6.0.0) and the ensemble mean of CMIP5 climate models' simulations on a set of standard regression model forcing variables. We find that the volcanic aerosol regression coefficients of the CMIP5 simulations are consistently significantly larger (by 40–49{\%}) than the volcanic aerosol coefficients of the observed temperature. The probability that the observed differences are caused just by chance is much less than 0.01. The overestimate is due to the climate models' response to volcanic aerosol radiative forcing. The largest overestimate occurs in the winter season of each hemisphere. We hypothesize that the models' parameterization of aerosol-cloud interactions within ice and mixed phase clouds is a likely source of this discrepancy. Furthermore, the models significantly underestimate the effect of solar variability on temperature for both hemispheres.},
author = {Chylek, Petr and Folland, Chris and Klett, James D. and Dubey, Manvendra K.},
doi = {10.1029/2020GL087047},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {feb},
number = {3},
pages = {e2020GL087047},
title = {{CMIP5 Climate Models Overestimate Cooling by Volcanic Aerosols}},
url = {https://onlinelibrary.wiley.com/doi/10.1029/2020GL087047},
volume = {47},
year = {2020}
}
@article{Ciais2019,
abstract = {The global land and ocean carbon sinks have increased proportionally with increasing carbon dioxide emissions during the past decades1. It is thought that Northern Hemisphere lands make a dominant contribution to the global land carbon sink2–7; however, the long-term trend of the northern land sink remains uncertain. Here, using measurements of the interhemispheric gradient of atmospheric carbon dioxide from 1958 to 2016, we show that the northern land sink remained stable between the 1960s and the late 1980s, then increased by 0.5 ± 0.4 petagrams of carbon per year during the 1990s and by 0.6 ± 0.5 petagrams of carbon per year during the 2000s. The increase of the northern land sink in the 1990s accounts for 65{\%} of the increase in the global land carbon flux during that period. The subsequent increase in the 2000s is larger than the increase in the global land carbon flux, suggesting a coincident decrease of carbon uptake in the Southern Hemisphere. Comparison of our findings with the simulations of an ensemble of terrestrial carbon models5,8 over the same period suggests that the decadal change in the northern land sink between the 1960s and the 1990s can be explained by a combination of increasing concentrations of atmospheric carbon dioxide, climate variability and changes in land cover. However, the increase during the 2000s is underestimated by all models, which suggests the need for improved consideration of changes in drivers such as nitrogen deposition, diffuse light and land-use change. Overall, our findings underscore the importance of Northern Hemispheric land as a carbon sink.},
author = {Ciais, P. and Tan, J. and Wang, X. and Roedenbeck, C. and Chevallier, F. and Piao, S.-L. and Moriarty, R. and Broquet, G. and {Le Qu{\'{e}}r{\'{e}}}, C. and Canadell, J. G. and Peng, S. and Poulter, B. and Liu, Z. and Tans, P.},
doi = {10.1038/s41586-019-1078-6},
issn = {0028-0836},
journal = {Nature},
month = {apr},
number = {7751},
pages = {221--225},
title = {{Five decades of northern land carbon uptake revealed by the interhemispheric CO2 gradient}},
url = {http://www.nature.com/articles/s41586-019-1078-6},
volume = {568},
year = {2019}
}
@article{cp-2019-55,
author = {Cleator, S F and Harrison, S P and Nichols, N K and Prentice, I C and Roulstone, I},
doi = {10.5194/cp-2019-55},
journal = {Climate of the Past},
pages = {699--712},
title = {{A new multi-variable benchmark for Last Glacial Maximum climate simulations}},
url = {https://doi.org/10.5194/cp-16-699-2020},
volume = {16},
year = {2020}
}
@article{Clement2015,
abstract = {Ocean circulation changes not needed What causes the pattern of sea surface temperature change that is seen in the North Atlantic Ocean? This naturally occurring quasi-cyclical variation, known as the Atlantic Multidecadal Oscillation (AMO), affects weather and climate. Some have suggested that the AMO is a consequence of variable large-scale ocean circulation. Clement et al. suggest otherwise. They find that the pattern of AMO variability can be produced in a model that does not include ocean circulation changes, but only the effects of changes in air temperatures and winds. Science, this issue p. 320 The Atlantic Multidecadal Oscillation (AMO) is a major mode of climate variability with important societal impacts. Most previous explanations identify the driver of the AMO as the ocean circulation, specifically the Atlantic Meridional Overturning Circulation (AMOC). Here we show that the main features of the observed AMO are reproduced in models where the ocean heat transport is prescribed and thus cannot be the driver. Allowing the ocean circulation to interact with the atmosphere does not significantly alter the characteristics of the AMO in the current generation of climate models. These results suggest that the AMO is the response to stochastic forcing from the mid-latitude atmospheric circulation, with thermal coupling playing a role in the tropics. In this view, the AMOC and other ocean circulation changes would be largely a response to, not a cause of, the AMO. The Atlantic Multidecadal Oscillation does not depend on variable whole-ocean circulation. The Atlantic Multidecadal Oscillation does not depend on variable whole-ocean circulation.},
author = {Clement, Amy C. and Bellomo, Katinka and Murphy, Lisa N. and Cane, Mark A. and Mauritsen, Thorsten and R{\"{a}}del, Gaby and Stevens, Bjorn},
doi = {10.1126/science.aab3980},
issn = {0036-8075, 1095-9203},
journal = {Science},
language = {en},
month = {oct},
number = {6258},
pages = {320--324},
title = {{The Atlantic Multidecadal Oscillation without a role for ocean circulation}},
volume = {350},
year = {2015}
}
@article{Clement1996,
author = {Clement, Amy C. and Seager, Richard and Cane, Mark A. and Zebiak, Stephen E.},
doi = {10.1175/1520-0442(1996)009<2190:AODT>2.0.CO;2},
issn = {0894-8755},
journal = {Journal of Climate},
month = {sep},
number = {9},
pages = {2190--2196},
title = {{An Ocean Dynamical Thermostat}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/1520-0442{\%}281996{\%}29009{\%}3C2190{\%}3AAODT{\%}3E2.0.CO{\%}3B2},
volume = {9},
year = {1996}
}
@article{Coats2016,
abstract = {Multidecadal droughts that occurred during the Medieval Climate Anomaly represent an important target for validating the ability of climate models to adequately characterize drought risk over the near-term future. A prominent hypothesis is that these megadroughts were driven by a centuries-long radiatively forced shift in the mean state of the tropical Pacific Ocean. Here we use a novel combination of spatiotemporal tree ring reconstructions of Northern Hemisphere hydroclimate to infer the atmosphere-ocean dynamics that coincide with megadroughts over the American West and find that these features are consistently associated with 10–30 year periods of frequent cold El Ni{\~{n}}o–Southern Oscillation conditions and not a centuries-long shift in the mean of the tropical Pacific Ocean. These results suggest an important role for internal variability in driving past megadroughts. State-of-the-art climate models from the Coupled Model Intercomparison Project Phase 5, however, do not simulate a consistent association between megadroughts and internal variability of the tropical Pacific Ocean, with implications for our confidence in megadrought risk projections},
author = {Coats, S. and Smerdon, J. E. and Cook, B. I. and Seager, R. and Cook, E. R. and Anchukaitis, K. J.},
doi = {10.1002/2016GL070105},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {sep},
number = {18},
pages = {9886--9894},
title = {{Internal ocean-atmosphere variability drives megadroughts in Western North America}},
volume = {43},
year = {2016}
}
@article{Coats2017,
author = {Coats, S. and Karnauskas, K. B.},
doi = {10.1002/2017GL074622},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {oct},
number = {19},
pages = {9928--9937},
title = {{Are Simulated and Observed Twentieth Century Tropical Pacific Sea Surface Temperature Trends Significant Relative to Internal Variability?}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2017GL074622},
volume = {44},
year = {2017}
}
@article{Cocco2013,
abstract = {{\textless}p{\textgreater}{\textless}p{\textgreater}{\textless}strong{\textgreater}Abstract.{\textless}/strong{\textgreater} Decadal-to-century scale trends for a range of marine environmental variables in the upper mesopelagic layer (UML, 100–600 m) are investigated using results from seven Earth System Models forced by a high greenhouse gas emission scenario. The models as a class represent the observation-based distribution of oxygen (O{\textless}sub{\textgreater}2{\textless}/sub{\textgreater}) and carbon dioxide (CO{\textless}sub{\textgreater}2{\textless}/sub{\textgreater}), albeit major mismatches between observation-based and simulated values remain for individual models. By year 2100 all models project an increase in SST between 2 °C and 3 °C, and a decrease in the pH and in the saturation state of water with respect to calcium carbonate minerals in the UML. A decrease in the total ocean inventory of dissolved oxygen by 2{\%} to 4{\%} is projected by the range of models. Projected O{\textless}sub{\textgreater}2{\textless}/sub{\textgreater} changes in the UML show a complex pattern with both increasing and decreasing trends reflecting the subtle balance of different competing factors such as circulation, production, remineralization, and temperature changes. Projected changes in the total volume of hypoxic and suboxic waters remain relatively small in all models. A widespread increase of CO{\textless}sub{\textgreater}2{\textless}/sub{\textgreater} in the UML is projected. The median of the CO{\textless}sub{\textgreater}2{\textless}/sub{\textgreater} distribution between 100 and 600m shifts from 0.1–0.2 mol m{\textless}sup{\textgreater}{\&}minus;3{\textless}/sup{\textgreater} in year 1990 to 0.2–0.4 mol m{\textless}sup{\textgreater}{\&}minus;3{\textless}/sup{\textgreater} in year 2100, primarily as a result of the invasion of anthropogenic carbon from the atmosphere. The co-occurrence of changes in a range of environmental variables indicates the need to further investigate their synergistic impacts on marine ecosystems and Earth System feedbacks.{\textless}/p{\textgreater}{\textless}/p{\textgreater}},
author = {Cocco, V. and Joos, F. and Steinacher, M. and Fr{\"{o}}licher, T. L. and Bopp, L. and Dunne, J. and Gehlen, M. and Heinze, C. and Orr, J. and Oschlies, A. and Schneider, B. and Segschneider, J. and Tjiputra, J.},
doi = {10.5194/bg-10-1849-2013},
issn = {1726-4189},
journal = {Biogeosciences},
month = {mar},
number = {3},
pages = {1849--1868},
title = {{Oxygen and indicators of stress for marine life in multi-model global warming projections}},
url = {https://www.biogeosciences.net/10/1849/2013/},
volume = {10},
year = {2013}
}
@article{collins2017aerchemmip,
abstract = {Abstract. The Aerosol Chemistry Model Intercomparison Project (AerChemMIP) is endorsed by the Coupled-Model Intercomparison Project 6 (CMIP6) and is designed to quantify the climate and air quality impacts of aerosols and chemically reactive gases. These are specifically near-term climate forcers (NTCFs: methane, tropospheric ozone and aerosols, and their precursors), nitrous oxide and ozone-depleting halocarbons. The aim of AerChemMIP is to answer four scientific questions. 1. How have anthropogenic emissions contributed to global radiative forcing and affected regional climate over the historical period? 2. How might future policies (on climate, air quality and land use) affect the abundances of NTCFs and their climate impacts? 3.How do uncertainties in historical NTCF emissions affect radiative forcing estimates? 4. How important are climate feedbacks to natural NTCF emissions, atmospheric composition, and radiative effects? These questions will be addressed through targeted simulations with CMIP6 climate models that include an interactive representation of tropospheric aerosols and atmospheric chemistry. These simulations build on the CMIP6 Diagnostic, Evaluation and Characterization of Klima (DECK) experiments, the CMIP6 historical simulations, and future projections performed elsewhere in CMIP6, allowing the contributions from aerosols and/or chemistry to be quantified. Specific diagnostics are requested as part of the CMIP6 data request to highlight the chemical composition of the atmosphere, to evaluate the performance of the models, and to understand differences in behaviour between them.},
author = {Collins, William J and Lamarque, Jean-Fran{\c{c}}ois and Schulz, Michael and Boucher, Olivier and Eyring, Veronika and Hegglin, Michaela I and Maycock, Amanda and Myhre, Gunnar and Prather, Michael and Shindell, Drew and Smith, Steven J.},
doi = {10.5194/gmd-10-585-2017},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {feb},
number = {2},
pages = {585--607},
title = {{AerChemMIP: quantifying the effects of chemistry and aerosols in CMIP6}},
url = {https://gmd.copernicus.org/articles/10/585/2017/},
volume = {10},
year = {2017}
}
@article{Collins2010,
author = {Collins, Mat and An, Soon-Il and Cai, Wenju and Ganachaud, Alexandre and Guilyardi, Eric and Jin, Fei-Fei and Jochum, Markus and Lengaigne, Matthieu and Power, Scott and Timmermann, Axel and Vecchi, Gabe and Wittenberg, Andrew},
doi = {10.1038/ngeo868},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {jun},
number = {6},
pages = {391--397},
publisher = {Nature Publishing Group},
title = {{The impact of global warming on the tropical Pacific Ocean and El Ni{\~{n}}o}},
url = {https://doi.org/10.1038/ngeo868 http://10.0.4.14/ngeo868 http://www.nature.com/articles/ngeo868},
volume = {3},
year = {2010}
}
@article{Comyn-Platt2018c,
abstract = {Global methane emissions from natural wetlands and carbon release from permafrost thaw have a positive feedback on climate, yet are not represented in most state-of-the-art climate models. Furthermore, a fraction of the thawed permafrost carbon is released as methane, enhancing the combined feedback strength. We present simulations with an inverted intermediate complexity climate model, which follows prescribed global warming pathways to stabilization at 1.5 or 2.0 °C above pre-industrial levels by the year 2100, and which incorporates a state-of-the-art global land surface model with updated descriptions of wetland and permafrost carbon release. We demonstrate that the climate feedbacks from those two processes are substantial. Specifically, permissible anthropogenic fossil fuel CO2 emission budgets are reduced by 9–15{\%} (25–38 GtC) for stabilization at 1.5 °C, and 6–10{\%} (33–52 GtC) for 2.0 °C stabilization. In our simulations these feedback processes respond more quickly at temperatures below 1.5 °C, and the differences between the 1.5 and 2 °C targets are disproportionately small. This key finding holds for transient emission pathways to 2100 and does not account for longer-term implications of these feedback processes. We conclude that natural feedback processes from wetlands and permafrost must be considered in assessments of transient emission pathways to limit global warming.},
author = {Comyn-Platt, Edward and Hayman, Garry and Huntingford, Chris and Chadburn, Sarah E and Burke, Eleanor J and Harper, Anna B and Collins, William J and Webber, Christopher P and Powell, Tom and Cox, Peter M and Gedney, Nicola and Sitch, Stephen},
doi = {10.1038/s41561-018-0174-9},
issn = {1752-0908},
journal = {Nature Geoscience},
number = {8},
pages = {568--573},
title = {{Carbon budgets for 1.5 and 2°C targets lowered by natural wetland and permafrost feedbacks}},
url = {https://doi.org/10.1038/s41561-018-0174-9},
volume = {11},
year = {2018}
}
@article{Cook2010d,
abstract = {The Asian monsoon system affects more than half of humanity worldwide, yet the dynamical processes that govern its complex spatiotemporal variability are not sufficiently understood to model and predict its behavior, due in part to inadequate long-term climate observations. Here we present the Monsoon Asia Drought Atlas (MADA), a seasonally resolved gridded spatial reconstruction of Asian monsoon drought and pluvials over the past millennium, derived from a network of tree-ring chronologies. MADA provides the spatiotemporal details of known historic monsoon failures and reveals the occurrence, severity, and fingerprint of previously unknown monsoon megadroughts and their close linkages to large-scale patterns of tropical Indo-Pacific sea surface temperatures. MADA thus provides a long-term context for recent monsoon variability that is critically needed for climate modeling, prediction, and attribution.},
author = {Cook, Edward R. and Anchukaitis, Kevin J. and Buckley, Brendan M. and D'Arrigo, Rosanne D. and Jacoby, Gordon C. and Wright, William E.},
doi = {10.1126/science.1185188},
isbn = {0036-8075},
issn = {0036-8075},
journal = {Science},
month = {apr},
number = {5977},
pages = {486--489},
pmid = {20413498},
title = {{Asian Monsoon Failure and Megadrought During the Last Millennium}},
url = {https://www.science.org/doi/10.1126/science.1185188},
volume = {328},
year = {2010}
}
@article{Cook2016c,
author = {Cook, Benjamin I. and Cook, Edward R. and Smerdon, Jason E. and Seager, Richard and Williams, A. Park and Coats, Sloan and Stahle, David W. and D{\'{i}}az, Jos{\'{e}} Villanueva},
doi = {10.1002/wcc.394},
issn = {17577780},
journal = {WIREs Climate Change},
month = {may},
number = {3},
pages = {411--432},
title = {{North American megadroughts in the Common Era: reconstructions and simulations}},
volume = {7},
year = {2016}
}
@article{Cook2015b,
abstract = {40 Climate model projections suggest widespread drying in the Mediterranean Basin and wetting in Fennoscandia in the coming decades largely as a consequence of greenhouse gas forcing of climate. To place these and other " Old World " climate projections into historical perspective based on more complete estimates of natural hydroclimatic variability, we have developed the " Old World Drought Atlas " (OWDA), a set of year-to-year maps of tree-ring reconstructed summer wetness and dryness over Europe and the Mediterranean Basin during the Common Era. The OWDA matches historical accounts of severe drought and wetness with a spatial completeness not previously available. In addition, megadroughts reconstructed over north-central Europe in the 11th and mid-15th centuries reinforce other evidence from North America and Asia that droughts were more severe, extensive, and prolonged over Northern Hemisphere land areas before the 20th century, with an inadequate understanding of their causes. The OWDA provides new data to determine the causes of Old World drought and wetness and attribute past climate variability to forced and/or internal variability.},
author = {Cook, Edward R. and Seager, Richard and Kushnir, Yochanan and Briffa, Keith R. and B{\"{u}}ntgen, Ulf and Frank, David and Krusic, Paul J. and Tegel, Willy and van der Schrier, Gerard and Andreu-Hayles, Laia and Baillie, Mike and Baittinger, Claudia and Bleicher, Niels and Bonde, Niels and Brown, David and Carrer, Marco and Cooper, Richard and {\v{C}}ufar, Katarina and Dittmar, Christoph and Esper, Jan and Griggs, Carol and Gunnarson, Bj{\"{o}}rn and G{\"{u}}nther, Bj{\"{o}}rn and Gutierrez, Emilia and Haneca, Kristof and Helama, Samuli and Herzig, Franz and Heussner, Karl-Uwe and Hofmann, Jutta and Janda, Pavel and Kontic, Raymond and K{\"{o}}se, Nesibe and Kyncl, Tom{\'{a}}{\v{s}} and Levani{\v{c}}, Tom and Linderholm, Hans and Manning, Sturt and Melvin, Thomas M. and Miles, Daniel and Neuwirth, Burkhard and Nicolussi, Kurt and Nola, Paola and Panayotov, Momchil and Popa, Ionel and Rothe, Andreas and Seftigen, Kristina and Seim, Andrea and Svarva, Helene and Svoboda, Miroslav and Thun, Terje and Timonen, Mauri and Touchan, Ramzi and Trotsiuk, Volodymyr and Trouet, Valerie and Walder, Felix and Wa{\.{z}}ny, Tomasz and Wilson, Rob and Zang, Christian},
doi = {10.1126/sciadv.1500561},
isbn = {2375-2548},
issn = {2375-2548},
journal = {Science Advances},
month = {nov},
number = {10},
pages = {e1500561},
pmid = {24889633},
title = {{Old World megadroughts and pluvials during the Common Era}},
url = {https://www.science.org/doi/10.1126/sciadv.1500561},
volume = {1},
year = {2015}
}
@article{Cook2016a,
abstract = {Recent Mediterranean droughts have highlighted concerns that climate change may be contributing to observed drying trends, but natural climate variability in the region is still poorly understood. We analyze 900 years (1100–2012) of Mediterranean drought variability in the Old World Drought Atlas (OWDA), a spatiotemporal tree ring reconstruction of the June-July-August self-calibrating Palmer Drought Severity Index. In the Mediterranean, the OWDA is highly correlated with spring precipitation (April–June), the North Atlantic Oscillation (January–April), the Scandinavian Pattern (January–March), and the East Atlantic Pattern (April–June). Drought variability displays significant east-west coherence across the basin on multidecadal to centennial timescales and north-south antiphasing in the eastern Mediterranean, with a tendency for wet anomalies in the Black Sea region (e.g., Greece, Anatolia, and the Balkans) when coastal Libya, the southern Levant, and the Middle East are dry, possibly related to the North Atlantic Oscillation. Recent droughts are centered in the western Mediterranean, Greece, and the Levant. Events of similar magnitude in the western Mediterranean and Greece occur in the OWDA, but the recent 15 year drought in the Levant (1998–2012) is the driest in the record. Estimating uncertainties using a resampling approach, we conclude that there is an 89{\%} likelihood that this drought is drier than any comparable period of the last 900 years and a 98{\%} likelihood that it is drier than the last 500 years. These results confirm the exceptional nature of this drought relative to natural variability in recent centuries, consistent with studies that have found evidence for anthropogenically forced drying in the region.},
author = {Cook, Benjamin I. and Anchukaitis, Kevin J. and Touchan, Ramzi and Meko, David M. and Cook, Edward R.},
doi = {10.1002/2015JD023929},
issn = {2169-897X},
journal = {Journal of Geophysical Research: Atmospheres},
month = {mar},
number = {5},
pages = {2060--2074},
title = {{Spatiotemporal drought variability in the Mediterranean over the last 900 years}},
url = {https://onlinelibrary.wiley.com/doi/10.1002/2015JD023929},
volume = {121},
year = {2016}
}
@article{Cook2004,
abstract = {The western United States is experiencing a severe multiyear drought that is unprecedented in some hydroclimatic records. Using gridded drought reconstructions that cover most of the western United States over the past 1200 years, we show that this drought pales in comparison to an earlier period of elevated aridity and epic drought in AD 900 to 1300, an interval broadly consistent with the Medieval Warm Period. If elevated aridity in the western United States is a natural response to climate warming, then any trend toward warmer temperatures in the future could lead to a serious long-term increase in aridity over western North America.},
author = {Cook, Edward R. and Woodhouse, Connie A. and Eakin, C. Mark and Meko, David M. and Stahle, David W.},
doi = {10.1126/science.1102586},
isbn = {0036-8075},
issn = {0036-8075},
journal = {Science},
month = {nov},
number = {5698},
pages = {1015--1018},
pmid = {15472040},
title = {{Long-Term Aridity Changes in the Western United States}},
url = {https://www.science.org/doi/10.1126/science.1102586},
volume = {306},
year = {2004}
}
@article{Cook2019b,
author = {Cook, Edward R. and Kushnir, Yochanan and Smerdon, Jason E. and Williams, A. Park and Anchukaitis, Kevin J. and Wahl, Eugene R.},
doi = {10.1007/s00382-019-04696-2},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {aug},
number = {3-4},
pages = {1567--1580},
title = {{A Euro-Mediterranean tree-ring reconstruction of the winter NAO index since 910 C.E.}},
url = {http://link.springer.com/10.1007/s00382-019-04696-2},
volume = {53},
year = {2019}
}
@article{Corvec2017,
abstract = {Abstract. The two components of the tropical overturning circulation, the meridional Hadley circulation (HC) and the zonal Walker circulation (WC), are key to the re-distribution of moisture, heat and mass in the atmosphere. The mid-Pliocene Warm Period (mPWP; ∼ 3.3–3 Ma) is considered a very rough analogue of near-term future climate change, yet changes to the tropical overturning circulations in the mPWP are poorly understood. Here, climate model simulations from the Pliocene Model Intercomparison Project (PlioMIP) are analyzed to show that the tropical overturning circulations in the mPWP were weaker than preindustrial circulations, just as they are projected to be in future climate change. The weakening HC response is consistent with future projections, and its strength is strongly related to the meridional gradient of sea surface warming between the tropical and subtropical oceans. The weakening of the WC is less robust in PlioMIP than in future projections, largely due to inter-model variations in simulated warming of the tropical Indian Ocean (TIO). When the TIO warms faster (slower) than the tropical mean, local upper tropospheric divergence increases (decreases) and the WC weakens less (more). These results provide strong evidence that changes to the tropical overturning circulation in the mPWP and future climate are primarily controlled by zonal (WC) and meridional (HC) gradients in tropical–subtropical sea surface temperatures.},
author = {Corvec, Shawn and Fletcher, Christopher G.},
doi = {10.5194/cp-13-135-2017},
issn = {1814-9332},
journal = {Climate of the Past},
month = {feb},
number = {2},
pages = {135--147},
title = {{Changes to the tropical circulation in the mid-Pliocene and their implications for future climate}},
url = {https://www.clim-past.net/13/135/2017/},
volume = {13},
year = {2017}
}
@article{Covey2018,
author = {Covey, Curt and Doutriaux, Charles and Gleckler, Peter J. and Taylor, Karl E. and Trenberth, Kevin E. and Zhang, Yongxin},
doi = {10.1029/2018GL078926},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {nov},
number = {22},
pages = {12514--12522},
title = {{High‐Frequency Intermittency in Observed and Model‐Simulated Precipitation}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GL078926 https://onlinelibrary.wiley.com/doi/10.1029/2018GL078926},
volume = {45},
year = {2018}
}
@article{Covey2016,
abstract = {Metrics are proposed—that is, a few summary statistics that condense large amounts of data from observations or model simulations—encapsulating the diurnal cycle of precipitation. Vector area averaging of Fourier amplitude and phase produces useful information in a reasonably small number of harmonic dial plots, a procedure familiar from atmospheric tide research. The metrics cover most of the globe but down-weight high-latitude wintertime ocean areas where baroclinic waves are most prominent. This enables intercomparison of a large number of climate models with observations and with each other. The diurnal cycle of precipitation has features not encountered in typical climate model intercomparisons, notably the absence of meaningful “average model” results that can be displayed in a single two-dimensional map. Displaying one map per model guides development of the metrics proposed here by making it clear that land and ocean areas must be averaged separately, but interpreting maps from all models becomes problematic as the size of a multimodel ensemble increases.},
author = {Covey, Curt and Gleckler, Peter J. and Doutriaux, Charles and Williams, Dean N. and Dai, Aiguo and Fasullo, John and Trenberth, Kevin and Berg, Alexis},
doi = {10.1175/JCLI-D-15-0664.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jun},
number = {12},
pages = {4461--4471},
title = {{Metrics for the Diurnal Cycle of Precipitation: Toward Routine Benchmarks for Climate Models}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-15-0664.1},
volume = {29},
year = {2016}
}
@article{Cowan2015,
author = {Cowan, Tim and Cai, Wenju and Ng, Benjamin and England, Matthew},
doi = {10.1175/JCLI-D-14-00661.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {apr},
number = {7},
pages = {2564--2583},
title = {{The Response of the Indian Ocean Dipole Asymmetry to Anthropogenic Aerosols and Greenhouse Gases}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-14-00661.1},
volume = {28},
year = {2015}
}
@article{doi:10.1002/qj.2297,
abstract = {Abstract Incomplete global coverage is a potential source of bias in global temperature reconstructions if the unsampled regions are not uniformly distributed over the planet's surface. The widely used Hadley Centre–Climatic Reseach Unit Version 4 (HadCRUT4) dataset covers on average about 84{\%} of the globe over recent decades, with the unsampled regions being concentrated at the poles and over Africa. Three existing reconstructions with near-global coverage are examined, each suggesting that HadCRUT4 is subject to bias due to its treatment of unobserved regions. Two alternative approaches for reconstructing global temperatures are explored, one based on an optimal interpolation algorithm and the other a hybrid method incorporating additional information from the satellite temperature record. The methods are validated on the basis of their skill at reconstructing omitted sets of observations. Both methods provide results superior to excluding the unsampled regions, with the hybrid method showing particular skill around the regions where no observations are available. Temperature trends are compared for the hybrid global temperature reconstruction and the raw HadCRUT4 data. The widely quoted trend since 1997 in the hybrid global reconstruction is two and a half times greater than the corresponding trend in the coverage-biased HadCRUT4 data. Coverage bias causes a cool bias in recent temperatures relative to the late 1990s, which increases from around 1998 to the present. Trends starting in 1997 or 1998 are particularly biased with respect to the global trend. The issue is exacerbated by the strong El Ni{\~{n}}o event of 1997–1998, which also tends to suppress trends starting during those years.},
author = {Cowtan, Kevin and Way, Robert G},
doi = {10.1002/qj.2297},
journal = {Quarterly Journal of the Royal Meteorological Society},
keywords = {coverage bias,instrumental temperature record,temperature trends},
number = {683},
pages = {1935--1944},
title = {{Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends}},
url = {https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/qj.2297},
volume = {140},
year = {2014}
}
@article{essd-5-187-2013,
author = {Crowley, T J and Unterman, M B},
doi = {10.5194/essd-5-187-2013},
journal = {Earth System Science Data},
number = {1},
pages = {187--197},
title = {{Technical details concerning development of a 1200 yr proxy index for global volcanism}},
url = {https://essd.copernicus.org/articles/5/187/2013/},
volume = {5},
year = {2013}
}
@article{Crueger2018,
abstract = {{\textcopyright}2018. American Geophysical Union. All Rights Reserved. We evaluate the new icosahedral nonhydrostatic atmospheric (ICON-A) general circulation model of the Max Planck Institute for Meteorology that is flexible to be run at grid spacings from a few tens of meters to hundreds of kilometers. A simulation with ICON-A at a low resolution (160 km) is compared to a not-tuned fourfold higher-resolution simulation (40 km). Simulations using the last release of the ECHAM climate model (ECHAM6.3) are also presented at two different resolutions. The ICON-A simulations provide a compelling representation of the climate and its variability. The climate of the low-resolution ICON-A is even slightly better than that of ECHAM6.3. Improvements are obtained in aspects that are sensitive to the representation of orography, including the representation of cloud fields over eastern-boundary currents, the latitudinal distribution of cloud top heights, and the spatial distribution of convection over the Indian Ocean and the Maritime Continent. Precipitation over land is enhanced, in particular at high-resolution ICON-A. The response of precipitation to El Ni{\~{n}}o sea surface temperature variability is close to observations, particularly over the eastern Indian Ocean. Some parameterization changes lead to improvements, for example, with respect to rain intensities and the representation of equatorial waves, but also imply a warmer troposphere, which we suggest leads to an unrealistic poleward mass shift. Many biases familiar to ECHAM6.3 are also evident in ICON-A, namely, a too zonal SPCZ, an inadequate representation of north hemispheric blocking, and a relatively poor representation of tropical intraseasonal variability.},
author = {Crueger, T. and Giorgetta, M. A. and Brokopf, R. and Esch, M. and Fiedler, S. and Hohenegger, C. and Kornblueh, L. and Mauritsen, T. and Nam, C. and Naumann, A. K. and Peters, K. and Rast, S. and Roeckner, E. and Sakradzija, M. and Schmidt, H. and Vial, J. and Vogel, R. and Stevens, B.},
doi = {10.1029/2017MS001233},
issn = {1942-2466},
journal = {Journal of Advances in Modeling Earth Systems},
month = {jul},
number = {7},
pages = {1638--1662},
title = {{ICON‐A, The Atmosphere Component of the ICON Earth System Model: II. Model Evaluation}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2017MS001233},
volume = {10},
year = {2018}
}
@article{DAgostino2020,
abstract = {Past changes of Southern Hemisphere (SH) monsoons are less investigated than their northern counterpart because of relatively scarce paleodata. In addition, projections of SH monsoons are less robust than in the Northern Hemisphere. Here, we use an energetic framework to shed lights on the mechanisms determining SH monsoonal response to external forcing: precession change at the mid-Holocene versus future greenhouse gas increase (RCP8.5). Mechanisms explaining the monsoon response are investigated by decomposing the moisture budget in thermodynamic and dynamic components. SH monsoons weaken and contract in the multimodel mean of midHolocene simulations as a result of decreased net energy input and weakening of the dynamic component. In contrast, SH monsoons strengthen and expand in the RCP8.5 multimodel mean, as a result of increased net energy input and strengthening of the thermodynamic component. However, important regional differences on monsoonal precipitation emerge from the local response of Hadley and Walker circulations. In the midHolocene, the combined effect of Walker–Hadley changes explains the land–ocean precipitation contrast. Conversely, the increased local gross moist stability explains the increased local precipitation and net energy input under circulation weakening in RCP8.5.},
author = {D'Agostino, Roberta and Brown, Josephine R. and Moise, Aurel and Nguyen, Hanh and {Silva Dias}, Pedro L. and Jungclaus, Johann},
doi = {10.1175/JCLI-D-19-0672.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {nov},
number = {22},
pages = {9595--9613},
title = {{Contrasting Southern Hemisphere Monsoon Response: MidHolocene Orbital Forcing versus Future Greenhouse Gas–Induced Global Warming}},
url = {https://journals.ametsoc.org/jcli/article/33/22/9595/353585/Contrasting-Southern-Hemisphere-Monsoon-Response},
volume = {33},
year = {2020}
}
@article{DAgostino2019a,
author = {D'Agostino, Roberta and Bader, J{\"{u}}rgen and Bordoni, Simona and Ferreira, David and Jungclaus, Johann},
doi = {10.1029/2018GL081589},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {feb},
number = {3},
pages = {1591--1601},
title = {{Northern Hemisphere Monsoon Response to Mid‐Holocene Orbital Forcing and Greenhouse Gas‐Induced Global Warming}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GL081589},
volume = {46},
year = {2019}
}
@article{DAndrea1998,
abstract = {{\{}$\backslash$enspace{\}}As a part of the Atmospheric Model Intercomparison Project (AMIP), the behaviour of 15 general circulation models has been analysed in order to diagnose and compare the ability of the different models in simulating Northern Hemisphere midlatitude atmospheric blocking. In accordance with the established AMIP procedure, the 10-year model integrations were performed using prescribed, time-evolving monthly mean observed SSTs spanning the period January 1979--December 1988. Atmospheric observational data (ECMWF analyses) over the same period have been also used to verify the models results. The models involved in this comparison represent a wide spectrum of model complexity, with different horizontal and vertical resolution, numerical techniques and physical parametrizations, and exhibit large differences in blocking behaviour. Nevertheless, a few common features can be found, such as the general tendency to underestimate both blocking frequency and the average duration of blocks. The problem of the possible relationship between model blocking and model systematic errors has also been assessed, although without resorting to ad-hoc numerical experimentation it is impossible to relate with certainty particular model deficiencies in representing blocking to precise parts of the model formulation.},
author = {D'Andrea, F and Tibaldi, S and Blackburn, M and Boer, G and D{\'{e}}qu{\'{e}}, M and Dix, M R and Dugas, B and Ferranti, L and Iwasaki, T and Kitoh, A and Pope, V and Randall, D and Roeckner, E and Strauss, D and Stern, W and {Van den Dool}, H. and Williamson, D},
doi = {10.1007/s003820050230},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {may},
number = {6},
pages = {385--407},
title = {{Northern Hemisphere atmospheric blocking as simulated by 15 atmospheric general circulation models in the period 1979–1988}},
url = {http://link.springer.com/10.1007/s003820050230},
volume = {14},
year = {1998}
}
@article{Datwyler2018a,
author = {D{\"{a}}twyler, Christoph and Neukom, Raphael and Abram, Nerilie J. and Gallant, Ailie J. E. and Grosjean, Martin and Jacques-Coper, Mart{\'{i}}n and Karoly, David J. and Villalba, Ricardo},
doi = {10.1007/s00382-017-4015-0},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {sep},
number = {5-6},
pages = {2321--2339},
title = {{Teleconnection stationarity, variability and trends of the Southern Annular Mode (SAM) during the last millennium}},
url = {http://link.springer.com/10.1007/s00382-017-4015-0},
volume = {51},
year = {2018}
}
@article{Dai2015,
abstract = {This study investigates global surface temperature data since 1920, and the Interdecadal Pacific Oscillation is found to be largely responsible for temperature fluctuations, exhibiting different spatial patterns to anthropogenic temperature drivers.},
author = {Dai, Aiguo and Fyfe, John C. and Xie, Shang-Ping and Dai, Xingang},
doi = {10.1038/nclimate2605},
isbn = {1758-6798},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {jun},
number = {6},
pages = {555--559},
title = {{Decadal modulation of global surface temperature by internal climate variability}},
url = {http://www.nature.com/articles/nclimate2605},
volume = {5},
year = {2015}
}
@article{Dai2019,
abstract = {{\textcopyright} 2018 Springer-Verlag GmbH Germany, part of Springer Nature It is known that internal climate variability (ICV) can influence trends seen in observations and individual model simulations over a period of decades. This makes it difficult to quantify the forced response to external forcing. Here we analyze two large ensembles of simulations from 1950 to 2100 by two fully-coupled climate models, namely the CESM1 and CanESM2, to quantify ICV's influences on estimated trends in annual surface air temperature (Tas) and precipitation (P) over different time periods. Results show that the observed trends since 1979 in global-mean Tas and P are within the spread of the CESM1-simulated trends while the CanESM2 overestimates the historical changes, likely due to its deficiencies in simulating historical non-CO2forcing. Both models show considerable spreads in the Tas and P trends among the individual simulations, and the spreads decrease rapidly as the record length increases to about 40 (50) years for global-mean Tas (P). Because of ICV, local and regional P trends may remain statistically insignificant and differ greatly among individual model simulations over most of the globe until the later part of the twenty-first century even under a high emissions scenario, while local Tas trends since 1979 are already statistically significant over many low-latitude regions and are projected to become significant over most of the globe by the 2030s. The largest influences of ICV come from the Inter-decadal Pacific Oscillation and polar sea ice. In contrast to the realization-dependent ICV, the forced Tas response to external forcing has a temporal evolution that is similar over most of the globe (except its amplitude). For annual precipitation, however, the temporal evolution of the forced response is similar (opposite) to that of Tas over many mid-high latitude areas and the ITCZ (subtropical regions), but close to zero over the transition zones between the regions with positive and negative trends. The ICV in the transient climate change simulations is slightly larger than that in the control run for P (and other related variables such as water vapor), but similar for Tas. Thus, the ICV for P from a control run may need to be scaled up in detection and attribution analyses.},
author = {Dai, Aiguo and Bloecker, Christine E.},
doi = {10.1007/s00382-018-4132-4},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jan},
number = {1-2},
pages = {289--306},
title = {{Impacts of internal variability on temperature and precipitation trends in large ensemble simulations by two climate models}},
url = {http://link.springer.com/10.1007/s00382-018-4132-4},
volume = {52},
year = {2019}
}
@article{Danabasoglu2016,
abstract = {Simulated inter-annual to decadal variability and trends in the North Atlantic for the 1958-2007 period from twenty global ocean - sea-ice coupled models are presented. These simulations are performed as contributions to the second phase of the Coordinated Ocean-ice Reference Experiments (CORE-II). The study is Part II of our companion paper (Danabasoglu et al., 2014) which documented the mean states in the North Atlantic from the same models. A major focus of the present study is the representation of Atlantic meridional overturning circulation (AMOC) variability in the participating models. Relationships between AMOC variability and those of some other related variables, such as subpolar mixed layer depths, the North Atlantic Oscillation (NAO), and the Labrador Sea upper-ocean hydrographic properties, are also investigated. In general, AMOC variability shows three distinct stages. During the first stage that lasts until the mid- to late-1970s, AMOC is relatively steady, remaining lower than its long-term (1958-2007) mean. Thereafter, AMOC intensifies with maximum transports achieved in the mid- to late-1990s. This enhancement is then followed by a weakening trend until the end of our integration period. This sequence of low frequency AMOC variability is consistent with previous studies. Regarding strengthening of AMOC between about the mid-1970s and the mid-1990s, our results support a previously identified variability mechanism where AMOC intensification is connected to increased deep water formation in the subpolar North Atlantic, driven by NAO-related surface fluxes. The simulations tend to show general agreement in their temporal representations of, for example, AMOC, sea surface temperature (SST), and subpolar mixed layer depth variabilities. In particular, the observed variability of the North Atlantic SSTs is captured well by all models. These findings indicate that simulated variability and trends are primarily dictated by the atmospheric datasets which include the influence of ocean dynamics from nature superimposed onto anthropogenic effects. Despite these general agreements, there are many differences among the model solutions, particularly in the spatial structures of variability patterns. For example, the location of the maximum AMOC variability differs among the models between Northern and Southern Hemispheres.},
author = {Danabasoglu, Gokhan and Yeager, Steve G. and Kim, Who M. and Behrens, Erik and Bentsen, Mats and Bi, Daohua and Biastoch, Arne and Bleck, Rainer and B{\"{o}}ning, Claus and Bozec, Alexandra and Canuto, Vittorio M. and Cassou, Christophe and Chassignet, Eric and Coward, Andrew C. and Danilov, Sergey and Diansky, Nikolay and Drange, Helge and Farneti, Riccardo and Fernandez, Elodie and Fogli, Pier Giuseppe and Forget, Gael and Fujii, Yosuke and Griffies, Stephen M. and Gusev, Anatoly and Heimbach, Patrick and Howard, Armando and Ilicak, Mehmet and Jung, Thomas and Karspeck, Alicia R. and Kelley, Maxwell and Large, William G. and Leboissetier, Anthony and Lu, Jianhua and Madec, Gurvan and Marsland, Simon J. and Masina, Simona and Navarra, Antonio and Nurser, A. J.George and Pirani, Anna and Romanou, Anastasia and y.M{\'{e}}lia David, Salas and Samuels, Bonita L. and Scheinert, Markus and Sidorenko, Dmitry and Sun, Shan and Treguier, Anne Marie and Tsujino, Hiroyuki and Uotila, Petteri and Valcke, Sophie and Voldoire, Aurore and Wang, Qiang and Yashayaev, Igor},
doi = {10.1016/j.ocemod.2015.11.007},
isbn = {14635003},
issn = {14635003},
journal = {Ocean Modelling},
keywords = {Atlantic meridional overturning circulation variab,Atmospheric forcing,Global ocean - sea-ice modelling,Inter-annual to decadal variability and mechanisms,Ocean model comparisons,Variability in the North Atlantic},
pages = {65--90},
title = {{North Atlantic simulations in Coordinated Ocean-ice Reference Experiments phase II (CORE-II). Part II: Inter-annual to decadal variability}},
url = {http://dx.doi.org/10.1016/j.ocemod.2013.10.005},
volume = {97},
year = {2016}
}
@article{Danabasoglu2014,
abstract = {Simulations characteristics from eighteen global ocean - seaice coupled models are presented with a focus on the mean Atlantic MOC and other related fields in the North Atlantic. These experiments use inter-annually varying atmospheric forcing data sets for the 60-year period from 1948 to 2007 and are performed as contributions to the second phase of the CORE-II. The protocol for conducting such CORE-II experiments is summarized. Despite using the same atmospheric forcing data sets, the solutions show significant inter-model differences. As most models also differ from available observations, biases in sea-ice cover, upper-ocean potential temperature and salinity distributions, and mixed layer depths in the labrador Sea region are identified as contributors to inter-model differences in AMOC. These differences and biases from observations are attributed primarily to use of a wide variety of sea-ice models and diverse snow and sea-ice albedo treatmnets as well as to use of different subgrid scale parameterizations and parameter values in the ocean models. Based on the metrics considered, the majority of the models appear suitable for use in studies involving the North Atlantic, but a few models need further improvements.},
author = {Danabasoglu, Gokhan and Yeager, S and Bailey, David and Behrens, Erik and Bentsen, Mats and Bi, Daohua and Biastoch, Arne and Boning, C and Bozec, Alexandra and Cassou, Christophe and Chassignet, Eric and Danilov, Sergey and Diansky, Nikolay and Drange, Helge and Farneti, Riccardo and Fernandez, Elodie and Fogli, Pier Giuseppe and Forget, Gael and Gusev, Anatoly and Heimbach, Patrick and Howard, Armando and Griffies, Stephen M. and Kelley, Maxwell and Large, William G. and Leboissetier, Anthony and Lu, Jianhua and Maisonnave, E and Marsland, Simon J. and Masina, Simona and Navarra, Antonio and Nurser, A J G and {Salas y Mejia}, D and Samuels, Bonita L. and Scheinert, Markus and Sidorenko, Dmitry and Terray, L and Treguier, A.-M. and Tsujino, Hiroyuki and Uotila, Petteri and Valcke, Sophie and Voldoire, Aurore and Wang, Qiang},
doi = {10.1016/j.ocemod.2013.10.005},
issn = {1463-5003},
journal = {Ocean Modelling},
keywords = {model},
month = {jan},
pages = {76--107},
publisher = {Elsevier},
title = {{North Atlantic Simulations in Coordinated Ocean-ice Reference Experiments phase 2 (CORE-II). Part 1: Mean States}},
url = {https://www.sciencedirect.com/science/article/pii/S1463500313001868 http://dx.doi.org/10.1016/j.ocemod.2013.10.005},
volume = {73},
year = {2014}
}
@article{Dangendorf2015,
abstract = {While there is scientific consensus that global and local mean sea level (GMSL and LMSL) has risen since the late nineteenth century, the relative contribution of natural and anthropogenic forcing remains unclear. Here we provide a probabilistic upper range of long-term persistent natural GMSL/LMSL variability (P=0.99), which in turn, determines the minimum/maximum anthropogenic contribution since 1900. To account for different spectral characteristics of various contributing processes, we separate LMSL into two components: a slowly varying volumetric component and a more rapidly changing atmospheric component. We find that the persistence of slow natural volumetric changes is underestimated in records where transient atmospheric processes dominate the spectrum. This leads to a local underestimation of possible natural trends of up to ∼1 mm per year erroneously enhancing the significance of anthropogenic footprints. The GMSL, however, remains unaffected by such biases. On the basis of a model assessment of the separate components, we conclude that it is virtually certain (P=0.99) that at least 45{\%} of the observed increase in GMSL is of anthropogenic origin.},
author = {Dangendorf, S{\"{o}}nke and Marcos, Marta and M{\"{u}}ller, Alfred and Zorita, Eduardo and Riva, Riccardo and Berk, Kevin and Jensen, J{\"{u}}rgen},
doi = {10.1038/ncomms8849},
isbn = {2041-1723},
issn = {20411723},
journal = {Nature Communications},
keywords = {Anthropology,Ocean sciences,Palaeoceanography},
month = {dec},
number = {1},
pages = {7849},
pmid = {26220773},
publisher = {Nature Publishing Group},
title = {{Detecting anthropogenic footprints in sea level rise}},
url = {http://www.nature.com/articles/ncomms8849},
volume = {6},
year = {2015}
}
@article{Dansgaard1993,
abstract = {RECENT results1,2 from two ice cores drilled in central Greenland have revealed large, abrupt climate changes of at least regional extent during the late stages of the last glaciation, suggesting that climate in the North Atlantic region is able to reorganize itself rapidly, perhaps even within a few decades. Here we present a detailed stable-isotope record for the full length of the Greenland Ice-core Project Summit ice core, extending over the past 250 kyr according to a calculated timescale. We find that climate instability was not confined to the last glaciation, but appears also to have been marked during the last interglacial (as explored more fully in a companion paper3) and during the previous Saale–Holstein glacial cycle. This is in contrast with the extreme stability of the Holocene, suggesting that recent climate stability may be the exception rather than the rule. The last interglacial seems to have lasted longer than is implied by the deep-sea SPECMAP record4, in agreement with other land-based observations5,6. We suggest that climate instability in the early part of the last interglacial may have delayed the melting of the Saalean ice sheets in America and Eurasia, perhaps accounting for this discrepancy.},
author = {Dansgaard, W and Johnsen, S J and Clausen, H B and Dahl-Jensen, D and Gundestrup, N S and Hammer, C U and Hvidberg, C S and Steffensen, J P and Sveinbj{\"{o}}rnsdottir, A E and Jouzel, J and Bond, G},
doi = {10.1038/364218a0},
issn = {1476-4687},
journal = {Nature},
number = {6434},
pages = {218--220},
title = {{Evidence for general instability of past climate from a 250-kyr ice-core record}},
url = {https://doi.org/10.1038/364218a0},
volume = {364},
year = {1993}
}
@article{bg-17-5129-2020,
author = {Davies-Barnard, T and Meyerholt, J and Zaehle, S and Friedlingstein, P and Brovkin, V and Fan, Y and Fisher, R A and Jones, C D and Lee, H and Peano, D and Smith, B and W{\aa}rlind, D and Wiltshire, A J},
doi = {10.5194/bg-17-5129-2020},
journal = {Biogeosciences},
number = {20},
pages = {5129--5148},
title = {{Nitrogen cycling in CMIP6 land surface models: progress and limitations}},
url = {https://bg.copernicus.org/articles/17/5129/2020/},
volume = {17},
year = {2020}
}
@article{davini2015tropical,
abstract = {Atlantic Multidecadal Variability (AMV) is known for influencing the mid-latitude climate variability, especially over the European region. This letter assesses the impact of the wintertime AMV in a group of 200-year atmospheric-only numerical experiments, in which the atmosphere is forced with positive and negative AMV-like sea surface temperatures (SSTs) and sea ice concentration patterns. Anomalies are applied separately to the whole North Atlantic ocean, to the extratropics (north of 30° N) and to the tropics (between 0° and 30° N). Results show that AMV anomalies considerably affect the North Atlantic Oscillation (NAO), the jet stream variability and the frequency of atmospheric blocking over the Euro-Atlantic sector, resulting in a negative (positive) NAO during positive (negative) AMV. It is found that the bulk of the signal is originated in the tropics and it is associated with a Gill-like response - an anomalous upper tropospheric streamfunction dipole over the tropical Atlantic driven by the SST anomalies - and with the subsequent structural change of the upper-tropospheric jet, which affects the propagation of Rossby waves in the North Atlantic. Conversely, the NAO response is almost negligible when the AMV anomalies are applied only to the extratropics, suggesting that the relevance of SST anomalies along the North Atlantic frontal zone may be overestimated.},
author = {Davini, Paolo and Hardenberg, Jost Von and Corti, Susanna},
doi = {10.1088/1748-9326/10/9/094010},
journal = {Environmental Research Letters},
keywords = {Atlantic Multidecadal Variability (AMV),Atmospheric blocking,Global Climate Models,North Atlantic Oscillation (NAO)},
number = {9},
pages = {94010},
publisher = {IOP Publishing},
title = {{Tropical origin for the impacts of the Atlantic Multidecadal Variability on the Euro-Atlantic climate}},
url = {https://iopscience.iop.org/article/10.1088/1748-9326/10/9/094010/pdf},
volume = {10},
year = {2015}
}
@article{ISI:000388677100009,
abstract = {The correct simulation of midlatitude atmospheric blocking has always been a main concern since the earliest days of numerical modeling of Earth's atmosphere. To this day blocking represents a considerable source of error for general circulation models from both a numerical weather prediction and a climate perspective. In the present work, 20 years of global climate model (GCM) developments are analyzed from the special point of view of Northern Hemisphere atmospheric blocking simulation. Making use of a series of equivalent metrics, three generations of GCMs are compared. This encompasses a total of 95 climate models, many of which are different-successive-versions of the same model. Results from model intercomparison projects AMIP1 (1992), CMIP3 (2007), and CMIP5 (2012) are taken into consideration. Although large improvements are seen over the Pacific Ocean, only minor advancements have been achieved over the Euro-Atlantic sector. Some of the most recent GCMs still exhibit the same negative bias as 20 years ago in this region, associated with large geopotential height systematic errors. Some individual models, nevertheless, have improved and do show good performances in both sectors. Negligible differences emerge among ocean-coupled or atmosphere-only simulations, suggesting weak relevance of sea surface temperature biases. Conversely, increased horizontal resolution seems to be able to alleviate the Euro-Atlantic blocking bias.},
address = {45 BEACON ST, BOSTON, MA 02108-3693 USA},
author = {Davini, Paolo and D'Andrea, Fabio},
doi = {10.1175/JCLI-D-16-0242.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {dec},
number = {24},
pages = {8823--8840},
publisher = {AMER METEOROLOGICAL SOC},
title = {{Northern Hemisphere Atmospheric Blocking Representation in Global Climate Models: Twenty Years of Improvements?}},
type = {Article},
volume = {29},
year = {2016}
}
@article{Davini2014,
abstract = {The representation of the wintertime North Atlantic Oscillation (NAO) and its relationship with atmospheric blocking and the Atlantic jet stream is investigated in a set of CMIP5 models. It is shown that some state-of-the-art climate models are unable to correctly simulate the physical processes connected to the NAO. This is especially true for models with a strongly underestimated frequency of high-latitude blocking over Greenland. In these models the first empirical orthogonal function (EOF1) of the Euro-Atlantic sector can represent at least three different categories of dominant modes of variability associated with different prevalent regions of blocking occurrence and jet stream displacements. It is therefore possible to show that such ``biased NAOs'' are connected with different dynamical processes with respect to the canonical NAO seen in observations. Since the NAO is a widely used concept in scientific community, the consequent ``dynamical misinterpretation'' of the NAO that can result when climate models are analyzed may have important implications for the NAO-related studies. This may be especially relevant for the ones involving climate scenarios, since these modeled NAOs may react differently to greenhouse gas forcing.},
annote = {Model evaluation of NAO in CMIP5 models
CMIP5 historical 1951-2005
In comparison to NCEP/NCAR and 20CR
- NAO defined through EOF of z500
- Tibaldi and Molteni (1990) blocking index
- Jet latitude index

- In a Taylor diagram of EOF-based NAO, no improvement from CMIP3 to CMIP5
- Woollings et al (2008): Greenland blocking as a key element of the NAO
- Majority of the models realistically simulate the association of EOF-based NAO with blocking and jet variations, but some models do not {\ldots} Blocking in equatorward instead of poleward side of jet, jet pulsing instead of wobbling, or too annular},
author = {Davini, Paolo and Cagnazzo, Chiara},
doi = {10.1007/s00382-013-1970-y},
issn = {1432-0894},
journal = {Climate Dynamics},
month = {sep},
number = {5},
pages = {1497--1511},
title = {{On the misinterpretation of the North Atlantic Oscillation in CMIP5 models}},
url = {https://doi.org/10.1007/s00382-013-1970-y},
volume = {43},
year = {2014}
}
@article{Davini2017,
abstract = {Abstract The numerical simulation of atmospheric blocking, in particular over the Euro-Atlantic region, still represents a main concern for the climate modeling community. We discuss the Northern Hemisphere winter atmospheric blocking representation in a set of 30 year atmosphere-only simulations using the EC-Earth Earth System Model with several ensemble members at five different horizontal resolutions (from 125 to 16 km). Results show that the negative bias in blocking frequency over Europe becomes negligible at resolutions of about 40 and 25 km. A combined effect by the more resolved orography and by a change in tropical precipitation is identified as the source of an upper tropospheric planetary wave. At the same time, a weakening of the meridional temperature gradient reduces the upper level baroclinicity and the zonal mean winds. Following these changes, in the high-resolution configurations the Atlantic eddy-driven jet stream is weakened favoring the breaking of synoptic Rossby waves over the Atlantic ridge and thus increasing the simulated European blocking frequency. However, at high-resolution the Atlantic jet stream is too weak and the blocking duration is still underestimated. This suggests that the optimal blocking frequencies are achieved through compensation of errors between eddies found at upper levels (too strong) and eddies at lower levels (too weak). This also implies that eddies are not necessarily better represented at higher resolutions.},
author = {Davini, P and Corti, S and D'Andrea, F and Rivi{\`{e}}re, G and von Hardenberg, J},
doi = {10.1002/2017MS001082},
journal = {Journal of Advances in Modeling Earth Systems},
number = {7},
pages = {2615--2634},
title = {{Improved Winter European Atmospheric Blocking Frequencies in High-Resolution Global Climate Simulations}},
volume = {9},
year = {2017}
}
@article{Davini2020c,
abstract = {A comprehensive analysis of the representation of winter and summer Northern Hemisphere atmospheric blocking in global climate simulations in both present and future climate is presented. Three generations of climate models are considered: CMIP3 (2007), CMIP5 (2012), and CMIP6 (2019). All models show common and extended underestimation of blocking frequencies, but a reduction of the negative biases in successive model generations is observed. However, in some specific regions and seasons such as the winter European sector, even CMIP6 models are not yet able to achieve the observed blocking frequency. For future decades the vast majority of models simulate a decrease of blocking frequency in both winter and summer, with the exception of summer blocking over the Urals and winter blocking over western North America. Winter predicted decreases may be even larger than currently estimated considering that models with larger blocking frequencies, and hence generally smaller errors, show larger reduction. Nonetheless, trends computed over the historical period are weak and often contrast with observations: This is particularly worrisome for summer Greenland blocking where models and observations significantly disagree. Finally, the intensity of global warming is related to blocking changes: wintertime European and North Pacific blocking are expected to decrease following larger global mean temperatures, while Ural summer blocking is expected to increase.},
author = {Davini, Paolo and D'Andrea, Fabio},
doi = {10.1175/JCLI-D-19-0862.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Blocking,Climate change,Climate models,Climate sensitivity,Climate variability,Jets},
number = {23},
pages = {10021--10038},
title = {{From CMIP3 to CMIP6: Northern hemisphere atmospheric blocking simulation in present and future climate}},
volume = {33},
year = {2020}
}
@article{Davis2017,
author = {Davis, Nicholas and Birner, Thomas},
doi = {10.1175/JCLI-D-16-0371.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {feb},
number = {4},
pages = {1211--1231},
title = {{On the Discrepancies in Tropical Belt Expansion between Reanalyses and Climate Models and among Tropical Belt Width Metrics}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-16-0371.1},
volume = {30},
year = {2017}
}
@article{Davy2020,
abstract = {Here we evaluate the sea ice, surface air temperature, and sea level pressure from 34 of the models used in phase 6 of the Coupled Model Intercomparison Project (CMIP6) for their biases, trends, and variability, and compare them to the CMIP5 ensemble and ERA5 for the period 1979 to 2004. The principal purpose of this assessment is to provide an overview of the ability of the CMIP6 ensemble to represent the Arctic climate, and to see how this has changed since the last phase of CMIP. Overall, we find a distinct improvement in the representation of the sea ice volume and extent, the latter mostly linked to improvements in the seasonal cycle in the Barents Sea. However, numerous model biases have persisted into CMIP6 including too-cold conditions in the winter (4-K cold bias) and a negative trend in the day-to-day variability over ice in winter. We find that under the low-emission scenario, SSP126, the Arctic climate is projected to stabilize by 2060 with an annual mean sea ice extent of around 2.5 million km2 and an annual mean temperature 4.7 K warmer than the early-twentieth-century average, compared to 1.7 K of warming globally.},
author = {Davy, Richard and Outten, Stephen},
doi = {10.1175/JCLI-D-19-0990.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {aug},
number = {18},
pages = {8047--8068},
title = {{The Arctic Surface Climate in CMIP6: Status and Developments since CMIP5}},
url = {https://doi.org/10.1175/JCLI-D-19-0990.1},
volume = {33},
year = {2020}
}
@article{Vries2019,
abstract = {The strong horizontal gradients in sea surface temperature (SST) of the Atlantic Gulf Stream exert a detectable influence on extratropical cyclones propagating across the region. This is shown in a sensitivity experiment where 24 winter storms taken from ERA-Interim are simulated with HARMONIE at 10-km resolution. Each storm is simulated twice. First, using observed SST (REF). In the second simulation a smoothed SST is offered (SMTH), while lateral and upper-level boundary conditions are unmodified. Each storm pair propagates approximately along the same track, however their intensities (as measured by maximal near-surface wind speed or 850-hPa relative vorticity) differ up to ± 25{\%}. A 30-member ensemble created for one of the storms shows that on a single-storm level the response is systematic rather than random. To explain the broad response in storm strength, we show that the SST-adjustment modifies two environmental parameters: surface latent heat flux (LHF) and low-level baroclinicity (B). LHF influences storms by modifying diabatic heating and boundary-layer processes such as vertical mixing. The position of each storm's track relative to the SST-front is important. South of the SST-front the smoothing leads to lower SST, reduced LHF and storms with generally weaker maximum near-surface winds. North of the SST-front the increased LHF tend to enhance the winds, but the accompanying changes in baroclinicity are not necessarily favourable. Together these mechanisms explain up to 80{\%} of the variability in the near-surface maximal wind speed change. Because the mechanisms are less effective in explaining more dynamics-oriented indicators like 850 hPa relative vorticity, we hypothesise that part of the wind-speed change is related to adjustment of the boundary-layer processes in response to the LHF and B changes.},
author = {de Vries, Hylke and Scher, Sebastian and Haarsma, Rein and Drijfhout, Sybren and van Delden, Aarnout},
doi = {10.1007/s00382-018-4486-7},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {9},
pages = {5899--5909},
title = {{How Gulf-Stream SST-fronts influence Atlantic winter storms}},
url = {https://doi.org/10.1007/s00382-018-4486-7},
volume = {52},
year = {2019}
}
@article{DelSole2018,
abstract = {Optimal fingerprinting is a standard method for detecting climate changes. Among the uncertainties taken into account by this method, one is the fact that the response to climate forcing is not known exactly, but in practice is estimated from ensemble averages of model simulations. This uncertainty can be taken into account using an Error-in-Variables model (or equivalently, the Total Least Squares method), and can be expressed through confidence intervals. Unfortunately, the predominant paradigm (likelihood ratio theory) for deriving confidence intervals is not guaranteed to work because the number of parameters that are estimated in the Error-in-Variables model grows with the number of observations. This paper discusses various methods for deriving confidence intervals and shows that the widely-used intervals proposed in the seminal paper by Allen and Stott are effectively equivalent to bias-corrected intervals from likelihood ratio theory. A new, computationally simpler, method for computing these intervals is derived. Nevertheless, these confidence intervals are incorrect in the ``weak-signal regime''. This conclusion does not necessarily invalidate previous detection and attribution studies because many such studies lie in the strong-signal regime, for which standard methods give correct confidence intervals. A new diagnostic is introduced to check whether or not a data set lies in the weak-signal regime. Finally, and most importantly, a bootstrap method is shown to give correct confidence intervals in both strong- and weak-signal regimes, and always produces finite confidence intervals, in contrast to the likelihood ratio method which can give unbounded intervals that do not match the actual uncertainty.},
author = {DelSole, Timothy and Trenary, Laurie and Yan, Xiaoqin and Tippett, Michael K},
doi = {10.1007/s00382-018-4356-3},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {apr},
number = {7-8},
pages = {4111--4126},
title = {{Confidence intervals in optimal fingerprinting}},
url = {http://link.springer.com/10.1007/s00382-018-4356-3},
volume = {52},
year = {2019}
}
@article{doi:10.1175/JCLI-D-14-00616.1,
abstract = { AbstractPortions of western North America have experienced prolonged drought over the last decade. This drought has occurred at the same time as the global warming hiatus—a decadal period with little increase in global mean surface temperature. Climate models and observational analyses are used to clarify the dual role of recent tropical Pacific changes in driving both the global warming hiatus and North American drought. When observed tropical Pacific wind stress anomalies are inserted into coupled models, the simulations produce persistent negative sea surface temperature anomalies in the eastern tropical Pacific, a hiatus in global warming, and drought over North America driven by SST-induced atmospheric circulation anomalies. In the simulations herein the tropical wind anomalies account for 92{\%} of the simulated North American drought during the recent decade, with 8{\%} from anthropogenic radiative forcing changes. This suggests that anthropogenic radiative forcing is not the dominant driver of the current drought, unless the wind changes themselves are driven by anthropogenic radiative forcing. The anomalous tropical winds could also originate from coupled interactions in the tropical Pacific or from forcing outside the tropical Pacific. The model experiments suggest that if the tropical winds were to return to climatological conditions, then the recent tendency toward North American drought would diminish. Alternatively, if the anomalous tropical winds were to persist, then the impact on North American drought would continue; however, the impact of the enhanced Pacific easterlies on global temperature diminishes after a decade or two due to a surface reemergence of warmer water that was initially subducted into the ocean interior. },
author = {Delworth, Thomas L and Zeng, Fanrong and Rosati, Anthony and Vecchi, Gabriel A and Wittenberg, Andrew T},
doi = {10.1175/JCLI-D-14-00616.1},
journal = {Journal of Climate},
number = {9},
pages = {3834--3845},
title = {{A Link between the Hiatus in Global Warming and North American Drought}},
url = {https://doi.org/10.1175/JCLI-D-14-00616.1},
volume = {28},
year = {2015}
}
@article{Delworth2017,
abstract = {AbstractThe relationship between the North Atlantic Oscillation (NAO) and Atlantic sea surface temperature (SST) variability is investigated using models and observations. Coupled climate models are used in which the ocean component is either a fully dynamic ocean or a slab ocean with no resolved ocean heat transport. On time scales less than 10 yr, NAO variations drive a tripole pattern of SST anomalies in both observations and models. This SST pattern is a direct response of the ocean mixed layer to turbulent surface heat flux anomalies associated with the NAO. On time scales longer than 10 yr, a similar relationship exists between the NAO and the tripole pattern of SST anomalies in models with a slab ocean. A different relationship exists both for the observations and for models with a dynamic ocean. In these models, a positive (negative) NAO anomaly leads, after a decadal-scale lag, to a monopole pattern of warming (cooling) that resembles the Atlantic multidecadal oscillation (AMO), although with smaller-than-observed amplitudes of tropical SST anomalies. Ocean dynamics are critical to this decadal-scale response in the models. The simulated Atlantic meridional overturning circulation (AMOC) strengthens (weakens) in response to a prolonged positive (negative) phase of the NAO, thereby enhancing (decreasing) poleward heat transport, leading to broad-scale warming (cooling). Additional simulations are used in which heat flux anomalies derived from observed NAO variations from 1901 to 2014 are applied to the ocean component of coupled models. It is shown that ocean dynamics allow models to reproduce important aspects of the observed AMO, mainly in the Subpolar Gyre.},
annote = {doi: 10.1175/JCLI-D-16-0358.1},
author = {Delworth, Thomas L and Zeng, Fanrong and Zhang, Liping and Zhang, Rong and Vecchi, Gabriel A and Yang, Xiaosong},
doi = {10.1175/JCLI-D-16-0358.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {feb},
number = {10},
pages = {3789--3805},
publisher = {American Meteorological Society},
title = {{The Central Role of Ocean Dynamics in Connecting the North Atlantic Oscillation to the Extratropical Component of the Atlantic Multidecadal Oscillation}},
url = {https://doi.org/10.1175/JCLI-D-16-0358.1},
volume = {30},
year = {2017}
}
@article{Delworth2006,
abstract = {In many climate model simulations using realistic, time-varying climate change forcing agents for the 20th and 21st centuries, the North Atlantic thermohaline circulation (THC) weakens in the 21st century, with little change in the 20th century. Here we use a comprehensive climate model to explore the impact of various climate change forcing agents on the THC. We conduct ensembles of integrations with subsets of climate change forcing agents. Increasing greenhouse gases ? in isolation ? produce a significant THC weakening in the late 20th century, but this change is partially offset by increasing anthropogenic aerosols, which tend to strengthen the THC. The competition between increasing greenhouse gases and anthropogenic aerosols thus produces no significant THC change in our 20th century simulations when all climate forcings are included. The THC weakening becomes significant several decades into the 21st century, when the effects of increasing greenhouse gases overwhelm the aerosol effects.},
annote = {doi: 10.1029/2005GL024980},
author = {Delworth, Thomas L and Dixon, Keith W},
doi = {10.1029/2005GL024980},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {jan},
number = {2},
pages = {L02606},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Have anthropogenic aerosols delayed a greenhouse gas-induced weakening of the North Atlantic thermohaline circulation?}},
url = {https://doi.org/10.1029/2005GL024980 http://doi.wiley.com/10.1029/2005GL024980},
volume = {33},
year = {2006}
}
@article{Dennison2016,
abstract = {Abstract We investigate the influence of ozone depletion and recovery on tropospheric blocking in the Southern Hemisphere. Blocking events are identified using a persistent positive anomaly method applied to 500 hPa geopotential height. Using the National Institute for Water and Atmospheric Research-United Kingdom Chemistry and Aerosols chemistry-climate model, we compare reference runs that include forcing due to greenhouse gases (GHGs) and ozone-depleting substances to sensitivity simulations in which ozone-depleting substances are fixed at their 1960 abundances and other sensitivity simulations with GHGs fixed at their 1960 abundances. Blocking events in the South Atlantic are shown to follow stratospheric positive anomalies in the Southern Annular Mode (SAM) index; this is not the case for South Pacific blocking events. This relationship means that summer ozone depletion, and corresponding positive SAM anomalies, leads to an increased frequency of blocking in the South Atlantic while having little effect in the South Pacific. Similarly, ozone recovery, having the opposite effect on the SAM, leads to a decline in blocking frequency in the South Atlantic, although this may be somewhat counteracted by the effect of increasing GHGs.},
author = {Dennison, Fraser W and McDonald, Adrian and Morgenstern, Olaf},
doi = {10.1002/2016JD025033},
issn = {2169897X},
journal = {Journal of Geophysical Research: Atmospheres},
month = {dec},
number = {24},
pages = {14,358--14,371},
title = {{The influence of ozone forcing on blocking in the Southern Hemisphere}},
url = {http://doi.wiley.com/10.1002/2016JD025033},
volume = {121},
year = {2016}
}
@article{Deppenmeier2016,
author = {Deppenmeier, Anna-Lena and Haarsma, Reindert J. and Hazeleger, Wilco},
doi = {10.1007/s00382-016-2992-z},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {oct},
number = {7-8},
pages = {2691--2707},
title = {{The Bjerknes feedback in the tropical Atlantic in CMIP5 models}},
url = {http://link.springer.com/10.1007/s00382-016-2992-z},
volume = {47},
year = {2016}
}
@article{Dergiades2016,
abstract = {We test two hypotheses that are derived from the anthropogenic theory of climate change. The first postulates that a growing population and increasing economic activity increase anthropogenic emissions of radiatively active gases relative to natural sources and sinks, and this alters global biogeochemical cycles in a way that increases the persistence of radiative forcing and temperature. The second postulates that the increase in the persistence of radiative forcing transmits a stochastic trend to the time series for temperature. Results indicate that the persistence of radiative forcing and temperature changes from I(0) to I(1) during the last 500 years and that the I(1) fingerprint in radiative forcing can be detected in a statistically measureable fashion in surface temperature. As such, our results are consistent with the physical mechanisms that underlie the theory of anthropogenic climate change.},
author = {Dergiades, Theologos and Kaufmann, Robert K. and Panagiotidis, Theodore},
doi = {10.1016/j.jeem.2015.11.005},
issn = {00950696},
journal = {Journal of Environmental Economics and Management},
month = {mar},
pages = {67--85},
title = {{Long-run changes in radiative forcing and surface temperature: The effect of human activity over the last five centuries}},
url = {https://linkinghub.elsevier.com/retrieve/pii/S0095069615000911},
volume = {76},
year = {2016}
}
@article{Deser2017,
abstract = {This study highlights the expected range of projected winter air temperature and precipitation trends over the next 30–50 years due to unpredictable fluctuations of the North Atlantic Oscillation (NAO) superimposed upon forced anthropogenic climate change. The findings are based on a 40-member initial-condition ensemble of simulations covering the period 1920–2100 conducted with the Community Earth System Model version 1 (CESM1) at 1° spatial resolution. The magnitude (and in some regions, even the sign) of the projected temperature and precipitation trends over Europe, Russia and parts of the Middle East vary considerably across the ensemble depending on the evolution of the NAO in each individual member. Thus, internal variability of the NAO imparts substantial uncertainty to future changes in regional climate over the coming decades. To validate the model results, we apply a simple scaling approach that relates the margin-of-error on a trend to the statistics of the interannual variability. In this way, we can obtain the expected range of projected climate trends using the interannual statistics of the observed NAO record in combination with the model's radiatively-forced response (given by the ensemble-mean of the 40 simulations). The results of this observationally-based estimate are similar to those obtained directly from the CESM ensemble, attesting to the fidelity of the model's representation of the NAO and the utility of this approach. Finally, we note that the interannual statistics of the NAO and associated surface climate impacts are subject to uncertainty due to sampling fluctuations, even when based on a century of data.},
annote = {NAO in CESM1-LENS (historical-RCP8.5)
Interannual variability of DJFM SLP (detrended) -{\textgreater} EOF over the N Atlantic
Compared to 20CRv2 SLP, GISTEMP, GPCC

- EOF 1 of each 93-yr (1920-2012) integration -{\textgreater} diversity
Statistics of the interannual NAO may not be precisely obtained from "only" 93-yr records 
- Decadal component of PC1 -{\textgreater} realictic amplitudes
- Ensemble mean of decadal component is small -{\textgreater} largelly internal
- Obs lag-1yr autocorrelation = 0.17, outside of the LENS ensemble, but not significantly different (max = 0.16, min = -0.28 in LENS)
- Uncertainty of 30-yr trend due to internal variability can be estimated from the autocorrelation
- Need of large ensemble},
author = {Deser, Clara and Hurrell, James W and Phillips, Adam S},
doi = {10.1007/s00382-016-3502-z},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {9},
pages = {3141--3157},
title = {{The role of the North Atlantic Oscillation in European climate projections}},
url = {https://doi.org/10.1007/s00382-016-3502-z},
volume = {49},
year = {2017}
}
@article{doi:10.1002/2017GL074273,
abstract = {Abstract The recent slowdown in global mean surface temperature (GMST) warming during boreal winter is examined from a regional perspective using 10-member initial-condition ensembles with two global coupled climate models in which observed tropical Pacific sea surface temperature anomalies (TPAC SSTAs) and radiative forcings are specified. Both models show considerable diversity in their surface air temperature (SAT) trend patterns across the members, attesting to the importance of internal variability beyond the tropical Pacific that is superimposed upon the response to TPAC SSTA and radiative forcing. Only one model shows a close relationship between the realism of its simulated GMST trends and SAT trend patterns. In this model, Eurasian cooling plays a dominant role in determining the GMST trend amplitude, just as in nature. In the most realistic member, intrinsic atmospheric dynamics and teleconnections forced by TPAC SSTA cause cooling over Eurasia (and North America), and contribute equally to its GMST trend.},
author = {Deser, Clara and Guo, Ruixia and Lehner, Flavio},
doi = {10.1002/2017GL074273},
journal = {Geophysical Research Letters},
keywords = {atmospheric variability,climate variability,global warming hiatus,internal variability,tropical Pacific},
number = {15},
pages = {7945--7954},
title = {{The relative contributions of tropical Pacific sea surface temperatures and atmospheric internal variability to the recent global warming hiatus}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2017GL074273},
volume = {44},
year = {2017}
}
@article{Deser2010,
author = {Deser, Clara and Phillips, Adam S. and Alexander, Michael A.},
doi = {10.1029/2010GL043321},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {may},
number = {10},
pages = {L10701},
title = {{Twentieth century tropical sea surface temperature trends revisited}},
url = {http://doi.wiley.com/10.1029/2010GL043321},
volume = {37},
year = {2010}
}
@article{Deutsch2014,
abstract = {Climate warming is expected to reduce oxygen (O2) supply to the ocean and expand its oxygen minimum zones (OMZs). We reconstructed variations in the extent of North Pacific anoxia since 1850 using a geochemical proxy for denitrification ($\delta$(15)N) from multiple sediment cores. Increasing $\delta$(15)N since {\~{}}1990 records an expansion of anoxia, consistent with observed O2 trends. However, this was preceded by a longer declining $\delta$(15)N trend that implies that the anoxic zone was shrinking for most of the 20th century. Both periods can be explained by changes in winds over the tropical Pacific that drive upwelling, biological productivity, and O2 demand within the OMZ. If equatorial Pacific winds resume their predicted weakening trend, the ocean's largest anoxic zone will contract despite a global O2 decline.},
author = {Deutsch, Curtis and Berelson, William and Thunell, Robert and Weber, Thomas and Tems, Caitlin and McManus, James and Crusius, John and Ito, Taka and Baumgartner, Timothy and Ferreira, Vicente and Mey, Jacob and van Geen, Alexander},
doi = {10.1126/science.1252332},
issn = {1095-9203},
journal = {Science},
month = {aug},
number = {6197},
pages = {665--8},
pmid = {25104384},
publisher = {American Association for the Advancement of Science},
title = {{Oceanography. Centennial changes in North Pacific anoxia linked to tropical trade winds.}},
url = {http://www.ncbi.nlm.nih.gov/pubmed/25104384},
volume = {345},
year = {2014}
}
@article{Dhame2020,
author = {Dhame, Shreya and Taschetto, Andr{\'{e}}a S. and Santoso, Agus and Meissner, Katrin J.},
doi = {10.1007/s00382-020-05369-1},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {oct},
number = {7-8},
pages = {2053--2073},
title = {{Indian Ocean warming modulates global atmospheric circulation trends}},
url = {http://link.springer.com/10.1007/s00382-020-05369-1},
volume = {55},
year = {2020}
}
@article{DiNezio2013a,
abstract = {AbstractChanges in the gradients in sea level pressure (SLP) and sea surface temperature (SST) along the equatorial Pacific are analyzed in observations and 101 numerical experiments performed with 37 climate models participating in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). The ensemble of numerical experiments simulates changes in the earth?s climate during the 1870?2004 period in response to changes in natural (solar variations and volcanoes) and anthropogenic (well-mixed greenhouse gases, ozone, direct aerosol forcing, and land use) radiative forcings. A reduction in the zonal SLP gradient is present in observational records and is the typical response of the ensemble, yet only 26 out of the 101 experiments exhibit a reduced SLP gradient within 95{\%} statistical confidence of the observed value. The multimodel response indicates a reduction of the Walker circulation to historical forcings, albeit an order of magnitude smaller than the observed value. There are multiple nonexclusive interpretations of these results: (i) the observed trend may not be entirely forced and includes a substantial component from internal variability; (ii) there are problems with the observational record that lead to a spuriously large trend; and (iii) the strength of the Walker circulation, as measured by the zonal SLP gradient, may be less sensitive to external forcing in models than in the real climate system. Analysis of a subset of experiments suggests that greenhouse gases act to weaken the circulation, but aerosol forcing drives a strengthening of the circulation, which appears to be overestimated by the models, resulting in a muted response to the combined anthropogenic forcings.},
annote = {doi: 10.1175/JCLI-D-12-00531.1},
author = {DiNezio, Pedro N and Vecchi, Gabriel A and Clement, Amy C},
doi = {10.1175/JCLI-D-12-00531.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jan},
number = {12},
pages = {4038--4048},
publisher = {American Meteorological Society},
title = {{Detectability of Changes in the Walker Circulation in Response to Global Warming}},
url = {https://doi.org/10.1175/JCLI-D-12-00531.1},
volume = {26},
year = {2013}
}
@article{DiNezio2013c,
abstract = {The Indo-Pacificwarm pool—the main source of heat and moisture to the global atmosphere—plays a prominent role in tropical and global climate variability. During the Last Glacial Maximum, temperatures within thewarm poolwere cooler than today and precipitation patterns were altered, but the mechanism responsible for these shifts remains unclear. Here we use a synthesis of proxy reconstructions of warm pool hydrology and a multi-model ensemble of climate simulations to assess the drivers of these changes. The proxy data suggest drier conditions throughout the centre of the warm pool and wetter conditions in the western Indian and Pacific oceans. Only one model out of twelve simulates a pattern of hydroclimate change similar to our reconstructions, as measured by the Cohen's $\kappa$ statistic. Exposure of the Sunda Shelf by lower glacial sea level plays a key role in the hydrologic pattern simulated by this model, which results from changes in theWalker circulation driven by weakened convection over the warm pool. We therefore conclude that on glacial–interglacial timescales, the growth and decay of ice sheets exert a first-order influence on tropical climate through the associated changes in global sea level. T},
author = {DiNezio, Pedro N. and Tierney, Jessica E.},
doi = {10.1038/ngeo1823},
isbn = {1752-0894},
issn = {17520894},
journal = {Nature Geoscience},
number = {6},
pages = {485--491},
title = {{The effect of sea level on glacial Indo-Pacific climate}},
volume = {6},
year = {2013}
}
@article{DiNezio2011a,
abstract = {The response of the Walker circulation to Last Glacial Maximum (LGM) forcing is analyzed using an ensemble of six coordinated coupled climate model experiments. The tropical atmospheric overturning circulation strengthens in all models in a manner that is dictated by the response of the hydrological cycle to tropical cooling. This response arises from the same mechanism that has been found to explain the weakening of the tropical circulation in response to anthropogenic global warming but with opposite sign. Analysis of the model differences shows that the ascending branch of the Walker circulation strengthens via this mechanism but vertical motion also weakens over areas of the Maritime Continent exposed due to lower sea level. Each model exhibits a different balance between these two mechanisms, and the result is a Pacific Walker circulation response that is not robust. Further, even those models that simulate a stronger Walker circulation during the LGM do not simulate clear patterns of surface cooling, such as La Nia-like cooling or enhanced equatorial cooling, as proposed by previous studies. In contrast, the changes in the Walker circulation have a robust and distinctive signature on the tilt of the equatorial thermocline, as expected from zonal momentum balance. The changes in the Walker circulation also have a clear signature on the spatial pattern of the precipitation changes. A reduction of the east-west salinity contrast in the Indian Ocean is related to the precipitation changes resulting from a weakening of the Indian Walker circulation. These results indicate that proxies of thermocline depth and sea surface salinity can be used to detect actual LGM changes in the Pacific and Indian Walker circulations, respectively, and help to constrain the sensitivity of the Walker circulation to tropical cooling. Copyright 2011 by the American Geophysical Union.},
author = {DiNezio, P. N. and Clement, A. and Vecchi, G. A. and Soden, B. and Broccoli, A. J. and Otto-Bliesner, B. L. and Braconnot, P.},
doi = {10.1029/2010PA002083},
isbn = {0883-8305},
issn = {08838305},
journal = {Paleoceanography},
month = {sep},
number = {3},
pages = {PA3217},
title = {{The response of the Walker circulation to Last Glacial Maximum forcing: Implications for detection in proxies}},
url = {http://doi.wiley.com/10.1029/2010PA002083},
volume = {26},
year = {2011}
}
@article{DiNezio2018,
author = {DiNezio, Pedro N and Tierney, Jessica E and Otto-Bliesner, Bette L and Timmermann, Axel and Bhattacharya, Tripti and Rosenbloom, Nan and Brady, Esther},
doi = {10.1126/sciadv.aat9658},
journal = {Science Advances},
number = {12},
pages = {eaat9658},
publisher = {American Association for the Advancement of Science},
title = {{Glacial changes in tropical climate amplified by the Indian Ocean}},
volume = {4},
year = {2018}
}
@article{doi:10.1002/2015GL064799,
abstract = {Abstract We examine the impact of sea surface temperature (SST) bias on interannual variability during boreal summer over the equatorial Atlantic using two suites of partially coupled model (PCM) experiments with and without surface heat flux correction. In the experiments, surface wind stress anomalies are specified from observations while the thermodynamic coupling between the atmospheric and oceanic components is still active as in the fully coupled model. The results show that the PCM can capture around 50{\%} of the observed variability associated with the Atlantic Ni{\~{n}}o from 1958 to 2013, but only when the bias is substantially reduced using heat flux correction, with no skill otherwise. We further show that ocean dynamics explain a large part of the SST variability in the eastern equatorial Atlantic in both observations (50–60{\%}) and the PCM experiments (50–70{\%}) with heat flux correction, implying that the seasonal predictability potential may be higher than currently thought.},
author = {Ding, Hui and Greatbatch, Richard J and Latif, Mojib and Park, Wonsun},
doi = {10.1002/2015GL064799},
journal = {Geophysical Research Letters},
keywords = {SST bias,Tropical Atlantic variability},
number = {13},
pages = {5540--5546},
title = {{The impact of sea surface temperature bias on equatorial Atlantic interannual variability in partially coupled model experiments}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2015GL064799},
volume = {42},
year = {2015}
}
@article{Ding2017,
abstract = {The Arctic has seen rapid sea-ice decline in the past three decades, whilst warming at about twice the global average rate. Yet the relationship between Arctic warming and sea-ice loss is not well understood. Here, we present evidence that trends in summertime atmospheric circulation may have contributed as much as 60{\%} to the September sea-ice extent decline since 1979. A tendency towards a stronger anticyclonic circulation over Greenland and the Arctic Ocean with a barotropic structure in the troposphere increased the downwelling longwave radiation above the ice by warming and moistening the lower troposphere. Model experiments, with reanalysis data constraining atmospheric circulation, replicate the observed thermodynamic response and indicate that the near-surface changes are dominated by circulation changes rather than feedbacks from the changing sea-ice cover. Internal variability dominates the Arctic summer circulation trend and may be responsible for about 30-50{\%} of the overall decline in September sea ice since 1979.},
author = {Ding, Qinghua and Schweiger, Axel and L'Heureux, Michelle and Battisti, David S. and Po-Chedley, Stephen and Johnson, Nathaniel C. and Blanchard-Wrigglesworth, Eduardo and Harnos, Kirstin and Zhang, Qin and Eastman, Ryan and Steig, Eric J.},
doi = {10.1038/nclimate3241},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {apr},
number = {4},
pages = {289--295},
publisher = {Nature Publishing Group},
title = {{Influence of high-latitude atmospheric circulation changes on summertime Arctic sea ice}},
url = {http://10.0.4.14/nclimate3241},
volume = {7},
year = {2017}
}
@article{Ding2019,
abstract = {The relative contribution and physical drivers of internal variability in recent Arctic sea ice loss remain open questions, leaving up for debate whether global climate models used for climate projection lack sufficient sensitivity in the Arctic to climate forcing. Here, through analysis of large ensembles of fully coupled climate model simulations with historical radiative forcing, we present an important internal mechanism arising from low-frequency Arctic atmospheric variability in models that can cause substantial summer sea ice melting in addition to that due to anthropogenic forcing. This simulated internal variability shows a strong similarity to the observed Arctic atmospheric change in the past 37 years. Through a fingerprint pattern matching method, we estimate that this internal variability contributes to about 40–50{\%} of observed multi-decadal decline in Arctic sea ice. Our study also suggests that global climate models may not actually underestimate sea ice sensitivities in the Arctic, but have trouble fully replicating an observed linkage between the Arctic and lower latitudes in recent decades. Further improvements in simulating the observed Arctic–global linkage are thus necessary before the Arctic's sensitivity to global warming in models can be quantified with confidence.},
author = {Ding, Qinghua and Schweiger, Axel and L'Heureux, Michelle and Steig, Eric J and Battisti, David S and Johnson, Nathaniel C and Blanchard-Wrigglesworth, Eduardo and Po-Chedley, Stephen and Zhang, Qin and Harnos, Kirstin and Bushuk, Mitchell and Markle, Bradley and Baxter, Ian},
doi = {10.1038/s41561-018-0256-8},
issn = {1752-0908},
journal = {Nature Geoscience},
number = {1},
pages = {28--33},
title = {{Fingerprints of internal drivers of Arctic sea ice loss in observations and model simulations}},
url = {https://doi.org/10.1038/s41561-018-0256-8},
volume = {12},
year = {2019}
}
@article{Dippe2018,
author = {Dippe, Tina and Greatbatch, Richard J. and Ding, Hui},
doi = {10.1007/s00382-017-3943-z},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jul},
number = {1-2},
pages = {597--612},
title = {{On the relationship between Atlantic Ni{\~{n}}o variability and ocean dynamics}},
url = {http://link.springer.com/10.1007/s00382-017-3943-z},
volume = {51},
year = {2018}
}
@article{Dittus,
abstract = {The relative importance of anthropogenic aerosol in decadal variations of historical climate is uncertain, largely due to uncertainty in aerosol radiative forcing. We analyze a novel large ensemble of simulations with HadGEM3-GC3.1 for 1850–2014, where anthropogenic aerosol and precursor emissions are scaled to sample a wide range of historical aerosol radiative forcing with present-day values ranging from –0.38 to –1.50 Wm–2. Five ensemble members are run for each of five aerosol scaling factors. Decadal variations in surface temperatures are strongly sensitive to aerosol forcing, particularly between 1950 and 1980. Post-1980, trends are dominated by greenhouse gas forcing, with much lower sensitivity to aerosol emission differences. Most realizations with aerosol forcing more negative than about –1 Wm–2 simulate stronger cooling trends in the mid-20th century compared with observations, while the simulated warming post-1980 always exceeds observed warming, likelydue to a warm bias in the transient climate response in HadGEM3-GC3.1.},
author = {Dittus, Andrea J. and Hawkins, Ed and Wilcox, Laura J. and Sutton, Rowan T. and Smith, Christopher J. and Andrews, Martin B. and Forster, Piers M.},
doi = {10.1029/2019GL085806},
issn = {19448007},
journal = {Geophysical Research Letters},
keywords = {Forcing uncertainty,Large ensemble,Transient Climate Response,climate model simulations,historical aerosol forcing},
number = {13},
pages = {e2019GL085806},
title = {{Sensitivity of Historical Climate Simulations to Uncertain Aerosol Forcing}},
volume = {47},
year = {2020}
}
@misc{Dlugokencky2020a,
address = {Boulder, CO, USA},
author = {Dlugokencky, E. J. and Mund, J. W. and Crotwell, A. M. and Crotwell, M. J. and Thoning, K. W.},
doi = {10.15138/wkgj-f215},
publisher = {National Oceanic and Atmospheric Administration (NOAA) Global Monitoring Laboratory (GML)},
title = {{Atmospheric Carbon Dioxide Dry Air Mole Fractions from the NOAA GML Carbon Cycle Cooperative Global Air Sampling Network, 1968–2019}},
url = {https://doi.org/10.15138/wkgj-f215},
year = {2020}
}
@misc{Dlugokencky2020b,
address = {Boulder, CO, USA},
author = {Dlugokencky, E. J. and Tans, P. P},
publisher = {National Oceanic and Atmospheric Administration (NOAA) Global Monitoring Laboratory (GML)},
title = {{Trends in Atmospheric Carbon Dioxide}},
url = {https://www.esrl.noaa.gov/gmd/ccgg/trends/gl{\_}data.html},
year = {2020}
}
@article{Docquier2019,
abstract = {Arctic sea-ice area and volume have substantially decreased since the beginning of the satellite era. Concurrently, the poleward heat transport from the North Atlantic Ocean into the Arctic has increased, partly contributing to the loss of sea ice. Increasing the horizontal resolution of general circulation models (GCMs) improves their ability to represent the complex interplay of processes at high latitudes. Here, we investigate the impact of model resolution on Arctic sea ice and Atlantic Ocean heat transport (OHT) by using five different state-of-the-art coupled GCMs (12 model configurations in total) that include dynamic representations of the ocean, atmosphere and sea ice. The models participate in the High Resolution Model Intercomparison Project (HighResMIP) of the sixth phase of the Coupled Model Intercomparison Project (CMIP6). Model results over the period 1950--2014 are compared to different observational datasets. In the models studied, a finer ocean resolution drives lower Arctic sea-ice area and volume and generally enhances Atlantic OHT. The representation of ocean surface characteristics, such as sea-surface temperature (SST) and velocity, is greatly improved by using a finer ocean resolution. This study highlights a clear anticorrelation at interannual time scales between Arctic sea ice (area and volume) and Atlantic OHT north of {\$}{\$}60$\backslash$,{\^{}}$\backslash$circ $\backslash$hbox {\{}N{\}}{\$}{\$}60∘Nin the models studied. However, the strength of this relationship is not systematically impacted by model resolution. The higher the latitude to compute OHT, the stronger the relationship between sea-ice area/volume and OHT. Sea ice in the Barents/Kara and Greenland--Iceland--Norwegian (GIN) Seas is more strongly connected to Atlantic OHT than other Arctic seas.},
author = {Docquier, David and Grist, Jeremy P and Roberts, Malcolm J and Roberts, Christopher D and Semmler, Tido and Ponsoni, Leandro and Massonnet, Fran{\c{c}}ois and Sidorenko, Dmitry and Sein, Dmitry V and Iovino, Doroteaciro and Bellucci, Alessio and Fichefet, Thierry},
doi = {10.1007/s00382-019-04840-y},
issn = {1432-0894},
journal = {Climate Dynamics},
month = {oct},
number = {7},
pages = {4989--5017},
title = {{Impact of model resolution on Arctic sea ice and North Atlantic Ocean heat transport}},
url = {https://doi.org/10.1007/s00382-019-04840-y},
volume = {53},
year = {2019}
}
@article{doi:10.1029/2018JD030077,
abstract = {Abstract Sudden stratospheric warming (SSW) events can exhibit long-lasting surface impacts that promise improvements in medium-range to seasonal predictability. Their surface impact is dominated by the negative phase of the North Atlantic Oscillation (NAO). Hence, the question arises if stratospheric variability, and in particular the frequency of SSW events, can in turn be estimated from surface NAO conditions. This is especially relevant for the period before frequent upper air observations became available, while daily surface observations of the NAO date back to 1850. The surface impact is here quantified by NAO characteristics that are commonly observed after SSW events: a switch from a positive to a negative NAO and an extended persistence of the negative NAO, termed NAO events. Two thirds of SSW events are found to be followed by either a persistence or switch NAO event, and a quarter of SSW events are followed by both. On the other hand, less than 25{\%} of winter surface NAO events are preceded by a SSW event. Based on these findings, an index purely based on surface NAO observations is derived that estimates SSW frequency for the satellite era and extends it back to 1850, indicating that decadal stratospheric variability was present for the entire time series, with no significant trend. The minimum in SSW frequency in the 1990s is found to be coincident with the longest absence of NAO events since 1850, indicating that the early 1990s may constitute the longest absence of SSW events for the 150-year record.},
author = {Domeisen, Daniela I.V.},
doi = {10.1029/2018JD030077},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {North Atlantic Oscillation,reconstruction,stratosphere-troposphere coupling,sudden stratospheric warming,upper atmosphere},
number = {6},
pages = {3180--3194},
title = {{Estimating the Frequency of Sudden Stratospheric Warming Events From Surface Observations of the North Atlantic Oscillation}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JD030077},
volume = {124},
year = {2019}
}
@article{Domeisen2019,
author = {Domeisen, Daniela I.V. and Garfinkel, Chaim I. and Butler, Amy H.},
doi = {10.1029/2018RG000596},
issn = {8755-1209},
journal = {Reviews of Geophysics},
month = {mar},
number = {1},
pages = {5--47},
title = {{The Teleconnection of El Ni{\~{n}}o Southern Oscillation to the Stratosphere}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018RG000596},
volume = {57},
year = {2019}
}
@article{Domingues2008,
abstract = {Changes in the climate system's energy budget are predominantly revealed in ocean temperatures1, 2 and the associated thermal expansion contribution to sea-level rise2. Climate models, however, do not reproduce the large decadal variability in globally averaged ocean heat content inferred from the sparse observational database3, 4, even when volcanic and other variable climate forcings are included. The sum of the observed contributions has also not adequately explained the overall multi-decadal rise2. Here we report improved estimates of near-global ocean heat content and thermal expansion for the upper 300 m and 700 m of the ocean for 1950–2003, using statistical techniques that allow for sparse data coverage5, 6, 7 and applying recent corrections8 to reduce systematic biases in the most common ocean temperature observations9. Our ocean warming and thermal expansion trends for 1961–2003 are about 50 per cent larger than earlier estimates but about 40 per cent smaller for 1993–2003, which is consistent with the recognition that previously estimated rates for the 1990s had a positive bias as a result of instrumental errors8, 9, 10. On average, the decadal variability of the climate models with volcanic forcing now agrees approximately with the observations, but the modelled multi-decadal trends are smaller than observed. We add our observational estimate of upper-ocean thermal expansion to other contributions to sea-level rise and find that the sum of contributions from 1961 to 2003 is about 1.5 plusminus 0.4 mm yr-1, in good agreement with our updated estimate of near-global mean sea-level rise (using techniques established in earlier studies6, 7) of 1.6 plusminus 0.2 mm yr-1},
author = {Domingues, Catia M. and Church, John A. and White, Neil J. and Gleckler, Peter J. and Wijffels, Susan E. and Barker, Paul M. and Dunn, Jeff R.},
doi = {10.1038/nature07080},
isbn = {0028-0836$\backslash$r1476-4687},
issn = {14764687},
journal = {Nature},
month = {jun},
number = {7198},
pages = {1090--1093},
pmid = {18563162},
publisher = {Nature Publishing Group},
title = {{Improved estimates of upper-ocean warming and multi-decadal sea-level rise}},
url = {http://www.nature.com/articles/nature07080},
volume = {453},
year = {2008}
}
@article{Dong2016,
annote = {IPO is the major driver of the decadal IOBM
- HadISST
- CESM1.2 historical-RCP4.5, POGA-H, POGA-C
- 8-yr low-pass filtered SST variability

- Both EOF of the observations and the pacemaker experiments show that the IPO is highly correlated and thus the major driver of the decadal IOBM (apart from radiative forcing)
- Correlation with the AMO is low
- Inter-basin association b/w the tropical IO and Pacific},
author = {Dong, Lu and Zhou, Tianjun and Dai, Aiguo and Song, Fengfei and Wu, Bo and Chen, Xiaolong},
doi = {10.1038/srep21251},
journal = {Scientific Reports},
month = {feb},
pages = {21251},
publisher = {The Author(s)},
title = {{The Footprint of the Inter-decadal Pacific Oscillation in Indian Ocean Sea Surface Temperatures}},
url = {http://dx.doi.org/10.1038/srep21251 http://10.0.4.14/srep21251 https://www.nature.com/articles/srep21251{\#}supplementary-information},
volume = {6},
year = {2016}
}
@article{doi:10.1175/JCLI-D-13-00396.1,
abstract = { AbstractThe Indian Ocean exhibits a robust basinwide sea surface temperature (SST) warming during the twentieth century that has affected the hydrological cycle, atmospheric circulation, and global climate change. The competing roles of greenhouse gases (GHGs) and anthropogenic aerosols (AAs) with regard to the Indian Ocean warming are investigated by using 17 models from phase 5 of the Coupled Model Intercomparison Project (CMIP5). The increasing GHGs are considered to be one reason for the warming. Here model evidence is provided that the emission of AAs has slowed down the warming rate. With AAs, the warming trend has been slowed down by 0.34 K century−1. However, the cooling effect is weakened when only the direct aerosol effect is considered. GHGs and AAs have competed with each other in forming the basinwide warming pattern as well as the equatorial east–west dipole warming pattern. Both the basinwide warming effect of GHGs and the cooling effect of AAs, mainly through indirect aerosol effect, are established through atmospheric processes via radiative and turbulent fluxes. The positive contributions of surface latent heat flux from atmosphere and surface longwave radiation due to GHGs forcing dominate the basinwide warming, while the reductions of surface shortwave radiation, surface longwave radiation, and latent heat flux from atmosphere associated with AAs induce the basinwide cooling. The positive Indian Ocean dipole warming pattern is seen in association with the surface easterly wind anomaly during 1870–2005 along the equator, which is produced by the increase of GHGs but weakened by AAs via direct aerosol effects. },
annote = {Indian ocean warming and its pattern in 1879-2005 in CMIP5
- CMIP5 historical, historicalGHG, historicalNat, historicalAA
- HadISST

- Observed 0.40 K/century warming is well captured by historical experiments (0.41 ± 0.16 K/century)
- The warming is a residual of competing effects of GHG and AA forcings
- Observations show basin-wide warming with its maximum in the equatorial western IO (i.e. positive IOD-like; confirmed from ERSSTv3)
- GHG forcing induces equatorial easterly anomalies (Walker circulation slowdown)
- Response to AA forcing depends on inclusion of indirect effect, but at least direct effect induces westerly anomalies
- Ocean dynamical processes are important for the IOD-like warming pattern},
author = {Dong, Lu and Zhou, Tianjun},
doi = {10.1175/JCLI-D-13-00396.1},
journal = {Journal of Climate},
number = {9},
pages = {3348--3362},
title = {{The Indian Ocean Sea Surface Temperature Warming Simulated by CMIP5 Models during the Twentieth Century: Competing Forcing Roles of GHGs and Anthropogenic Aerosols}},
url = {https://doi.org/10.1175/JCLI-D-13-00396.1},
volume = {27},
year = {2014}
}
@article{Dong2017,
abstract = {AbstractBoth the Indian and Pacific Oceans exhibit prominent decadal time scale variations in sea surface temperature (SST), linked dynamically via atmospheric and oceanic processes. However, the relationship between SST in these two basins underwent a dramatic transformation beginning around 1985. Prior to that, SST variations associated with the Indian Ocean Basin Mode (IOB) and the Inter-decadal Pacific Oscillation (IPO) were positively correlated, while afterwards they were much less clearly synchronized. We present evidence from both observations and coupled state-of-the-art climate models that enhanced external forcing, particularly increased anthropogenic greenhouse gases, was the principal cause of this changed relationship. Using coupled climate model experiments, we determine that without external forcing, the evolution of the IOB would be strongly forced by variations in the IPO. However, with strong external forcing, the dynamical linkage between the IOB and the IPO weakens and so that the neg...},
annote = {Change of decadal IOBM-IPO relationship in the mid-1985s
- Han et al (2014 ClimDyn) {\ldots} Change of IPO-decadal IOBM correlation across 1985
- HadISST, ERSST, Kaplan SST
- NCAR CESM1.2 historical-RCP4.5, POGA-H (each 3 members)
- CMIP5 historical, historicalGHG, historicalAA, historicalNat
- CCSM4 historical, RCP2.6, RCP8.5
- Detrend -{\textgreater} 13-yr low-pass -{\textgreater} SST EOF1 over 30S-30N40-120E (decadal IOBM) and SST EOF1 over 60S-60N120E-70W

- The apparent change of running 21-yr IPO-decadal IOBM correlation {\ldots} from positive to negative around 1985
- POGA-H reproduces this change
- When pure response to radiative forcing is removed, the correlation becomes stable
- The positive decadal IOBM after 2000 despite the negative IPO due to external forcing {\ldots} Rapid increase of GHG and recovery from Pinatubo
- The negative phase of IPO during 2000-2012 is likely internally-driven, it is suggested to have been enhanced by the rapid IO warming},
author = {Dong, Lu and McPhaden, Michael J.},
doi = {10.1175/JCLI-D-16-0313.1},
isbn = {0894-8755 1520-0442},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Atmosphere-ocean interaction,Climate models,Decadal variability,Greenhouse gases,Indian Ocean,Pacific decadal oscillation},
number = {6},
pages = {1971--1983},
title = {{Why has the relationship between Indian and Pacific Ocean decadal variability changed in recent decades?}},
volume = {30},
year = {2017}
}
@article{Dong2014,
abstract = {The mechanism responsible for Indian Ocean Sea surface temperature (SST) basin-wide warming trend during 1958–2004 is studied based on both observational data analysis and numerical experiments with a climate system model FGOALS-gl. To quantitatively estimate the relative contributions of external forcing (anthropogenic and natural forcing) and internal variability, three sets of numerical experiments are conducted, viz. an all forcing run forced by both anthropogenic forcing (greenhouse gases and sulfate aerosols) and natural forcing (solar constant and volcanic aerosols), a natural forcing run driven by only natural forcing, and a pre-industrial control run. The model results are compared to the observations. The results show that the observed warming trend during 1958–2004 (0.5 K (47-year)−1) is largely attributed to the external forcing (more than 90 {\%} of the total trend), while the residual is attributed to the internal variability. Model results indicate that the anthropogenic forcing accounts for approximately 98.8 {\%} contribution of the external forcing trend. Heat budget analysis shows that the surface latent heat flux due to atmosphere and surface longwave radiation, which are mainly associated with anthropogenic forcing, are in favor of the basin-wide warming trend. The basin-wide warming is not spatially uniform, but with an equatorial IOD-like pattern in climate model. The atmospheric processes, oceanic processes and climatological latent heat flux together form an equatorial IOD-like warming pattern, and the oceanic process is the most important in forming the zonal dipole pattern. Both the anthropogenic forcing and natural forcing result in easterly wind anomalies over the equator, which reduce the wind speed, thereby lead to less evaporation and warmer SST in the equatorial western basin. Based on Bjerknes feedback, the easterly wind anomalies uplift the thermocline, which is unfavorable to SST warming in the eastern basin, and contribute to SST warming via deeper thermocline in the western basin. The easterly anomalies also drive westward anomalous equatorial currents, against the eastward climatology currents, which is in favor of the SST warming in the western basin via anomalous warm advection. Therefore, both the atmospheric and oceanic processes are in favor of the IOD-like warming pattern formation over the equator.},
annote = {Attribution of IO warming with FGOALS-gl
- FGOALS-gl 20C3M, 20c natural forcing run, piControl run
- HadISST, Kaplan v2, HadCRUT3
- 1958-2004

- Spatial pattern and time evolution of the IO SST increase are reaonably reproduced by 20C3M
- More than 90{\%} of the warming is attributable to external forcing (98.8{\%} by anthropogenic)
- Basin-wide warming is primarily through atmospheric forcing rather than ocean dynamics
- The forced warming is "IOD-like" with the max and min in the western and eastern TIO, to which oceanic processes (easterly anomalies uplift and deepen thermocline in the east and west, respectively) are important but atmos processes (easterly anomalies counteract mean westerlies and suppress evap in the WIO) also contribute},
author = {Dong, Lu and Zhou, Tianjun and Wu, Bo},
doi = {10.1007/s00382-013-1722-z},
isbn = {1432-0894},
issn = {09307575},
journal = {Climate Dynamics},
keywords = {Climate system model,External forcing,Indian Ocean,Internal variability,SST warming},
number = {1-2},
pages = {203--217},
title = {{Indian Ocean warming during 1958-2004 simulated by a climate system model and its mechanism}},
volume = {42},
year = {2014}
}
@article{Dong2014a,
abstract = {This paper explores the contributions of internal variability, greenhouse gases (GHGs), and anthropogenic aerosols (AAs) in driving the magnitude and evolution of Pacific Decadal Variability (PDV) during the twentieth century by analyzing 129 Coupled Model Intercomparison Project Phase 5 model realizations. Evidence shows that PDV phase transition is dominated by internal variability, but it is also significantly affected by external forcing agents such as GHGs and aerosols. The combined effects of GHGs and AAs favor the positive phase of PDV with stronger ocean warming in the tropics than the extratropical Pacific. The GHG forcing induces the increased surface downward longwave radiation, especially over the tropical Pacific, and results in stronger warming in that area. The AA forcing results in a stronger cooling in the North Pacific region, due to the reduced surface downward shortwave radiation via cloud-aerosol interaction: this offsets the substantial warming caused by GHG forcing.},
author = {Dong, Lu and Zhou, Tianjun and Chen, Xiaolong},
doi = {10.1002/2014GL062269},
isbn = {0094-8276},
issn = {19448007},
journal = {Geophysical Research Letters},
keywords = {Pacific decadal variability,aerosol,greenhouse gases,internal variability},
number = {23},
pages = {8570--8577},
title = {{Changes of Pacific decadal variability in the twentieth century driven by internal variability, greenhouse gases, and aerosols}},
volume = {41},
year = {2014}
}
@article{Dong2020,
abstract = {While the IPCC Fifth Assessment Working Group I report assessed observed changes in extreme precipitation on the basis of both absolute and percentile-based extreme indices, human influence on extreme precipitation has rarely been evaluated on the basis of percentile-based extreme indices. Here we conduct a formal detection and attribution analysis on changes in four percentile-based precipitation extreme indices. The indices include annual precipitation totals from days with precipitation exceeding the 99th and 95th percentiles of wet-day precipitation in 1961–90 (R99p and R95p) and their contributions to annual total precipitation (R99pTOT and R95pTOT). We compare these indices from a set of newly compiled observations during 1951–2014 with simulations from models participating in phase 6 of the Coupled Model Intercomparison Project (CMIP6). We show that most land areas with observations experienced increases in these extreme indices with global warming during the historical period 1951–2014. The new CMIP6 models are able to reproduce these overall increases, although with considerable over- or underestimations in some regions. An optimal fingerprinting analysis reveals detectable anthropogenic signals in the observations of these indices averaged over the globe and over most continents. Furthermore, signals of greenhouse gases can be separately detected, taking other forcing into account, over the globe and over Asia in these indices except for R95p. In contrast, signals of anthropogenic aerosols and natural forcings cannot be detected in any of these indices at either global or continental scales.},
address = {Boston MA, USA},
author = {Dong, Siyan and Sun, Ying and Li, Chao and Zhang, Xuebin and Min, Seung-Ki and Kim, Yeon-Hee},
doi = {10.1175/jcli-d-19-1017.1},
issn = {0894-8755},
journal = {Journal of Climate},
language = {English},
number = {3},
pages = {871--881},
publisher = {American Meteorological Society},
title = {{Attribution of Extreme Precipitation with Updated Observations and CMIP6 Simulations}},
url = {https://journals.ametsoc.org/view/journals/clim/34/3/JCLI-D-19-1017.1.xml},
volume = {34},
year = {2020}
}
@article{Douville2020,
author = {Douville, H. and Decharme, B. and Delire, C. and Colin, J. and Joetzjer, E. and Roehrig, R. and Saint‐Martin, D. and Oudar, Thomas and Stchepouboff, R. and Voldoire, A},
doi = {10.1007/s00382-020-05351-x},
journal = {Climate Dynamics},
title = {{Drivers of the enhanced decline of land near-surface relative humidity to abrupt 4xCO2 in CNRM-CM6-1}},
url = {https://doi.org/10.1007/s00382-020-05351-x},
volume = {55},
year = {2020}
}
@article{Douville2019,
author = {Douville, Herv{\'{e}} and Ribes, A. and Tyteca, S.},
doi = {10.1007/s00382-018-4141-3},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jan},
number = {1-2},
pages = {29--48},
title = {{Breakdown of NAO reproducibility into internal versus externally-forced components: a two-tier pilot study}},
url = {http://link.springer.com/10.1007/s00382-018-4141-3},
volume = {52},
year = {2019}
}
@article{Douville2017,
author = {Douville, H. and Plazzotta, M.},
doi = {10.1002/2017GL075353},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {oct},
number = {19},
pages = {9967--9975},
title = {{Midlatitude Summer Drying: An Underestimated Threat in CMIP5 Models?}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2017GL075353},
volume = {44},
year = {2017}
}
@article{Dow2020,
abstract = {Past studies have suggested that regional trends in anthropogenic aerosols can influence the Pacific decadal oscillation (PDO) through modulation of the Aleutian low. However, the robustness of this connection is debated. This study analyzes changes to the Aleutian low in an ensemble of climate models forced with large, idealized global and regional black carbon (BC) and sulfate aerosol perturbations. To isolate the role of ocean feedbacks, the experiments are performed with an interactive ocean and with prescribed sea surface temperatures. The results show a robust weakening of the Aleutian low forced by a global tenfold increase in BC in both experiment configurations. A linearized steady-state primitive equation model is forced with diabatic heating anomalies to investigate the mechanisms through which heating from BC emissions influences the Aleutian low. The heating from BC absorption over India and East Asia generates Rossby wave trains that propagate into the North Pacific sector, forming an upper-tropospheric ridge. Sources of BC outside of East Asia enhance the weakening of the Aleutian low. The responses to a global fivefold and regional tenfold increase in sulfate aerosols over Asia show poor consistency across climate models, with a multimodel mean response that does not project strongly onto the Aleutian low. These findings for a large, idealized step increase in regional sulfate aerosol differ from previous studies that suggest the transient increase in sulfate aerosols over Asia during the early twenty-first century weakened the Aleutian low and induced a transition to a negative PDO phase.},
author = {Dow, William J. and Maycock, Amanda C. and Lofverstrom, Marcus and Smith, Christopher J.},
doi = {10.1175/jcli-d-20-0423.1},
issn = {0894-8755},
journal = {Journal of Climate},
number = {5},
pages = {1725--1741},
title = {{The Effect of Anthropogenic Aerosols on the Aleutian Low}},
volume = {34},
year = {2020}
}
@article{Downes2013,
abstract = {AbstractThirteen state-of-the-art climate models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) are used to evaluate the response of the Antarctic Circumpolar Current (ACC) transport and Southern Ocean meridional overturning circulation to surface wind stress and buoyancy changes. Understanding how these flows?fundamental players in the global distribution of heat, gases, and nutrients?respond to climate change is currently a widely debated issue among oceanographers. Here, the authors analyze the circulation responses of these coarse-resolution coupled models to surface fluxes. Under a future CMIP5 climate pathway where the equivalent atmospheric CO2 reaches 1370 ppm by 2100, the models robustly project reduced Southern Ocean density in the upper 2000 m accompanied by strengthened stratification. Despite an overall increase in overlying wind stress ({\~{}}20{\%}), the projected ACC transports lie within ±15{\%} of their historical state, and no significant relationship with changes in the magnitude or position of the wind stress is identified. The models indicate that a weakening of ACC transport at the end of the twenty-first century is correlated with a strong increase in the surface heat and freshwater fluxes in the ACC region. In contrast, the surface heat gain across the ACC region and the wind-driven surface transports are significantly correlated with an increased upper and decreased lower Eulerian-mean meridional overturning circulation. The change in the eddy-induced overturning in both the depth and density spaces is quantified, and it is found that the CMIP5 models project partial eddy compensation of the upper and lower overturning cells.},
author = {Downes, Stephanie M and Hogg, Andrew McC.},
doi = {10.1175/JCLI-D-12-00504.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {mar},
number = {18},
pages = {7198--7220},
publisher = {American Meteorological Society},
title = {{Southern Ocean Circulation and Eddy Compensation in CMIP5 Models}},
volume = {26},
year = {2013}
}
@article{Downes2018,
author = {Downes, S M and Spence, P and Hogg, A M},
doi = {10.1016/j.ocemod.2018.01.005},
issn = {1463-5003},
journal = {Ocean Modelling},
pages = {98--109},
title = {{Understanding variability of the Southern Ocean overturning circulation in CORE-II models}},
volume = {123},
year = {2018}
}
@article{Drews2016,
author = {Drews, Annika and Greatbatch, Richard J.},
doi = {10.1002/2016GL069815},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {aug},
number = {15},
pages = {8199--8206},
title = {{Atlantic Multidecadal Variability in a model with an improved North Atlantic Current}},
url = {http://doi.wiley.com/10.1002/2016GL069815},
volume = {43},
year = {2016}
}
@article{Drijfhout2018,
author = {Drijfhout, Sybren},
doi = {10.1038/s41598-018-25342-7},
issn = {2045-2322},
journal = {Scientific Reports},
month = {dec},
number = {1},
pages = {7402},
title = {{The relation between natural variations in ocean heat uptake and global mean surface temperature anomalies in CMIP5}},
url = {http://www.nature.com/articles/s41598-018-25342-7},
volume = {8},
year = {2018}
}
@article{doi:10.1175/2008JCLI2590.1,
abstract = { Abstract El Ni{\~{n}}o induces a basin-wide increase in tropical Indian Ocean (TIO) sea surface temperature (SST) with a lag of one season. The north IO (NIO), in particular, displays a peculiar double-peak warming with the second peak larger in magnitude and persisting well through the summer. Motivated by recent studies suggesting the importance of the TIO warming for the Northwest Pacific and East Asian summer monsoons, the present study investigates the mechanisms for the second peak of the NIO warming using observations and general circulation models. This analysis reveals that internal air–sea interaction within the TIO is key to sustaining the TIO warming through summer. During El Ni{\~{n}}o, anticyclonic wind curl anomalies force a downwelling Rossby wave in the south TIO through Walker circulation adjustments, causing a sustained SST warming in the tropical southwest IO (SWIO) where the mean thermocline is shallow. During the spring and early summer following El Ni{\~{n}}o, this SWIO warming sustains an antisymmetric pattern of atmospheric anomalies with northeasterly (northwesterly) wind anomalies north (south) of the equator. Over the NIO as the mean winds turn into southwesterly in May, the northeasterly anomalies force the second SST peak that persists through summer by reducing the wind speed and surface evaporation. Atmospheric general circulation model experiments show that the antisymmetric atmospheric pattern is a response to the TIO warming, suggestive of their mutual interaction. Thus, ocean dynamics and Rossby waves in particular are important for the warming not only locally in SWIO but also on the basin-scale north of the equator, a result with important implications for climate predictability and prediction. },
author = {Du, Yan and Xie, Shang-Ping and Huang, Gang and Hu, Kaiming},
doi = {10.1175/2008JCLI2590.1},
journal = {Journal of Climate},
number = {8},
pages = {2023--2038},
title = {{Role of Air–Sea Interaction in the Long Persistence of El Ni{\~{n}}o–Induced North Indian Ocean Warming}},
url = {https://doi.org/10.1175/2008JCLI2590.1},
volume = {22},
year = {2009}
}
@article{Dunn2017c,
author = {Dunn, R J H and Willett, K M and Ciavarella, A and Stott, P A},
doi = {10.5194/esd-8-719-2017},
journal = {Earth System Dynamics},
number = {3},
pages = {719--747},
title = {{Comparison of land surface humidity between observations and CMIP5 models}},
volume = {8},
year = {2017}
}
@article{Dunn-Sigouin2013,
abstract = {Northern Hemisphere (NH) blocking climatology is examined using a subset of climate models participating in the Coupled Model Intercomparison Project phase 5 (CMIP5). Both historical and Representative Concentration Pathway (RCP) 8.5 integrations are analyzed to evaluate the performance of the CMIP5 models and to identify possible changes in NH blocking frequency and duration in a warmer climate. Comparison with reanalysis data reveals that CMIP5 models can reproduce the NH blocking climatology reasonably well, although the frequency of Euro-Atlantic blockings, particularly those with relatively short duration, is significantly underestimated during the cold season. In most models, overestimation of the Pacific blocking frequency is also evident for all durations throughout the year. In comparison to historical integrations, RCP 8.5 integrations show significant decreases in blocking frequency over both the North Pacific and north Atlantic regions, with a hint of increasing blocking frequency over western Russia. However, there is no noticeable change in the duration of individual blocking events for all durations.},
address = {2000 FLORIDA AVE NW},
author = {Dunn-Sigouin, Etienne and Son, Seok-Woo},
doi = {10.1002/jgrd.50143},
issn = {2169897X},
journal = {Journal of Geophysical Research: Atmospheres},
month = {feb},
number = {3},
pages = {1179--1188},
publisher = {AMER GEOPHYSICAL UNION},
title = {{Northern Hemisphere blocking frequency and duration in the CMIP5 models}},
url = {http://doi.wiley.com/10.1002/jgrd.50143},
volume = {118},
year = {2013}
}
@article{Dunne2020,
abstract = {We describe the baseline coupled model configuration and simulation characteristics of GFDL's Earth System Model Version 4.1 (ESM4.1), which builds on component and coupled model developments at GFDL over 2013–2018 for coupled carbon-chemistry-climate simulation contributing to the sixth phase of the Coupled Model Intercomparison Project. In contrast with GFDL's CM4.0 development effort that focuses on ocean resolution for physical climate, ESM4.1 focuses on comprehensiveness of Earth system interactions. ESM4.1 features doubled horizontal resolution of both atmosphere (2° to 1°) and ocean (1° to 0.5°) relative to GFDL's previous-generation coupled ESM2-carbon and CM3-chemistry models. ESM4.1 brings together key representational advances in CM4.0 dynamics and physics along with those in aerosols and their precursor emissions, land ecosystem vegetation and canopy competition, and multiday fire; ocean ecological and biogeochemical interactions, comprehensive land-atmosphere-ocean cycling of CO2, dust and iron, and interactive ocean-atmosphere nitrogen cycling are described in detail across this volume of JAMES and presented here in terms of the overall coupling and resulting fidelity. ESM4.1 provides much improved fidelity in CO2 and chemistry over ESM2 and CM3, captures most of CM4.0's baseline simulations characteristics, and notably improves on CM4.0 in (1) Southern Ocean mode and intermediate water ventilation, (2) Southern Ocean aerosols, and (3) reduced spurious ocean heat uptake. ESM4.1 has reduced transient and equilibrium climate sensitivity compared to CM4.0. Fidelity concerns include (1) moderate degradation in sea surface temperature biases, (2) degradation in aerosols in some regions, and (3) strong centennial scale climate modulation by Southern Ocean convection.},
author = {Dunne, J. P. and Horowitz, L. W. and Adcroft, A. J. and Ginoux, P. and Held, I. M. and John, J. G. and Krasting, J. P. and Malyshev, S. and Naik, V. and Paulot, F. and Shevliakova, E. and Stock, C. A. and Zadeh, N. and Balaji, V. and Blanton, C. and Dunne, K. A. and Dupuis, C. and Durachta, J. and Dussin, R. and Gauthier, P. P.G. and Griffies, S. M. and Guo, H. and Hallberg, R. W. and Harrison, M. and He, J. and Hurlin, W. and McHugh, C. and Menzel, R. and Milly, P. C.D. and Nikonov, S. and Paynter, D. J. and Ploshay, J. and Radhakrishnan, A. and Rand, K. and Reichl, B. G. and Robinson, T. and Schwarzkopf, D. M. and Sentman, L. T. and Underwood, S. and Vahlenkamp, H. and Winton, M. and Wittenberg, A. T. and Wyman, B. and Zeng, Y. and Zhao, M.},
doi = {10.1029/2019MS002015},
issn = {19422466},
journal = {Journal of Advances in Modeling Earth Systems},
keywords = {Earth system model,biogeochemistry,climate model},
number = {11},
pages = {e2019MS002015},
title = {{The GFDL Earth System Model Version 4.1 (GFDL-ESM 4.1): Overall Coupled Model Description and Simulation Characteristics}},
volume = {12},
year = {2020}
}
@article{Durack2012,
abstract = {Fundamental thermodynamics and climate models suggest that dry regions will become drier and wet regions will become wetter in response to warming. Efforts to detect this long-term response in sparse surface observations of rainfall and evaporation remain ambiguous. We show that ocean salinity patterns express an identifiable fingerprint of an intensifying water cycle. Our 50-year observed global surface salinity changes, combined with changes from global climate models, present robust evidence of an intensified global water cycle at a rate of 8 ± 5{\%} per degree of surface warming. This rate is double the response projected by current-generation climate models and suggests that a substantial (16 to 24{\%}) intensification of the global water cycle will occur in a future 2° to 3° warmer world.},
author = {Durack, Paul J. and Wijffels, Susan E. and Matear, Richard J.},
doi = {10.1126/science.1212222},
isbn = {1095-9203 (Electronic)$\backslash$n0036-8075 (Linking)},
issn = {10959203},
journal = {Science},
month = {apr},
number = {6080},
pages = {455--458},
pmid = {22539717},
publisher = {American Association for the Advancement of Science},
title = {{Ocean salinities reveal strong global water cycle intensification during 1950 to 2000}},
url = {http://www.ncbi.nlm.nih.gov/pubmed/22539717},
volume = {336},
year = {2012}
}
@article{Durack2013,
abstract = {Long-term global ocean salinity variation provides an insight into water cycle change. This connection reflects changes to the evaporation and precipitation (E-P) fields along with terrestrial runoff, which comprises the global water cycle and sets the spatial pattern of salinity on the ocean surface. The dynamic nature of the global ocean ensures that along with E-P, temperature and circulation changes also play a role in driving patterns of salinity change. This chapter provides an introduction to the global water cycle, briefly outlines the history of ocean salinity observation, and introduces results that relate resolved salinity change to water cycle change. Because of sparse observational coverage, the use of climate models are necessary to investigate these relationships. Long-term changes to global ocean salinity suggest that an unambiguous and coherent water cycle change has occurred over the twentieth and early twenty-first centuries. Climate model simulations project that such changes will intensify in the twenty-first century in response to continued greenhouse gas emissions. {\textcopyright} 2013 Elsevier Ltd.},
author = {Durack, Paul J. and Wijffels, Susan E. and Boyer, Tim P.},
doi = {10.1016/B978-0-12-391851-2.00028-3},
isbn = {00746142 (ISSN)},
issn = {00746142},
journal = {International Geophysics},
keywords = {Climate change,Climate model,Climate variability,Evaporation,History,Hydrography,Measurement,Precipitation,Rainfall,Salinity,Water cycle},
month = {jan},
pages = {727--757},
publisher = {Academic Press},
title = {{Long-term salinity changes and implications for the global water cycle}},
url = {https://www.sciencedirect.com/science/article/pii/B9780123918512000283},
volume = {103},
year = {2013}
}
@article{Durack2015,
abstract = {Alterations to the global water cycle are of concern as Earth's climate changes. Although policymakers are mainly interested in changes to terrestrial rainfall—where, when, and how much it's going to rain—the largest component of the global water cycle operates over the ocean where nearly all of Earth's free water resides. Approximately 80{\%} of Earth's surface freshwater fluxes occur over the ocean; its surface salinity responds to changing evaporation and precipitation patterns by displaying salty or fresh anomalies. The salinity field integrates sporadic surface fluxes over time, and after accounting for ocean circulation and mixing, salinity changes resulting from longterm alternations to surface evaporation and precipitation are evident. Thus, ocean salinity measurements can provide insights into water-cycle operation and its longterm change. Although poor observational coverage and an incomplete view of the interaction of all water-cycle components limits our understanding, climate models are beginning to provide insights that are complementing observations. This new information suggests that the global water cycle is rapidly intensifying.},
archivePrefix = {arXiv},
arxivId = {1011.1669},
author = {Durack, Paul J.},
doi = {10.5670/oceanog.2015.03},
eprint = {1011.1669},
isbn = {9788578110796},
issn = {10428275},
journal = {Oceanography},
month = {mar},
number = {1},
pages = {20--31},
pmid = {25246403},
title = {{Ocean salinity and the global water cycle}},
url = {https://tos.org/oceanography/article/ocean-salinity-and-the-global-water-cycle},
volume = {28},
year = {2015}
}
@article{Durack2010a,
abstract = {Using over 1.6 million profiles of salinity, potential temperature, and neutral density from historical archives and the international Argo Program, this study develops the three-dimensional field of multidecadal linear change for ocean-state properties. The period of analysis extends from 1950 to 2008, taking care to minimize the aliasing associated with the seasonal and major global El Ni{\~{n}}o-Southern Oscillation modes. Large, robust, and spatially coherent multidecadal linear trends in salinity to 2000-dbar depth are found. Salinity increases at the sea surface are found in evaporation-dominated regions and freshening in precipitationdominated regions, with the spatial pattern of change strongly resembling that of the mean salinity field, consistent with an amplification of the global hydrological cycle. Subsurface salinity changes on pressure surfaces are attributable to both isopycnal heave and real water-mass modification of the temperature-salinity relationship. Subduction and circulation by the ocean's mean flow of surface salinity and temperature anomalies appear to account for most regional subsurface salinity changes on isopycnals. Broad-scale surface warming and the associated poleward migration of isopycnal outcrops drive a clear and repeating pattern of subsurface isopycnal salinity change in each independent ocean basin. Qualitatively, the observed global multidecadal salinity changes are thus consonant with both broad-scale surface warming and the amplification of the global hydrological cycle. {\textcopyright} 2010 American Meteorological Society.},
author = {Durack, Paul J. and Wijffels, Susan E.},
doi = {10.1175/2010JCLI3377.1},
isbn = {1520-0442},
issn = {08948755},
journal = {Journal of Climate},
keywords = {ENSO,Global warming,Salinity,Trends},
month = {aug},
number = {16},
pages = {4342--4362},
title = {{Fifty-Year trends in global ocean salinities and their relationship to broad-scale warming}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/2010JCLI3377.1},
volume = {23},
year = {2010}
}
@article{Durack2014b,
abstract = {Of the many processes contributing to long-term sea-level change, little attention has been paid to the large-scale contributions of salinity-driven halosteric changes. We evaluate observed and simulated estimates of long-term (1950-present) halosteric patterns and compare these to corresponding thermosteric changes. Spatially coherent halosteric patterns are visible in the historical record, and are consistent with estimates of long-term water cycle amplification. Our results suggest that long-term basin-scale halosteric changes in the Pacific and Atlantic are substantially larger than previously assumed, with observed estimates and coupled climate models suggesting magnitudes of ∼25{\%} of the corresponding thermosteric changes. In both observations and simulations, Pacific basin-scale freshening leads to a density reduction that augments coincident thermosteric expansion, whereas in the Atlantic halosteric changes partially compensate strong thermosteric expansion via a basin-scale enhanced salinity density increase. Although regional differences are apparent, at basin-scales consistency is found between the observed and simulated partitioning of halosteric and thermosteric changes, and suggests that models are simulating the processes driving observed long-term basin-scale steric changes. Further analysis demonstrates that the observed halosteric changes and their basin partitioning are consistent with CMIP5 simulations that include anthropogenic CO{\textless}inf{\textgreater}2{\textless}/inf{\textgreater} forcings (Historical), but are found to be inconsistent with simulations that exclude anthropogenic forcings (HistoricalNat).},
author = {Durack, Paul J. and Wijffels, Susan E. and Gleckler, Peter J.},
doi = {10.1088/1748-9326/9/11/114017},
issn = {17489326},
journal = {Environmental Research Letters},
keywords = {CMIP5,climate model,global change,oceanography,salinity,sea level,water cycle},
number = {11},
pages = {114017},
title = {{Long-term sea-level change revisited: The role of salinity}},
volume = {9},
year = {2014}
}
@article{Durack2014d,
abstract = {The ocean stores over 90{\%} of the heat due to anthropogenic warming. This study uses satellite observations and climate models to investigate the warming of the upper ocean (0–700 m) and finds that warming is biased low, most likely because of poor Southern Hemisphere sampling. Applying adjustments results in a large increase in upper-ocean heat content estimates.},
author = {Durack, Paul J. and Gleckler, Peter J. and Landerer, Felix W. and Taylor, Karl E.},
doi = {10.1038/nclimate2389},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {nov},
number = {11},
pages = {999--1005},
publisher = {Nature Publishing Group},
title = {{Quantifying underestimates of long-term upper-ocean warming}},
volume = {4},
year = {2014}
}
@article{Durack2018a,
author = {Durack, Paul J. and Gleckler, Peter J. and Purkey, Sarah G. and Johnson, Gregory C. and Lyman, John M. and Boyer, Tim P.},
doi = {10.5670/oceanog.2018.227},
issn = {10428275},
journal = {Oceanography},
month = {jun},
number = {2},
pages = {41--51},
title = {{Ocean Warming: From the Surface to the Deep in Observations and Models}},
url = {https://tos.org/oceanography/article/ocean-warming-from-the-surface-to-the-deep-in-observations-and-models},
volume = {31},
year = {2018}
}
@article{Dwyer2014,
abstract = {Models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) project changes to the seasonality of both tropical sea surface temperature (SST) and precipitation when forced by an increase in greenhouse gases. Nearly all models project an amplification and a phase delay of the annual cycle for both quantities, indicating a greater annual range and extrema reached later in the year. The authors investigate the nature of the seasonal precipitation changes in AGCM experiments forced by SST perturbations, which represent idealizations of the changes in annual mean, amplitude, and phase as simulated by CMIP5 models. A uniform SST warming is sufficient to force both amplification and a delay of the annual cycle of precipitation. The amplification is due to an increase in the annual mean vertical water vapor gradient, while the delay is affected by changes in the seasonality of the circulation. A budget analysis of this simulation reveals a large degree of similarity with the CMIP5 results. In the second experiment, only the seasonal characteristics of SST are changed. In response to an amplified annual cycle of SST, the annual cycle of precipitation is amplified, while for a delayed SST, the annual cycle of precipitation is delayed. Assuming that SST changes can entirely explain the seasonal precipitation changes, the AGCM simulations herein suggest that the annual mean warming explains most of the amplitude increase and much of the phase delay in the CMIP5 models. However, imperfect agreement between the changes in the SST-forced AGCM simulations and the CMIP5 coupled simulations suggests that coupled effects may play a significant role.},
author = {Dwyer, John G. and Biasutti, Michela and Sobel, Adam H.},
doi = {10.1175/JCLI-D-13-00216.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jun},
number = {12},
pages = {4544--4565},
title = {{The Effect of Greenhouse Gas–Induced Changes in SST on the Annual Cycle of Zonal Mean Tropical Precipitation}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-13-00216.1},
volume = {27},
year = {2014}
}
@article{Emile-Geay2016a,
author = {Emile-Geay, J. and Cobb, K. M. and Carr{\'{e}}, M. and Braconnot, P. and Leloup, J. and Zhou, Y. and Harrison, S. P. and Corr{\`{e}}ge, T. and McGregor, H. V. and Collins, M. and Driscoll, R. and Elliot, M. and Schneider, B. and Tudhope, A.},
doi = {10.1038/ngeo2608},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {feb},
number = {2},
pages = {168--173},
title = {{Links between tropical Pacific seasonal, interannual and orbital variability during the Holocene}},
url = {http://www.nature.com/articles/ngeo2608},
volume = {9},
year = {2016}
}
@article{England2014,
abstract = {Despite ongoing increases in atmospheric greenhouse gases, the Earth[rsquor]s global average surface air temperature has remained more or less steady since 2001. A variety of mechanisms have been proposed to account for this slowdown in surface warming. A key component of the global hiatus that has been identified is cool eastern Pacific sea surface temperature, but it is unclear how the ocean has remained relatively cool there in spite of ongoing increases in radiative forcing. Here we show that a pronounced strengthening in Pacific trade winds over the past two decades[mdash]unprecedented in observations/reanalysis data and not captured by climate models[mdash]is sufficient to account for the cooling of the tropical Pacific and a substantial slowdown in surface warming through increased subsurface ocean heat uptake. The extra uptake has come about through increased subduction in the Pacific shallow overturning cells, enhancing heat convergence in the equatorial thermocline. At the same time, the accelerated trade winds have increased equatorial upwelling in the central and eastern Pacific, lowering sea surface temperature there, which drives further cooling in other regions. The net effect of these anomalous winds is a cooling in the 2012 global average surface air temperature of 0.1-0.2 [deg]C, which can account for much of the hiatus in surface warming observed since 2001. This hiatus could persist for much of the present decade if the trade wind trends continue, however rapid warming is expected to resume once the anomalous wind trends abate.},
author = {England, Matthew H. and Mcgregor, Shayne and Spence, Paul and Meehl, Gerald A. and Timmermann, Axel and Cai, Wenju and Gupta, Alex Sen and Mcphaden, Michael J. and Purich, Ariaan and Santoso, Agus},
doi = {10.1038/nclimate2106},
isbn = {1758-678X$\backslash$r1758-6798},
issn = {17586798},
journal = {Nature Climate Change},
number = {3},
pages = {222--227},
title = {{Recent intensification of wind-driven circulation in the Pacific and the ongoing warming hiatus}},
volume = {4},
year = {2014}
}
@article{England2019,
abstract = {Over the last half century, the Arctic sea ice cover has declined dramatically. Current estimates suggest that, for the Arctic as a whole, nearly one-half of the observed loss of summer sea ice cover is not due to anthropogenic forcing but rather is due to internal variability. Using the 40 members of the Community Earth System Model Large Ensemble (CESM-LE), our analysis provides the first regional assessment of the role of internal variability on the observed sea ice loss. The CESM-LE is one of the best available models for such an analysis, because it performs better than other CMIP5 models for many metrics of importance. Our study reveals that the local contribution of internal variability has a large range and strongly depends on the month and region in question. We find that the pattern of internal variability is highly nonuniform over the Arctic, with internal variability accounting for less than 10{\%} of late summer (August–September) East Siberian Sea sea ice loss but more than 60{\%} of the Kara Sea sea ice loss. In contrast, spring (April–May) sea ice loss, notably in the Barents Sea, has so far been dominated by internal variability.},
author = {England, Mark and Jahn, Alexandra and Polvani, Lorenzo},
doi = {10.1175/JCLI-D-18-0864.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jun},
number = {13},
pages = {4039--4053},
title = {{Nonuniform Contribution of Internal Variability to Recent Arctic Sea Ice Loss}},
url = {https://doi.org/10.1175/JCLI-D-18-0864.1},
volume = {32},
year = {2019}
}
@article{England2015,
author = {England, Matthew H and Kajtar, Jules B and Maher, Nicola},
doi = {10.1038/nclimate2575},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {may},
number = {5},
pages = {394--396},
publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.},
title = {{Robust warming projections despite the recent hiatus}},
url = {http://dx.doi.org/10.1038/nclimate2575 http://10.0.4.14/nclimate2575 https://www.nature.com/articles/nclimate2575{\#}supplementary-information http://www.nature.com/articles/nclimate2575},
volume = {5},
year = {2015}
}
@article{Erb2018,
abstract = {Carbon stocks in vegetation have a key role in the climate system. However, the magnitude, patterns and uncertainties of carbon stocks and the effect of land use on the stocks remain poorly quantified. Here we show, using state-of-the-art datasets, that vegetation currently stores around 450 petagrams of carbon. In the hypothetical absence of land use, potential vegetation would store around 916 petagrams of carbon, under current climate conditions. This difference highlights the massive effect of land use on biomass stocks. Deforestation and other land-cover changes are responsible for 53-58{\%} of the difference between current and potential biomass stocks. Land management effects (the biomass stock changes induced by land use within the same land cover) contribute 42-47{\%}, but have been underestimated in the literature. Therefore, avoiding deforestation is necessary but not sufficient for mitigation of climate change. Our results imply that trade-offs exist between conserving carbon stocks on managed land and raising the contribution of biomass to raw material and energy supply for the mitigation of climate change. Efforts to raise biomass stocks are currently verifiable only in temperate forests, where their potential is limited. By contrast, large uncertainties hinder verification in the tropical forest, where the largest potential is located, pointing to challenges for the upcoming stocktaking exercises under the Paris agreement.},
author = {Erb, Karl-Heinz and Kastner, Thomas and Plutzar, Christoph and Bais, Anna Liza S. and Carvalhais, Nuno and Fetzel, Tamara and Gingrich, Simone and Haberl, Helmut and Lauk, Christian and Niedertscheider, Maria and Pongratz, Julia and Thurner, Martin and Luyssaert, Sebastiaan},
doi = {10.1038/nature25138},
issn = {0028-0836},
journal = {Nature},
month = {jan},
number = {7686},
pages = {73--76},
title = {{Unexpectedly large impact of forest management and grazing on global vegetation biomass}},
url = {http://www.nature.com/articles/nature25138},
volume = {553},
year = {2018}
}
@article{Estrada2013,
abstract = {The warming of the climate system is unequivocal as evidenced by an increase in global temperatures by 0.8C over the past century. However, the attribution of the observed warming to human activities remains less clear, particularly because of the apparent slow-down in warming since the late 1990s. Here we analyse radiative forcing and temperature time series with state-of-the-art statistical methods to address this question without climate model simulations. We show that long-term trends in total radiative forcing and temperatures have largely been determined by atmospheric greenhouse gas concentrations, and modulated by other radiative factors. We identify a pronounced increase in the growth rates of both temperatures and radiative forcing around 1960, which marks the onset of sustained global warming. Our analyses also reveal a contribution of human interventions to two periods when global warming slowed down. Our statistical analysis suggests that the reduction in the emissions of ozone-depleting substances under the Montreal Protocol, as well as a reduction in methane emissions, contributed to the lower rate of warming since the 1990s. Furthermore, we identify a contribution from the two world wars and the Great Depression to the documented cooling in the mid-twentieth century, through lower carbon dioxide emissions. We conclude that reductions in greenhouse gas emissions are effective in slowing the rate of warming in the short term. {\textcopyright} 2013 Macmillan Publishers Limited.},
author = {Estrada, Francisco and Perron, Pierre and Mart{\'{i}}nez-L{\'{o}}pez, Benjam{\'{i}}n},
doi = {10.1038/ngeo1999},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {dec},
number = {12},
pages = {1050--1055},
title = {{Statistically derived contributions of diverse human influences to twentieth-century temperature changes}},
url = {http://www.nature.com/articles/ngeo1999},
volume = {6},
year = {2013}
}
@article{Eyring2013,
abstract = {Ozone changes and associated climate impacts in the Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations are analyzed over the historical (1960-2005) and future (2006-2100) period under four Representative Concentration Pathways (RCP). In contrast to CMIP3, where half of the models prescribed constant stratospheric ozone, CMIP5 models all consider past ozone depletion and future ozone recovery. Multimodel mean climatologies and long-term changes in total and tropospheric column ozone calculated from CMIP5 models with either interactive or prescribed ozone are in reasonable agreement with observations. However, some large deviations from observations exist for individual models with interactive chemistry, and these models are excluded in the projections. Stratospheric ozone projections forced with a single halogen, but four greenhouse gas (GHG) scenarios show largest differences in the northern midlatitudes and in the Arctic in spring ({\~{}}20 and 40 Dobson units (DU) by 2100, respectively). By 2050, these differences are much smaller and negligible over Antarctica in austral spring. Differences in future tropospheric column ozone are mainly caused by differences in methane concentrations and stratospheric input, leading to {\~{}}10 DU increases compared to 2000 in RCP 8.5. Large variations in stratospheric ozone particularly in CMIP5 models with interactive chemistry drive correspondingly large variations in lower stratospheric temperature trends. The results also illustrate that future Southern Hemisphere summertime circulation changes are controlled by both the ozone recovery rate and the rate of GHG increases, emphasizing the importance of simulating and taking into account ozone forcings when examining future climate projections. Key PointsCMIP5 models all consider past ozone depletion and future ozone recoveryMultimodel ozone agrees well with observations but individual models deviateFuture climate is sensitive to rates of both ozone recovery and GHG increases {\textcopyright}2013. American Geophysical Union. All Rights Reserved.},
author = {Eyring, V. and Arblaster, J. M. and Cionni, I. and Sedl{\'{a}}{\v{c}}ek, J. and Perlwitz, J. and Young, P. J. and Bekki, S. and Bergmann, D. and Cameron-Smith, P. and Collins, W. J. and Faluvegi, G. and Gottschaldt, K. D. and Horowitz, L. W. and Kinnison, D. E. and Lamarque, J. F. and Marsh, D. R. and Saint-Martin, D. and Shindell, D. T. and Sudo, K. and Szopa, S. and Watanabe, S.},
doi = {10.1002/jgrd.50316},
isbn = {2169-897X},
issn = {21698996},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {CMIP5,chemistry-climate coupling,stratospheric ozone,stratospheric temperature trends,tropospheric ozone,zonal wind changes},
month = {may},
number = {10},
pages = {5029--5060},
title = {{Long-term ozone changes and associated climate impacts in CMIP5 simulations}},
url = {http://doi.wiley.com/10.1002/jgrd.50316},
volume = {118},
year = {2013}
}
@article{Eyring2016a,
abstract = {{\textless}p{\textgreater}{\textless}p{\textgreater}{\textless}strong{\textgreater}Abstract.{\textless}/strong{\textgreater} The Coupled Model Intercomparison Project (CMIP) has successfully provided the climate community with a rich collection of simulation output from Earth system models (ESMs) that can be used to understand past climate changes and make projections and uncertainty estimates of the future. Confidence in ESMs can be gained because the models are based on physical principles and reproduce many important aspects of observed climate. More research is required to identify the processes that are most responsible for systematic biases and the magnitude and uncertainty of future projections so that more relevant performance tests can be developed. At the same time, there are many aspects of ESM evaluation that are well established and considered an essential part of systematic evaluation but have been implemented ad hoc with little community coordination. Given the diversity and complexity of ESM analysis, we argue that the CMIP community has reached a critical juncture at which many baseline aspects of model evaluation need to be performed much more efficiently and consistently. Here, we provide a perspective and viewpoint on how a more systematic, open, and rapid performance assessment of the large and diverse number of models that will participate in current and future phases of CMIP can be achieved, and announce our intention to implement such a system for CMIP6. Accomplishing this could also free up valuable resources as many scientists are frequently "re-inventing the wheel" by re-writing analysis routines for well-established analysis methods. A more systematic approach for the community would be to develop and apply evaluation tools that are based on the latest scientific knowledge and observational reference, are well suited for routine use, and provide a wide range of diagnostics and performance metrics that comprehensively characterize model behaviour as soon as the output is published to the Earth System Grid Federation (ESGF). The CMIP infrastructure enforces data standards and conventions for model output and documentation accessible via the ESGF, additionally publishing observations (obs4MIPs) and reanalyses (ana4MIPs) for model intercomparison projects using the same data structure and organization as the ESM output. This largely facilitates routine evaluation of the ESMs, but to be able to process the data automatically alongside the ESGF, the infrastructure needs to be extended with processing capabilities at the ESGF data nodes where the evaluation tools can be executed on a routine basis. Efforts are already underway to develop community-based evaluation tools, and we encourage experts to provide additional diagnostic codes that would enhance this capability for CMIP. At the same time, we encourage the community to contribute observations and reanalyses for model evaluation to the obs4MIPs and ana4MIPs archives. The intention is to produce through the ESGF a widely accepted quasi-operational evaluation framework for CMIP6 that would routinely execute a series of standardized evaluation tasks. Over time, as this capability matures, we expect to produce an increasingly systematic characterization of models which, compared with early phases of CMIP, will more quickly and openly identify the strengths and weaknesses of the simulations. This will also reveal whether long-standing model errors remain evident in newer models and will assist modelling groups in improving their models. This framework will be designed to readily incorporate updates, including new observations and additional diagnostics and metrics as they become available from the research community.{\textless}/p{\textgreater}{\textless}/p{\textgreater}},
author = {Eyring, Veronika and Gleckler, Peter J. and Heinze, Christoph and Stouffer, Ronald J. and Taylor, Karl E. and Balaji, V. and Guilyardi, Eric and Joussaume, Sylvie and Kindermann, Stephan and Lawrence, Bryan N. and Meehl, Gerald A. and Righi, Mattia and Williams, Dean N.},
doi = {10.5194/esd-7-813-2016},
issn = {2190-4987},
journal = {Earth System Dynamics},
month = {nov},
number = {4},
pages = {813--830},
title = {{Towards improved and more routine Earth system model evaluation in CMIP}},
url = {https://www.earth-syst-dynam.net/7/813/2016/},
volume = {7},
year = {2016}
}
@article{Eyring2016c,
abstract = {By coordinating the design and distribution of global climate model simulations of the past, current, and future climate, the Coupled Model Intercomparison Project (CMIP) has become one of the foundational elements of climate science. However, the need to address an ever- expanding range of scientific questions arising from more and more research communities has made it necessary to re- vise the organization of CMIP. After a long and wide com- munity consultation, a new and more federated structure has been put in place. It consists of three major elements: (1) a handful of common experiments, the DECK (Diagnostic, Evaluation and Characterization of Klima) and CMIP his- torical simulations (1850–near present) that will maintain continuity and help document basic characteristics of mod- els across different phases of CMIP; (2) common standards, coordination, infrastructure, and documentation that will fa- cilitate the distribution of model outputs and the characteriza- tion of the model ensemble; and (3) an ensemble of CMIP- Endorsed Model Intercomparison Projects (MIPs) that will be specific to a particular phase of CMIP (now CMIP6) and that will build on the DECK and CMIP historical simulations to address a large range of specific questions and fill the sci- entific gaps of the previous CMIP phases. The DECK and CMIP historical simulations, together with the use of CMIP data standards, will be the entry cards for models participat- ing in CMIP. Participation in CMIP6-Endorsed MIPs by in- dividual modelling groups will be at their own discretion and will depend on their scientific interests and priorities. With the Grand Science Challenges of theWorld Climate Research Programme (WCRP) as its scientific backdrop, CMIP6 will address three broad questions: – How does the Earth system respond to forcing? – What are the origins and consequences of systematic model biases? – How can we assess future climate changes given inter- nal climate variability, predictability, and uncertainties in scenarios? This CMIP6 overview paper presents the background and ra- tionale for the new structure of CMIP, provides a detailed description of the DECK and CMIP6 historical simulations, and includes a brief introduction to the 21 CMIP6-Endorsed MIPs.},
author = {Eyring, Veronika and Bony, Sandrine and Meehl, Gerald A. and Senior, Catherine A. and Stevens, Bjorn and Stouffer, Ronald J. and Taylor, Karl E.},
doi = {10.5194/gmd-9-1937-2016},
isbn = {1991-9603},
issn = {19919603},
journal = {Geoscientific Model Development},
month = {may},
number = {5},
pages = {1937--1958},
title = {{Overview of the Coupled Model Intercomparison Project Phase 6 (CMIP6) experimental design and organization}},
url = {https://www.geosci-model-dev.net/9/1937/2016/},
volume = {9},
year = {2016}
}
@article{Eyring2019,
abstract = {T he Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) concluded that the warming of the climate system is unequivocal and human influence on the climate system is clear 1. Observed increases of greenhouse gases have contributed significantly to warming of the atmosphere and ocean, sea-ice decline and sea-level rise. The size and rapidity of these changes is concerning. Human-caused climate change is already affecting many aspects of societies and ecosystems. These impacts will become more visible and more serious in the twenty-first century. It should, therefore , be an international priority to improve our understanding of the climate system, and to reduce current uncertainties in projections of future change. This will rely on information from theory, observations, and Earth system model (ESM) simulations that are coordinated as part of the World Climate Research Programme (WCRP) Coupled Model Intercomparison Project (CMIP; refs. 2-5). CMIP is now in its sixth phase (CMIP6) 5 and is confronted with a number of new challenges. Compared to CMIP5, an increased number of institutions participate in CMIP6, many with multiple model versions. The latest generation of climate models feature increases in spatial resolution, improvements in physical parameterizations (in the representation of clouds, for example) and inclusion of additional Earth system processes (such as nutrient limitations on the terrestrial carbon cycle) and components (such as ice sheets). These additional processes are needed to represent key feedbacks that affect climate change, but are also likely to increase the spread of climate projections across the mul-timodel ensemble. This escalates the need for innovative and comprehensive model evaluation approaches. CMIP provides the basis for multimodel evaluation and has, over the years, revealed a variety of systematic differences between models and observations, with many persisting from one model generation to the next 6,7. An important issue that remains to be fully addressed is the extent to which model errors affect the quality of climate projections and subsequent impact assessments 8. Traditionally, many climate projections are shown as multimodel averages in the peer-reviewed literature and IPCC reports, with the spread across models presented as a measure of projection uncertainty 9. There is now emerging evidence that weighting based on model performance may improve projections for specific applicatio{\ldots}},
author = {Eyring, Veronika and Cox, Peter M. and Flato, Gregory M. and Gleckler, Peter J. and Abramowitz, Gab and Caldwell, Peter and Collins, William D. and Gier, Bettina K. and Hall, Alex D. and Hoffman, Forrest M. and Hurtt, George C. and Jahn, Alexandra and Jones, Chris D. and Klein, Stephen A. and Krasting, John P. and Kwiatkowski, Lester and Lorenz, Ruth and Maloney, Eric and Meehl, Gerald A. and Pendergrass, Angeline G. and Pincus, Robert and Ruane, Alex C. and Russell, Joellen L. and Sanderson, Benjamin M. and Santer, Benjamin D. and Sherwood, Steven C. and Simpson, Isla R. and Stouffer, Ronald J. and Williamson, Mark S.},
doi = {10.1038/s41558-018-0355-y},
issn = {17586798},
journal = {Nature Climate Change},
number = {2},
pages = {102--110},
title = {{Taking climate model evaluation to the next level}},
volume = {9},
year = {2019}
}
@article{gmd-13-3383-2020,
author = {Eyring, V and Bock, L and Lauer, A and Righi, M and Schlund, M and Andela, B and Arnone, E and Bellprat, O and Br{\"{o}}tz, B and Caron, L.-P. and Carvalhais, N and Cionni, I and Cortesi, N and Crezee, B and Davin, E L and Davini, P and Debeire, K and de Mora, L and Deser, C and Docquier, D and Earnshaw, P and Ehbrecht, C and Gier, B K and Gonzalez-Reviriego, N and Goodman, P and Hagemann, S and Hardiman, S and Hassler, B and Hunter, A and Kadow, C and Kindermann, S and Koirala, S and Koldunov, N and Lejeune, Q and Lembo, V and Lovato, T and Lucarini, V and Massonnet, F and M{\"{u}}ller, B and Pandde, A and P{\'{e}}rez-Zan{\'{o}}n, N and Phillips, A and Predoi, V and Russell, J and Sellar, A and Serva, F and Stacke, T and Swaminathan, R and Torralba, V and Vegas-Regidor, J and von Hardenberg, J and Weigel, K and Zimmermann, K},
doi = {10.5194/gmd-13-3383-2020},
journal = {Geoscientific Model Development},
number = {7},
pages = {3383--3438},
title = {{Earth System Model Evaluation Tool (ESMValTool) v2.0 – an extended set of large-scale diagnostics for quasi-operational and comprehensive evaluation of Earth system models in CMIP}},
url = {https://gmd.copernicus.org/articles/13/3383/2020/},
volume = {13},
year = {2020}
}
@article{Ezer2013,
abstract = {Recent studies indicate that the rates of sea level rise (SLR) along the U.S. mid-Atlantic coast have accelerated in recent decades, possibly due to a slowdown of the Atlantic Meridional Overturning Circulation (AMOC) and its upper branch, the Gulf Stream (GS). We analyzed the GS elevation gradient obtained from altimeter data, the Florida Current transport obtained from cable measurements, the North Atlantic Oscillation (NAO) index, and coastal sea level obtained from 10 tide gauge stations in the Chesapeake Bay and the mid-Atlantic coast. An Empirical Mode Decomposition/Hilbert-Huang Transformation (EMD/HHT) method was used to separate long-term trends from oscillating modes. The coastal sea level variations were found to be strongly influenced by variations in the GS on timescales ranging from a few months to decades. It appears that the GS has shifted from a 6?8?year oscillation cycle to a continuous weakening trend since about 2004 and that this trend may be responsible for recent acceleration in local SLR. The correlation between long-term changes in the coastal sea level and changes in the GS strength was extremely high (R?=??0.85 with more than 99.99{\%} confidence that the correlation is not zero). The impact of the GS on SLR rates over the past decade seems to be larger in the southern portion of the mid-Atlantic Bight near Cape Hatteras and is reduced northward along the coast. The study suggests that regional coastal sea level rise projections due to climate change must take into account the impact of spatial changes in ocean dynamics.},
annote = {doi: 10.1002/jgrc.20091},
author = {Ezer, Tal and Atkinson, Larry P and Corlett, William B and Blanco, Jose L},
doi = {10.1002/jgrc.20091},
issn = {2169-9275},
journal = {Journal of Geophysical Research: Oceans},
keywords = {Florida Current,Gulf Stream,climate change,mid-Atlantic,sea level rise},
month = {feb},
number = {2},
pages = {685--697},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Gulf Stream's induced sea level rise and variability along the U.S. mid-Atlantic coast}},
url = {https://doi.org/10.1002/jgrc.20091},
volume = {118},
year = {2013}
}
@article{Fabiano2020,
author = {Fabiano, F. and Christensen, H.M. and Strommen, K. and Athanasiadis, Panos and Baker, A and Schiemann, Reinhard and Corti, Susanna},
doi = {10.1007/s00382-020-05271-w},
journal = {Climate Dynamics},
pages = {5031--5048},
title = {{Euro-Atlantic weather Regimes in the PRIMAVERA coupled climate simulations: impact of resolution and mean state biases on model performance}},
url = {https://doi.org/10.1007/s00382-020-05271-w},
volume = {54},
year = {2020}
}
@article{Fasullo9999,
abstract = {The adequate simulation of internal climate variability is key for our understanding of climate as it underpins efforts to attribute historical events, predict on seasonal and decadal time scales, and isolate the effects of climate change. Here the skill of models in reproducing observed modes of climate variability is assessed, both across and within the CMIP3, CMIP5, and CMIP6 archives, in order to document model capabilities, progress across ensembles, and persisting biases. A focus is given to the well-observed tropical and extratropical modes that exhibit small intrinsic variability relative to model structural uncertainty. These include El Ni{\~{n}}o–Southern Oscillation (ENSO), the Pacific decadal oscillation (PDO), the North Atlantic Oscillation (NAO), and the northern and southern annular modes (NAM and SAM). Significant improvements are identified in models' representation of many modes. Canonical biases, which involve both amplitudes and patterns, are generally reduced across model generations. For example, biases in ENSO-related equatorial Pacific sea surface temperature, which extend too far westward, and associated atmospheric teleconnections, which are too weak, are reduced. Stronger tropical expression of the PDO in successive CMIP generations has characterized their improvement, with some CMIP6 models generating patterns that lie within the range of observed estimates. For the NAO, NAM, and SAM, pattern correlations with observations are generally higher than for other modes and slight improvements are identified across successive model generations. For ENSO and PDO spectra and extratropical modes, changes are small compared to internal variability, precluding definitive statements regarding improvement.},
author = {Fasullo, John T. and Phillips, A. S. and Deser, C.},
doi = {10.1175/jcli-d-19-1024.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jul},
number = {13},
pages = {5527--5545},
title = {{Evaluation of Leading Modes of Climate Variability in the CMIP Archives}},
url = {https://journals.ametsoc.org/jcli/article/33/13/5527/346000/Evaluation-of-Leading-Modes-of-Climate-Variability},
volume = {33},
year = {2020}
}
@article{Fasullo2018,
abstract = {The satellite altimeter record has provided an unprecedented database for understanding sea-level rise and has recently reached a major milestone at 25 years in length. A challenge now exists in understanding its broader significance and its consequences for sea-level rise in the coming decades and beyond. A key question is whether the pattern of altimeter-era change is representative of longer-term trends driven by anthropogenic forcing. In this work, two multimember climate ensembles, the Community Earth System Model (CESM) and the Earth System Model Version 2M (ESM2M), are used to estimate patterns of forced change [also known as the forced response (FR)] and their magnitudes relative to internal variability. It is found that the spatial patterns of 1993–2018 trends in the ensembles correlate significantly with the contemporaneous FRs (0.55 ± 0.10 in the CESM and 0.61 ± 0.09 in the ESM2M) and the 1950–2100 FRs (0.43 ± 0.10 in the CESM and 0.51 ± 0.11 in the ESM2M). Unforced runs for each model show such correlations to be extremely unlikely to have arisen by chance, indicating an emergence of both the altimeter-era and long-term FRs and suggesting a similar emergence in nature. Projected patterns of the FR over the coming decades resemble those simulated during the altimeter era, suggesting a continuation of the forced pattern of change in nature in the coming decades. Notably, elevated rates of rise are projected to continue in regions that are susceptible to tropical cyclones, exacerbating associated impacts in a warming climate.},
author = {Fasullo, John T and Nerem, R Steven},
doi = {10.1073/pnas.1813233115},
issn = {0027-8424},
journal = {Proceedings of the National Academy of Sciences},
month = {dec},
number = {51},
pages = {12944--12949},
title = {{Altimeter-era emergence of the patterns of forced sea-level rise in climate models and implications for the future}},
url = {http://www.pnas.org/lookup/doi/10.1073/pnas.1813233115},
volume = {115},
year = {2018}
}
@article{Fathrio2017a,
abstract = {The western Indian Ocean sea surface temperature (SST) is among the key factors that affect precipitation over India and East Africa. This study examined the western Indian Ocean SST biases among the Coupled Model Intercomparison Project phase 5 (CMIP5) models. It was found that the multimodel ensemble-mean SST biases over the western equatorial Indian Ocean are warmer than the observations during the summer monsoon season. However, about half the models show positive SST biases, whereas negative ones in the other half. The models with warmer SST biases exhibit a pattern similar to the Indian Ocean Dipole, with stronger equatorial easterly wind biases during fall and a deeper thermocline in the western equatorial Indian Ocean. In the models with cooler SST biases, negative SST biases are observed over the entire tropical Indian Ocean throughout the year and the wind biases over the equatorial Indian Ocean are southeasterly during summer and fall. Heat budget analysis revealed the importance of ocean currents in forming the early summer development of SST biases over the western equatorial Indian Ocean. The formation of SST biases is related to surface current biases induced by the weaker biases of southwesterly monsoon winds and SST biases over the southwestern equatorial Indian Ocean, which are advected by the East African Coastal Currents. On the other hand, almost of all the CMIP5 models show prominent cold SST biases over the northern Arabian Sea during the premonsoon season. The SST biases are induced by excess surface cooling during the winter monsoon season.},
author = {Fathrio, Ibnu and Iizuka, Satoshi and Manda, Atsuyoshi and Kodama, Yasu Masa and Ishida, Sachinobu and Moteki, Qoosaku and Yamada, Hiroyuki and Tachibana, Yoshihiro},
doi = {10.1002/2016JC012443},
issn = {21699291},
journal = {Journal of Geophysical Research: Oceans},
keywords = {CMIP5,SST bias,heat budget analysis,western equatorial Indian Ocean},
month = {apr},
number = {4},
pages = {3123--3140},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Assessment of western Indian Ocean SST bias of CMIP5 models}},
url = {http://doi.wiley.com/10.1002/2016JC012443},
volume = {122},
year = {2017}
}
@article{Fathrio2017,
abstract = {Prior to future climate assessment of the 5th Coupled Model Intercomparison (CMIP5) experiments, how well CMIP5 models simulates present climate should be examined. Sea surface salinity (sss) play important role in ocean stratification and indirectly affects air sea interaction. However, few studies have been carried out to evaluate sss in CMIP5 models. In this study, performance of CMIP5 models in simulating sss in Indian Ocean was examined with respect to the observation. Our results showed that multi model ensemble (MME) mean of CMIP5 models displayed annual and seasonal salinity bias in three regions i.e. Western Indian Ocean (WIO), Bay of Bengal (BOB) and Southeastern Indian Ocean (SEIO). CMIP5 models overestimate sss in BOB about 1.5 psu and underestimated sss in WIO and SEIO about 0.4 psu. Biases in WIO and BOB were mainly attributed to bias in precipitation. CMIP5 models overestimated (underestimated) precipitation in WIO (BOB) with greater bias found during Boreal summer to winter. Meanwhile, advection process was responsible for negative SSS bias in SEIO.},
author = {Fathrio, Ibnu and Manda, Atsuyoshi and Iizuka, Satoshi and Kodama, Yasu Masa and Ishida, Sachinobu},
doi = {10.1088/1755-1315/54/1/012039},
issn = {17551315},
journal = {IOP Conference Series: Earth and Environmental Science},
month = {jan},
number = {1},
pages = {012039},
publisher = {IOP Publishing},
title = {{Evaluation of CMIP5 models on sea surface salinity in the Indian Ocean}},
url = {http://stacks.iop.org/1755-1315/54/i=1/a=012039?key=crossref.b06b7a6135dd153ff923b10a7dc2478d},
volume = {54},
year = {2017}
}
@article{Fay2014,
author = {Fay, Amanda R. and McKinley, Galen A. and Lovenduski, Nicole S.},
doi = {10.1002/2014GL061324},
issn = {00948276},
journal = {Geophysical Research Letters},
keywords = {Southern Ocean,carbon cycle,pCO2,trend analysis},
month = {oct},
number = {19},
pages = {6833--6840},
publisher = {Wiley-Blackwell},
title = {{Southern Ocean carbon trends: Sensitivity to methods}},
url = {http://doi.wiley.com/10.1002/2014GL061324},
volume = {41},
year = {2014}
}
@article{Fay2013,
author = {Fay, A. R. and McKinley, G. A.},
doi = {10.1002/gbc.20051},
issn = {08866236},
journal = {Global Biogeochemical Cycles},
keywords = {carbon trends,climate change,surface ocean pCO2},
month = {jun},
number = {2},
pages = {541--557},
publisher = {Wiley-Blackwell},
title = {{Global trends in surface ocean pCO2 from in situ data}},
url = {http://doi.wiley.com/10.1002/gbc.20051},
volume = {27},
year = {2013}
}
@article{Feldstein2006c,
author = {Feldstein, Steven B. and Franzke, Christian},
doi = {10.1175/JAS3798.1},
issn = {0022-4928},
journal = {Journal of the Atmospheric Sciences},
month = {nov},
number = {11},
pages = {2915--2930},
title = {{Are the North Atlantic Oscillation and the Northern Annular Mode Distinguishable?}},
volume = {63},
year = {2006}
}
@article{Ferreira2014,
abstract = {AbstractThe response of the Southern Ocean to a repeating seasonal cycle of ozone loss is studied in two coupled climate models and is found to comprise both fast and slow processes. The fast response is similar to the interannual signature of the southern annular mode (SAM) on sea surface temperature (SST), onto which the ozone hole forcing projects in the summer. It comprises enhanced northward Ekman drift, inducing negative summertime SST anomalies around Antarctica, earlier sea ice freeze-up the following winter, and northward expansion of the sea ice edge year-round. The enhanced northward Ekman drift, however, results in upwelling of warm waters from below the mixed layer in the region of seasonal sea ice. With sustained bursts of westerly winds induced by ozone hole depletion, this warming from below eventually dominates over the cooling from anomalous Ekman drift. The resulting slow time-scale response (years to decades) leads to warming of SSTs around Antarctica and ultimately a reduction in sea ice cover year-round. This two-time-scale behavior?rapid cooling followed by slow but persistent warming?is found in the two coupled models analyzed: one with an idealized geometry and the other with a complex global climate model with realistic geometry. Processes that control the time scale of the transition from cooling to warming and their uncertainties are described. Finally the implications of these results are discussed for rationalizing previous studies of the effect of the ozone hole on SST and sea ice extent.},
annote = {doi: 10.1175/JCLI-D-14-00313.1},
author = {Ferreira, David and Marshall, John and Bitz, Cecilia M and Solomon, Susan and Plumb, Alan},
doi = {10.1175/JCLI-D-14-00313.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {nov},
number = {3},
pages = {1206--1226},
publisher = {American Meteorological Society},
title = {{Antarctic Ocean and Sea Ice Response to Ozone Depletion: A Two-Time-Scale Problem}},
url = {https://doi.org/10.1175/JCLI-D-14-00313.1},
volume = {28},
year = {2014}
}
@article{Fettweis2013,
abstract = {Abstract. Since 2007, there has been a series of surface melt records over the Greenland ice sheet (GrIS), continuing the trend towards increased melt observed since the end of the 1990's. The last two decades are characterized by an increase of negative phases of the North Atlantic Oscillation (NAO) favouring warmer and drier summers than normal over GrIS. In this context, we use a circulation type classification based on daily 500 hPa geopotential height to evaluate the role of atmospheric dynamics in this surface melt acceleration for the last two decades. Due to the lack of direct observations, the interannual melt variability is gauged here by the summer (June–July–August) mean temperature from reanalyses at 700 hPa over Greenland; analogous atmospheric circulations in the past show that {\~{}}70{\%} of the 1993–2012 warming at 700 hPa over Greenland has been driven by changes in the atmospheric flow frequencies. Indeed, the occurrence of anticyclones centred over the GrIS at the surface and at 500 hPa has doubled since the end of 1990's, which induces more frequent southerly warm air advection along the western Greenland coast and over the neighbouring Canadian Arctic Archipelago (CAA). These changes in the NAO modes explain also why no significant warming has been observed these last summers over Svalbard, where northerly atmospheric flows are twice as frequent as before. Therefore, the recent warmer summers over GrIS and CAA cannot be considered as a long-term climate warming but are more a consequence of NAO variability affecting atmospheric heat transport. Although no global model from the CMIP5 database projects subsequent significant changes in NAO through this century, we cannot exclude the possibility that the observed NAO changes are due to global warming.},
author = {Fettweis, X. and Hanna, E. and Lang, C. and Belleflamme, A. and Erpicum, M. and Gall{\'{e}}e, H.},
doi = {10.5194/tc-7-241-2013},
issn = {1994-0424},
journal = {The Cryosphere},
month = {feb},
number = {1},
pages = {241--248},
title = {{Brief communication “Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet”}},
url = {https://www.the-cryosphere.net/7/241/2013/},
volume = {7},
year = {2013}
}
@article{Fettweis2020,
author = {Fettweis, Xavier and Hofer, Stefan and Krebs-Kanzow, Uta and Amory, Charles and Aoki, Teruo and Berends, Constantijn J. and Born, Andreas and Box, Jason E. and Delhasse, Alison and Fujita, Koji and Gierz, Paul and Goelzer, Heiko and Hanna, Edward and Hashimoto, Akihiro and Huybrechts, Philippe and Kapsch, Marie-Luise and King, Michalea D. and Kittel, Christoph and Lang, Charlotte and Langen, Peter L. and Lenaerts, Jan T. M. and Liston, Glen E. and Lohmann, Gerrit and Mernild, Sebastian H. and Mikolajewicz, Uwe and Modali, Kameswarrao and Mottram, Ruth H. and Niwano, Masashi and No{\"{e}}l, Brice and Ryan, Jonathan C. and Smith, Amy and Streffing, Jan and Tedesco, Marco and van de Berg, Willem Jan and van den Broeke, Michiel and van de Wal, Roderik S. W. and van Kampenhout, Leo and Wilton, David and Wouters, Bert and Ziemen, Florian and Zolles, Tobias},
doi = {10.5194/tc-14-3935-2020},
issn = {1994-0424},
journal = {The Cryosphere},
keywords = {Accumulation zone,Climate model,Climatology,Cryosphere,Geology,Greenland ice sheet,Ice core,Ice sheet,Meltwater,Snow},
month = {nov},
number = {11},
pages = {3935--3958},
title = {{GrSMBMIP: intercomparison of the modelled 1980–2012 surface mass balance over the Greenland Ice Sheet}},
url = {https://tc.copernicus.org/articles/14/3935/2020/},
volume = {14},
year = {2020}
}
@article{Fiedler2020,
abstract = {The representation of tropical precipitation is evaluated across three generations of models participating in phases 3, 5, and 6 of the Coupled Model Intercomparison Project (CMIP). Compared to state-of-the-art observations, improvements in tropical precipitation in the CMIP6 models are identified for some metrics, but we find no general improvement in tropical precipitation on different temporal and spatial scales. Our results indicate overall little changes across the CMIP phases for the summer monsoons, the double-ITCZ bias, and the diurnal cycle of tropical precipitation. We find a reduced amount of drizzle events in CMIP6, but tropical precipitation occurs still too frequently. Continuous improvements across the CMIP phases are identified for the number of consecutive dry days, for the representation of modes of variability, namely, the Madden-Julian oscillation and El Ni{\~{n}}o-Southern Oscillation, and for the trends in dry months in the twentieth century. The observed positive trend in extreme wet months is, however, not captured by any of the CMIP phases, which simulate negative trends for extremely wet months in the twentieth century. The regional biases are larger than a climate change signal one hopes to use the models to identify. Given the pace of climate change as compared to the pace of model improvements to simulate tropical precipitation, we question the past strategy of the development of the present class of global climate models as the mainstay of the scientific response to climate change. We suggest the exploration of alternative approaches such as high-resolution storm-resolving models that can offer better prospects to inform us about how tropical precipitation might change with anthropogenic warming.},
author = {Fiedler, Stephanie and Crueger, Traute and D'Agostino, Roberta and Peters, Karsten and Becker, Tobias and Leutwyler, David and Paccini, Laura and Burdanowitz, J{\"{o}}rg and Buehler, Stefan A. and Cortes, Alejandro Uribe and Dauhut, Thibaut and Dommenget, Dietmar and Fraedrich, Klaus and Jungandreas, Leonore and Maher, Nicola and Naumann, Ann Kristin and Rugenstein, Maria and Sakradzija, Mirjana and Schmidt, Hauke and Sielmann, Frank and Stephan, Claudia and Timmreck, Claudia and Zhu, Xiuhua and Stevens, Bjorn},
doi = {10.1175/MWR-D-19-0404.1},
issn = {15200493},
journal = {Monthly Weather Review},
number = {9},
pages = {3653--3680},
title = {{Simulated tropical precipitation assessed across three major phases of the coupled model intercomparison project (CMIP)}},
volume = {148},
year = {2020}
}
@article{Flannaghan2014,
abstract = {The comparison of trends in various climate indices in observations and models is of fundamental importance for judging the credibility of climate projections. Tropical tropospheric temperature trends have attracted particular attention as this comparison may suggest a model deficiency. One can think of this problem as composed of two parts: one focused on tropical surface temperature trends and the associated issues related to forcing, feedbacks, and ocean heat uptake and a second part focusing on connections between surface and tropospheric temperatures and the vertical profile of trends in temperature. Here we focus on the atmospheric component of the problem. We show that two ensembles of Geophysical Fluid Dynamics Laboratory HiRAM model runs (similar results are shown for National Center for Atmospheric Research's CAM4 model) with different commonly used prescribed sea surface temperatures (SSTs), namely, the HadISST1 and “Hurrell” data sets, have a difference in upper tropical tropospheric temperature trends (∼0.1 K/decade at 300 hPa for the period 1984–2008) that is about a factor 3 larger than expected from moist adiabatic scaling of the tropical average SST trend difference. We show that this surprisingly large discrepancy in temperature trends is a consequence of SST trend differences being largest in regions of deep convection. Further, trends, and the degree of agreement with observations, not only depend on SST data set and the particular atmospheric temperature data set but also on the period chosen for comparison. Due to the large impact on atmospheric temperatures, these systematic uncertainties in SSTs need to be resolved before the fidelity of climate models' tropical temperature trend profiles can be assessed.},
author = {Flannaghan, T. J. and Fueglistaler, S. and Held, I. M. and Po‐Chedley, S. and Wyman, B. and Zhao, M.},
doi = {10.1002/2014JD022365},
issn = {2169-897X},
journal = {Journal of Geophysical Research: Atmospheres},
month = {dec},
number = {23},
pages = {13327--13337},
title = {{Tropical temperature trends in Atmospheric General Circulation Model simulations and the impact of uncertainties in observed SSTs}},
url = {https://onlinelibrary.wiley.com/doi/10.1002/2014JD022365},
volume = {119},
year = {2014}
}
@incollection{Flato2013,
address = {Cambridge, United Kingdom and New York, NY, USA},
author = {Flato, G. and Marotzke, J. and Abiodun, B. and Braconnot, Pascale and Chou, S.C. C and Collins, W. and Cox, P. and Driouech, F. and Emori, S. and Eyring, V. and Forest, C. and Gleckler, P. and Guilyardi, {\'{E}}ric and Jakob, C. and Kattsov, V. and Reason, C. and Rummukainen, M. and Guilyardi, E and Jakob, C. and Kattsov, V. and Reason, C. and Rummukainen, M.},
booktitle = {Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change},
chapter = {9},
doi = {10.1017/CBO9781107415324.020},
editor = {Stocker, T F and Qin, D and Plattner, G.-K. and Tignor, M and Allen, S K and Boschung, J and Nauels, A and Xia, Y and Bex, V and Midgley, P M},
isbn = {9781107661820},
pages = {741--866},
publisher = {Cambridge University Press},
title = {{Evaluation of climate models}},
url = {https://www.ipcc.ch/report/ar5/wg1},
year = {2013}
}
@article{Fleischer2019a,
abstract = {Global terrestrial models currently predict that the Amazon rainforest will continue to act as a carbon sink in the future, primarily owing to the rising atmospheric carbon dioxide (CO2) concentration. Soil phosphorus impoverishment in parts of the Amazon basin largely controls its functioning, but the role of phosphorus availability has not been considered in global model ensembles—for example, during the Fifth Climate Model Intercomparison Project. Here we simulate the planned free-air CO2 enrichment experiment AmazonFACE with an ensemble of 14 terrestrial ecosystem models. We show that phosphorus availability reduces the projected CO2-induced biomass carbon growth by about 50{\%} to 79 ± 63 g C m−2 yr−1 over 15 years compared to estimates from carbon and carbon–nitrogen models. Our results suggest that the resilience of the region to climate change may be much less than previously assumed. Variation in the biomass carbon response among the phosphorus-enabled models is considerable, ranging from 5 to 140 g C m−2 yr−1, owing to the contrasting plant phosphorus use and acquisition strategies considered among the models. The Amazon forest response thus depends on the interactions and relative contributions of the phosphorus acquisition and use strategies across individuals, and to what extent these processes can be upregulated under elevated CO2.},
author = {Fleischer, Katrin and Rammig, Anja and {De Kauwe}, Martin G. and Walker, Anthony P. and Domingues, Tomas F. and Fuchslueger, Lucia and Garcia, Sabrina and Goll, Daniel S. and Grandis, Adriana and Jiang, Mingkai and Haverd, Vanessa and Hofhansl, Florian and Holm, Jennifer A. and Kruijt, Bart and Leung, Felix and Medlyn, Belinda E. and Mercado, Lina M. and Norby, Richard J. and Pak, Bernard and von Randow, Celso and Quesada, Carlos A. and Schaap, Karst J. and Valverde-Barrantes, Oscar J. and Wang, Ying-Ping and Yang, Xiaojuan and Zaehle, S{\"{o}}nke and Zhu, Qing and Lapola, David M.},
doi = {10.1038/s41561-019-0404-9},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {sep},
number = {9},
pages = {736--741},
title = {{Amazon forest response to CO2 fertilization dependent on plant phosphorus acquisition}},
url = {http://www.nature.com/articles/s41561-019-0404-9},
volume = {12},
year = {2019}
}
@article{Fleming2016,
author = {Fleming, Laura E. and Anchukaitis, Kevin J.},
doi = {10.1007/s00382-016-3041-7},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {dec},
number = {12},
pages = {3783--3801},
title = {{North Pacific decadal variability in the CMIP5 last millennium simulations}},
url = {http://link.springer.com/10.1007/s00382-016-3041-7},
volume = {47},
year = {2016}
}
@article{Fletcher2015b,
abstract = {The northern annular mode (NAM) influences wintertime climate variability in the Northern Hemisphere, and understanding the processes controlling its sign and amplitude is of critical importance. Mounting evidence supports a robust teleconnection between the El Ni{\~{n}}o-Southern Oscillation (ENSO) and the NAM, while internal variability generated in the tropical Indian Ocean (TIO) may be associated with a NAM response of the opposite sign. This study uses a coupled ocean-atmosphere model to separate the influence on the NAM from teleconnections driven by ENSO and the TIO. In composites constructed using a long preindustrial control integration, increased December-February precipitation in the central/eastern Pacific drives a negative late-winter NAM response. When isolated from ENSO variability, increased precipitation over the western-central TIO drives a strong and persistent positive NAM response throughout the winter. Opposite linear interference of the anomalous wave teleconnections explains most of the opposite-signed planetary wavedriving of the NAM responses. The case with combined ENSO and TIO variability yields cancellation of the wave interference and a weak NAM response. This mechanism is confirmed using experiments where the tropical ocean is nudged separately over the Pacific and TIO to the large-amplitude 1997/98-1998/99 ENSO cycle. The phases of the Rossby wave and NAM responses in these two cases are of opposite sign, providing strong evidence that internal variability over the TIO can induce teleconnections independent of-and with opposite sign to-those associated with ENSO.},
author = {Fletcher, Christopher G. and Cassou, Christophe},
doi = {10.1175/JCLI-D-14-00839.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Annular mode,Coupled models,ENSO,Indian Ocean,Planetary waves,Teleconnections},
month = {oct},
number = {20},
pages = {7985--8002},
title = {{The dynamical influence of separate teleconnections from the Pacific and Indian oceans on the northern annular mode}},
volume = {28},
year = {2015}
}
@article{Flynn2020,
author = {Flynn, Clare Marie and Mauritsen, Thorsten},
doi = {10.5194/acp-20-7829-2020},
issn = {1680-7324},
journal = {Atmospheric Chemistry and Physics},
month = {jul},
number = {13},
pages = {7829--7842},
title = {{On the climate sensitivity and historical warming evolution in recent coupled model ensembles}},
url = {https://acp.copernicus.org/articles/20/7829/2020/},
volume = {20},
year = {2020}
}
@article{Fogt2017,
author = {Fogt, Ryan L. and Goergens, Chad A. and Jones, Julie M. and Schneider, David P. and Nicolas, Julien P. and Bromwich, David H. and Dusselier, Hallie E.},
doi = {10.1002/2017GL075079},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {oct},
number = {19},
pages = {9918--9927},
title = {{A twentieth century perspective on summer Antarctic pressure change and variability and contributions from tropical SSTs and ozone depletion}},
url = {http://doi.wiley.com/10.1002/2017GL075079},
volume = {44},
year = {2017}
}
@article{Folland2002,
abstract = {[1] The South Pacific Convergence Zone (SPCZ), one of the most extensive features of the global atmospheric circulation, is shown to vary its location according to both the polarity of the El Nino/Southern Oscillation (ENSO), and of the Interdecadal Pacific Oscillation (IPO). We first demonstrate that the IPO can be regarded as the quasi-symmetric Pacific-wide manifestation of the Pacific Decadal Oscillation that has been described for the North Pacific. Shifts in the position of the SPCZ related to ENSO on interannual time scales and to the IPO on decadal time scales appear to be of similar magnitude and are largely linearly independent. A station pressure-based index of variations in SPCZ latitude is shown to be significantly related to the polarity of the IPO when ENSO influences are accounted for. Movements of this sensitive section of the SPCZ have occurred in phase with those of the IPO since the 1890s.},
author = {Folland, C. K. and Renwick, J. A. and Salinger, M. J. and Mullan, A. B.},
doi = {10.1029/2001GL014201},
isbn = {0094-8276},
issn = {00948276},
journal = {Geophysical Research Letters},
keywords = {http://dx.doi.org/10.1029/2001GL014201, doi:10.102},
number = {13},
pages = {2--5},
title = {{Relative influences of the Interdecadal Pacific Oscillation and ENSO on the South Pacific Convergence Zone}},
volume = {29},
year = {2002}
}
@article{Folland2018,
abstract = {The time series of monthly global mean surface temperature (GST) since 1891 is successfully reconstructed from known natural and anthropogenic forcing factors, including internal climate variability, using a multiple regression technique. Comparisons are made with the performance of 40 CMIP5 models in predicting GST. The relative contributions of the various forcing factors to GST changes vary in time, but most of the warming since 1891 is found to be attributable to the net influence of increasing greenhouse gases and anthropogenic aerosols. Separate statistically independent analyses are also carried out for three periods of GST slowdown (1896–1910, 1941–1975, and 1998–2013 and subperiods); two periods of strong warming (1911–1940 and 1976–1997) are also analyzed. A reduction in total incident solar radiation forcing played a significant cooling role over 2001–2010. The only serious disagreements between the reconstructions and observations occur during the Second World War, especially in the period 1944–1945, when observed near-worldwide sea surface temperatures (SSTs) may be significantly warm-biased. In contrast, reconstructions of near-worldwide SSTs were rather warmer than those observed between about 1907 and 1910. However, the generally high reconstruction accuracy shows that known external and internal forcing factors explain all the main variations in GST between 1891 and 2015, allowing for our current understanding of their uncertainties. Accordingly, no important additional factors are needed to explain the two main warming and three main slowdown periods during this epoch.},
author = {Folland, Chris K. and Boucher, Olivier and Colman, Andrew and Parker, David E.},
doi = {10.1126/sciadv.aao5297},
issn = {2375-2548},
journal = {Science Advances},
month = {jun},
number = {6},
pages = {eaao5297},
title = {{Causes of irregularities in trends of global mean surface temperature since the late 19th century}},
url = {https://www.science.org/doi/10.1126/sciadv.aao5297},
volume = {4},
year = {2018}
}
@article{Foltz2019,
author = {Foltz, G. R. and Brandt, P. and Richter, I. and Rodr{\'{i}}guez-Fonseca, B. and Hernandez, F. and Dengler, M. and Rodrigues, R. R. and Schmidt, J. O. and Yu, L. and Lefevre, N. and {Da Cunha}, L. Cotrim and McPhaden, M. J. and Araujo, M. and Karstensen, J. and Hahn, J. and Mart{\'{i}}n-Rey, M. and Patricola, C. M. and Poli, P. and Zuidema, P. and Hummels, R. and Perez, R. C. and Hatje, V. and L{\"{u}}bbecke, J. F. and Polo, I. and Lumpkin, R. and Bourl{\`{e}}s, B. and Asuquo, F. E. and Lehodey, P. and Conchon, A. and Chang, P. and Dandin, P. and Schmid, C. and Sutton, A. and Giordani, H. and Xue, Y. and Illig, S. and Losada, T. and Grodsky, S. A. and Gasparin, F. and Lee, T. and Mohino, E. and Nobre, P. and Wanninkhof, R. and Keenlyside, N. and Garcon, V. and S{\'{a}}nchez-G{\'{o}}mez, E. and Nnamchi, H. C. and Dr{\'{e}}villon, M. and Storto, A. and Remy, E. and Lazar, A. and Speich, S. and Goes, M. and Dorrington, T. and Johns, W. E. and Moum, J. N. and Robinson, C. and Perruche, C. and de Souza, R. B. and Gaye, A. T. and L{\'{o}}pez-Parages, J. and Monerie, P.-A. and Castellanos, P. and Benson, N. U. and Hounkonnou, M. N. and Duh{\'{a}}, J. Trotte and Laxenaire, R. and Reul, N.},
doi = {10.3389/fmars.2019.00206},
issn = {2296-7745},
journal = {Frontiers in Marine Science},
month = {may},
pages = {206},
title = {{The Tropical Atlantic Observing System}},
url = {https://www.frontiersin.org/article/10.3389/fmars.2019.00206/full},
volume = {6},
year = {2019}
}
@article{Forkel2016b,
abstract = {The combined effects of climate change and vegetation dynamics at high northern latitudes have amplified the seasonal variation of atmospheric CO2 concentrations over the past half century. Forkel et al. combined observations and models to show that climate warming has caused the photosynthetic uptake of carbon to increase faster than its respiratory release from the terrestrial biosphere. This has increased the difference from summer to winter, as well as the latitudinal gradient. Because of the physiological limitations to carbon uptake by terrestrial vegetation, this negative feedback to warming in the boreal north and Arctic cannot continue indefinitely.Science, this issue p. 696Atmospheric monitoring of high northern latitudes (above 40{\{}$\backslash$textdegree{\}}N) has shown an enhanced seasonal cycle of carbon dioxide (CO2) since the 1960s, but the underlying mechanisms are not yet fully understood. The much stronger increase in high latitudes relative to low ones suggests that northern ecosystems are experiencing large changes in vegetation and carbon cycle dynamics. We found that the latitudinal gradient of the increasing CO2 amplitude is mainly driven by positive trends in photosynthetic carbon uptake caused by recent climate change and mediated by changing vegetation cover in northern ecosystems. Our results underscore the importance of climate{\{}$\backslash$textendash{\}}vegetation{\{}$\backslash$textendash{\}}carbon cycle feedbacks at high latitudes; moreover, they indicate that in recent decades, photosynthetic carbon uptake has reacted much more strongly to warming than have carbon release processes.},
author = {Forkel, Matthias and Carvalhais, Nuno and R{\"{o}}denbeck, Christian and Keeling, Ralph and Heimann, Martin and Thonicke, Kirsten and Zaehle, S{\"{o}}nke and Reichstein, Markus},
doi = {10.1126/science.aac4971},
issn = {0036-8075},
journal = {Science},
number = {6274},
pages = {696--699},
publisher = {American Association for the Advancement of Science},
title = {{Enhanced seasonal CO2 exchange caused by amplified plant productivity in northern ecosystems}},
volume = {351},
year = {2016}
}
@article{Frajka-Williams2017,
author = {Frajka-Williams, Eleanor and Beaulieu, Claudie and Duchez, Aurelie},
doi = {10.1038/s41598-017-11046-x},
issn = {2045-2322},
journal = {Scientific Reports},
month = {dec},
number = {1},
pages = {11224},
title = {{Emerging negative Atlantic Multidecadal Oscillation index in spite of warm subtropics}},
url = {http://www.nature.com/articles/s41598-017-11046-x},
volume = {7},
year = {2017}
}
@article{Frauen2010,
abstract = {Interannual variability of tropical Pacific sea surface temperatures (SST) has an asymmetry with stronger positive events, El Ni{\~{n}}o, and weaker negative events, La Ni{\~{n}}a, which is generally attributed to processes in the ocean. Here we present evidence from a new hybrid coupled model that the asymmetry and seasonality of El Ni{\~{n}}o can be caused by nonlinear and seasonally varying atmospheric feedbacks. The model consists of the ECHAM5 global atmospheric general circulation model (GCM) coupled to the 2-dimensional El Ni{\~{n}}o linear recharge oscillator ocean model in the tropical Pacific and a mixed layer ocean elsewhere. Despite the models simplistic and, by construction, linear representation of the ocean dynamics, it is able to simulate the main statistical features of El Ni{\~{n}}o including period, seasonality, skewness, and kurtosis. Analyses of the model show that a nonlinear relationship between zonal wind stress and SST is causing the El Ni{\~{n}}o-La Ni{\~{n}}a asymmetry.},
annote = {doi: 10.1029/2010GL044444},
author = {Frauen, Claudia and Dommenget, Dietmar},
doi = {10.1029/2010GL044444},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {ENSO},
month = {sep},
number = {18},
pages = {L18801},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{El Ni{\~{n}}o and La Ni{\~{n}}a amplitude asymmetry caused by atmospheric feedbacks}},
url = {https://doi.org/10.1029/2010GL044444},
volume = {37},
year = {2010}
}
@article{Freund2019d,
abstract = {El Ni{\~{n}}o events differ substantially in their spatial pattern and intensity. Canonical Eastern Pacific El Ni{\~{n}}o events have sea surface temperature anomalies that are strongest in the far eastern equatorial Pacific, whereas peak ocean warming occurs further west during Central Pacific El Ni{\~{n}}o events. The event types differ in their impacts on the location and intensity of temperature and precipitation anomalies globally. Evidence is emerging that Central Pacific El Ni{\~{n}}o events have become more common, a trend that is projected by some studies to continue with ongoing climate change. Here we identify spatial and temporal patterns in observed sea surface temperatures that distinguish the evolution of Eastern and Central Pacific El Ni{\~{n}}o events in the tropical Pacific. We show that these patterns are recorded by a network of 27 seasonally resolved coral records, which we then use to reconstruct Central and Eastern Pacific El Ni{\~{n}}o activity for the past four centuries. We find a simultaneous increase in Central Pacific events and a decrease in Eastern Pacific events since the late twentieth century that leads to a ratio of Central to Eastern Pacific events that is unusual in a multicentury context. Compared to the past four centuries, the most recent 30 year period includes fewer, but more intense, Eastern Pacific El Ni{\~{n}}o events.},
author = {Freund, Mandy B and Henley, Benjamin J and Karoly, David J and McGregor, Helen V and Abram, Nerilie J and Dommenget, Dietmar},
doi = {10.1038/s41561-019-0353-3},
issn = {1752-0908},
journal = {Nature Geoscience},
number = {6},
pages = {450--455},
title = {{Higher frequency of Central Pacific El Ni{\~{n}}o events in recent decades relative to past centuries}},
url = {https://doi.org/10.1038/s41561-019-0353-3},
volume = {12},
year = {2019}
}
@article{Friedlingstein2019,
author = {Friedlingstein, Pierre and Jones, Matthew W. and O'Sullivan, Michael and Andrew, Robbie M. and Hauck, Judith and Peters, Glen P. and Peters, Wouter and Pongratz, Julia and Sitch, Stephen and {Le Qu{\'{e}}r{\'{e}}}, Corinne and Bakker, Dorothee C. E. and Canadell, Josep G. and Ciais, Philippe and Jackson, Robert B. and Anthoni, Peter and Barbero, Leticia and Bastos, Ana and Bastrikov, Vladislav and Becker, Meike and Bopp, Laurent and Buitenhuis, Erik and Chandra, Naveen and Chevallier, Fr{\'{e}}d{\'{e}}ric and Chini, Louise P. and Currie, Kim I. and Feely, Richard A. and Gehlen, Marion and Gilfillan, Dennis and Gkritzalis, Thanos and Goll, Daniel S. and Gruber, Nicolas and Gutekunst, S{\"{o}}ren and Harris, Ian and Haverd, Vanessa and Houghton, Richard A. and Hurtt, George and Ilyina, Tatiana and Jain, Atul K. and Joetzjer, Emilie and Kaplan, Jed O. and Kato, Etsushi and {Klein Goldewijk}, Kees and Korsbakken, Jan Ivar and Landsch{\"{u}}tzer, Peter and Lauvset, Siv K. and Lef{\`{e}}vre, Nathalie and Lenton, Andrew and Lienert, Sebastian and Lombardozzi, Danica and Marland, Gregg and McGuire, Patrick C. and Melton, Joe R. and Metzl, Nicolas and Munro, David R. and Nabel, Julia E. M. S. and Nakaoka, Shin-Ichiro and Neill, Craig and Omar, Abdirahman M. and Ono, Tsuneo and Peregon, Anna and Pierrot, Denis and Poulter, Benjamin and Rehder, Gregor and Resplandy, Laure and Robertson, Eddy and R{\"{o}}denbeck, Christian and S{\'{e}}f{\'{e}}rian, Roland and Schwinger, J{\"{o}}rg and Smith, Naomi and Tans, Pieter P. and Tian, Hanqin and Tilbrook, Bronte and Tubiello, Francesco N. and van der Werf, Guido R. and Wiltshire, Andrew J. and Zaehle, S{\"{o}}nke},
doi = {10.5194/essd-11-1783-2019},
issn = {1866-3516},
journal = {Earth System Science Data},
month = {dec},
number = {4},
pages = {1783--1838},
title = {{Global Carbon Budget 2019}},
url = {https://essd.copernicus.org/articles/11/1783/2019/},
volume = {11},
year = {2019}
}
@article{Friedman2017,
abstract = {Sea surface salinity (SSS) is a major ocean circulation component and indicator of the hydrological cycle. Here we investigate an unprecedented Atlantic SSS compilation from 1896 to 2013 and analyze the main modes of SSS decadal variability. Using principal component analysis, we find that the low-latitude (tropical and subtropical) Atlantic and the subpolar Atlantic have distinct variability. Subpolar and low-latitude SSS are negatively correlated, with subpolar anomalies leading low-latitude anomalies by about a decade. Subpolar SSS varies in phase with the Atlantic Multidecadal Oscillation (AMO), whereas low-latitude SSS varies in phase with the North Atlantic Oscillation (NAO). Additionally, northern tropical SSS is anticorrelated with Sahel rainfall, suggesting that SSS reflects the Intertropical Convergence Zone latitude. The 1896–2013 SSS trend shows amplification of the mean SSS field, with subpolar freshening and low-latitude salinification. The AMO and NAO have little effect on the long-term trend but contribute to the trend since 1970.},
author = {Friedman, Andrew R. and Reverdin, Gilles and Khodri, Myriam and Gastineau, Guillaume},
doi = {10.1002/2017GL072582},
issn = {19448007},
journal = {Geophysical Research Letters},
keywords = {Atlantic Ocean,Sahel rainfall,climate variability,historical trends,hydrological cycle,surface salinity},
month = {feb},
number = {4},
pages = {1866--1876},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{A new record of Atlantic sea surface salinity from 1896 to 2013 reveals the signatures of climate variability and long-term trends}},
url = {https://doi.org/10.1002/2017GL072582},
volume = {44},
year = {2017}
}
@article{Friedman2020,
abstract = {The sea surface temperature (SST) contrast between the Northern Hemisphere (NH) and Southern Hemisphere (SH) influences the location of the intertropical convergence zone (ITCZ) and the intensity of the monsoon systems. This study examines the contributions of external forcing and unforced internal variability to the interhemispheric SST contrast in HadSST3 and ERSSTv5 observations, and 10 models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) from 1881 to 2012. Using multimodel mean fingerprints, a significant influence of anthropogenic, but not natural, forcing is detected in the interhemispheric SST contrast, with the observed response larger than that of the model mean in ERSSTv5. The forced response consists of asymmetric NH–SH SST cooling from the mid-twentieth century to around 1980, followed by opposite NH–SH SST warming. The remaining best-estimate residual or unforced component is marked by NH–SH SST maxima in the 1930s and mid-1960s, and a rapid NH–SH SST decrease around 1970. Examination of decadal shifts in the observed interhemispheric SST contrast highlights the shift around 1970 as the most prominent from 1881 to 2012. Both NH and SH SST variability contributed to the shift, which appears not to be attributable to external forcings. Most models examined fail to capture such large-magnitude shifts in their control simulations, although some models with high interhemispheric SST variability are able to produce them. Large-magnitude shifts produced by the control simulations feature disparate spatial SST patterns, some of which are consistent with changes typically associated with the Atlantic meridional overturning circulation (AMOC).},
author = {Friedman, Andrew R. and Hegerl, Gabriele C. and Schurer, Andrew P. and Lee, Shih-Yu and Kong, Wenwen and Cheng, Wei and Chiang, John C. H.},
doi = {10.1175/JCLI-D-19-0102.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {may},
number = {9},
pages = {3487--3509},
title = {{Forced and Unforced Decadal Behavior of the Interhemispheric SST Contrast during the Instrumental Period (1881–2012): Contextualizing the Late 1960s–Early 1970s Shift}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-19-0102.1},
volume = {33},
year = {2020}
}
@article{doi:10.1175/BAMS-D-16-0153.1,
author = {Fu{\v{c}}kar, Neven S and Massonnet, Fran{\c{c}}ois and Guemas, Virginie and Garc{\'{i}}a-Serrano, Javier and Bellprat, Omar and Acosta, Mario and Doblas-Reyes, Francisco J},
doi = {10.1175/BAMS-D-16-0153.1},
journal = {Bulletin of the American Meteorological Society},
number = {12},
pages = {S136--S140},
title = {{Record Low Northern Hemisphere Sea Ice Extent in March 2015}},
url = {https://doi.org/10.1175/BAMS-D-16-0153.1},
volume = {97},
year = {2016}
}
@article{Fyke2014,
abstract = {Surface mass balance (SMB) trends influence observed Greenland Ice Sheet (GrIS) mass loss, but the component of these trends related to anthropogenic forcing is unclear. Here we study the simulated spatial pattern of emergence of an anthropogenically derived GrIS SMB signal between 1850 and 2100 using the Community Earth System Model. We find emergence timing heterogeneity, with a bimodal structure reflecting interior snowfall increases against a background of low SMB variability, and peripheral surface melting increases against a backdrop of high SMB variability. We also find a nonemerging intermediate region. We conclude that (1) a bimodal pattern of GrIS SMB change will unambiguously reflect the impact of anthropogenic forcing; (2) present-day peripheral and interior SMB trends likely have an underlying anthropogenically forced component; (3) local emergence occurs well before emergence of a spatially integrated signal; and (4) the GrIS summit region may be an ideal location for monitoring regional/global climate change.},
author = {Fyke, Jeremy G. and Vizca{\'{i}}no, Miren and Lipscomb, William H.},
doi = {10.1002/2014GL060735},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {aug},
number = {16},
pages = {6002--6008},
title = {{The pattern of anthropogenic signal emergence in Greenland Ice Sheet surface mass balance}},
url = {http://doi.wiley.com/10.1002/2014GL060735},
volume = {41},
year = {2014}
}
@article{Gomez-Navarro2013,
author = {G{\'{o}}mez-Navarro, J. J. and Zorita, E.},
doi = {10.1002/grl.50628},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {jun},
number = {12},
pages = {3232--3236},
title = {{Atmospheric annular modes in simulations over the past millennium: No long-term response to external forcing}},
url = {http://doi.wiley.com/10.1002/grl.50628},
volume = {40},
year = {2013}
}
@article{doi:10.1002/2014GL062231,
abstract = {Abstract Continuous monitoring of the polar regions by satellites has shown that sea ice extent (SIE) in the Antarctic has increased slightly since 1979. By contrast, climate model simulations including all major anthropogenic and natural climate influences simulate an average decrease in SIE since 1979. Here we take a longer view and assess the consistency of observed and simulated changes in Antarctic SIE using recently recovered satellite-based estimates of Antarctic SIE for September 1964 and May–July 1966, hence extending the current observational record from 35 to 50 years. While there is evidence of inconsistency between observed trends in Antarctic SIE and those simulated since 1979, particularly in models with realistic interannual variability, the observed trends since the mid-1960s fall within the 5–95{\%} range of simulated trends. Thus, our results broadly support the hypothesis that the recent increase in Antarctic SIE is due to internal variability, though the reasons for the inconsistency in simulated and observed changes since 1979 remain to be determined.},
author = {Gagn{\'{e}}, M.-{\`{E}}. and Gillett, N P and Fyfe, J C},
doi = {10.1002/2014GL062231},
journal = {Geophysical Research Letters},
keywords = {Antarctic,NSIDC,Nimbus,modelling,observations,sea ice},
number = {1},
pages = {90--95},
title = {{Observed and simulated changes in Antarctic sea ice extent over the past 50 years}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2014GL062231},
volume = {42},
year = {2015}
}
@article{doi:10.1002/2016GL071941,
abstract = {Abstract Updated observational data sets without climatological infilling show that there was an increase in sea ice concentration in the eastern Arctic between 1950 and 1975, contrary to earlier climatology infilled observational data sets that show weak interannual variations during that time period. We here present climate model simulations showing that this observed sea ice concentration increase was primarily a consequence of cooling induced by increasing anthropogenic aerosols and natural forcing. Indeed, sulphur dioxide emissions, which lead to the formation of sulphate aerosols, peaked around 1980 causing a sharp increase in the burden of sulphate between the 1950s and 1970s; but since 1980, the burden has dropped. Our climate model simulations show that the cooling contribution of aerosols offset the warming effect of increasing greenhouse gases over the midtwentieth century resulting in the expansion of the Arctic sea ice cover. These results challenge the perception that Arctic sea ice extent was unperturbed by human influence until the 1970s, suggesting instead that it exhibited earlier forced multidecadal variations, with implications for our understanding of impacts and adaptation in human and natural Arctic systems.},
author = {Gagn{\'{e}}, Marie-{\`{E}}ve and Fyfe, John C and Gillett, Nathan P and Polyakov, Igor V and Flato, Gregory M},
doi = {10.1002/2016GL071941},
journal = {Geophysical Research Letters},
keywords = {Arctic,aerosols,climate variability,cryosphere,modeling,sea ice},
number = {14},
pages = {7338--7346},
title = {{Aerosol-driven increase in Arctic sea ice over the middle of the twentieth century}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2016GL071941},
volume = {44},
year = {2017}
}
@article{Gagne2017b,
abstract = {Abstract Using a large initial condition ensemble of climate model simulations, we examine the impact of volcanic activity on Arctic sea ice cover from 1960 to 2005, a period that includes three very large tropical eruptions. Ensemble averaging across simulations with natural (volcanic and solar) forcings alone reduces noise due to internal variability to show a decade of increased Arctic sea extent (of up to half a million square kilometers) following each of the Mount Agung (1963), Mount El Chich{\'{o}}n (1982), and Mount Pinatubo (1991) eruptions. A similar impact is seen when averaging over a large ensemble of simulations with natural and all-known anthropogenic forcings. We show that the volcanic response in sea ice cover is sensitive to preeruption temperature, with warmer conditions before an eruption being associated with a larger than average response. Finally, a detection and attribution analysis using second-generation Canadian Earth System Model (CanESM2) did not identify a significant response in the observations, while finding no evidence of inconsistency between observations and CanESM2 since regression coefficients were consistent with unity. A similar detection and attribution analysis using the somewhat stronger volcanic response from the simulations in the average of the CMIP5 models did identify a detectable natural forcing response in four observational sea ice extent data sets.},
author = {Gagn{\'{e}}, M.-{\`{E}}. and Kirchmeier-Young, M C and Gillett, N P and Fyfe, J C},
doi = {10.1002/2017JD027038},
journal = {Journal of Geophysical Research: Atmospheres},
number = {15},
pages = {8071--8078},
title = {{Arctic sea ice response to the eruptions of Agung, El Chich{\'{o}}n, and Pinatubo}},
volume = {122},
year = {2017}
}
@article{Gan2019,
author = {Gan, Zewen and Guan, Xiaodan and Kong, Xiangning and Guo, Ruixia and Huang, Haiyan and Huang, Wei and Xu, Yanjun},
doi = {10.1029/2018EA000443},
issn = {2333-5084},
journal = {Earth and Space Science},
month = {mar},
number = {3},
pages = {387--397},
title = {{The Key Role of Atlantic Multidecadal Oscillation in Minimum Temperature Over North America During Global Warming Slowdown}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018EA000443},
volume = {6},
year = {2019}
}
@article{https://doi.org/10.1029/2008JD010239,
abstract = {Understanding natural causes of climate change is vital to evaluate the relative impacts of human pollution and land surface modification on climate. We have investigated one of the most important natural causes of climate change, volcanic eruptions, by using 54 ice core records from both the Arctic and Antarctica. Our recently collected suite of ice core data, more than double the number of cores ever used before, reduces errors inherent in reconstructions based on a single or small number of cores, which enables us to obtain much higher accuracy in both detection of events and quantification of the radiative effects. We extracted volcanic deposition signals from each ice core record by applying a high-pass loess filter to the time series and examining peaks that exceed twice the 31-year running median absolute deviation. We then studied the spatial pattern of volcanic sulfate deposition on Greenland and Antarctica and combined this knowledge with a new understanding of stratospheric transport of volcanic aerosols to produce a forcing data set as a function of month, latitude, and altitude for the past 1500 years. We estimated the uncertainties associated with the choice of volcanic signal extraction criteria, ice core sulfate deposition to stratospheric loading calibration factor, and the season for the eruptions without a recorded month. We forced an energy balance climate model with this new volcanic forcing data set, together with solar and anthropogenic forcing, to simulate the large-scale temperature response. The results agree well with instrumental observations for the past 150 years and with proxy records for the entire period. Through better characterization of the natural causes of climate change, this new data set will lead to improved prediction of anthropogenic impacts on climate. The new data set of stratospheric sulfate injections from volcanic eruptions for the past 1500 years, as a function of latitude, altitude, and month, is available for download in a format suitable for forcing general circulation models of the climate system.},
author = {Gao, Chaochao and Robock, Alan and Ammann, Caspar},
doi = {10.1029/2008JD010239},
issn = {0148-0227},
journal = {Journal of Geophysical Research},
keywords = {climate change,ice cores,volcanoes},
month = {dec},
number = {D23},
pages = {D23111},
title = {{Volcanic forcing of climate over the past 1500 years: An improved ice core-based index for climate models}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2008JD010239 http://doi.wiley.com/10.1029/2008JD010239},
volume = {113},
year = {2008}
}
@article{Garreaud2017a,
abstract = {Abstract. Since 2010 an uninterrupted sequence of dry years, with annual rainfall deficits ranging from 25 to 45{\%}, has prevailed in central Chile (western South America, 30–38°S). Although intense 1- or 2-year droughts are recurrent in this Mediterranean-like region, the ongoing event stands out because of its longevity and large extent. The extraordinary character of the so-called central Chile megadrought (MD) was established against century long historical records and a millennial tree-ring reconstruction of regional precipitation. The largest MD-averaged rainfall relative anomalies occurred in the northern, semi-arid sector of central Chile, but the event was unprecedented to the south of 35°S. ENSO-neutral conditions have prevailed since 2011 (except for the strong El Ni{\~{n}}o in 2015), contrasting with La Ni{\~{n}}a conditions that often accompanied past droughts. The precipitation deficit diminished the Andean snowpack and resulted in amplified declines (up to 90{\%}) of river flow, reservoir volumes and groundwater levels along central Chile and westernmost Argentina. In some semi-arid basins we found a decrease in the runoff-to-rainfall coefficient. A substantial decrease in vegetation productivity occurred in the shrubland-dominated, northern sector, but a mix of greening and browning patches occurred farther south, where irrigated croplands and exotic forest plantations dominate. The ongoing warming in central Chile, making the MD one of the warmest 6-year periods on record, may have also contributed to such complex vegetation changes by increasing potential evapotranspiration. We also report some of the measures taken by the central government to relieve the MD effects and the public perception of this event. The understanding of the nature and biophysical impacts of the MD helps as a foundation for preparedness efforts to confront a dry, warm future regional climate scenario.},
author = {Garreaud, Ren{\'{e}} D. and Alvarez-Garreton, Camila and Barichivich, Jonathan and Boisier, Juan Pablo and Christie, Duncan and Galleguillos, Mauricio and LeQuesne, Carlos and McPhee, James and Zambrano-Bigiarini, Mauricio},
doi = {10.5194/hess-21-6307-2017},
issn = {1607-7938},
journal = {Hydrology and Earth System Sciences},
month = {dec},
number = {12},
pages = {6307--6327},
title = {{The 2010–2015 megadrought in central Chile: impacts on regional hydroclimate and vegetation}},
volume = {21},
year = {2017}
}
@article{Garry2019a,
author = {Garry, F. K. and McDonagh, E. L. and Blaker, A. T. and Roberts, C. D. and Desbruy{\`{e}}res, D. G. and Frajka‐Williams, E. and King, B. A.},
doi = {10.1029/2018JC014225},
issn = {2169-9275},
journal = {Journal of Geophysical Research: Oceans},
keywords = {decadal variability,deep oceans,observational uncertainties,ocean heat content,ocean modeling,temperature trends},
month = {feb},
number = {2},
pages = {1155--1169},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Model‐Derived Uncertainties in Deep Ocean Temperature Trends Between 1990 and 2010}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JC014225},
volume = {124},
year = {2019}
}
@article{gastineau2015influence,
abstract = {Using the monthly GOADS dataset and NMC-NCAR archives we show that significant anomalies of the atmospheric circulation are related to previous SST anomalies in the North Atlantic. A signal over the northwest Labrador Sea in late spring is associated with the dominant mode of SST variability during the preceeding winter. It is more clearly seen in the mid-troposhere than at sea level and appears to be related to the anomalous surface heat exchanges that slowly damp the SST anomalies. In addition, a NAO-like signal in early winter is associated with SST anomalies east of Newfoundland and in the eastern subtropical North Atlantic during the preceeding summer.},
author = {Gastineau, Guillaume and Frankignoul, Claude},
doi = {10.1175/JCLI-D-14-00424.1},
issn = {08948755},
journal = {Journal of Climate},
number = {4},
pages = {1396--1416},
title = {{Influence of the North Atlantic SST variability on the atmospheric circulation during the twentieth century}},
volume = {28},
year = {2015}
}
@article{Gastineau2019,
author = {Gastineau, Guillaume and Friedman, Andrew R. and Khodri, Myriam and Vialard, J{\'{e}}r{\^{o}}me},
doi = {10.1007/s00382-018-4387-9},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jul},
number = {1-2},
pages = {1187--1208},
title = {{Global ocean heat content redistribution during the 1998–2012 Interdecadal Pacific Oscillation negative phase}},
url = {http://link.springer.com/10.1007/s00382-018-4387-9},
volume = {53},
year = {2019}
}
@article{Gebbie2019a,
abstract = {Proxy records show that before the onset of modern anthropogenic warming, globally coherent cooling occurred from the Medieval Warm Period to the Little Ice Age. The long memory of the ocean suggests that these historical surface anomalies are associated with ongoing deep-ocean temperature adjustments. Combining an ocean model with modern and paleoceanographic data leads to a prediction that the deep Pacific is still adjusting to the cooling going into the Little Ice Age, whereas temperature trends in the surface ocean and deep Atlantic reflect modern warming. This prediction is corroborated by temperature changes identified between the HMS Challenger expedition of the 1870s and modern hydrography. The implied heat loss in the deep ocean since 1750 CE offsets one-fourth of the global heat gain in the upper ocean.},
author = {Gebbie, G and Huybers, P},
doi = {10.1126/science.aar8413},
issn = {1095-9203},
journal = {Science},
month = {jan},
number = {6422},
pages = {70--74},
pmid = {30606843},
publisher = {American Association for the Advancement of Science},
title = {{The Little Ice Age and 20th-century deep Pacific cooling}},
url = {http://www.ncbi.nlm.nih.gov/pubmed/30606843},
volume = {363},
year = {2019}
}
@book{Gedney2014,
abstract = {Anthropogenic aerosols in the atmosphere have the potential to affect regional-scale land hydrology through solar dimming1, 2. Increased aerosol loading may have reduced historical surface evaporation over some locations3, but the magnitude and extent of this effect is uncertain. Any reduction in evaporation due to historical solar dimming may have resulted in an increase in river flow. Here we formally detect and quantify the historical effect of changing aerosol concentrations, via solar radiation, on observed river flow over the heavily industrialized, northern extra-tropics. We use a state-of-the-art estimate of twentieth century surface meteorology4 as input data for a detailed land surface model5, and show that the simulations capture the observed strong inter-annual variability in runoff in response to climatic fluctuations. Using statistical techniques, we identify a detectable aerosol signal in the observed river flow both over the combined region, and over individual river basins in Europe and North America. We estimate that solar dimming due to rising aerosol concentrations in the atmosphere around 1980 led to an increase in river runoff by up to 25{\%} in the most heavily polluted regions in Europe. We propose that, conversely, these regions may experience reduced freshwater availability in the future, as air quality improvements are set to lower aerosol loading and solar dimming.},
author = {Gedney, N. and Huntingford, C. and Weedon, G. P. and Bellouin, N. and Boucher, O. and Cox, P. M.},
booktitle = {Nature Geoscience},
doi = {10.1038/ngeo2263},
issn = {17520908},
number = {11},
pages = {796--800},
publisher = {Nature Geoscience},
title = {{Detection of solar dimming and brightening effects on Northern Hemisphere river flow}},
volume = {7},
year = {2014}
}
@article{Geen2020,
author = {Geen, Ruth and Bordoni, Simona and Battisti, David S. and Hui, Katrina},
doi = {10.1029/2020RG000700},
issn = {8755-1209},
journal = {Reviews of Geophysics},
month = {dec},
number = {4},
pages = {e2020RG000700},
title = {{Monsoons, ITCZs, and the Concept of the Global Monsoon}},
url = {https://onlinelibrary.wiley.com/doi/10.1029/2020RG000700},
volume = {58},
year = {2020}
}
@article{Gent2016,
abstract = {Observations show that the Southern Hemisphere zonal wind stress maximum has increased significantly over the past 30 years. Eddy-resolving ocean models show that the resulting increase in the Southern Ocean mean flow meridional overturning circulation (MOC) is partially compensated by an increase in the eddy MOC. This effect can be reproduced in the non-eddy-resolving ocean component of a climate model, providing the eddy parameterization coefficient is variable and not a constant. If the coefficient is a constant, then the Southern Ocean mean MOC change is balanced by an unrealistically large change in the Atlantic Ocean MOC. Southern Ocean eddy compensation means that Southern Hemisphere winds cannot be the dominant mechanism driving midlatitude North Atlantic MOC variability.},
author = {Gent, Peter R},
doi = {10.1146/annurev-marine-122414-033929},
issn = {1941-1405},
journal = {Annual Review of Marine Science},
month = {jan},
number = {1},
pages = {79--94},
publisher = {Annual Reviews},
title = {{Effects of Southern Hemisphere Wind Changes on the Meridional Overturning Circulation in Ocean Models}},
volume = {8},
year = {2016}
}
@article{ISI:000339135200020,
abstract = {The impact of anthropogenic forcing on the summertime austral circulation is assessed across three climate model datasets: the Chemistry–Climate Model Validation activity 2 and phases 3 and 5 of the Coupled Model Intercomparison Project. Changes in stratospheric ozone and greenhouse gases impact the Southern Hemisphere in this season, and a simple framework based on temperature trends in the lower polar stratosphere and upper tropical troposphere is developed to separate their effects. It suggests that shifts in the jet stream and Hadley cell are driven by changes in the upper-troposphere–lower-stratosphere temperature gradient. The mean response is comparable in the three datasets; ozone has chiefly caused the poleward shift observed in recent decades, while ozone and greenhouse gases largely offset each other in the future.},
address = {45 BEACON ST, BOSTON, MA 02108-3693 USA},
author = {Gerber, Edwin P and Son, Seok-Woo},
doi = {10.1175/JCLI-D-13-00539.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jul},
number = {14},
pages = {5538--5559},
publisher = {AMER METEOROLOGICAL SOC},
title = {{Quantifying the Summertime Response of the Austral Jet Stream and Hadley Cell to Stratospheric Ozone and Greenhouse Gases}},
type = {Article},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-13-00539.1},
volume = {27},
year = {2014}
}
@article{Gettelman2019a,
abstract = {The Whole Atmosphere Community Climate Model version 6 (WACCM6) is a major update of the whole atmosphere modeling capability in the Community Earth System Model (CESM), featuring enhanced physical, chemical and aerosol parameterizations. This work describes WACCM6 and some of the important features of the model. WACCM6 can reproduce many modes of variability and trends in the middle atmosphere, including the quasi-biennial oscillation, stratospheric sudden warmings, and the evolution of Southern Hemisphere springtime ozone depletion over the twentieth century. WACCM6 can also reproduce the climate and temperature trends of the 20th century throughout the atmospheric column. The representation of the climate has improved in WACCM6, relative to WACCM4. In addition, there are improvements in high-latitude climate variability at the surface and sea ice extent in WACCM6 over the lower top version of the model (CAM6) that comes from the extended vertical domain and expanded aerosol chemistry in WACCM6, highlighting the importance of the stratosphere and tropospheric chemistry for high-latitude climate variability.},
author = {Gettelman, A. and Mills, M. J. and Kinnison, D. E. and Garcia, R. R. and Smith, A. K. and Marsh, D. R. and Tilmes, S. and Vitt, F. and Bardeen, C. G. and McInerny, J. and Liu, H. L. and Solomon, S. C. and Polvani, L. M. and Emmons, L. K. and Lamarque, J. F. and Richter, J. H. and Glanville, A. S. and Bacmeister, J. T. and Phillips, A. S. and Neale, R. B. and Simpson, I. R. and DuVivier, A. K. and Hodzic, A. and Randel, W. J.},
doi = {10.1029/2019JD030943},
issn = {21698996},
journal = {Journal of Geophysical Research: Atmospheres},
number = {23},
pages = {12380--12403},
title = {{The Whole Atmosphere Community Climate Model Version 6 (WACCM6)}},
volume = {124},
year = {2019}
}
@article{Gettelman2015,
author = {Gettelman, A. and Shindell, D. T. and Lamarque, J. F.},
doi = {10.1007/s00382-014-2464-2},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {oct},
number = {7-8},
pages = {2165--2179},
title = {{Impact of aerosol radiative effects on 2000–2010 surface temperatures}},
url = {http://link.springer.com/10.1007/s00382-014-2464-2},
volume = {45},
year = {2015}
}
@article{Giannini2019,
author = {Giannini, Alessandra and Kaplan, Alexey},
doi = {10.1007/s10584-018-2341-9},
issn = {0165-0009},
journal = {Climatic Change},
month = {mar},
number = {3-4},
pages = {449--466},
title = {{The role of aerosols and greenhouse gases in Sahel drought and recovery}},
url = {http://link.springer.com/10.1007/s10584-018-2341-9},
volume = {152},
year = {2019}
}
@article{Gierz2017,
author = {Gierz, Paul and Werner, Martin and Lohmann, Gerrit},
doi = {10.1002/2017MS001056},
issn = {19422466},
journal = {Journal of Advances in Modeling Earth Systems},
month = {sep},
number = {5},
pages = {2027--2045},
title = {{Simulating climate and stable water isotopes during the Last Interglacial using a coupled climate-isotope model}},
url = {http://doi.wiley.com/10.1002/2017MS001056},
volume = {9},
year = {2017}
}
@article{Gillett2013b,
abstract = {We investigate simulated changes in the annular modes in historical and RCP 4.5 scenario simulations of 37 models from the fifth Coupled Model Intercomparison Project (CMIP5), a much larger ensemble of models than has previously been used to investigate annular mode trends, with improved resolution and forcings. The CMIP5 models on average simulate increases in the Northern Annular Mode (NAM) and Southern Annular Mode (SAM) in every season by 2100, and no CMIP5 model simulates a significant decrease in either the NAM or SAM in any season. No significant increase in the NAM or North Atlantic Oscillation (NAO) is simulated in response to volcanic aerosol, and no significant NAM or NAO response to solar irradiance variations is simulated. The CMIP5 models simulate a significant negative SAM response to volcanic aerosol in MAM and JJA, and a significant positive SAM response to solar irradiance variations in MAM, JJA and DJF.},
author = {Gillett, N P and Fyfe, J C},
doi = {10.1002/grl.50249},
journal = {Geophysical Research Letters},
number = {6},
pages = {1189--1193},
title = {{Annular mode changes in the CMIP5 simulations}},
volume = {40},
year = {2013}
}
@article{gmd-9-3685-2016,
abstract = {Detection and attribution (D{\&}A) simulations were important components of CMIP5 and underpinned the climate change detection and attribution assessments of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. The primary goals of the Detection and Attribution Model Intercomparison Project (DAMIP) are to facilitate improved estimation of the contributions of anthropogenic and natural forcing changes to observed global warming as well as to observed global and regional changes in other climate variables; to contribute to the estimation of how historical emissions have altered and are altering contemporary climate risk; and to facilitate improved observationally constrained projections of future climate change. D{\&}A studies typically require unforced control simulations and historical simulations including all major anthropogenic and natural forcings. Such simulations will be carried out as part of the DECK and the CMIP6 historical simulation. In addition D{\&}A studies require simulations covering the historical period driven by individual forcings or subsets of forcings only: such simulations are proposed here. Key novel features of the experimental design presented here include firstly new historical simulations with aerosols-only, stratospheric-ozone-only, CO2-only, solar-only, and volcanic-only forcing, facilitating an improved estimation of the climate response to individual forcing, secondly future single forcing experiments, allowing observationally constrained projections of future climate change, and thirdly an experimental design which allows models with and without coupled atmospheric chemistry to be compared on an equal footing.},
author = {Gillett, Nathan P. and Shiogama, Hideo and Funke, Bernd and Hegerl, Gabriele and Knutti, Reto and Matthes, Katja and Santer, Benjamin D. and Stone, Daithi and Tebaldi, Claudia},
doi = {10.5194/gmd-9-3685-2016},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {oct},
number = {10},
pages = {3685--3697},
title = {{The Detection and Attribution Model Intercomparison Project (DAMIP v1.0) contribution to CMIP6}},
volume = {9},
year = {2016}
}
@article{doi:10.1002/grl.50500,
abstract = {AbstractHuman influence on atmospheric sea level pressure (SLP) has previously been detected globally, but the contributions of greenhouse gas, aerosol, and ozone changes to the observed trends have not been separately identified. We use simulations from eight climate models to show that greenhouse gas, aerosol, and ozone changes each drive distinct seasonal and geographical patterns of trends, which are separately detectable in observed seasonal SLP trends over the 1951–2011 period. This detection is driven by significant low-latitude SLP responses to greenhouse gas, aerosol, and ozone changes, as well as the more frequently-studied high latitude responses. These results aid in understanding past atmospheric circulation changes, and have potential to improve projections of future circulation changes.},
author = {Gillett, Nathan P and Fyfe, John C and Parker, David E},
doi = {10.1002/grl.50500},
journal = {Geophysical Research Letters},
keywords = {SLP,aerosol,attribution,detection,ozone,sea level pressure},
number = {10},
pages = {2302--2306},
title = {{Attribution of observed sea level pressure trends to greenhouse gas, aerosol, and ozone changes}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/grl.50500},
volume = {40},
year = {2013}
}
@article{Gillett2003c,
abstract = {Abstract We investigate the atmospheric response to doubled CO2 and stratospheric ozone depletion in three versions of a general-circulation model with differing vertical resolution and upper-boundary heights. We find that an approximate doubling of the vertical resolution below 10 hPa reduces the temperature response to a doubling of CO2 from 3.4 K to 2.5 K. Much of this difference is associated with changes in the cloud response. All model versions show an increase in the Arctic Oscillation index in response to a doubling of CO2, but the increase is no larger in the model with an upper boundary at 0.01 hPa than in the standard model with a top level at 5 hPa. All models also show general stratospheric cooling in response to doubling CO2. However, unlike some other authors, we find no cooling in the Arctic winter vortex below around 10 hPa in the stratosphere-resolving model, and a weakening of the zonal winds throughout this region. This effect is due to enhanced upward propagation of planetary waves from the troposphere, and is an effect found only in the northern hemisphere, probably because of its larger zonal asymmetries. All models show a small but significant surface cooling in response to a reconstruction of 1998 stratospheric ozone depletion, and an increase in the Antarctic Oscillation index in the southern summer. The cooling extends through most of the atmosphere, and reaches a maximum in the region of the Antarctic ozone hole in November and December. {\textcopyright} Royal Meteorological Society, 2003. K. D. Williams's contribution is Crown copyright.},
author = {Gillett, N P and Allen, M R and Williams, K D},
doi = {10.1256/qj.02.102},
journal = {Quarterly Journal of the Royal Meteorological Society},
number = {589},
pages = {947--966},
title = {{Modelling the atmospheric response to doubled CO2 and depleted stratospheric ozone using a stratosphere-resolving coupled GCM}},
volume = {129},
year = {2003}
}
@article{Gillett2021,
abstract = {F or more than 20 years, detection and attribution techniques have been used to identify human influence on global temperature changes and to quantify the contributions of individual forcings to observed changes 1-3. The commitment of parties to the Paris Agreement 4 to "holding the increase in the global average temperature to well below 2 °C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C above pre-industrial levels", and the Global Stocktake process, which aims to monitor progress towards the Paris Agreement goals, give new relevance to efforts to quantify human climate influence so far. While the Paris Agreement is not explicit about the meaning of either 'global average temperature' or 'pre-industrial levels' , much of the climate impacts literature on which assessment of dangerous anthropogenic interference in climate is based has used globally complete global mean near-surface air temperature (GSAT) from climate models to assess future climate impacts. Therefore, we primarily assess human influence on GSAT in this Article. Recent literature has demonstrated that, in climate models, this metric of global mean temperature warms more than blended sea surface temperatures over ocean and near-surface air temperature over land, masked with observational coverage (global mean surface temperature (GMST)) 5-7. Previous attribution studies have typically estimated attributable trends over the past 50-60 years in GMST 8 , but estimates of warming relative to pre-industrial levels are more relevant to monitoring progress towards Paris Agreement goals. While multiple possible periods over the Holocene could be chosen as pre-industrial base periods 9 , we follow the IPCC Special Report on Global Warming of 1.5 °C (ref. 10 ; SR1.5) and choose 1850-1900. Comparison of global mean temperature metrics Annual means of global mean temperature anomalies in the fourth Hadley Centre/Climatic Research Unit Temperature (HadCRUT4) 11 dataset relative to 1850-1900 and based on an area-weighted global mean of monthly mean anomalies are shown in Fig. 1a. These are compared with global mean blended sea surface temperatures over ocean and near-surface air temperatures over land and ice masked with HadCRUT4 coverage 5 (GMST, Methods) in individual Coupled Model Intercomparison Project Phase 6 (CMIP6) 12 historical simulations merged with Shared Socioeconomic Pathway 2-4.5 (SSP2-4.5) 13 simulations (historical-ssp245 simulations hereafter). The simulated warming in 2010-2019 is on average 17{\%} (5-95{\%} ensemble range of 10{\%}-24{\%}) stronger in globally complete GSAT than in HadCRUT4-masked GMST (Fig. 1a) (similar to previous results based on Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations 14,15), demonstrating the importance of the choice of metric for assessing attributable warming. Comparing globally complete versions of GSAT and GMST, the simulated warming in GSAT is only 6{\%} stronger (5-95{\%} range of 2-8{\%}). Therefore, the largest contribution to the enhanced warming in globally complete GSAT versus HadCRUT4-masked GMST comes from the observational masking. Multiplying the observed 2010-2019 warming in HadCRUT4 GMST of 0.94 °C (5-95{\%} range of 0.90-0.99 °C, Supplementary Table 1) by the ratio of simulated warming in globally complete GSAT to HadCRUT4-masked GMST (1.17), we infer a best estimate of observed 2010-2019 warming in GSAT of 1.10 °C (5-95{\%} range of 1.01-1.20 °C). Similar calculations using HadCRUT5 Parties to the Paris Agreement agreed to holding global average temperature increases "well below 2 °C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C above pre-industrial levels". Monitoring the contributions of human-induced climate forcings to warming so far is key to understanding progress towards these goals. Here we use climate model simulations from the Detection and Attribution Model Intercomparison Project, as well as regularized optimal fingerprinting, to show that anthropogenic forcings caused 0.9 to 1.3 °C of warming in global mean near-surface air temperature in 2010-2019 relative to 1850-1900, compared with an observed warming of 1.1 °C. Greenhouse gases and aerosols contributed changes of 1.2 to 1.9 °C and −0.7 to −0.1 °C, respectively, and natural forcings contributed negligibly. These results demonstrate the substantial human influence on climate so far and the urgency of action needed to meet the Paris Agreement goals. NATuRe CLiMATe CHANGe | www.nature.com/natureclimatechange},
author = {Gillett, Nathan P. and Kirchmeier-Young, Megan and Ribes, Aur{\'{e}}lien and Shiogama, Hideo and Hegerl, Gabriele C. and Knutti, Reto and Gastineau, Guillaume and John, Jasmin G. and Li, Lijuan and Nazarenko, Larissa and Rosenbloom, Nan and Seland, {\O}yvind and Wu, Tongwen and Yukimoto, Seiji and Ziehn, Tilo},
doi = {10.1038/s41558-020-00965-9},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {mar},
number = {3},
pages = {207--212},
title = {{Constraining human contributions to observed warming since the pre-industrial period}},
url = {http://www.nature.com/articles/s41558-020-00965-9},
volume = {11},
year = {2021}
}
@article{Gillett2003a,
abstract = {Greenhouse gases and tropospheric sulphate aerosols—the main human influences on climate—have been shown to have had a detectable effect on surface air temperature1,2,3, the temperature of the free troposphere and stratosphere2,4 and ocean temperature5,6. Nevertheless, the question remains as to whether human influence is detectable in any variable other than temperature. Here we detect an influence of anthropogenic greenhouse gases and sulphate aerosols in observations of winter sea-level pressure (December to February), using combined simulations from four climate models. We find increases in sea-level pressure over the subtropical North Atlantic Ocean, southern Europe and North Africa, and decreases in the polar regions and the North Pacific Ocean, in response to human influence. Our analysis also indicates that the climate models substantially underestimate the magnitude of the sea-level pressure response. This discrepancy suggests that the upward trend in the North Atlantic Oscillation index7 (corresponding to strengthened westerlies in the North Atlantic region), as simulated in a number of global warming scenarios8,9,10, may be too small, leading to an underestimation of the impacts of anthropogenic climate change on European climate.},
author = {Gillett, Nathan P and Zwiers, Francis W and Weaver, Andrew J and Stott, Peter A},
doi = {10.1038/nature01487},
issn = {1476-4687},
journal = {Nature},
number = {6929},
pages = {292--294},
title = {{Detection of human influence on sea-level pressure}},
url = {https://doi.org/10.1038/nature01487},
volume = {422},
year = {2003}
}
@article{Gleckler2008a,
author = {Gleckler, P. J. and Taylor, K. E. and Doutriaux, C.},
doi = {10.1029/2007JD008972},
issn = {0148-0227},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {Performance metrics,climate models,model evaluation},
month = {mar},
number = {D6},
pages = {D06104},
publisher = {Wiley-Blackwell},
title = {{Performance metrics for climate models}},
url = {http://doi.wiley.com/10.1029/2007JD008972},
volume = {113},
year = {2008}
}
@article{Gleckler2012a,
abstract = {The possibility of anthropogenic ocean warming has led to a range of concerns, from impacts on fisheries and ocean acidification to rising sea level and changes in tropical cyclone frequency and intensity. This study substantially strengthens the attribution of the recently observed global ocean warming to human activity.},
author = {Gleckler, P. J. and Santer, B. D. and Domingues, C. M. and Pierce, D. W. and Barnett, T. P. and Church, J. A. and Taylor, K. E. and AchutaRao, K. M. and Boyer, T. P. and Ishii, M. and Caldwell, P. M.},
doi = {10.1038/nclimate1553},
issn = {1758-678X},
journal = {Nature Climate Change},
keywords = {Climate change,Physical oceanography},
month = {jul},
number = {7},
pages = {524--529},
publisher = {Nature Publishing Group},
title = {{Human-induced global ocean warming on multidecadal timescales}},
url = {http://www.nature.com/articles/nclimate1553},
volume = {2},
year = {2012}
}
@article{Gleckler2016a,
abstract = {Formal detection and attribution studies have used observations and climate models to identify an anthropogenic warming signature in the upper (0-700 m) ocean. Recently, as a result of the so-called surface warming hiatus, there has been considerable interest in global ocean heat content (OHC) changes in the deeper ocean, including natural and anthropogenically forced changes identified in observational, modelling and data re-analysis studies. Here, we examine OHC changes in the context of the Earth{\^{a}} €™ s global energy budget since early in the industrial era (circa 1865-2015) for a range of depths. We rely on OHC change estimates from a diverse collection of measurement systems including data from the nineteenth-century Challenger expedition, a multi-decadal record of ship-based in situ mostly upper-ocean measurements, the more recent near-global Argo floats profiling to intermediate (2,000 m) depths, and full-depth repeated transoceanic sections. We show that the multi-model mean constructed from the current generation of historically forced climate models is consistent with the OHC changes from this diverse collection of observational systems. Our model-based analysis suggests that nearly half of the industrial-era increases in global OHC have occurred in recent decades, with over a third of the accumulated heat occurring below 700 m and steadily rising.},
author = {Gleckler, Peter J. and Durack, Paul J. and Stouffer, Ronald J. and Johnson, Gregory C. and Forest, Chris E.},
doi = {10.1038/nclimate2915},
issn = {17586798},
journal = {Nature Climate Change},
keywords = {Mathematics and computing,Ocean sciences},
month = {apr},
number = {4},
pages = {394--398},
publisher = {Nature Publishing Group},
title = {{Industrial-era global ocean heat uptake doubles in recent decades}},
url = {http://www.nature.com/articles/nclimate2915},
volume = {6},
year = {2016}
}
@article{Golaz2019,
abstract = {This work documents the first version of the U.S. Department of Energy (DOE) new Energy Exascale Earth System Model (E3SMv1). We focus on the standard resolution of the fully coupled physical model designed to address DOE mission-relevant water cycle questions. Its components include atmosphere and land (110-km grid spacing), ocean and sea ice (60 km in the midlatitudes and 30 km at the equator and poles), and river transport (55 km) models. This base configuration will also serve as a foundation for additional configurations exploring higher horizontal resolution as well as augmented capabilities in the form of biogeochemistry and cryosphere configurations. The performance of E3SMv1 is evaluated by means of a standard set of Coupled Model Intercomparison Project Phase 6 (CMIP6) Diagnosis, Evaluation, and Characterization of Klima simulations consisting of a long preindustrial control, historical simulations (ensembles of fully coupled and prescribed SSTs) as well as idealized CO2 forcing simulations. The model performs well overall with biases typical of other CMIP-class models, although the simulated Atlantic Meridional Overturning Circulation is weaker than many CMIP-class models. While the E3SMv1 historical ensemble captures the bulk of the observed warming between preindustrial (1850) and present day, the trajectory of the warming diverges from observations in the second half of the twentieth century with a period of delayed warming followed by an excessive warming trend. Using a two-layer energy balance model, we attribute this divergence to the model's strong aerosol-related effective radiative forcing (ERFari+aci = −1.65 W/m2) and high equilibrium climate sensitivity (ECS = 5.3 K).},
author = {Golaz, Jean‐Christophe and Caldwell, Peter M. and {Van Roekel}, Luke P. and Petersen, Mark R. and Tang, Qi and Wolfe, Jonathan D. and Abeshu, Guta and Anantharaj, Valentine and Asay‐Davis, Xylar S. and Bader, David C. and Baldwin, Sterling A. and Bisht, Gautam and Bogenschutz, Peter A. and Branstetter, Marcia and Brunke, Michael A. and Brus, Steven R. and Burrows, Susannah M. and Cameron‐Smith, Philip J. and Donahue, Aaron S. and Deakin, Michael and Easter, Richard C. and Evans, Katherine J. and Feng, Yan and Flanner, Mark and Foucar, James G. and Fyke, Jeremy G. and Griffin, Brian M. and Hannay, C{\'{e}}cile and Harrop, Bryce E. and Hoffman, Mattthew J. and Hunke, Elizabeth C. and Jacob, Robert L. and Jacobsen, Douglas W. and Jeffery, Nicole and Jones, Philip W. and Keen, Noel D. and Klein, Stephen A. and Larson, Vincent E. and Leung, L. Ruby and Li, Hong‐Yi and Lin, Wuyin and Lipscomb, William H. and Ma, Po‐Lun and Mahajan, Salil and Maltrud, Mathew E. and Mametjanov, Azamat and McClean, Julie L. and McCoy, Renata B. and Neale, Richard B. and Price, Stephen F. and Qian, Yun and Rasch, Philip J. and {Reeves Eyre}, J. E. Jack and Riley, William J. and Ringler, Todd D. and Roberts, Andrew F. and Roesler, Erika L. and Salinger, Andrew G. and Shaheen, Zeshawn and Shi, Xiaoying and Singh, Balwinder and Tang, Jinyun and Taylor, Mark A. and Thornton, Peter E. and Turner, Adrian K. and Veneziani, Milena and Wan, Hui and Wang, Hailong and Wang, Shanlin and Williams, Dean N. and Wolfram, Phillip J. and Worley, Patrick H. and Xie, Shaocheng and Yang, Yang and Yoon, Jin‐Ho and Zelinka, Mark D. and Zender, Charles S. and Zeng, Xubin and Zhang, Chengzhu and Zhang, Kai and Zhang, Yuying and Zheng, Xue and Zhou, Tian and Zhu, Qing},
doi = {10.1029/2018MS001603},
issn = {1942-2466},
journal = {Journal of Advances in Modeling Earth Systems},
month = {jul},
number = {7},
pages = {2089--2129},
title = {{The DOE E3SM Coupled Model Version 1: Overview and Evaluation at Standard Resolution}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018MS001603},
volume = {11},
year = {2019}
}
@article{Golledge2019,
abstract = {Government policies currently commit us to surface warming of three to four degrees Celsius above pre-industrial levels by 2100, which will lead to enhanced ice-sheet melt. Ice-sheet discharge was not explicitly included in Coupled Model Intercomparison Project phase 5, so effects on climate from this melt are not currently captured in the simulations most commonly used to inform governmental policy. Here we show, using simulations of the Greenland and Antarctic ice sheets constrained by satellite-based measurements of recent changes in ice mass, that increasing meltwater from Greenland will lead to substantial slowing of the Atlantic overturning circulation, and that meltwater from Antarctica will trap warm water below the sea surface, creating a positive feedback that increases Antarctic ice loss. In our simulations, future ice-sheet melt enhances global temperature variability and contributes up to 25 centimetres to sea level by 2100. However, uncertainties in the way in which future changes in ice dynamics are modelled remain, underlining the need for continued observations and comprehensive multi-model assessments.},
author = {Golledge, Nicholas R and Keller, Elizabeth D and Gomez, Natalya and Naughten, Kaitlin A and Bernales, Jorge and Trusel, Luke D and Edwards, Tamsin L},
doi = {10.1038/s41586-019-0889-9},
issn = {1476-4687},
journal = {Nature},
number = {7742},
pages = {65--72},
title = {{Global environmental consequences of twenty-first-century ice-sheet melt}},
url = {https://doi.org/10.1038/s41586-019-0889-9},
volume = {566},
year = {2019}
}
@article{1748-9326-12-1-014001,
abstract = {Distinct biases are found in the pattern and teleconnections of the Arctic Oscillation (AO) in 32 climate models that participate the Coupled Model Intercomparison Project Phase 5 (CMIP5). Compared with observations, the Pacific (Atlantic) center of AO is excessively strong (weak) in most of the 32 CMIP5 models, and the AO-related surface air temperature anomalies are generally weak over the Eurasian continent and North America. These biases are closely tied to the excessively strong linkage, which is marginal in observations, between AO and the North Pacific mode (NPM)—the leading variability of the North Pacific sea level pressure. It implies that the AO in CMIP5 models may be compounded with some regional mode over the North Pacific. Accordingly, a bias-correction method was proposed via correcting the AO index (AOI) to improve the diagnostic estimates of the AO teleconnections. The results suggest that the biases in the pattern and teleconnections of AO can be significantly reduced when the NPM variability is linearly removed from the AOI.},
annote = {AO reproducibility in CMIP5
- CMIP5 historical 1961-2005 DJF
- ERA-40 + ERA-Interim
- EOF1 of SLP over 20-90N

- SLP anom is more emphasized in the Pacific than Atlantic sectors in CMIP5
- Associated SAT anomalies are overall too weak
- Related to too strong PNA-AO linkage},
author = {Gong, Hainan and Wang, Lin and Chen, Wen and Chen, Xiaolong and Nath, Debashis},
doi = {10.1088/1748-9326/12/1/014001},
journal = {Environmental Research Letters},
number = {1},
pages = {014001},
title = {{Biases of the wintertime Arctic Oscillation in CMIP5 models}},
url = {http://stacks.iop.org/1748-9326/12/i=1/a=014001},
volume = {12},
year = {2017}
}
@article{Gong1999,
author = {Gong, Daoyi and Wang, Shaowu},
doi = {10.1029/1999GL900003},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {feb},
number = {4},
pages = {459--462},
title = {{Definition of Antarctic Oscillation index}},
url = {http://doi.wiley.com/10.1029/1999GL900003},
volume = {26},
year = {1999}
}
@article{Gonzalez2014,
author = {Gonzalez, Paula L M and Polvani, L.M. and Seager, R. and Correa, Gustavo J P},
doi = {10.1007/s00382-013-1777-x},
journal = {Climate Dynamics},
number = {7-8},
pages = {1775--1792},
title = {{Stratospheric ozone depletion: a key driver of recent precipitation trends in Southeastern South America}},
volume = {42},
year = {2014}
}
@article{Good2013,
abstract = {We present version 4 of the Met Office Hadley Centre "EN" series of data sets of global quality controlled ocean temperature and salinity profiles and monthly objective analyses, which covers the period 1900 to present. We briefly describe the EN4 data sources, processing, quality control procedures, and the method of generating the analyses. In particular, we highlight improvements relative to previous versions, which include a ne profile removal procedure and the inclusion of three new quality control checks. We discuss in detail a novel method for providing uncertainty estimates for the objective analyses and improving the background error variance estimates used by the analysis system. These were calculated using an iterative method that is relatively robust to initial misspecification of background error variances. We also show how the method can be used to identify issues with the analyses such as those caused by misspecification of error variances and demonstrate the impact of changes in the observing system on the uncertainty in the analyses. Key Points EN4 dataset of quality-controlled temperature and salinity profiles is described Dataset covers 1900 to present and includes monthly objective analyses A novel method is presented to estimate uncertainty in the objective analyses {\textcopyright} 2013. American Geophysical Union. All Rights Reserved.},
author = {Good, Simon A. and Martin, Matthew J. and Rayner, Nick A.},
doi = {10.1002/2013JC009067},
issn = {21699291},
journal = {Journal of Geophysical Research: Oceans},
keywords = {objective analysis,ocean observations,quality control,uncertainty estimation},
month = {dec},
number = {12},
pages = {6704--6716},
publisher = {Wiley-Blackwell},
title = {{EN4: Quality controlled ocean temperature and salinity profiles and monthly objective analyses with uncertainty estimates}},
url = {http://doi.wiley.com/10.1002/2013JC009067},
volume = {118},
year = {2013}
}
@article{Good2021,
abstract = {Precipitation and atmospheric circulation are the coupled processes through which tropical ocean surface temperatures drive global weather and climate1–5. Local sea surface warming tends to increase precipitation, but this local control is difficult to disentangle from remote effects of conditions elsewhere. As an example of such a remote effect, El Ni{\~{n}}o Southern Oscillation (ENSO) events in the equatorial Pacific Ocean alter precipitation across the tropics. Atmospheric circulations associated with tropical precipitation are predominantly deep, extending up to the tropopause. Shallow atmospheric circulations6–8 affecting the lower troposphere also occur, but the importance of their interaction with precipitation is unclear. Uncertainty in precipitation observations9,10 and limited observations of shallow circulations11 further obstruct our understanding of the ocean's influence on weather and climate. Despite decades of research, persistent biases remain in many numerical model simulations12–18, including excessively wide tropical rainbands14,18, the ‘double-intertropical convergence zone problem'12,16,17 and too-weak responses to ENSO15. These biases demonstrate gaps in our understanding, reducing confidence in forecasts and projections. Here we use observations to show that seasonal tropical precipitation has a high sensitivity to local sea surface temperature. Our best observational estimate is an 80 per cent change in precipitation for every gram per kilogram change in the saturation specific humidity (itself a function of the sea surface temperature). This observed sensitivity is higher than in 43 of the 47 climate models studied, and is associated with strong shallow circulations. Models with more realistic (closer to 80{\%}) sensitivity have smaller biases across a wide range of metrics. Our results apply to both temporal and spatial variation, over regions where climatological precipitation is about one millimetre per day or more. Our analyses of multiple independent observations, physical constraints and model data underpin these findings. The spread in model behaviour is further linked to differences in shallow convection, thus providing a focus for accelerated research to improve seasonal forecasts through multidecadal climate projections.},
author = {Good, Peter and Chadwick, Robin and Holloway, Christopher E. and Kennedy, John and Lowe, Jason A. and Roehrig, Romain and Rushley, Stephanie S.},
doi = {10.1038/s41586-020-2887-3},
issn = {14764687},
journal = {Nature},
number = {7842},
pages = {408--414},
pmid = {33106670},
title = {{High sensitivity of tropical precipitation to local sea surface temperature}},
volume = {589},
year = {2021}
}
@article{doi:10.1029/2009GL040546,
abstract = {Simulations performed with general circulation models and a model of intermediate complexity show that the variability of the September sea ice extent in the Arctic of the 21st century increases first when the mean extent decreases from present-day values. A maximum of the variance is found when the mean September ice extent is around 3 million km2. For lower extents, the variance declines with the mean extent. The behavior is clearly different in Antarctica where the variance always decreases as the mean ice extent decreases, following roughly a square-root law compatible with very simple geometric arguments. Several mechanisms are responsible for the non-linear behavior of the Arctic. However, the strong interhemispheric contrast suggests that the difference in geometrical setting, with an open ocean in the south and a semi-closed basin in the north, plays a significant role.},
author = {Goosse, H and Arzel, O and Bitz, C M and de Montety, A and Vancoppenolle, M},
doi = {10.1029/2009GL040546},
journal = {Geophysical Research Letters},
keywords = {Arctic,sea ice,variability},
number = {23},
pages = {L23702},
title = {{Increased variability of the Arctic summer ice extent in a warmer climate}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2009GL040546},
volume = {36},
year = {2009}
}
@article{Gopika2020,
abstract = {Coupled Model Intercomparison Project (CMIP5) models project an inhomogeneous anthropogenic surface warming of the Indian Ocean by the end of the 21st century, with strongest warming in the Arabian Sea and Western equatorial Indian Ocean. Previous studies have warned that this “Indian Ocean Dipole (IOD)-like” warming pattern could yield more Arabian Sea cyclones, more extreme IOD events and decrease monsoonal rains. Here we show that CMIP5 models also produce an “IOD-like” pattern over the 1871–2016 period, in broad agreement with observations. Single-models ensemble simulations however indicate a strong aliasing of the warming pattern “signal” by the internal climate variability “noise” over that period. While the average Indian Ocean warming emerges around 1950 in CMIP5 and observations, regional contrasts are more difficult to detect. The only detectable signal by 2016 in CMIP5 is a stronger Arabian Sea than Bay of Bengal warming in {\textgreater} 80{\%} of the models, which is not detected in HadSST3 observations. Conversely, observations already detect a stronger Northern than Southern Indian ocean warming, while this signal only emerges by {\~{}} 2060 in {\textgreater} 80{\%} of the models. Subsampling observations to only retain the most accurate values however indicate that this observed signal most likely results from sampling issues in the Southern hemisphere. In light of this large aliasing by internal climate variability and observational uncertainties, the broad agreement between CMIP5 and observations over 1871–2016 may be largely coincidental. Overall, these results call for extreme caution when interpreting spatial patterns of anthropogenic surface warming.},
author = {Gopika, S. and Izumo, Takeshi and Vialard, J{\'{e}}r{\^{o}}me and Lengaigne, Matthieu and Suresh, Iyyappan and Kumar, M. R.Ramesh},
doi = {10.1007/s00382-019-05049-9},
issn = {14320894},
journal = {Climate Dynamics},
keywords = {Anthropogenic climate change,Coupled model intercomparison project (CMIP),Indian Ocean,Natural climate variability,Sea surface temperature (SST),Spatial pattern of Indian Ocean SST change},
number = {1-2},
pages = {1093--1111},
title = {{Aliasing of the Indian Ocean externally-forced warming spatial pattern by internal climate variability}},
volume = {54},
year = {2020}
}
@article{Gorte2020,
abstract = {Abstract. An increase in Antarctic Ice Sheet (AIS) surface mass balance (SMB) has the potential to mitigate future sea level rise that is driven by enhanced solid ice discharge from the ice sheet. For climate models, AIS SMB provides a difficult challenge, as it is highly susceptible to spatial, seasonal, and interannual variability. Here we use a reconstructed data set of AIS snow accumulation as “true” observational data, to evaluate the ability of the CMIP5 and CMIP6 suites of models in capturing the mean, trends, temporal variability, and spatial variability in SMB over the historical period (1850–2000). This gives insight into which models are most reliable for predicting SMB into the future. We found that the best scoring models included the National Aeronautics and Space Administration (NASA) GISS model and the Max Planck Institute (MPI) for Meteorology's model for CMIP5, as well as one of the Community Earth System Model v2 (CESM2) models and one MPI model for CMIP6. Using a scoring system based on SMB mean value, trend, and temporal variability across the AIS, as well as spatial SMB variability, we selected a subset of the top 10th percentile of models to refine 21st century (2000–2100) AIS-integrated SMB projections to 2274 ± 282 Gt yr−1, 2358 ± 286 Gt yr−1, and 2495 ± 291 Gt yr−1 for Representative Concentration Pathways (RCPs) 2.6, 4.5, and 8.5, respectively. We also reduced the spread in AIS-integrated mean SMB by 79 {\%}, 79 {\%}, and 74 {\%} in RCPs 2.6, 4.5, and 8.5, respectively. Notably, we find that there is no improvement from CMIP5 to CMIP6 in overall score. In fact, CMIP6 performed slightly worse on average compared to CMIP5 at capturing the aforementioned SMB criteria. Our results also indicate that model performance scoring is affected by internal climate variability (particularly the spatial variability), which is illustrated by the fact that the range in overall score between ensemble members within the CESM1 Large Ensemble is comparable to the range in overall score between CESM1 model simulations within the CMIP5 model suite. We also find that a higher horizontal resolution does not yield to a conclusive improvement in score.},
author = {Gorte, Tessa and Lenaerts, Jan T. M. and Medley, Brooke},
doi = {10.5194/tc-14-4719-2020},
issn = {1994-0424},
journal = {The Cryosphere},
month = {dec},
number = {12},
pages = {4719--4733},
title = {{Scoring Antarctic surface mass balance in climate models to refine future projections}},
url = {https://tc.copernicus.org/articles/14/4719/2020/},
volume = {14},
year = {2020}
}
@article{Govin2014,
author = {Govin, Aline and Varma, Vidya and Prange, Matthias},
doi = {10.1002/2013GL058999},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {mar},
number = {6},
pages = {2117--2125},
title = {{Astronomically forced variations in western African rainfall (21°N-20°S) during the Last Interglacial period}},
url = {http://doi.wiley.com/10.1002/2013GL058999},
volume = {41},
year = {2014}
}
@article{https://doi.org/10.1029/2020GL090849,
abstract = {Abstract Changes to the Southern Hemisphere (SH) surface westerlies fundamentally control regional patterns of air temperature, storm tracks and precipitation, while also regulating ocean circulation, heat transport and carbon uptake. Wind-forced ocean perturbation experiments commonly apply idealized poleward wind shifts ranging between 0.5 – 10 degrees of latitude, and wind intensification factors of between 10 – 300{\%}. In addition, changes in winds are often prescribed ad-hoc as a zonally uniform anomaly and can neglect important seasonal differences. Here we quantify historical and projected SH westerly wind changes based on examination of CMIP5, CMIP6 and reanalysis data. We find a significant reduction in the location bias in CMIP6 and an associated reduction in the projected poleward shift compared to CMIP5. Under a high emission scenario, we find a projected end of 21st Century ensemble mean wind increase of ∼10{\%} and a poleward shift of ∼0.8° latitude, although there are important seasonal and regional variations.},
annote = {e2020GL090849 2020GL090849},
author = {Goyal, Rishav and {Sen Gupta}, Alex and Jucker, Martin and England, Matthew H},
doi = {10.1029/2020GL090849},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {CMIP6,Ocean modelling,Southern Annular Mode,Southern Ocean,Westerly winds},
month = {feb},
number = {4},
pages = {e2020GL090849},
title = {{Historical and Projected Changes in the Southern Hemisphere Surface Westerlies}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL090849 https://onlinelibrary.wiley.com/doi/10.1029/2020GL090849},
volume = {48},
year = {2021}
}
@article{Graven2013b,
abstract = {Seasonal variations of atmospheric carbon dioxide (CO 2 ) in the Northern Hemisphere have increased since the 1950s, but sparse observations have prevented a clear assessment of the patterns of long-term change and the underlying mechanisms. We compare recent aircraft-based observations of CO 2 above the North Pacific and Arctic Oceans to earlier data from 1958 to 1961 and find that the seasonal amplitude at altitudes of 3 to 6 km increased by 50{\%} for 45° to 90°N but by less than 25{\%} for 10° to 45°N. An increase of 30 to 60{\%} in the seasonal exchange of CO 2 by northern extratropical land ecosystems, focused on boreal forests, is implicated, substantially more than simulated by current land ecosystem models. The observations appear to signal large ecological changes in northern forests and a major shift in the global carbon cycle.},
author = {Graven, H D and Keeling, R F and Piper, S C and Patra, P K and Stephens, B B and Wofsy, S C and Welp, L R and Sweeney, C and Tans, P P and Kelley, J J and Daube, B C and Kort, E A and Santoni, G W and Bent, J D},
doi = {10.1126/science.1239207},
issn = {0036-8075},
journal = {Science},
month = {sep},
number = {6150},
pages = {1085--1089},
publisher = {American Association for the Advancement of Science},
title = {{Enhanced Seasonal Exchange of CO2 by Northern Ecosystems Since 1960}},
url = {https://www.sciencemag.org/lookup/doi/10.1126/science.1239207},
volume = {341},
year = {2013}
}
@article{Gray2014b,
author = {Gray, Josh M and Frolking, Steve and Kort, Eric A and Ray, Deepak K and Kucharik, Christopher J and Ramankutty, Navin and Friedl, Mark A},
doi = {10.1038/nature13957},
issn = {0028-0836},
journal = {Nature},
month = {nov},
number = {7527},
pages = {398--401},
publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.},
title = {{Direct human influence on atmospheric CO2 seasonality from increased cropland productivity}},
url = {http://www.nature.com/articles/nature13957},
volume = {515},
year = {2014}
}
@article{Gray2016,
author = {Gray, L. J. and Woollings, T. J. and Andrews, M. and Knight, J.},
doi = {10.1002/qj.2782},
issn = {00359009},
journal = {Quarterly Journal of the Royal Meteorological Society},
month = {jul},
number = {698},
pages = {1890--1903},
title = {{Eleven-year solar cycle signal in the NAO and Atlantic/European blocking}},
url = {http://doi.wiley.com/10.1002/qj.2782},
volume = {142},
year = {2016}
}
@article{doi:10.1029/2001GL014575,
abstract = {The HadCM3 AOGCM has been used to undertake an ensemble of four integrations from 1860 to 1999 with forcings due to all major anthropogenic and natural climate factors. The simulated decreasing trend in average Arctic sea ice extent for 1970–1999 (−2.5{\%} per decade) is very similar to observations. HadCM3 indicates that internal variability and natural forcings (solar and volcanic) of the climate system are very unlikely by themselves to have caused a trend of this size. The simulated decreasing trend in Arctic sea ice volume (−3.4{\%} per decade for 1961–1998) is less than some recent observationally based estimates. Extending the integrations into the 21st century, Arctic sea ice area and volume continue to decline. Area decreases linearly as global-average temperature rises (by 13{\%} per K), and volume diminishes more rapidly than area. By the end of the century, in some scenarios, the Arctic is ice-free in late summer.},
author = {Gregory, J M and Stott, P A and Cresswell, D J and Rayner, N A and Gordon, C and Sexton, D M H},
doi = {10.1029/2001GL014575},
journal = {Geophysical Research Letters},
number = {24},
pages = {24--28},
title = {{Recent and future changes in Arctic sea ice simulated by the HadCM3 AOGCM}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2001GL014575},
volume = {29},
year = {2002}
}
@article{Gregory2016,
abstract = {We investigate the climate feedback parameter $\alpha$ (W m-2 K-1) during the historical period (since 1871) in experiments using the HadGEM2 and HadCM3 atmosphere general circulation models (AGCMs) with constant preindustrial atmospheric composition and time-dependent observational sea surface temperature (SST) and sea ice boundary conditions. In both AGCMs, for the historical period as a whole, the effective climate sensitivity is ∼2 K ($\alpha$≃1.7 W m-2 K-1), and $\alpha$ shows substantial decadal variation caused by the patterns of SST change. Both models agree with the AGCMs of the latest Coupled Model Intercomparison Project in showing a considerably smaller effective climate sensitivity of ∼1.5 K ($\alpha$ = 2.3 ± 0.7 W m-2 K-1), given the time-dependent changes in sea surface conditions observed during 1979-2008, than the corresponding coupled atmosphere-ocean general circulation models (AOGCMs) give under constant quadrupled CO2 concentration. These findings help to relieve the apparent contradiction between the larger values of effective climate sensitivity diagnosed from AOGCMs and the smaller values inferred from historical climate change.},
author = {Gregory, J. M. and Andrews, T.},
doi = {10.1002/2016GL068406},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {apr},
number = {8},
pages = {3911--3920},
title = {{Variation in climate sensitivity and feedback parameters during the historical period}},
url = {http://doi.wiley.com/10.1002/2016GL068406},
volume = {43},
year = {2016}
}
@article{Greve2014c,
author = {Greve, Peter and Orlowsky, Boris and Mueller, Brigitte and Sheffield, Justin and Reichstein, Markus and Seneviratne, Sonia I},
doi = {10.1038/ngeo2247},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {oct},
number = {10},
pages = {716--721},
title = {{Global assessment of trends in wetting and drying over land}},
url = {http://www.nature.com/articles/ngeo2247},
volume = {7},
year = {2014}
}
@article{Griffies2015,
abstract = {AbstractThe authors characterize impacts on heat in the ocean climate system from transient ocean mesoscale eddies. Their tool is a suite of centennial-scale 1990 radiatively forced numerical climate simulations from three GFDL coupled models comprising the Climate Model, version 2.0–Ocean (CM2-O), model suite. CM2-O models differ in their ocean resolution: CM2.6 uses a 0.1° ocean grid, CM2.5 uses an intermediate grid with 0.25° spacing, and CM2-1deg uses a nominal 1.0° grid.Analysis of the ocean heat budget reveals that mesoscale eddies act to transport heat upward in a manner that partially compensates (or offsets) for the downward heat transport from the time-mean currents. Stronger vertical eddy heat transport in CM2.6 relative to CM2.5 accounts for the significantly smaller temperature drift in CM2.6. The mesoscale eddy parameterization used in CM2-1deg also imparts an upward heat transport, yet it differs systematically from that found in CM2.6. This analysis points to the fundamental role that ocea...},
author = {Griffies, Stephen M. and Winton, Michael and Anderson, Whit G. and Benson, Rusty and Delworth, Thomas L. and Dufour, Carolina O. and Dunne, John P. and Goddard, Paul and Morrison, Adele K. and Rosati, Anthony and Wittenberg, Andrew T. and Yin, Jianjun and Zhang, Rong},
doi = {10.1175/JCLI-D-14-00353.1},
isbn = {8610829952},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Climate models,Eddies,Mesoscale processes,Ocean circulation,Parameterization,Transport},
month = {feb},
number = {3},
pages = {952--977},
title = {{Impacts on ocean heat from transient mesoscale eddies in a hierarchy of climate models}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-14-00353.1},
volume = {28},
year = {2015}
}
@article{Griffin2014c,
abstract = {For the past three years (2012–2014), California has experienced the most severe drought conditions in its last century. But how unusual is this event? Here we use two paleoclimate reconstructions of drought and precipitation for Central and Southern California to place this current event in the context of the last millennium. We demonstrate that while 3 year periods of persistent below-average soil moisture are not uncommon, the current event is the most severe drought in the last 1200 years, with single year (2014) and accumulated moisture deficits worse than any previous continuous span of dry years. Tree ring chronologies extended through the 2014 growing season reveal that precipitation during the drought has been anomalously low but not outside the range of natural variability. The current California drought is exceptionally severe in the context of at least the last millennium and is driven by reduced though not unprecedented precipitation and record high temperatures. Citation:},
author = {Griffin, Daniel and Anchukaitis, Kevin J.},
doi = {10.1002/2014GL062433},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {dec},
number = {24},
pages = {9017--9023},
title = {{How unusual is the 2012–2014 California drought?}},
url = {http://doi.wiley.com/10.1002/2014GL062433},
volume = {41},
year = {2014}
}
@article{Grise2018,
author = {Grise, Kevin M. and Davis, Sean M. and Staten, Paul W. and Adam, Ori},
doi = {10.1175/JCLI-D-18-0060.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {sep},
number = {17},
pages = {6839--6856},
title = {{Regional and Seasonal Characteristics of the Recent Expansion of the Tropics}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-18-0060.1},
volume = {31},
year = {2018}
}
@article{Grise2019,
author = {Grise, Kevin M. and Davis, Sean M. and Simpson, Isla R. and Waugh, Darryn W. and Fu, Qiang and Allen, Robert J. and Rosenlof, Karen H. and Ummenhofer, Caroline C. and Karnauskas, Kristopher B. and Maycock, Amanda C. and Quan, Xiao-Wei and Birner, Thomas and Staten, Paul W.},
doi = {10.1175/JCLI-D-18-0444.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {mar},
number = {5},
pages = {1551--1571},
title = {{Recent Tropical Expansion: Natural Variability or Forced Response?}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-18-0444.1},
volume = {32},
year = {2019}
}
@article{Grise2020,
author = {Grise, Kevin M. and Davis, Sean M.},
doi = {10.5194/acp-20-5249-2020},
issn = {1680-7324},
journal = {Atmospheric Chemistry and Physics},
month = {may},
number = {9},
pages = {5249--5268},
title = {{Hadley cell expansion in CMIP6 models}},
url = {https://acp.copernicus.org/articles/20/5249/2020/},
volume = {20},
year = {2020}
}
@article{Grist2016,
abstract = {A novel assessment of recent changes in air-sea freshwater fluxes has been conducted using a surface temperature-salinity framework applied to four atmospheric reanalyses. Viewed in the T-S space of the ocean surface, the complex pattern of the longitude-latitude space mean global Precipitation minus Evaporation (PME) reduces to three distinct regions. The analysis is conducted for the period 1979-2007 for which there is most evidence for a broadening of the (atmospheric) tropical belt. All four of the reanalyses display an increase in strength of the water cycle. The range of increase is between 2{\%} and 30{\%} over the period analyzed, with an average of 14{\%}. Considering the average across the reanalyses, the water cycle changes are dominated by changes in tropical as opposed to mid-high latitude precipitation. The increases in the water cycle strength, are consistent in sign, but larger than in a 1{\%} greenhouse gas run of the HadGEM3 climate model. In the model a shift of the precipitation/evaporation cells to higher temperatures is more evident, due to the much stronger global warming signal. The observed changes in freshwater fluxes appear to be reflected in changes in the T-S distribution of the Global Ocean. Specifically, across the diverse range of atmospheric reanalyses considered here, there was an acceleration of the hydrological cycle during 1979-2007 which led to a broadening of the ocean's salinity distribution. Finally, although the reanalyses indicate that the warm temperature tropical precipitation dominated water cycle change, ocean observations suggest that ocean processes redistributed the freshening to lower ocean temperatures.},
author = {Grist, Jeremy P. and Josey, Simon A. and Zika, Jan D. and Evans, Dafydd Gwyn and Skliris, Nikolaos},
doi = {10.1002/2016JC012091},
issn = {21699291},
journal = {Journal of Geophysical Research: Oceans},
keywords = {Global Ocean,atmospheric reanalysis,evaporation,precipitation,temperature-salinity},
month = {dec},
number = {12},
pages = {8787--8806},
publisher = {Wiley-Blackwell},
title = {{Assessing recent air–sea freshwater flux changes using a surface temperature–salinity space framework}},
url = {http://doi.wiley.com/10.1002/2016JC012091},
volume = {121},
year = {2016}
}
@article{doi:10.1029/2018JC014387,
abstract = {Abstract Recent increases in resolution of coupled ocean-atmosphere models have the potential to improve the representation of poleward heat transport within the climate system. Here we examine the interplay between model resolution-dependent changes in Atlantic Ocean heat transport (AOHT) and surface heat fluxes. The different roles of changes in atmospheric and ocean resolution are isolated using three different climate models (The Centro Euro-Mediterraneo sui Cambiamenti Climatici Climate Model 2, Hadley Centre Global Environmental Model 3 – Global Coupled configuration 2, and European Community Earth-System Model 3.1) and comparing runs in which (a) only the ocean resolution changes, (b) only the atmosphere resolution changes, and (c) both change. Enhancing ocean resolution from eddy parameterized to eddy permitting increases the AOHT throughout the basin, values changing from 1.0 to 1.2 PW at 26°N, bringing the AOHT into the range of estimates from the RAPID observing array. This increase in AOHT is associated with higher North Atlantic sea surface temperatures and increased ocean heat loss to the atmosphere. Increasing the atmospheric resolution alone has little impact on the AOHT due to regionally compensating changes in the components of the net heat flux. Finally, in a fourth experiment the impact of resolution changes in both components and the transition to an eddy-resolving ocean is assessed. This additional resolution increase is accompanied by a further change in the AOHT and improves agreement with observations in the tropics but not the subpolar regions. However, unlike with the increase to the eddy-permitting ocean, when the greatest AOHT change occurs in the subtropics and subpolar region, the most significant increase now occurs in the tropics.},
author = {Grist, Jeremy P and Josey, Simon A and New, Adrian L and Roberts, Malcolm and Koenigk, Torben and Iovino, Doroteaciro},
doi = {10.1029/2018JC014387},
journal = {Journal of Geophysical Research: Oceans},
keywords = {Atlantic ocean,climate models,model resolution,ocean heat transport,surface fluxes},
number = {11},
pages = {8624--8637},
title = {{Increasing Atlantic Ocean Heat Transport in the Latest Generation Coupled Ocean–Atmosphere Models: The Role of Air–Sea Interaction}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JC014387},
volume = {123},
year = {2018}
}
@article{Grodsky2012,
abstract = {At its seasonal peak the Amazon/Orinoco plume covers a region of 10 6km2 in the western tropical Atlantic with more than 1m of extra freshwater, creating a near-surface barrier layer (BL) that inhibits mixing and warms the sea surface temperature (SST) to {\textgreater}29°C. Here new sea surface salinity (SSS) observations from the Aquarius/SACD and SMOS satellites help elucidate the ocean response to hurricane Katia, which crossed the plume in early fall, 2011. Its passage left a 1.5 psu high haline wake covering {\textgreater}105km2 (in its impact on density, the equivalent of a 3.5°C cooling) due to mixing of the shallow BL. Destruction of this BL apparently decreased SST cooling in the plume, and thus preserved higher SST and evaporation than outside. Combined with SST, the new satellite SSS data provide a new and better tool to monitor the plume extent and quantify tropical cyclone upper ocean responses with important implications for forecasting. {\textcopyright} 2012. American Geophysical Union. All Rights Reserved.},
author = {Grodsky, Semyon A. and Reul, Nicolas and Lagerloef, Gary and Reverdin, Gilles and Carton, James A. and Chapron, Bertrand and Quilfen, Yves and Kudryavtsev, Vladimir N. and Kao, Hsun Ying},
doi = {10.1029/2012GL053335},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {oct},
number = {20},
pages = {2012GL053335},
title = {{Haline hurricane wake in the Amazon/Orinoco plume: AQUARIUS/SACD and SMOS observations}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2012GL053335},
volume = {39},
year = {2012}
}
@article{Grose2020,
author = {Grose, M. R. and Narsey, S. and Delage, F. P. and Dowdy, A. J. and Bador, M. and Boschat, G. and Chung, C. and Kajtar, J. B. and Rauniyar, S. and Freund, M. B. and Lyu, K. and Rashid, H. and Zhang, X. and Wales, S. and Trenham, C. and Holbrook, N. J. and Cowan, T. and Alexander, L. and Arblaster, J. M. and Power, S.},
doi = {10.1029/2019EF001469},
issn = {2328-4277},
journal = {Earth's Future},
month = {may},
number = {5},
pages = {e2019EF001469},
title = {{Insights From CMIP6 for Australia's Future Climate}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019EF001469},
volume = {8},
year = {2020}
}
@article{Gu2018,
author = {Gu, G and Adler, Robert F.},
doi = {10.1175/JCLI-D-17-0550.1},
journal = {Journal of Climate},
pages = {4775--4790},
title = {{Precipitation Intensity Changes in the Tropics from Observations and Models}},
volume = {31},
year = {2018}
}
@article{Guan2015a,
author = {Guan, Xiaodan and Huang, Jianping and Guo, Ruixia and Lin, Pu},
doi = {10.1038/srep12669},
issn = {2045-2322},
journal = {Scientific Reports},
month = {oct},
number = {1},
pages = {12669},
title = {{The role of dynamically induced variability in the recent warming trend slowdown over the Northern Hemisphere}},
volume = {5},
year = {2015}
}
@article{Guarino2020,
abstract = {The Last Interglacial (LIG), a warmer period 130,000–116,000 years before present, is a potential analogue for future climate change. Stronger LIG summertime insolation at high northern latitudes drove Arctic land summer temperatures 4–5 °C higher than in the pre-industrial era. Climate model simulations have previously failed to capture these elevated temperatures, possibly because they were unable to correctly capture LIG sea-ice changes. Here, we show that the latest version of the fully coupled UK Hadley Center climate model (HadGEM3) simulates a more accurate Arctic LIG climate, including elevated temperatures. Improved model physics, including a sophisticated sea-ice melt-pond scheme, result in a complete simulated loss of Arctic sea ice in summer during the LIG, which has yet to be simulated in past generations of models. This ice-free Arctic yields a compelling solution to the long-standing puzzle of what drove LIG Arctic warmth and supports a fast retreat of future Arctic summer sea ice.},
author = {Guarino, Maria-Vittoria and Sime, Louise C and Schr{\"{o}}eder, David and Malmierca-Vallet, Irene and Rosenblum, Erica and Ringer, Mark and Ridley, Jeff and Feltham, Danny and Bitz, Cecilia and Steig, Eric J and Wolff, Eric and Stroeve, Julienne and Sellar, Alistair},
doi = {10.1038/s41558-020-0865-2},
issn = {1758-6798},
journal = {Nature Climate Change},
number = {10},
pages = {928--932},
title = {{Sea-ice-free Arctic during the Last Interglacial supports fast future loss}},
url = {https://doi.org/10.1038/s41558-020-0865-2},
volume = {10},
year = {2020}
}
@article{Gudmundsson2021,
abstract = {Anthropogenic climate change is expected to affect global river flow. Here, we analyze time series of low, mean, and high river flows from 7250 observatories around the world covering the years 1971 to 2010. We identify spatially complex trend patterns, where some regions are drying and others are wetting consistently across low, mean, and high flows. Trends computed from state-of-the-art model simulations are consistent with the observations only if radiative forcing that accounts for anthropogenic climate change is considered. Simulated effects of water and land management do not suffice to reproduce the observed trend pattern. Thus, the analysis provides clear evidence for the role of externally forced climate change as a causal driver of recent trends in mean and extreme river flow at the global scale.},
author = {Gudmundsson, Lukas and Boulange, Julien and Do, Hong X. and Gosling, Simon N. and Grillakis, Manolis G. and Koutroulis, Aristeidis G. and Leonard, Michael and Liu, Junguo and {M{\"{u}}ller Schmied}, Hannes and Papadimitriou, Lamprini and Pokhrel, Yadu and Seneviratne, Sonia I. and Satoh, Yusuke and Thiery, Wim and Westra, Seth and Zhang, Xuebin and Zhao, Fang},
doi = {10.1126/science.aba3996},
issn = {0036-8075},
journal = {Science},
month = {mar},
number = {6534},
pages = {1159--1162},
title = {{Globally observed trends in mean and extreme river flow attributed to climate change}},
url = {https://www.sciencemag.org/lookup/doi/10.1126/science.aba3996},
volume = {371},
year = {2021}
}
@article{Gudmundsson2017,
author = {Gudmundsson, Lukas and Seneviratne, Sonia I and Zhang, Xuebin},
doi = {10.1038/nclimate3416},
journal = {Nature Climate Change},
month = {oct},
pages = {813},
publisher = {Nature Publishing Group},
title = {{Anthropogenic climate change detected in European renewable freshwater resources}},
url = {http://dx.doi.org/10.1038/nclimate3416 http://10.0.4.14/nclimate3416 https://www.nature.com/articles/nclimate3416{\#}supplementary-information},
volume = {7},
year = {2017}
}
@article{Guemas2013,
author = {Guemas, Virginie and Doblas-Reyes, Francisco J and Andreu-Burillo, Isabel and Asif, Muhammad},
doi = {10.1038/nclimate1863},
journal = {Nature Climate Change},
month = {apr},
pages = {649},
publisher = {Nature Publishing Group},
title = {{Retrospective prediction of the global warming slowdown in the past decade}},
url = {http://dx.doi.org/10.1038/nclimate1863 http://10.0.4.14/nclimate1863 https://www.nature.com/articles/nclimate1863{\#}supplementary-information},
volume = {3},
year = {2013}
}
@article{Guilyardi2012a,
abstract = {The El Ni�o?Southern Oscillation (ENSO) is a naturally occurring fluctuation$\backslash$nthat originates in the tropical Pacific region with severe weather$\backslash$nand societal impacts worldwide (McPhaden et al. 2006). Despite considerable$\backslash$nprogress in our understanding of the impact of climate change on$\backslash$nmany of the processes that contribute to ENSO variability, it is$\backslash$nnot yet possible to say whether ENSO activity will be enhanced or$\backslash$nmdamped, or if the frequency of events will change in the coming$\backslash$ndecades (Vecchi {\&} Wittenberg 2010, Collins et al. 2010). As changes$\backslash$nin ENSO have the potential to be one of the largest manifestations$\backslash$nof anthropogenic climate change, this status has profound impacts$\backslash$non the reliability of regional attribution of climate variability$\backslash$nand change.},
author = {Guilyardi, Eric and Bellenger, Hugo and Collins, Mat and Ferrett, Samantha and Cai, Wenju and Wittenberg, Andrew},
journal = {Clivar Exchanges},
number = {58},
pages = {29--32},
title = {{A first look at ENSO in CMIP5}},
url = {https://www.clivar.org/sites/default/files/documents/Exchanges58.pdf},
volume = {17},
year = {2012}
}
@article{Guo2015a,
abstract = {Comparison of single-forcing varieties of 20th century historical experiments in a subset of models from the Fifth Coupled Model Intercomparison Project (CMIP5) reveals that South Asian summer monsoon rainfall increases towards the present day in Greenhouse Gas (GHG)-only experiments with respect to pre-industrial levels, while it decreases in anthropogenic aerosol-only experiments. Comparison of these single-forcing experiments with the all-forcings historical experiment suggests aerosol emissions have dominated South Asian monsoon rainfall trends in recent decades, especially during the 1950s to 1970s. The variations in South Asian monsoon rainfall in these experiments follows approximately the time evolution of inter-hemispheric temperature gradient over the same period, suggesting a contribution from the large-scale background state relating to the asymmetric distribution of aerosol emissions about the equator. By examining the 24 available all-forcings historical experiments, we show that models including aerosol indirect effects dominate the negative rainfall trend. Indeed, models including only the direct radiative effect of aerosol show an increase in monsoon rainfall, consistent with the dominance of increasing greenhouse gas emissions and planetary warming on monsoon rainfall in those models. For South Asia, reduced rainfall in the models with indirect effects is related to decreased evaporation at the land surface rather than from anomalies in horizontal moisture flux, suggesting the impact of indirect effects on local aerosol emissions. This is confirmed by examination of aerosol loading and cloud droplet number trends over the South Asia region. Thus, while remote aerosols and their asymmetric distribution about the equator play a role in setting the inter-hemispheric temperature distribution on which the South Asian monsoon, as one of the global monsoons, operates, the addition of indirect aerosol effects acting on very local aerosol emissions also plays a role in declining monsoon rainfall. The disparity between the response of monsoon rainfall to increasing aerosol emissions in models containing direct aerosol effects only and those also containing indirect effects needs to be urgently investigated since the suggested future decline in Asian anthropogenic aerosol emissions inherent to the representative concentration pathways (RCPs) used for future climate projection may turn out to be optimistic. In addition, both groups of models show declining rainfall over China, also relating to local aerosol mechanisms. We hypothesize that aerosol emissions over China are large enough, in the CMIP5 models, to cause declining monsoon rainfall even in the absence of indirect aerosol effects. The same is not true for India.},
annote = {South Asian summer monsoon
CMIP5 historical, historicalGHG, historicalAA
MJJAS South Asia precipitation (10-35N, 70-90E)
ANN global air-sea surface temperature contrast

- GHG increase acts to enhance South Asian summer monsoon precip and ANN global air-sea contrast
- Aerosol increase acts to reduce South Asian summer monsoon precip and ANN global air-sea contrast
- For summer South Asian monsoon precipitation, aerosol influence has dominated in all forcing
- Models with indirect effect show stronger decrease in rainfall since the 1950s, suggesting importance of indirect effect},
author = {Guo, L. and Turner, A. G. and Highwood, E. J.},
doi = {10.5194/acp-15-6367-2015},
isbn = {1680-7316},
issn = {16807324},
journal = {Atmospheric Chemistry and Physics},
number = {11},
pages = {6367--6378},
title = {{Impacts of 20th century aerosol emissions on the South Asian monsoon in the CMIP5 models}},
volume = {15},
year = {2015}
}
@article{gmd-12-3241-2019,
author = {Gutjahr, O and Putrasahan, D and Lohmann, K and Jungclaus, J H and von Storch, J.-S. and Br{\"{u}}ggemann, N and Haak, H and St{\"{o}}ssel, A},
doi = {10.5194/gmd-12-3241-2019},
journal = {Geoscientific Model Development},
number = {7},
pages = {3241--3281},
title = {{Max Planck Institute Earth System Model (MPI-ESM1.2) for the High-Resolution Model Intercomparison Project (HighResMIP)}},
url = {https://www.geosci-model-dev.net/12/3241/2019/},
volume = {12},
year = {2019}
}
@article{Gainusa-Bogdan2018,
abstract = {Despite decades of efforts and improvements in the representation of processes as well as in model resolution, current global climate models still suffer from a set of important, systematic biases in sea surface temperature (SST), not much different from the previous generation of climate models. Many studies have looked at errors in the wind field, cloud representation or oceanic upwelling in coupled models to explain the SST errors. In this paper we highlight the relationship between latent heat flux (LH) biases in forced atmospheric simulations and the SST biases models develop in coupled mode, at the scale of the entire intertropical domain. By analyzing 22 pairs of forced atmospheric and coupled ocean-atmosphere simulations from the CMIP5 database, we show a systematic, negative correlation between the spatial patterns of these two biases. This link between forced and coupled bias patterns is also confirmed by two sets of dedicated sensitivity experiments with the IPSL-CM5A-LR model. The analysis of the sources of the atmospheric LH bias pattern reveals that the near-surface wind speed bias dominates the zonal structure of the LH bias and that the near-surface relative humidity dominates the east–west contrasts.},
author = {Găinuşă-Bogdan, Alina and Hourdin, Fr{\'{e}}d{\'{e}}ric and Traore, Abdoul Khadre and Braconnot, Pascale},
doi = {10.1007/s00382-017-4057-3},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {oct},
number = {7-8},
pages = {2927--2941},
title = {{Omens of coupled model biases in the CMIP5 AMIP simulations}},
url = {http://link.springer.com/10.1007/s00382-017-4057-3},
volume = {51},
year = {2018}
}
@article{Haarsma2016a,
abstract = {Abstract. Robust projections and predictions of climate variability and change, particularly at regional scales, rely on the driving processes being represented with fidelity in model simulations. The role of enhanced horizontal resolution in improved process representation in all components of the climate system is of growing interest, particularly as some recent simulations suggest both the possibility of significant changes in large-scale aspects of circulation as well as improvements in small-scale processes and extremes. However, such high-resolution global simulations at climate timescales, with resolutions of at least 50 km in the atmosphere and 0.25° in the ocean, have been performed at relatively few research centres and generally without overall coordination, primarily due to their computational cost. Assessing the robustness of the response of simulated climate to model resolution requires a large multi-model ensemble using a coordinated set of experiments. The Coupled Model Intercomparison Project 6 (CMIP6) is the ideal framework within which to conduct such a study, due to the strong link to models being developed for the CMIP DECK experiments and other model intercomparison projects (MIPs). Increases in high-performance computing (HPC) resources, as well as the revised experimental design for CMIP6, now enable a detailed investigation of the impact of increased resolution up to synoptic weather scales on the simulated mean climate and its variability. The High Resolution Model Intercomparison Project (HighResMIP) presented in this paper applies, for the first time, a multi-model approach to the systematic investigation of the impact of horizontal resolution. A coordinated set of experiments has been designed to assess both a standard and an enhanced horizontal-resolution simulation in the atmosphere and ocean. The set of HighResMIP experiments is divided into three tiers consisting of atmosphere-only and coupled runs and spanning the period 1950–2050, with the possibility of extending to 2100, together with some additional targeted experiments. This paper describes the experimental set-up of HighResMIP, the analysis plan, the connection with the other CMIP6 endorsed MIPs, as well as the DECK and CMIP6 historical simulations. HighResMIP thereby focuses on one of the CMIP6 broad questions, “what are the origins and consequences of systematic model biases?”, but we also discuss how it addresses the World Climate Research Program (WCRP) grand challenges.},
author = {Haarsma, Reindert J and Roberts, Malcolm J and Vidale, Pier Luigi and Senior, Catherine A and Bellucci, Alessio and Bao, Qing and Chang, Ping and Corti, Susanna and Fu{\v{c}}kar, Neven S and Guemas, Virginie and von Hardenberg, Jost and Hazeleger, Wilco and Kodama, Chihiro and Koenigk, Torben and Leung, L Ruby and Lu, Jian and Luo, Jing-Jia and Mao, Jiafu and Mizielinski, Matthew S and Mizuta, Ryo and Nobre, Paulo and Satoh, Masaki and Scoccimarro, Enrico and Semmler, Tido and Small, Justin and von Storch, Jin-Song},
doi = {10.5194/gmd-9-4185-2016},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {nov},
number = {11},
pages = {4185--4208},
title = {{High Resolution Model Intercomparison Project (HighResMIP v1.0) for CMIP6}},
url = {https://www.geosci-model-dev.net/9/4185/2016/ https://gmd.copernicus.org/articles/9/4185/2016/},
volume = {9},
year = {2016}
}
@article{Haimberger2012,
abstract = {This article describes progress in the homogenization of global radiosonde temperatures with updated versions of the Radiosonde Observation Correction Using Reanalyses (RAOBCORE) and Radiosonde Innovation Composite Homogenization (RICH) software packages. These are automated methods to homogenize the global radiosonde temperature dataset back to 1958. The break dates are determined from analysis of time series of differences between radiosonde temperatures (obs) and background forecasts (bg) of climate data assimilation systems used for the 40-yr European Centre for Medium-RangeWeather Forecasts (ECMWF) Re-Analysis (ERA-40) and the ongoing interim ECMWF Re-Analysis (ERA-Interim). RAOBCORE uses the obs2bg time series also for estimating the break sizes. RICH determines the break sizes either by comparing the observations of a tested time series with observations of neighboring radiosonde time series (RICH-obs) or by comparing their background departures (RICH-$\tau$). Consequently RAOBCORE results may be influenced by inhomogeneities in the bg, whereas break size estimation with RICH-obs is independent of the bg. The adjustment quality of RICH-obs, on the other hand, may suffer from large interpolation errors at remote stations. RICH-$\tau$ is a compromise that substantially reduces interpolation errors at the cost of slight dependence on the bg. Adjustment uncertainty is estimated by comparing the three methods and also by varying parameters in RICH. The adjusted radiosonde time series are compared with recent temperature datasets based on (Advanced) Microwave Sounding Unit [(A)MSU] radiances. The overall spatiotemporal consistency of the homogenized dataset has improved compared to earlier versions, particularly in the presatellite era. Vertical profiles of temperature trends are more consistent with satellite data as well. {\textcopyright} 2012 American Meteorological Society.},
author = {Haimberger, Leopold and Tavolato, Christina and Sperka, Stefan},
doi = {10.1175/JCLI-D-11-00668.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Climate change,Climatology},
number = {23},
pages = {8108--8131},
title = {{Homogenization of the global radiosonde temperature dataset through combined comparison with reanalysis background series and neighboring stations}},
volume = {25},
year = {2012}
}
@article{Halder2020,
author = {Halder, Subrota and Parekh, Anant and Chowdary, Jasti S. and Gnanaseelan, Chellappan and Kulkarni, Ashwini},
doi = {10.1002/joc.6975},
issn = {0899-8418},
journal = {International Journal of Climatology},
month = {mar},
number = {4},
pages = {2568--2588},
title = {{Assessment of CMIP6 models' skill for tropical Indian Ocean sea surface temperature variability}},
url = {https://onlinelibrary.wiley.com/doi/10.1002/joc.6975},
volume = {41},
year = {2021}
}
@article{hallberg2013using,
author = {Hallberg, Robert},
doi = {10.1016/j.ocemod.2013.08.007},
journal = {Ocean Modelling},
pages = {92--103},
publisher = {Elsevier},
title = {{Using a resolution function to regulate parameterizations of oceanic mesoscale eddy effects}},
volume = {72},
year = {2013}
}
@article{hallberg2006role,
abstract = {The Modeling Eddies in the Southern Ocean (MESO) project uses numerical sensitivity studies to examine the role played by Southern Ocean winds and eddies in determining the density structure of the global ocean and the magnitude and structure of the global overturning circulation. A hemispheric isopycnal-coordinate ocean model (which avoids numerical diapycnal diffusion) with realistic geometry is run with idealized forcing at a range of resolutions from coarse (2°) to eddy-permitting (1/6°). A comparison of coarse resolutions with fine resolutions indicates that explicit eddies affect both the structure of the overturning and the response of the overturning to wind stress changes. While the presence of resolved eddies does not greatly affect the prevailing qualitative picture of the ocean circulation, it alters the overturning cells involving the Southern Ocean transformation of dense deep waters and light waters of subtropical origin into intermediate waters. With resolved eddies, the surface-to-intermediate water cell extends farther southward by hundreds of kilometers and the deep-to-intermediate cell draws on comparatively lighter deep waters. The overturning response to changes in the winds is also sensitive to the presence of eddies. In noneddying simulations, changing the Ekman transport produces comparable changes in the overturning, much of it involving transformation of deep waters and resembling the mean circulation. In the eddy-permitting simulations, a significant fraction of the Ekman transport changes are compensated by eddy-induced transport drawing from lighter waters than does the mean overturning. This significant difference calls into question the ability of coarse-resolution ocean models to accurately capture the impact of changes in the Southern Ocean on the global ocean circulation.},
author = {Hallberg, Robert and Gnanadesikan, Anand},
doi = {10.1175/JPO2980.1},
issn = {1520-0485},
journal = {Journal of Physical Oceanography},
month = {dec},
number = {12},
pages = {2232--2252},
title = {{The Role of Eddies in Determining the Structure and Response of the Wind-Driven Southern Hemisphere Overturning: Results from the Modeling Eddies in the Southern Ocean (MESO) Project}},
url = {http://journals.ametsoc.org/doi/10.1175/JPO2980.1},
volume = {36},
year = {2006}
}
@article{Han2014a,
abstract = {Capsule Our current knowledge of decadal and multi-decadal time scale variability in the Indian Ocean region is limited and subject to considerable uncertainty. Improved definition and understanding of this variability will support climate prediction efforts that have the potential to benefit a large percentage of the world's population living in Indian Ocean rim countries and elsewhere around the globe. Abstract The international scientific community has highlighted decadal and multi-decadal climate variability as a priority area for climate research. The Indian Ocean rim region is home to one third of the world's population, mostly living in developing countries that are vulnerable to climate variability and to the increasing pressure of anthropogenic climate change. Yet, while prominent decadal and multidecadal variations occur in the Indian Ocean, they have been less studied than those in the Pacific and Atlantic oceans. This paper reviews existing literature on these Indian Ocean variations, includin...},
author = {Han, Weiqing and Vialard, J{\'{e}}r{\^{o}}me and McPhaden, Michael J. and Lee, Tong and Masumoto, Yukio and Feng, Ming and {De Ruijter}, Will P.M.},
doi = {10.1175/BAMS-D-13-00028.1},
isbn = {0003-0007},
issn = {00030007},
journal = {Bulletin of the American Meteorological Society},
number = {11},
pages = {1679--1703},
title = {{Indian ocean decadal variability: A review}},
volume = {95},
year = {2014}
}
@article{Han2014,
abstract = {Previous studies have linked the rapid sea level rise (SLR) in the western tropical Pacific (WTP) since the early 1990s to the Pacific decadal climate modes, notably the Pacific Decadal Oscillation in the north Pacific or Interdecadal Pacific Oscillation (IPO) considering its basin wide signature. Here, the authors investigate the changing patterns of decadal (10--20 years) and multidecadal ({\textgreater}20 years) sea level variability (global mean SLR removed) in the Pacific associated with the IPO, by analyzing satellite and in situ observations, together with reconstructed and reanalysis products, and performing ocean and atmosphere model experiments. Robust intensification is detected for both decadal and multidecadal sea level variability in the WTP since the early 1990s. The IPO intensity, however, did not increase and thus cannot explain the faster SLR. The observed, accelerated WTP SLR results from the combined effects of Indian Ocean and WTP warming and central-eastern tropical Pacific cooling associated with the IPO cold transition. The warm Indian Ocean acts in concert with the warm WTP and cold central-eastern tropical Pacific to drive intensified easterlies and negative Ekman pumping velocity in western-central tropical Pacific, thereby enhancing the western tropical Pacific SLR. On decadal timescales, the intensified sea level variability since the late 1980s or early 1990s results from the ``out of phase'' relationship of sea surface temperature anomalies between the Indian and central-eastern tropical Pacific since 1985, which produces ``in phase'' effects on the WTP sea level variability.},
author = {Han, Weiqing and Meehl, Gerald A and Hu, Aixue and Alexander, Michael A and Yamagata, Toshio and Yuan, Dongliang and Ishii, Masayoshi and Pegion, Philip and Zheng, Jian and Hamlington, Benjamin D and Quan, Xiao-Wei and Leben, Robert R},
doi = {10.1007/s00382-013-1951-1},
issn = {1432-0894},
journal = {Climate Dynamics},
month = {sep},
number = {5},
pages = {1357--1379},
title = {{Intensification of decadal and multi-decadal sea level variability in the western tropical Pacific during recent decades}},
url = {https://doi.org/10.1007/s00382-013-1951-1},
volume = {43},
year = {2014}
}
@article{Hanna2015a,
author = {Hanna, Edward and Cropper, Thomas E. and Jones, Philip D. and Scaife, Adam A. and Allan, Rob},
doi = {10.1002/joc.4157},
issn = {08998418},
journal = {International Journal of Climatology},
month = {jul},
number = {9},
pages = {2540--2554},
title = {{Recent seasonal asymmetric changes in the NAO (a marked summer decline and increased winter variability) and associated changes in the AO and Greenland Blocking Index}},
volume = {35},
year = {2015}
}
@article{Hanna2018,
author = {Hanna, Edward and Fettweis, Xavier and Hall, Richard J.},
doi = {10.5194/tc-12-3287-2018},
issn = {1994-0424},
journal = {The Cryosphere},
month = {oct},
number = {10},
pages = {3287--3292},
title = {{Brief communication: Recent changes in summer Greenland blocking captured by none of the CMIP5 models}},
url = {https://www.the-cryosphere.net/12/3287/2018/},
volume = {12},
year = {2018}
}
@article{Hannart2016,
abstract = {{\textcopyright} 2016 American Meteorological Society. The present paper introduces and illustrates methodological developments intended for so-called optimal fingerprinting methods, which are of frequent use in detection and attribution studies. These methods used to involve three independent steps: Preliminary reduction of the dimension of the data, estimation of the covariance associated to internal climate variability, and, finally, linear regression inference with associated uncertainty assessment. It is argued that such a compartmentalized treatment presents several issues; an integrated method is thus introduced to address them. The suggested approach is based on a single-piece statistical model that represents both linear regression and control runs. The unknown covariance is treated as a nuisance parameter that is eliminated by integration. This allows for the introduction of regularization assumptions. Point estimates and confidence intervals follow from the integrated likelihood. Further, it is shown that preliminary dimension reduction is not required for implementability and that computational issues associated to using the raw, high-dimensional, spatiotemporal data can be resolved quite easily. Results on simulated data show improved performance compared to existing methods w.r.t. both estimation error and accuracy of confidence intervals and also highlight the need for further improvements regarding the latter. The method is illustrated on twentieth-century precipitation and surface temperature, suggesting a potentially high informational benefit of using the raw, nondimension-reduced data in detection and attribution (D{\&}A), provided model error is appropriately built into the inference.},
author = {Hannart, A.},
doi = {10.1175/JCLI-D-14-00124.1},
journal = {Journal of Climate},
number = {6},
pages = {1977--1998},
title = {{Integrated optimal fingerprinting: Method description and illustration}},
volume = {29},
year = {2016}
}
@article{Hannart2018,
abstract = {Multiple changes in Earth's climate system have been observed over the past decades. Determining how likely each of these changes is to have been caused by human influence is important for decision making with regard to mitigation and adaptation policy. Here we describe an approach for deriving the probability that anthropogenic forcings have caused a given observed change. The proposed approach is anchored into causal counterfactual theory (Pearl 2009), which was introduced recently, and in fact partly used already, in the context of extreme weather event attribution (EA). We argue that these concepts are also relevant to, and can be straightforwardly extended to, the context of detection and attribution of long-term trends associated with climate change (D {\&} A). For this purpose, and in agreement with the principle of fingerprinting applied in the conventional D {\&} A framework, a trajectory of change is converted into an event occurrence defined by maximizing the causal evidence associated to the forcing under scrutiny. Other key assumptions used in the conventional D {\&} A framework, in particular those related to numerical model error, can also be adapted conveniently to this approach. Our proposal thus allows us to bridge the conventional framework with the standard causal theory, in an attempt to improve the quantification of causal probabilities. An illustration suggests that our approach is prone to yield a significantly higher estimate of the probability that anthropogenic forcings have caused the observed temperature change, thus supporting more assertive causal claims.},
archivePrefix = {arXiv},
arxivId = {1712.00063},
author = {Hannart, Alexis and Naveau, Philippe},
doi = {10.1175/JCLI-D-17-0304.1},
eprint = {1712.00063},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Climate change,Climate models,Climate variability,Statistical techniques},
number = {14},
pages = {5507--5524},
title = {{Probabilities of causation of climate changes}},
volume = {31},
year = {2018}
}
@article{doi:10.1002/2013GL058653,
abstract = {Detection and attribution studies routinely use linear regression methods referred to as optimal fingerprinting. Within the latter methodological paradigm, it is usually recognized that multiple sources of uncertainty affect both the observations and the simulated climate responses used as regressors. These include for instance internal variability, climate model error, or observational error. When all errors share the same covariance, the statistical inference is usually performed with the so-called total least squares procedure, but to date no inference procedure is readily available in the climate literature to treat the general case where this assumption does not hold. Here we address this deficiency. After a brief outlook on the error-in-variable models literature, we describe an inference procedure based on likelihood maximization, inspired by a recent article dealing with a similar situation in geodesy. We evaluate the performance of our approach via an idealized test bed. We find the procedure to outperform existing procedures when the latter wrongly neglect some sources of uncertainty.},
author = {Hannart, Alexis and Ribes, Aur{\'{e}}lien and Naveau, Philippe},
doi = {10.1002/2013GL058653},
journal = {Geophysical Research Letters},
keywords = {detection and attribution,linear regression,optimal fingerprinting},
number = {4},
pages = {1261--1268},
title = {{Optimal fingerprinting under multiple sources of uncertainty}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2013GL058653},
volume = {41},
year = {2014}
}
@article{Hardiman2020,
author = {Hardiman, Steven C. and Dunstone, Nick J. and Scaife, Adam A. and Smith, Doug M. and Knight, Jeff R. and Davies, Paul and Claus, Martin and Greatbatch, Richard J.},
doi = {10.1002/asl.1005},
issn = {1530-261X},
journal = {Atmospheric Science Letters},
month = {dec},
number = {12},
pages = {e1005},
title = {{Predictability of European winter 2019/20: Indian Ocean dipole impacts on the NAO}},
url = {https://onlinelibrary.wiley.com/doi/10.1002/asl.1005},
volume = {21},
year = {2020}
}
@article{Hargreaves2014c,
author = {Hargreaves, J.C. and Annan, J},
doi = {10.1002/wcc.288},
journal = {WIREs Climate Change},
pages = {435--440},
title = {{Can we trust climate models?}},
volume = {5},
year = {2014}
}
@article{Harlaß2018,
author = {Harla{\ss}, Jan and Latif, Mojib and Park, Wonsun},
doi = {10.1007/s00382-017-3760-4},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {apr},
number = {7-8},
pages = {2605--2635},
title = {{Alleviating tropical Atlantic sector biases in the Kiel climate model by enhancing horizontal and vertical atmosphere model resolution: climatology and interannual variability}},
url = {http://link.springer.com/10.1007/s00382-017-3760-4},
volume = {50},
year = {2018}
}
@article{Harper2018b,
abstract = {Scenarios that limit global warming to below 2 °C by 2100 assume significant land-use change to support large-scale carbon dioxide (CO2) removal from the atmosphere by afforestation/reforestation, avoided deforestation, and Biomass Energy with Carbon Capture and Storage (BECCS). The more ambitious mitigation scenarios require even greater land area for mitigation and/or earlier adoption of CO2 removal strategies. Here we show that additional land-use change to meet a 1.5 °C climate change target could result in net losses of carbon from the land. The effectiveness of BECCS strongly depends on several assumptions related to the choice of biomass, the fate of initial above ground biomass, and the fossil-fuel emissions offset in the energy system. Depending on these factors, carbon removed from the atmosphere through BECCS could easily be offset by losses due to land-use change. If BECCS involves replacing high-carbon content ecosystems with crops, then forest-based mitigation could be more efficient for atmospheric CO2 removal than BECCS.},
author = {Harper, Anna B. and Powell, Tom and Cox, Peter M. and House, Joanna and Huntingford, Chris and Lenton, Timothy M. and Sitch, Stephen and Burke, Eleanor and Chadburn, Sarah E. and Collins, William J. and Comyn-Platt, Edward and Daioglou, Vassilis and Doelman, Jonathan C. and Hayman, Garry and Robertson, Eddy and van Vuuren, Detlef and Wiltshire, Andy and Webber, Christopher P. and Bastos, Ana and Boysen, Lena and Ciais, Philippe and Devaraju, Narayanappa and Jain, Atul K. and Krause, Andreas and Poulter, Ben and Shu, Shijie},
doi = {10.1038/s41467-018-05340-z},
issn = {2041-1723},
journal = {Nature Communications},
month = {dec},
number = {1},
pages = {2938},
title = {{Land-use emissions play a critical role in land-based mitigation for Paris climate targets}},
url = {http://www.nature.com/articles/s41467-018-05340-z},
volume = {9},
year = {2018}
}
@article{doi:10.1002/joc.3711,
abstract = {ABSTRACT This paper describes the construction of an updated gridded climate dataset (referred to as CRU TS3.10) from monthly observations at meteorological stations across the world's land areas. Station anomalies (from 1961 to 1990 means) were interpolated into 0.5° latitude/longitude grid cells covering the global land surface (excluding Antarctica), and combined with an existing climatology to obtain absolute monthly values. The dataset includes six mostly independent climate variables (mean temperature, diurnal temperature range, precipitation, wet-day frequency, vapour pressure and cloud cover). Maximum and minimum temperatures have been arithmetically derived from these. Secondary variables (frost day frequency and potential evapotranspiration) have been estimated from the six primary variables using well-known formulae. Time series for hemispheric averages and 20 large sub-continental scale regions were calculated (for mean, maximum and minimum temperature and precipitation totals) and compared to a number of similar gridded products. The new dataset compares very favourably, with the major deviations mostly in regions and/or time periods with sparser observational data. CRU TS3.10 includes diagnostics associated with each interpolated value that indicates the number of stations used in the interpolation, allowing determination of the reliability of values in an objective way. This gridded product will be publicly available, including the input station series (http://www.cru.uea.ac.uk/ and http://badc.nerc.ac.uk/data/cru/). {\textcopyright} 2013 Royal Meteorological Society},
author = {Harris, I and Jones, P D and Osborn, T J and Lister, D H},
doi = {10.1002/joc.3711},
journal = {International Journal of Climatology},
keywords = {gridded climate data,high resolution,precipitation,temperature},
number = {3},
pages = {623--642},
title = {{Updated high-resolution grids of monthly climatic observations – the CRU TS3.10 Dataset}},
url = {https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/joc.3711},
volume = {34},
year = {2014}
}
@article{Harrison2016c,
abstract = {Copyright {\"{i}}¿½ 2016 The Authors. Journal of Quaternary Science Published by John Wiley  {\&}  Sons Ltd. There has been a gradual evolution in the way that palaeoclimate modelling and palaeoenvironmental data are used together to understand how the Earth System works, from an initial and largely descriptive phase through explicit hypothesis testing to diagnosis of underlying mechanisms. Analyses of past climate states are now regarded as integral to the evaluation of climate models, and have become part of the toolkit used to assess the likely realism of future projections. Palaeoclimate assessment has demonstrated that changes in large-scale features of climate that are governed by the energy and water balance show consistent responses to changes in forcing in different climate states, and these consistent responses are reproduced by climate models. However, state-of-the-art models are still largely unable to reproduce observed changes in climate at a regional scale reliably. While palaeoclimate analyses of state-of-the-art climate models suggest an urgent need for model improvement, much work is also needed on extending and improving palaeoclimate reconstructions and quantifying and reducing both numerical and interpretative uncertainties.},
author = {Harrison, S.P. and Bartlein, P.J. and Prentice, I.C.},
doi = {10.1002/jqs.2842},
journal = {Journal of Quaternary Science},
number = {4},
pages = {363--385},
title = {{What have we learnt from palaeoclimate simulations?}},
volume = {31},
year = {2016}
}
@article{Harrison1998,
abstract = {E1 Nifio-Southern Oscillation (ENSO) peri- ods, which occur irregularly every few years, are a major perturbation of the Earth's climate system that involves large-scale changes in winds, rainfall, sea surface tem- perature (SST), and surface pressure. In some areas of the world there are disastrous droughts, and in others there is serious flooding. North American weather pat- terns are also affected. It is important to develop skillful forecasts for ENSO periods. Our goal here is to provide an overview of the global ocean and atmosphere surface changes that typically occur during ENSO periods. Knowledge of these anomaly patterns is needed in order to improve our understanding and forecasts of ENSO. With a global surface data set we describe the statisti- cally significant patterns of SST, surface wind, and sur- face pressure changes that on average are associated with the 10 post-World War II ENSO periods. We present these average anomaly results as an "ENSO composite." It is useful to identify phases of the typical ENSO and examine the statistically significant elements phase by phase. An ENSO by ENSO period search indicates that about two thirds of these elements occur in 90{\%} or more of the ENSO periods: we define a "Robust ENSO Composite" from these frequently oc- curring elements and find it to be an Indo-Pacific phe- nomenon. Limitations in the surface data set make it possible that this study has not identified all the impor- tant aspects of ENSO periods; data are very sparse in both space and time over much of the tropics and the southern hemisphere. However, we suggest that any theory or model of ENSO should at least exhibit the features of this robust composite, and is unlikely to able to represent adequately the large-scale environmental impacts of ENSO unless it does so},
author = {Harrison, D. E. and Larkin, Narasimhan K.},
doi = {10.1029/98RG00715},
issn = {87551209},
journal = {Reviews of Geophysics},
number = {3},
pages = {353--399},
title = {{El Ni{\~{n}}o-Southern Oscillation sea surface temperature and wind anomalies, 1946–1993}},
volume = {36},
year = {1998}
}
@article{Harrison2015a,
abstract = {Structural differences among models account for much of the uncertainty in projected climate changes, at least until the mid-twenty-first century. Recent observations encompass too limited a range of climate variability to provide a robust test of the ability to simulate climate changes. Past climate changes provide a unique opportunity for out-of-sample evaluation of model performance. Palaeo-evaluation has shown that the large-scale changes seen in twenty-first-century projections, including enhanced land-sea temperature contrast, latitudinal amplification, changes in temperature seasonality and scaling of precipitation with temperature, are likely to be realistic. Although models generally simulate changes in large-scale circulation sufficiently well to shift regional climates in the right direction, they often do not predict the correct magnitude of these changes. Differences in performance are only weakly related to modern-day biases or climate sensitivity, and more sophisticated models are not better at simulating climate changes. Although models correctly capture the broad patterns of climate change, improvements are required to produce reliable regional projections.},
author = {Harrison, S. P. and Bartlein, P. J. and Izumi, K. and Li, G. and Annan, J. and Hargreaves, J. and Braconnot, P. and Kageyama, M.},
doi = {10.1038/nclimate2649},
issn = {17586798},
journal = {Nature Climate Change},
number = {8},
pages = {735--743},
title = {{Evaluation of CMIP5 palaeo-simulations to improve climate projections}},
volume = {5},
year = {2015}
}
@article{Harrison2014,
author = {Harrison, S. P. and Bartlein, P. J. and Brewer, S. and Prentice, I. C. and Boyd, M. and Hessler, I. and Holmgren, K. and Izumi, K. and Willis, K.},
doi = {10.1007/s00382-013-1922-6},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {aug},
number = {3-4},
pages = {671--688},
publisher = {Springer Berlin Heidelberg},
title = {{Climate model benchmarking with glacial and mid-Holocene climates}},
url = {http://link.springer.com/10.1007/s00382-013-1922-6},
volume = {43},
year = {2014}
}
@article{https://doi.org/10.1029/2020JD032701,
abstract = {Abstract The representation of the Northern Hemisphere (NH) storm tracks and jet streams and their response to climate change have been evaluated in climate model simulations from Phases 3, 5, and 6 of the Coupled Model Intercomparison Project (CMIP3, CMIP5, and CMIP6, respectively). The spatial patterns of the multimodel biases in CMIP3, CMIP5, and CMIP6 are similar; however, the magnitudes of the biases in the CMIP6 models are substantially lower. For instance, the multimodel mean RMSE of the North Atlantic storm track for the CMIP6 models (as measured by time-filtered sea-level pressure variance) is over 50{\%} smaller than that of the CMIP3 models in both winter and summer, and over 40{\%} smaller for the North Pacific. The magnitude of the jet stream biases is also reduced in CMIP6, but by a lesser extent. Despite this improved representation of the current climate, the spatial patterns of the climate change response of the NH storm tracks and jet streams remain similar in the CMIP3, CMIP5, and CMIP6 models. The SSP2-4.5 scenario responses in the CMIP6 models are substantially larger than in the RCP4.5 CMIP5 models, which is consistent with the larger climate sensitivities of the CMIP6 models compared to CMIP5.},
author = {Harvey, B J and Cook, P and Shaffrey, L C and Schiemann, R},
doi = {10.1029/2020JD032701},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {CMIP6,climate change,climate models,jet streams,storm tracks},
number = {23},
pages = {e2020JD032701},
title = {{The Response of the Northern Hemisphere Storm Tracks and Jet Streams to Climate Change in the CMIP3, CMIP5, and CMIP6 Climate Models}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020JD032701},
volume = {125},
year = {2020}
}
@article{Hasselmann1997,
abstract = {The multi-variate optimal fingerprint method for the detection of an externally forced climate change signal in the presence of natural internal variability is extended to the attribution problem. To determine whether a climate change signal which has been detected in observed climate data can be attributed to a particular climate forcing mechanism, or combination of mechanisms, the predicted space-time dependent climate change signal patterns for the candidate climate forcings must be specified. In addition to the signal patterns, the method requires input information on the space-time dependent covariance matrices of the natural climate variability and of the errors of the predicted signal patterns. The detection and attribution problem is treated as a sequence of individual consistency tests applied to all candidate forcing mechanisms, as well as to the null hypothesis that no climate change has taken place, within the phase space spanned by the predicted climate change patterns. As output the method yields a significance level for the detection of a climate change signal in the observed data and individual confidence levels for the consistency of the retrieved climate change signal with each of the forcing mechanisms. A statistically significant climate change signal is regarded as consistent with a given forcing mechanism if the statistical confidence level exceeds a given critical value, but is attributed to that forcing only if all other candidate climate change mechanisms (from a finite set of proposed mechanisms) are rejected at that confidence level. Although all relations can be readily expressed in standard matrix notation, the analysis is carried out using tensor notation, with a metric given by the natural-variability covariance matrix. This simplifies the derivations and clarifies the invariant relation between the covariant signal patterns and their contravariant fingerprint counterparts. The signal patterns define the reduced vector space in which the climate trajectories are analyzed, while the fingerprints are needed to project the climate trajectories onto this reduced space.},
author = {Hasselmann, K.},
doi = {10.1007/s003820050185},
issn = {14320894},
journal = {Climate Dynamics},
number = {9},
pages = {601--611},
publisher = {Springer Verlag},
title = {{Multi-pattern fingerprint method for detection and attribution of climate change}},
volume = {13},
year = {1997}
}
@article{Hausfathere1601207,
abstract = {Sea surface temperature (SST) records are subject to potential biases due to changing instrumentation and measurement practices. Significant differences exist between commonly used composite SST reconstructions from the National Oceanic and Atmospheric Administration{\{}$\backslash$textquoteright{\}}s Extended Reconstruction Sea Surface Temperature (ERSST), the Hadley Centre SST data set (HadSST3), and the Japanese Meteorological Agency{\{}$\backslash$textquoteright{\}}s Centennial Observation-Based Estimates of SSTs (COBE-SST) from 2003 to the present. The update from ERSST version 3b to version 4 resulted in an increase in the operational SST trend estimate during the last 19 years from 0.07{\{}$\backslash$textdegree{\}} to 0.12{\{}$\backslash$textdegree{\}}C per decade, indicating a higher rate of warming in recent years. We show that ERSST version 4 trends generally agree with largely independent, near-global, and instrumentally homogeneous SST measurements from floating buoys, Argo floats, and radiometer-based satellite measurements that have been developed and deployed during the past two decades. We find a large cooling bias in ERSST version 3b and smaller but significant cooling biases in HadSST3 and COBE-SST from 2003 to the present, with respect to most series examined. These results suggest that reported rates of SST warming in recent years have been underestimated in these three data sets.},
author = {Hausfather, Zeke and Cowtan, Kevin and Clarke, David C and Jacobs, Peter and Richardson, Mark and Rohde, Robert},
doi = {10.1126/sciadv.1601207},
issn = {2375-2548},
journal = {Science Advances},
month = {jan},
number = {1},
pages = {e1601207},
publisher = {American Association for the Advancement of Science},
title = {{Assessing recent warming using instrumentally homogeneous sea surface temperature records}},
url = {https://www.science.org/doi/10.1126/sciadv.1601207},
volume = {3},
year = {2017}
}
@article{Haustein2017,
abstract = {We propose a simple real-time index of global human-induced warming and assess its robustness to uncertainties in climate forcing and short-term climate fluctuations. This index provides improved scientific context for temperature stabilisation targets and has the potential to decrease the volatility of climate policy. We quantify uncertainties arising from temperature observations, climate radiative forcings, internal variability and the model response. Our index and the associated rate of human-induced warming is compatible with a range of other more sophisticated methods to estimate the human contribution to observed global temperature change.},
author = {Haustein, K. and Allen, M.R. and Forster, P.M. and Otto, F.E.L. and Mitchell, D.M. and Matthews, H.D. and Frame, D.J.},
doi = {10.1038/s41598-017-14828-5},
journal = {Scientific Reports},
number = {1},
pages = {15417},
title = {{A real-time Global Warming Index}},
volume = {7},
year = {2017}
}
@article{Haustein2019a,
abstract = {The early twentieth-century warming (EW; 1910–45) and the mid-twentieth-century cooling (MC; 1950–80) have been linked to both internal variability of the climate system and changes in external radiative forcing. The degree to which either of the two factors contributed to EW and MC, or both, is still debated. Using a two-box impulse response model, we demonstrate that multidecadal ocean variability was unlikely to be the driver of observed changes in global mean surface temperature (GMST) after AD 1850. Instead, virtually all (97{\%}–98{\%}) of the global low-frequency variability ({\textgreater}30 years) can be explained by external forcing. We find similarly high percentages of explained variance for interhemispheric and land–ocean temperature evolution. Three key aspects are identified that underpin the conclusion of this new study: inhomogeneous anthropogenic aerosol forcing (AER), biases in the instrumental sea surface temperature (SST) datasets, and inadequate representation of the response to varying forcing factors. Once the spatially heterogeneous nature of AER is accounted for, the MC period is reconcilable with external drivers. SST biases and imprecise forcing responses explain the putative disagreement between models and observations during the EW period. As a consequence, Atlantic multidecadal variability (AMV) is found to be primarily controlled by external forcing too. Future attribution studies should account for these important factors when discriminating between externally forced and internally generated influences on climate. We argue that AMV must not be used as a regressor and suggest a revised AMV index instead [the North Atlantic Variability Index (NAVI)]. Our associated best estimate for the transient climate response (TCR) is 1.57 K (±0.70 at the 5{\%}–95{\%} confidence level).},
author = {Haustein, Karsten and Otto, Friederike E.L. and Venema, Victor and Jacobs, Peter and Cowtan, Kevin and Hausfather, Zeke and Way, Robert G. and White, Bethan and Subramanian, Aneesh and Schurer, Andrew P.},
doi = {10.1175/JCLI-D-18-0555.1},
issn = {08948755},
journal = {Journal of Climate},
month = {aug},
number = {16},
pages = {4893--4917},
title = {{A limited role for unforced internal variability in twentieth-century warming}},
volume = {32},
year = {2019}
}
@article{Haywood2013d,
abstract = {Abstract. Climate and environments of the mid-Pliocene warm period (3.264 to 3.025 Ma) have been extensively studied. Whilst numerical models have shed light on the nature of climate at the time, uncertainties in their predictions have not been systematically examined. The Pliocene Model Intercomparison Project quantifies uncertainties in model outputs through a coordinated multi-model and multi-model/data intercomparison. Whilst commonalities in model outputs for the Pliocene are clearly evident, we show substantial variation in the sensitivity of models to the implementation of Pliocene boundary conditions. Models appear able to reproduce many regional changes in temperature reconstructed from geological proxies. However, data/model comparison highlights that models potentially underestimate polar amplification. To assert this conclusion with greater confidence, limitations in the time-averaged proxy data currently available must be addressed. Furthermore, sensitivity tests exploring the known unknowns in modelling Pliocene climate specifically relevant to the high latitudes are essential (e.g. palaeogeography, gateways, orbital forcing and trace gasses). Estimates of longer-term sensitivity to CO2 (also known as Earth System Sensitivity; ESS), support previous work suggesting that ESS is greater than Climate Sensitivity (CS), and suggest that the ratio of ESS to CS is between 1 and 2, with a "best" estimate of 1.5.},
author = {Haywood, A. M. and Hill, D. J. and Dolan, A. M. and Otto-Bliesner, B. L. and Bragg, F. and Chan, W.-L. and Chandler, M. A. and Contoux, C. and Dowsett, H. J. and Jost, A. and Kamae, Y. and Lohmann, G. and Lunt, D. J. and Abe-Ouchi, A. and Pickering, S. J. and Ramstein, G. and Rosenbloom, N. A. and Salzmann, U. and Sohl, L. and Stepanek, C. and Ueda, H. and Yan, Q. and Zhang, Z.},
doi = {10.5194/cp-9-191-2013},
isbn = {1814-9324},
issn = {1814-9332},
journal = {Climate of the Past},
month = {jan},
number = {1},
pages = {191--209},
title = {{Large-scale features of Pliocene climate: results from the Pliocene Model Intercomparison Project}},
url = {https://cp.copernicus.org/articles/9/191/2013/},
volume = {9},
year = {2013}
}
@article{cp-12-663-2016,
author = {Haywood, A M and Dowsett, H J and Dolan, A M and Rowley, D and Abe-Ouchi, A and Otto-Bliesner, B and Chandler, M A and Hunter, S J and Lunt, D J and Pound, M and Salzmann, U},
doi = {10.5194/cp-12-663-2016},
journal = {Climate of the Past},
number = {3},
pages = {663--675},
title = {{The Pliocene Model Intercomparison Project (PlioMIP) Phase 2: scientific objectives and experimental design}},
url = {https://www.clim-past.net/12/663/2016/},
volume = {12},
year = {2016}
}
@article{Haywood2014,
author = {Haywood, Jim M. and Jones, Andy and Jones, Gareth S.},
doi = {10.1002/asl2.471},
issn = {1530261X},
journal = {Atmospheric Science Letters},
month = {apr},
number = {2},
pages = {92--96},
title = {{The impact of volcanic eruptions in the period 2000–2013 on global mean temperature trends evaluated in the HadGEM2-ES climate model}},
url = {http://doi.wiley.com/10.1002/asl2.471},
volume = {15},
year = {2014}
}
@article{cp-16-2095-2020,
author = {Haywood, A M and Tindall, J C and Dowsett, H J and Dolan, A M and Foley, K M and Hunter, S J and Hill, D J and Chan, W.-L. and Abe-Ouchi, A and Stepanek, C and Lohmann, G and Chandan, D and Peltier, W R and Tan, N and Contoux, C and Ramstein, G and Li, X and Zhang, Z and Guo, C and Nisancioglu, K H and Zhang, Q and Li, Q and Kamae, Y and Chandler, M A and Sohl, L E and Otto-Bliesner, B L and Feng, R and Brady, E C and von der Heydt, A S and Baatsen, M L J and Lunt, D J},
doi = {10.5194/cp-16-2095-2020},
journal = {Climate of the Past},
number = {6},
pages = {2095--2123},
title = {{The Pliocene Model Intercomparison Project Phase 2: large-scale climate features and climate sensitivity}},
url = {https://cp.copernicus.org/articles/16/2095/2020/},
volume = {16},
year = {2020}
}
@article{Hedemann2017,
author = {Hedemann, Christopher and Mauritsen, Thorsten and Jungclaus, Johann and Marotzke, Jochem},
doi = {10.1038/nclimate3274},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {may},
number = {5},
pages = {336--339},
publisher = {Nature Publishing Group},
title = {{The subtle origins of surface-warming hiatuses}},
url = {http://www.nature.com/articles/nclimate3274},
volume = {7},
year = {2017}
}
@article{Hegerl2018c,
author = {Hegerl, Gabriele C. and Br{\"{o}}nnimann, Stefan and Schurer, Andrew and Cowan, Tim},
doi = {10.1002/wcc.522},
issn = {17577780},
journal = {WIREs Climate Change},
month = {jul},
number = {4},
pages = {e522},
title = {{The early 20th century warming: Anomalies, causes, and consequences}},
volume = {9},
year = {2018}
}
@article{Hegerl2011,
author = {Hegerl, Gabriele c. and Zwiers, Francis},
doi = {10.1002/wcc.121},
issn = {17577780},
journal = {WIREs Climate Change},
month = {jul},
number = {4},
pages = {570--591},
title = {{Use of models in detection and attribution of climate change}},
url = {http://doi.wiley.com/10.1002/wcc.121},
volume = {2},
year = {2011}
}
@article{Hegerl1996,
abstract = {A strategy using statistically optimal fingerprints to detect anthropogenic climate change is outlined and applied to near-surface temperature trends. The components of this strategy include observations, information about natural climate variability, and a "guess pattern" representing the expected time–space pattern of anthropogenic climate change. The expected anthropogenic climate change is identified through projection of the observations onto an appropriate optimal fingerprint, yielding a scalar-detection variable. The statistically optimal fingerprint is obtained by weighting the components of the guess pattern (truncated to some small-dimensional space) toward low-noise directions. The null hypothesis that the observed climate change is part of natural climate variability is then tested. This strategy is applied to detecting a greenhouse-gas-induced climate change in the spatial pattern of near-surface temperature trends defined for time intervals of 15–30 years. The expected pattern of climate change is derived from a transient simulation with a coupled ocean–atmosphere general circulation model. Global gridded near-surface temperature observations are used to represent the observed climate change. Information on the natural variability needed to establish the statistics of the detection variable is extracted from long control simulations of coupled ocean–atmosphere models and, additionally, from the observations themselves (from which an estimated greenhouse warming signal has been removed). While the model control simulations contain only variability caused by the internal dynamics of the atmosphere–ocean system, the observations additionally contain the response to various external forcings (e.g., volcanic eruptions, changes in solar radiation, and residual anthropogenic forcing). The resulting estimate of climate noise has large uncertainties but is qualitatively the best the authors can presently offer. The null hypothesis that the latest observed 20-yr and 30-yr trend of near-surface temperature (ending in 1994) is part of natural variability is rejected with a risk of less than 2.5{\%} to 5{\%} (the 5{\%} level is derived from the variability of one model control simulation dominated by a questionable extreme event). In other words, the probability that the warming is due to our estimated natural variability is less than 2.5{\%} to 5{\%}. The increase in the signal-to-noise ratio by optimization of the fingerprint is of the order of 10{\%}–30{\%} in most cases. The predicted signals are dominated by the global mean component; the pattern correlation excluding the global mean is positive but not very high. Both the evolution of the detection variable and also the pattern correlation results are consistent with the model prediction for greenhouse-gas-induced climate change. However, in order to attribute the observed warming uniquely to anthropogenic greenhouse gas forcing, more information on the climate's response to other forcing mechanisms (e.g., changes in solar radiation, volcanic, or anthropogenic sulfate aerosols) and their interaction is needed. It is concluded that a statistically significant externally induced warming has been observed, but our caveat that the estimate of the internal climate variability is still uncertain is emphasized.},
author = {Hegerl, Gabriele C. and von Storch, Hans and Hasselmann, Klaus and Santer, Benjamin D. and Cubasch, Ulrich and Jones, Philip D.},
doi = {10.1175/1520-0442(1996)009<2281:DGGICC>2.0.CO;2},
issn = {0894-8755},
journal = {Journal of Climate},
month = {oct},
number = {10},
pages = {2281--2306},
publisher = {American Meteorological Society},
title = {{Detecting Greenhouse-Gas-Induced Climate Change with an Optimal Fingerprint Method}},
url = {http://journals.ametsoc.org/doi/10.1175/1520-0442(1996)009{\%}3C2281:DGGICC{\%}3E2.0.CO;2},
volume = {9},
year = {1996}
}
@article{Hegerl2015a,
abstract = {Understanding observed changes to the global water cycle is key to predicting future climate changes and their impacts. While many datasets document crucial variables such as precipitation, ocean salinity, runoff, and humidity, most are uncertain for determining longterm changes. In situ networks provide long time series over land, but are sparse in many regions, particularly the tropics. Satellite and reanalysis datasets provide global coverage, but their longterm stability is lacking. However, comparisons of changes among related variables can give insights into the robustness of observed changes. For example, ocean salinity, interpreted with an understanding of ocean processes, can help crossvalidate precipitation. Observational evidence for human influences on the water cycle is emerging, but uncertainties resulting from internal variability and observational errors are too large to determine whether the observed and simulated changes are consistent. Improvements to the in situ and satellite observing networks that monitor the changing water cycle are required, yet continued data coverage is threatened by funding reductions. Uncertainty both in the role of anthropogenic aerosols and because of the large climate variability presently limits confidence in attribution of observed changes.},
author = {Hegerl, Gabriele C. and Black, Emily and Allan, Richard P. and Ingram, William J. and Polson, Debbie and Trenberth, Kevin E. and Chadwick, Robin S. and Arkin, Phillip A. and Sarojini, Beena Balan and Becker, Andreas and Dai, Aiguo and Durack, Paul J. and Easterling, David and Fowler, Hayley J. and Kendon, Elizabeth J. and Huffman, George J. and Liu, Chunlei and Marsh, Robert and New, Mark and Osborn, Timothy J. and Skliris, Nikolaos and Stott, Peter A. and Vidale, Pier Luigi and Wijffels, Susan E. and Wilcox, Laura J. and Willett, Kate M. and Zhang, Xuebin},
doi = {10.1175/BAMS-D-13-00212.1},
issn = {00030007},
journal = {Bulletin of the American Meteorological Society},
number = {7},
pages = {1097--1115},
title = {{Challenges in quantifying changes in the global water cycle}},
volume = {96},
year = {2015}
}
@article{Hegerl2019,
abstract = {This review addresses the causes of observed climate variations across the industrial period, from 1750 to present. It focuses on long-term changes, both in response to external forcing and to climate variability in the ocean and atmosphere. A synthesis of results from attribution studies based on palaeoclimatic reconstructions covering the recent few centuries to the 20th century, and instrumental data shows how greenhouse gases began to cause warming since the beginning of industrialization, causing trends that are attributable to greenhouse gases by 1900 in proxy-based temperature reconstructions. Their influence increased over time, dominating recent trends. However, other forcings have caused substantial deviations from this emerging greenhouse warming trend: volcanic eruptions have caused strong cooling following a period of unusually heavy activity, such as in the early 19th century; or warming during periods of low activity, such as in the early-to-mid 20th century. Anthropogenic aerosol forcing most likely masked some global greenhouse warming over the 20th century, especially since the accelerated increase in sulphate aerosol emissions starting around 1950. Based on modelling and attribution studies, aerosol forcing has also influenced regional temperatures, caused long-term changes in monsoons and imprinted on Atlantic variability. Multi-decadal variations in atmospheric modes can also cause long-term climate variability, as apparent for the example of the North Atlantic Oscillation, and have influenced Atlantic ocean variability. Long-term precipitation changes are more difficult to attribute to external forcing due to spatial sparseness of data and noisiness of precipitation changes, but the observed pattern of precipitation response to warming from station data supports climate model simulated changes and with it, predictions. The long-term warming has also led to significant differences in daily variability as, for example, visible in long European station data. Extreme events over the historical record provide valuable samples of possible extreme events and their mechanisms.},
author = {Hegerl, Gabriele C and Br{\"{o}}nnimann, Stefan and Cowan, Tim and Friedman, Andrew R and Hawkins, Ed and Iles, Carley and M{\"{u}}ller, Wolfgang and Schurer, Andrew and Undorf, Sabine},
doi = {10.1088/1748-9326/ab4557},
issn = {1748-9326},
journal = {Environmental Research Letters},
month = {dec},
number = {12},
pages = {123006},
title = {{Causes of climate change over the historical record}},
url = {http://iopscience.iop.org/10.1088/1748-9326/ab4557 https://iopscience.iop.org/article/10.1088/1748-9326/ab4557},
volume = {14},
year = {2019}
}
@article{Henley2015,
abstract = {A new index is developed for the Interdecadal Pacific Oscillation, termed the IPO Tripole Index (TPI). The IPO is associated with a distinct ‘tripole' pattern of sea surface temperature anomalies (SSTA), with three large centres of action and variations on decadal timescales, evident in the second principal component (PC) of low-pass filtered global SST. The new index is based on the difference between the SSTA averaged over the central equatorial Pacific and the average of the SSTA in the Northwest and Southwest Pacific. The TPI is an easily calculated, non-PC-based index for tracking decadal SST variability associated with the IPO. The TPI time series bears a close resemblance to previously published PC-based indices and has the advantages of being simpler to compute and more consistent with indices used to track the El Ni{\~{n}}o–Southern Oscillation (ENSO), such as Ni{\~{n}}o 3.4. The TPI also provides a simple metric in physical units of °C for evaluating decadal and interdecadal variability of SST fields in a straightforward manner, and can be used to evaluate the skill of dynamical decadal prediction systems. Composites of SST and mean sea level pressure anomalies reveal that the IPO has maintained a broadly stable structure across the seven most recent positive and negative epochs that occurred during 1870–2013. The TPI is shown to be a robust and stable representation of the IPO phenomenon in instrumental records, with relatively more variance in decadal than shorter timescales compared to Ni{\~{n}}o 3.4, due to the explicit inclusion of off-equatorial SST variability associated with the IPO.},
author = {Henley, Benjamin J. and Gergis, Joelle and Karoly, David J. and Power, Scott and Kennedy, John and Folland, Chris K.},
doi = {10.1007/s00382-015-2525-1},
isbn = {0038201525251},
issn = {14320894},
journal = {Climate Dynamics},
keywords = {IPO,Interdecadal Pacific Oscillation,PDO,PDV,Pacific Decadal Oscillation,Pacific Decadal Variability,TPI},
number = {11-12},
pages = {3077--3090},
publisher = {Springer Berlin Heidelberg},
title = {{A Tripole Index for the Interdecadal Pacific Oscillation}},
url = {http://dx.doi.org/10.1007/s00382-015-2525-1},
volume = {45},
year = {2015}
}
@article{HENLEY201742,
abstract = {Pacific decadal variability (PDV) plays a critical role in the climate system. Here I present a review of indices and patterns of decadal climate variability in the Pacific from observations and palaeoclimate reconstructions. I examine the spatial characteristics of Pacific sea surface temperature variability and the metrics used to track observations of PDV. I find commonalities between the PDV patterns, the Interdecadal Pacific Oscillation (IPO) and its North and South Pacific counterparts, the Pacific Decadal and South Pacific Decadal Oscillations (PDO and SPDO). I present a tool to provide probabilistic quantification of the recent state of the IPO, and use the tool to provide reliable estimates of IPO state up to 2years prior to the present. The tool indicates a probability of 80–90{\%} that the IPO remained in its negative state until 2014–2015. I review palaeoclimate reconstructions of the IPO and PDO, and outline advances and challenges in our pre-instrumental understanding of PDV. I draw attention to a Pacific-wide tropical-extratropical mechanism that suggests that the cool and warm phases of PDV are not driven by tropical or extratropical variability alone, but are instead the result of continuous tropical-extratropical interactions on decadal timescales. I conclude by noting key sources of remaining uncertainty and emphasising the need to better understand decadal variability. This will occur through continual improvements in observations, an expansion of palaeoclimate exploration and data collection, and renewed efforts in model development.},
author = {Henley, Benjamin J},
doi = {10.1016/j.gloplacha.2017.06.004},
issn = {0921-8181},
journal = {Global and Planetary Change},
keywords = {IPO,Interdecadal Pacific Oscillation,PDO,PDV,Pacific Decadal Oscillation,Pacific decadal variability},
pages = {42--55},
title = {{Pacific decadal climate variability: Indices, patterns and tropical-extratropical interactions}},
url = {http://www.sciencedirect.com/science/article/pii/S0921818116304398},
volume = {155},
year = {2017}
}
@article{1748-9326-12-4-044011,
abstract = {Accelerated warming and hiatus periods in the long-term rise of Global Mean Surface Temperature (GMST) have, in recent decades, been associated with the Interdecadal Pacific Oscillation (IPO). Critically, decadal climate prediction relies on the skill of state-of-the-art climate models to reliably represent these low-frequency climate variations. We undertake a systematic evaluation of the simulation of the IPO in the suite of Coupled Model Intercomparison Project 5 (CMIP5) models. We track the IPO in pre-industrial (control) and all-forcings (historical) experiments using the IPO tripole index (TPI). The TPI is explicitly aligned with the observed spatial pattern of the IPO, and circumvents assumptions about the nature of global warming. We find that many models underestimate the ratio of decadal-to-total variance in sea surface temperatures (SSTs). However, the basin-wide spatial pattern of positive and negative phases of the IPO are simulated reasonably well, with spatial pattern correlation coefficients between observations and models spanning the range 0.4–0.8. Deficiencies are mainly in the extratropical Pacific. Models that better capture the spatial pattern of the IPO also tend to more realistically simulate the ratio of decadal to total variance. Of the 13{\%} of model centuries that have a fractional bias in the decadal-to-total TPI variance of 0.2 or less, 84{\%} also have a spatial pattern correlation coefficient with the observed pattern exceeding 0.5. This result is highly consistent across both IPO positive and negative phases. This is evidence that the IPO is related to one or more inherent dynamical mechanisms of the climate system.},
author = {Henley, Benjamin J and Meehl, Gerald and Power, Scott B and Folland, Chris K and King, Andrew D and Brown, Jaclyn N and Karoly, David J and Delage, Francois and Gallant, Ailie J E and Freund, Mandy and Neukom, Raphael},
doi = {10.1088/1748-9326/aa5cc8},
journal = {Environmental Research Letters},
number = {4},
pages = {44011},
title = {{Spatial and temporal agreement in climate model simulations of the Interdecadal Pacific Oscillation}},
url = {http://stacks.iop.org/1748-9326/12/i=4/a=044011},
volume = {12},
year = {2017}
}
@article{Hernandez2020,
abstract = {The North Atlantic Oscillation (NAO) is the major atmospheric mode that controls winter European climate variability because its strength and phase determine regional temperature, precipitation and storm tracks. The NAO spatial structure and associated climatic impacts over Europe are not stationary making it crucial to understanding its past evolution in order to improve the predictability of future scenarios. In this regard, there has been a dramatic increase in the number of studies aimed at reconstructing past NAO variability, but the information related to decadal-scale NAO evolution beyond the last millennium is scarce and inconclusive. We present a new 2,000-year multi-annual, proxy-based reconstruction of local NAO impact, with associated uncertainties, obtained by a Bayesian approach. This new local NAO reconstruction is obtained from a mountain lacustrine sedimentary archive of the Iberian Peninsula. This geographical area is not included in previous NAO reconstructions despite being a widely used region for instrumental-based NAO measurements. We assess the main external forcings (i.e., volcanic eruptions and solar activity) on NAO variability which, on a decadal scale, show that a low number of sunspots correlate to low NAO values. By comparison with other previously published NAO reconstructions in our analyses we can test the stationarity of the solar influence on the NAO signal across a latitudinal gradient based on the position of the employed archives for each NAO reconstruction. Inconclusive results on the volcanic forcing on NAO variability over decadal time-scales indicates the need for further studies. Moreover, we highlight the potential role of other North Atlantic modes of variability (i.e., East Atlantic pattern) on the non-stationary behaviour of the NAO throughout the Common Era, likely via solar forcing.},
author = {Hern{\'{a}}ndez, Armand and S{\'{a}}nchez-L{\'{o}}pez, Guiomar and Pla-Rabes, Sergi and Comas-Bru, Laia and Parnell, Andrew and Cahill, Niamh and Geyer, Adelina and Trigo, Ricardo M. and Giralt, Santiago},
doi = {10.1038/s41598-020-71372-5},
issn = {2045-2322},
journal = {Scientific Reports},
month = {dec},
number = {1},
pages = {14961},
title = {{A 2,000-year Bayesian NAO reconstruction from the Iberian Peninsula}},
url = {http://www.nature.com/articles/s41598-020-71372-5},
volume = {10},
year = {2020}
}
@article{Herold2016,
author = {Herold, N. and Alexander, L. V. and Donat, Markus G. and Contractor, Steefan and Becker, A},
doi = {10.1002/2015GL066615},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {jan},
number = {1},
pages = {341--348},
title = {{How much does it rain over land?}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2015GL066615},
volume = {43},
year = {2016}
}
@article{os-2020-66,
abstract = {Abstract. Deep and bottom water formation are crucial components of the global ocean circulation, yet they were poorly represented in the previous generation of climate models. We here quantify biases in Antarctic Bottom Water (AABW) and North Atlantic Deep Water (NADW) formation, properties, transport, and global extent in 35 climate models that participated in the latest Climate Model Intercomparison Project (CMIP6). Several CMIP6 models are correctly forming AABW via shelf processes, but 28 models in the Southern Ocean and all 35 models in the North Atlantic form deep and bottom water via open-ocean deep convection too deeply, too often, and/or over too large an area. Models that convect the least form the most accurate AABW but the least accurate NADW. The four CESM2 models with their overflow parameterisation are among the most accurate models. In the Atlantic, the colder the AABW, the stronger the abyssal overturning at 30∘ S, and the further north the AABW layer extends. The saltier the NADW, the stronger the Atlantic Meridional Overturning Circulation (AMOC), and the further south the NADW layer extends. In the Indian and Pacific oceans in contrast, the fresher models are the ones which extend the furthest regardless of the strength of their abyssal overturning, most likely because they are also the models with the weakest fronts in the Antarctic Circumpolar Current. There are clear improvements since CMIP5: several CMIP6 models correctly represent or parameterise Antarctic shelf processes, fewer models exhibit Southern Ocean deep convection, more models convect at the right location in the Labrador Sea, bottom density biases are reduced, and abyssal overturning is more realistic. However, more improvements are required, e.g. by generalising the use of overflow parameterisations or by coupling to interactive ice sheet models, before deep and bottom water formation, and hence heat and carbon storage, are represented accurately.},
author = {Heuz{\'{e}}, C{\'{e}}line},
doi = {10.5194/os-17-59-2021},
issn = {1812-0792},
journal = {Ocean Science},
month = {jan},
number = {1},
pages = {59--90},
title = {{Antarctic Bottom Water and North Atlantic Deep Water in CMIP6 models}},
url = {https://os.copernicus.org/preprints/os-2020-66/ https://os.copernicus.org/articles/17/59/2021/},
volume = {17},
year = {2021}
}
@article{Heuze2013,
abstract = {Southern Ocean deep water properties and formation processes in climate models are indicative of their capability to simulate future climate, heat and carbon uptake, and sea level rise. Southern Ocean temperature and density averaged over 1986?2005 from 15 CMIP5 (Coupled Model Intercomparison Project Phase 5) climate models are compared with an observed climatology, focusing on bottom water. Bottom properties are reasonably accurate for half the models. Ten models create dense water on the Antarctic shelf, but it mixes with lighter water and is not exported as bottom water as in reality. Instead, most models create deep water by open ocean deep convection, a process occurring rarely in reality. Models with extensive deep convection are those with strong seasonality in sea ice. Optimum bottom properties occur in models with deep convection in the Weddell and Ross Gyres. Bottom Water formation processes are poorly represented in ocean models and are a key challenge for improving climate predictions.},
author = {Heuz{\'{e}}, C{\'{e}}line and Heywood, Karen J and Stevens, David P and Ridley, Jeff K},
doi = {10.1002/grl.50287},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {mar},
number = {7},
pages = {1409--1414},
publisher = {Wiley-Blackwell},
title = {{Southern Ocean bottom water characteristics in CMIP5 models}},
volume = {40},
year = {2013}
}
@article{Heuze2015a,
abstract = {AbstractChanges in bottom temperature, salinity, and density in the global ocean by 2100 for CMIP5 climate models are investigated for the climate change scenarios RCP4.5 and RCP8.5. The mean of 24 models shows a decrease in density in all deep basins, except the North Atlantic, which becomes denser. The individual model responses to climate change forcing are more complex: regarding temperature, the 24 models predict a warming of the bottom layer of the global ocean; in salinity, there is less agreement regarding the sign of the change, especially in the Southern Ocean. The magnitude and equatorward extent of these changes also vary strongly among models. The changes in properties can be linked with changes in the mean transport of key water masses. The Atlantic meridional overturning circulation weakens in most models and is directly linked to changes in bottom density in the North Atlantic. These changes are the result of the intrusion of modified Antarctic Bottom Water, made possible by the decrease in North Atlantic Deep Water formation. In the Indian, Pacific, and South Atlantic Oceans, changes in bottom density are congruent with the weakening in Antarctic Bottom Water transport through these basins. The authors argue that the greater the 1986?2005 meridional transports, the more changes have propagated equatorward by 2100. However, strong decreases in density over 100 yr of climate change cause a weakening of the transports. The speed at which these property changes reach the deep basins is critical for a correct assessment of the heat storage capacity of the oceans as well as for predictions of future sea level rise.},
author = {Heuz{\'{e}}, C{\'{e}}line and Heywood, Karen J and Stevens, David P and Ridley, Jeff K},
doi = {10.1175/JCLI-D-14-00381.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {nov},
number = {8},
pages = {2917--2944},
publisher = {American Meteorological Society},
title = {{Changes in Global Ocean Bottom Properties and Volume Transports in CMIP5 Models under Climate Change Scenarios}},
volume = {28},
year = {2015}
}
@misc{Hewitt2017a,
abstract = {As the importance of the ocean in the weather and climate system is increasingly recognised, operational systems are now moving towards coupled prediction not only for seasonal to climate timescales but also for short-range forecasts. A three-way tension exists between the allocation of computing resources to refine model resolution, the expansion of model complexity/capability, and the increase of ensemble size. Here we review evidence for the benefits of increased ocean resolution in global coupled models, where the ocean component explicitly represents transient mesoscale eddies and narrow boundary currents. We consider lessons learned from forced ocean/sea-ice simulations; from studies concerning the SST resolution required to impact atmospheric simulations; and from coupled predictions. Impacts of the mesoscale ocean in western boundary current regions on the large-scale atmospheric state have been identified. Understanding of air-sea feedback in western boundary currents is modifying our view of the dynamics in these key regions. It remains unclear whether variability associated with open ocean mesoscale eddies is equally important to the large-scale atmospheric state. We include a discussion of what processes can presently be parameterised in coupled models with coarse resolution non-eddying ocean models, and where parameterizations may fall short. We discuss the benefits of resolution and identify gaps in the current literature that leave important questions unanswered.},
author = {Hewitt, Helene T. and Bell, Michael J. and Chassignet, Eric P. and Czaja, Arnaud and Ferreira, David and Griffies, Stephen M. and Hyder, Pat and McClean, Julie L. and New, Adrian L. and Roberts, Malcolm J.},
booktitle = {Ocean Modelling},
doi = {10.1016/j.ocemod.2017.11.002},
issn = {14635003},
keywords = {Atmosphere,Coupled,Ocean,Parameterisation,Resolution},
month = {dec},
pages = {120--136},
publisher = {Elsevier Ltd},
title = {{Will high-resolution global ocean models benefit coupled predictions on short-range to climate timescales?}},
volume = {120},
year = {2017}
}
@article{Hewitt2016,
abstract = {{\textless}p{\textgreater}Abstract. There is mounting evidence that resolving mesoscale eddies and western boundary currents as well as topographically controlled flows can play an important role in air–sea interaction associated with vertical and lateral transports of heat and salt. Here we describe the development of the Met Office Global Coupled Model version 2 (GC2) with increased resolution relative to the standard model: the ocean resolution is increased from 1/4 to 1/12° (28 to 9 km at the Equator), the atmosphere resolution increased from 60 km (N216) to 25 km (N512) and the coupling period reduced from 3 hourly to hourly. The technical developments that were required to build a version of the model at higher resolution are described as well as results from a 20-year simulation. The results demonstrate the key role played by the enhanced resolution of the ocean model: reduced sea surface temperature (SST) biases, improved ocean heat transports, deeper and stronger overturning circulation and a stronger Antarctic Circumpolar Current. Our results suggest that the improvements seen here require high resolution in both atmosphere and ocean components as well as high-frequency coupling. These results add to the body of evidence suggesting that ocean resolution is an important consideration when developing coupled models for weather and climate applications.{\textless}/p{\textgreater}},
author = {Hewitt, Helene T. and Roberts, Malcolm J. and Hyder, Pat and Graham, Tim and Rae, Jamie and Belcher, Stephen E. and Bourdall{\'{e}}-Badie, Romain and Copsey, Dan and Coward, Andrew and Guiavarch, Catherine and Harris, Chris and Hill, Richard and Hirschi, Jo{\"{e}}l J.-M. and Madec, Gurvan and Mizielinski, Matthew S. and Neininger, Erica and New, Adrian L. and Rioual, Jean-Christophe and Sinha, Bablu and Storkey, David and Shelly, Ann and Thorpe, Livia and Wood, Richard A.},
doi = {10.5194/gmd-9-3655-2016},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {oct},
number = {10},
pages = {3655--3670},
title = {{The impact of resolving the Rossby radius at mid-latitudes in the ocean: results from a high-resolution version of the Met Office GC2 coupled model}},
url = {https://www.geosci-model-dev.net/9/3655/2016/},
volume = {9},
year = {2016}
}
@article{Hewitt2020,
abstract = {Assessment of the impact of ocean resolution in Earth System models on the mean state, variability, and future projections and discussion of prospects for improved parameterisations to represent the ocean mesoscale. The majority of centres participating in CMIP6 employ ocean components with resolutions of about 1 degree in their full Earth System models (eddy-parameterising models). In contrast, there are also models submitted to CMIP6 (both DECK and HighResMIP) that employ ocean components of approximately 1/4 degree and 1/10 degree (eddy-present and eddy-rich models). Evidence to date suggests that whether the ocean mesoscale is explicitly represented or parameterised affects not only the mean state of the ocean but also the climate variability and the future climate response, particularly in terms of the Atlantic meridional overturning circulation (AMOC) and the Southern Ocean. Recent developments in scale-aware parameterisations of the mesoscale are being developed and will be included in future Earth System models. Although the choice of ocean resolution in Earth System models will always be limited by computational considerations, for the foreseeable future, this choice is likely to affect projections of climate variability and change as well as other aspects of the Earth System. Future Earth System models will be able to choose increased ocean resolution and/or improved parameterisation of processes to capture physical processes with greater fidelity.},
author = {Hewitt, Helene T. and Roberts, Malcolm and Mathiot, Pierre and Biastoch, Arne and Blockley, Ed and Chassignet, Eric P. and Fox-Kemper, Baylor and Hyder, Pat and Marshall, David P. and Popova, Ekaterina and Treguier, Anne-Marie and Zanna, Laure and Yool, Andrew and Yu, Yongqiang and Beadling, Rebecca and Bell, Mike and Kuhlbrodt, Till and Arsouze, Thomas and Bellucci, Alessio and Castruccio, Fred and Gan, Bolan and Putrasahan, Dian and Roberts, Christopher D. and {Van Roekel}, Luke and Zhang, Qiuying},
doi = {10.1007/s40641-020-00164-w},
issn = {2198-6061},
journal = {Current Climate Change Reports},
keywords = {Atmospheric Sciences,Climate Change,Climate Change Management and Policy,Climatology,Oceanography},
month = {dec},
number = {4},
pages = {137--152},
publisher = {Springer},
title = {{Resolving and Parameterising the Ocean Mesoscale in Earth System Models}},
url = {http://link.springer.com/10.1007/s40641-020-00164-w https://link.springer.com/10.1007/s40641-020-00164-w},
volume = {6},
year = {2020}
}
@article{Hirabayashi2016,
abstract = {Observational evidence indicates that a number of glaciers have lost mass in the past. Given that glaciers are highly impacted by the surrounding climate, human-influenced global warming may be partly responsible for mass loss. However, previous research studies have been limited to analyzing the past several decades, and it remains unclear whether past glacier mass losses are within the range of natural internal climate variability. Here, we apply an optimal fingerprinting technique to observed and reconstructed mass losses as well as multi-model general circulation model (GCM) simulations of mountain glacier mass to detect and attribute past glacier mass changes. An 8,800-year control simulation of glaciers enabled us to evaluate detectability. The results indicate that human-induced increases in greenhouse gases have contributed to the decreased area-weighted average masses of 85 analyzed glaciers. The effect was larger than the mass increase caused by natural forcing, although the contributions of natural and anthropogenic forcing to decreases in mass varied at the local scale. We also showed that the detection of anthropogenic or natural influences could not be fully attributed when natural internal climate variability was taken into account.},
author = {Hirabayashi, Yukiko and Nakano, Kazunari and Zhang, Yong and Watanabe, Satoshi and Tanoue, Masahiro and Kanae, Shinjiro},
doi = {10.1038/srep29723},
issn = {20452322},
journal = {Scientific Reports},
keywords = {Cryospheric science,Hydrology},
month = {sep},
number = {1},
pages = {29723},
publisher = {Nature Publishing Group},
title = {{Contributions of natural and anthropogenic radiative forcing to mass loss of Northern Hemisphere mountain glaciers and quantifying their uncertainties}},
url = {http://www.nature.com/articles/srep29723},
volume = {6},
year = {2016}
}
@article{Hirons2018,
abstract = {The role of the Indian Ocean dipole (IOD) in controlling interannual variability in the East African short rains, from October to December, is examined in state-of-the-art models and in detail in one particular climate model. In observations, a wet short-rainy season is associated with the positive phase of the IOD and anomalous easterly low-level flow across the equatorial Indian Ocean. A model's ability to capture the teleconnection to the positive IOD is closely related to its representation of the mean state. During the short-rains season, the observed low-level wind in the equatorial Indian Ocean is westerly. However, half of the models analyzed exhibit mean-state easterlies across the entire basin. Specifically, those models that exhibit mean-state low-level equatorial easterlies in the Indian Ocean, rather than the observed westerlies, are unable to capture the latitudinal structure of moisture advection into East Africa during a positive IOD. Furthermore, the associated anomalous easterly surface wind stress causes upwelling in the eastern Indian Ocean. This upwelling draws up cool subsurface waters, enhancing the zonal sea surface temperature gradient between west and east and strengthening the positive IOD pattern, further amplifying the easterly wind stress. This positive Bjerknes coupled feedback is stronger in easterly mean-state models, resulting in a wetter East African short-rain precipitation bias in those models.},
author = {Hirons, Linda and Turner, Andrew},
doi = {10.1175/JCLI-D-17-0804.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {aug},
number = {16},
pages = {6611--6631},
title = {{The Impact of Indian Ocean Mean-State Biases in Climate Models on the Representation of the East African Short Rains}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-17-0804.1},
volume = {31},
year = {2018}
}
@article{HOBBS2016228,
abstract = {Over the past 37years, satellite records show an increase in Antarctic sea ice cover that is most pronounced in the period of sea ice growth. This trend is dominated by increased sea ice coverage in the western Ross Sea, and is mitigated by a strong decrease in the Bellingshausen and Amundsen seas. The trends in sea ice areal coverage are accompanied by related trends in yearly duration. These changes have implications for ecosystems, as well as global and regional climate. In this review, we summarise the research to date on observing these trends, identifying their drivers, and assessing the role of anthropogenic climate change. Whilst the atmosphere is thought to be the primary driver, the ocean is also essential in explaining the seasonality of the trend patterns. Detecting an anthropogenic signal in Antarctic sea ice is particularly challenging for a number of reasons: the expected response is small compared to the very high natural variability of the system; the observational record is relatively short; and the ability of global coupled climate models to faithfully represent the complex Antarctic climate system is in doubt.},
author = {Hobbs, William R and Massom, Rob and Stammerjohn, Sharon and Reid, Phillip and Williams, Guy and Meier, Walter},
doi = {10.1016/j.gloplacha.2016.06.008},
issn = {0921-8181},
journal = {Global and Planetary Change},
pages = {228--250},
title = {{A review of recent changes in Southern Ocean sea ice, their drivers and forcings}},
url = {http://www.sciencedirect.com/science/article/pii/S0921818116300364},
volume = {143},
year = {2016}
}
@article{doi:10.1175/JCLI-D-14-00367.1,
abstract = { AbstractUsing optimal fingerprinting techniques, a detection analysis is performed to determine whether observed trends in Southern Ocean sea ice extent since 1979 are outside the expected range of natural variability. Consistent with previous studies, it is found that for the seasons of maximum sea ice cover (i.e., winter and early spring), the observed trends are not outside the range of natural variability and in some West Antarctic sectors they may be partially due to tropical variability. However, when information about the spatial pattern of trends is included in the analysis, the summer and autumn trends fall outside the range of internal variability. The detectable signal is dominated by strong and opposing trends in the Ross Sea and the Amundsen–Bellingshausen Sea regions. In contrast to the observed pattern, an ensemble of 20 CMIP5 coupled climate models shows that a decrease in Ross Sea ice cover would be expected in response to external forcings. The simulated decreases in the Ross, Bellingshausen, and Amundsen Seas for the autumn season are significantly different from unforced internal variability at the 95{\%} confidence level. Unlike earlier work, the authors formally show that the simulated sea ice response to external forcing is different from both the observed trends and simulated internal variability and conclude that in general the CMIP5 models do not adequately represent the forced response of the Antarctic climate system. },
author = {Hobbs, William Richard and Bindoff, Nathaniel L and Raphael, Marilyn N},
doi = {10.1175/JCLI-D-14-00367.1},
journal = {Journal of Climate},
number = {4},
pages = {1543--1560},
title = {{New Perspectives on Observed and Simulated Antarctic Sea Ice Extent Trends Using Optimal Fingerprinting Techniques}},
url = {https://doi.org/10.1175/JCLI-D-14-00367.1},
volume = {28},
year = {2015}
}
@article{Hobbs2021,
abstract = {In this study, we compare observed Southern Ocean temperature and salinity changes with the historical simulations from 13 models from phase 5 of the Coupled Model Intercomparison Project (CMIP5), using an optimal fingerprinting framework. We show that there is an unequivocal greenhouse gas-forced warming in the Southern Ocean. This warming is strongest in the Subantarctic Mode Waters but is also detectable in denser water masses, which has not been shown in previous studies. We also find greenhouse gas-forced salinity changes, most notably a freshening of Antarctic Intermediate Waters. Our analysis also shows that non-greenhouse gas anthropogenic forcings-anthropogenic aerosols and stratospheric ozone depletion-have played an important role in mitigating the Southern Ocean's warming. However, the detectability of these responses using optimal fingerprinting is model dependent, and this result is therefore not as robust as for the greenhouse gas response.},
address = {Boston MA, USA},
author = {Hobbs, William R. and Roach, Christopher and Roy, Tilla and Sall{\'{e}}e, Jean Baptiste and Bindoff, Nathaniel},
doi = {10.1175/JCLI-D-20-0454.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Climate change,Coupled models,Model comparison,Ocean,Southern Ocean},
language = {English},
number = {1},
pages = {215--228},
publisher = {American Meteorological Society},
title = {{Anthropogenic temperature and salinity changes in the Southern ocean}},
url = {https://journals.ametsoc.org/view/journals/clim/34/1/jcliD200454.xml},
volume = {34},
year = {2021}
}
@incollection{Hock2019,
author = {Hock, R. and Rasul, G. and Adler, C. and C{\'{a}}ceres, B. and Gruber, S. and Hirabayashi, Y. and Jackson, M. and K{\"{a}}{\"{a}}b, A. and Kang, S. and Kutuzov, S. and Milner, Al. and Molau, U. and Morin, S. and Orlove, B. and Steltzer, H.},
booktitle = {IPCC Special Report on the Ocean and Cryosphere in a Changing Climate},
chapter = {2},
doi = {https://www.ipcc.ch/srocc/chapter/chapter-2},
editor = {Pörtner, H.-O. and Roberts, D.C. and Masson-Delmotte, V. and Zhai, P. and Tignor, M. and Poloczanska, E. and Mintenbeck, K. and Alegría, A. and Nicolai, M. and Okem, A. and Petzold, J. and Rama, B. and Weyer, N.M.},
pages = {131--202},
publisher = {In Press},
title = {{High Mountain Areas}},
url = {https://www.ipcc.ch/srocc/chapter/chapter-2},
year = {2019}
}
@article{Hock2019a,
abstract = {Global-scale 21st-century glacier mass change projections from six published global glacier models are systematically compared as part of the Glacier Model Intercomparison Project. In total 214 projections of annual glacier mass and area forced by 25 General Circulation Models (GCMs) and four Representative Concentration Pathways (RCP) emission scenarios and aggregated into 19 glacier regions are considered. Global mass loss of all glaciers (outside the Antarctic and Greenland ice sheets) by 2100 relative to 2015 averaged over all model runs varies from 18 ± 7{\%} (RCP2.6) to 36 ± 11{\%} (RCP8.5) corresponding to 94 ± 25 and 200 ± 44 mm sea-level equivalent (SLE), respectively. Regional relative mass changes by 2100 correlate linearly with relative area changes. For RCP8.5 three models project global rates of mass loss (multi-GCM means) of {\textgreater}3 mm SLE per year towards the end of the century. Projections vary considerably between regions, and also among the glacier models. Global glacier mass changes per degree global air temperature rise tend to increase with more pronounced warming indicating that mass-balance sensitivities to temperature change are not constant. Differences in glacier mass projections among the models are attributed to differences in model physics, calibration and downscaling procedures, initial ice volumes and varying ensembles of forcing GCMs.},
author = {Hock, Regine and Marzeion, Ben E.N. and Bliss, Andrew and Giesen, Rianne H. and Hirabayashi, Yukiko and Huss, Matthias and Radic, Valentina and Slangen, Aim{\'{e}}e Aime{\'{e}} B.A. and Marzeion, Ben E.N. and Giesen, Rianne H. and Hirabayashi, Yukiko and Huss, Matthias and Radic, Valentina and Slangen, Aim{\'{e}}e Aime{\'{e}} B.A.},
doi = {10.1017/jog.2019.22},
issn = {00221430},
journal = {Journal of Glaciology},
keywords = {glacier mass balance,glacier modeling,ice and climate,mountain glaciers},
month = {jun},
number = {251},
pages = {453--467},
publisher = {Cambridge University Press},
title = {{GlacierMIP – A model intercomparison of global-scale glacier mass-balance models and projections}},
volume = {65},
year = {2019}
}
@article{Hoell2017,
author = {Hoell, Andrew and Hoerling, Martin and Eischeid, Jon and Quan, Xiao-Wei and Liebmann, Brant},
doi = {10.1175/JCLI-D-16-0558.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {mar},
number = {6},
pages = {1939--1957},
title = {{Reconciling Theories for Human and Natural Attribution of Recent East Africa Drying}},
volume = {30},
year = {2017}
}
@article{doi:10.1002/2013JG002381,
abstract = {The strength of feedbacks between a changing climate and future CO2 concentrations is uncertain and difficult to predict using Earth System Models (ESMs). We analyzed emission-driven simulations—in which atmospheric CO2levels were computed prognostically—for historical (1850–2005) and future periods (Representative Concentration Pathway (RCP) 8.5 for 2006–2100) produced by 15 ESMs for the Fifth Phase of the Coupled Model Intercomparison Project (CMIP5). Comparison of ESM prognostic atmospheric CO2 over the historical period with observations indicated that ESMs, on average, had a small positive bias in predictions of contemporary atmospheric CO2. Weak ocean carbon uptake in many ESMs contributed to this bias, based on comparisons with observations of ocean and atmospheric anthropogenic carbon inventories. We found a significant linear relationship between contemporary atmospheric CO2 biases and future CO2levels for the multimodel ensemble. We used this relationship to create a contemporary CO2 tuned model (CCTM) estimate of the atmospheric CO2 trajectory for the 21st century. The CCTM yielded CO2estimates of 600±14 ppm at 2060 and 947±35 ppm at 2100, which were 21 ppm and 32 ppm below the multimodel mean during these two time periods. Using this emergent constraint approach, the likely ranges of future atmospheric CO2, CO2-induced radiative forcing, and CO2-induced temperature increases for the RCP 8.5 scenario were considerably narrowed compared to estimates from the full ESM ensemble. Our analysis provided evidence that much of the model-to-model variation in projected CO2 during the 21st century was tied to biases that existed during the observational era and that model differences in the representation of concentration-carbon feedbacks and other slowly changing carbon cycle processes appear to be the primary driver of this variability. By improving models to more closely match the long-term time series of CO2from Mauna Loa, our analysis suggests that uncertainties in future climate projections can be reduced.},
author = {Hoffman, F M and Randerson, J T and Arora, V K and Bao, Q and Cadule, P and Ji, D and Jones, C D and Kawamiya, M and Khatiwala, S and Lindsay, K and Obata, A and Shevliakova, E and Six, K D and Tjiputra, J F and Volodin, E M and Wu, T},
doi = {10.1002/2013JG002381},
journal = {Journal of Geophysical Research: Biogeosciences},
keywords = {Intergovernmental Panel on Climate Change (IPCC),climate warming,climate–carbon cycle feedbacks,greenhouse gases,terrestrial and oceanic carbon sinks,uncertainty quantification},
number = {2},
pages = {141--162},
title = {{Causes and implications of persistent atmospheric carbon dioxide biases in Earth System Models}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2013JG002381},
volume = {119},
year = {2014}
}
@article{Hoffman2019a,
abstract = {Modeling and observations suggest that Thwaites Glacier, West Antarctica, has begun unstable retreat. Concurrently, oceanographic observations have revealed substantial multiyear variability in the temperature of the ocean water driving retreat through melting of the ice shelf that restrains inland glacier flow. Using an ensemble of 72 ice-sheet model simulations that include an idealized representation of ocean temperature variability, we find that variable ice-shelf melting causes delays in grounding line retreat, mass loss, and sea level contribution relative to steady forcing. Modeled delays are up to 43 years after 500 years of simulation, corresponding to a 10{\%} reduction in glacier mass loss. Delays are primarily caused by asymmetric melt forcing in the presence of variability. For the “warm cavity” conditions beneath Thwaites Ice Shelf, increases in access of warm, deeper water are unable to raise water temperatures in the cavity by much, whereas increases in access of significantly colder, shallow water reduce cavity water temperatures substantially. This leads to lowered mean melt rates under variable ocean temperature forcing. Additionally, about one quarter of the mass loss delay is caused by a nonlinear ice dynamic response to varying ice-shelf thinning rate, which is amplified during the initial phases of unstable, bed-topography-driven retreat. Mass loss rates under variability differ by up to 50{\%} from ensemble mean values at any given time. Our results underscore the need for taking climate variability into account when modeling ice sheet evolution and for continued efforts toward the coupling of ice sheet models to ocean and climate models.},
author = {Hoffman, Matthew J. and Asay‐Davis, Xylar and Price, Stephen F. and Fyke, Jeremy and Perego, Mauro},
doi = {10.1029/2019JF005155},
issn = {2169-9003},
journal = {Journal of Geophysical Research: Earth Surface},
month = {dec},
number = {12},
pages = {2798--2822},
title = {{Effect of Subshelf Melt Variability on Sea Level Rise Contribution From Thwaites Glacier, Antarctica}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JF005155},
volume = {124},
year = {2019}
}
@article{Holland2017,
abstract = {We assess the sea ice response to Southern Annular Mode (SAM) anomalies for pre-industrial control simulations from the Coupled Model Intercomparison Project (CMIP5). Consistent with work by Ferreira et al. (J Clim 28:1206--1226, 2015. doi:10.1175/JCLI-D-14-00313.1), the models generally simulate a two-timescale response to positive SAM anomalies, with an initial increase in ice followed by an eventual sea ice decline. However, the models differ in the cross-over time at which the change in ice response occurs, in the overall magnitude of the response, and in the spatial distribution of the response. Late twentieth century Antarctic sea ice trends in CMIP5 simulations are related in part to different modeled responses to SAM variability acting on different time-varying transient SAM conditions. This explains a significant fraction of the spread in simulated late twentieth century southern hemisphere sea ice extent trends across the model simulations. Applying the modeled sea ice response to SAM variability but driven by the observed record of SAM suggests that variations in the austral summer SAM, which has exhibited a significant positive trend, have driven a modest sea ice decrease. However, additional work is needed to narrow the considerable model uncertainty in the climate response to SAM variability and its implications for 20th--21st century trends.},
author = {Holland, Marika M and Landrum, Laura and Kostov, Yavor and Marshall, John},
doi = {10.1007/s00382-016-3424-9},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {5},
pages = {1813--1831},
title = {{Sensitivity of Antarctic sea ice to the Southern Annular Mode in coupled climate models}},
url = {https://doi.org/10.1007/s00382-016-3424-9},
volume = {49},
year = {2017}
}
@article{Holland2019a,
abstract = {Recent ice loss from the West Antarctic Ice Sheet has been caused by ocean melting of ice shelves in the Amundsen Sea. Eastward wind anomalies at the shelf break enhance the import of warm Circumpolar Deep Water onto the Amundsen Sea continental shelf, which creates transient melting anomalies with an approximately decadal period. No anthropogenic influence on this process has been established. Here, we combine observations and climate model simulations to suggest that increased greenhouse gas forcing caused shelf-break winds to transition from mean easterlies in the 1920s to the near-zero mean zonal winds of the present day. Strong internal climate variability, primarily linked to the tropical Pacific, is superimposed on this forced trend. We infer that the Amundsen Sea experienced decadal ocean variability throughout the twentieth century, with warm anomalies gradually becoming more prevalent, offering a credible explanation for the ongoing ice loss. Existing climate model projections show that strong future greenhouse gas forcing creates persistent mean westerly shelf-break winds by 2100, suggesting a further enhancement of warm ocean anomalies. These wind changes are weaker under a scenario in which greenhouse gas concentrations are stabilized.},
author = {Holland, Paul R. and Bracegirdle, Thomas J. and Dutrieux, Pierre and Jenkins, Adrian and Steig, Eric J.},
doi = {10.1038/s41561-019-0420-9},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {sep},
number = {9},
pages = {718--724},
title = {{West Antarctic ice loss influenced by internal climate variability and anthropogenic forcing}},
url = {http://www.nature.com/articles/s41561-019-0420-9},
volume = {12},
year = {2019}
}
@article{gmd-12-3149-2019,
author = {Hollis, C J and {Dunkley Jones}, T and Anagnostou, E and Bijl, P K and Cramwinckel, M J and Cui, Y and Dickens, G R and Edgar, K M and Eley, Y and Evans, D and Foster, G L and Frieling, J and Inglis, G N and Kennedy, E M and Kozdon, R and Lauretano, V and Lear, C H and Littler, K and Lourens, L and Meckler, A N and Naafs, B D A and P{\"{a}}like, H and Pancost, R D and Pearson, P N and R{\"{o}}hl, U and Royer, D L and Salzmann, U and Schubert, B A and Seebeck, H and Sluijs, A and Speijer, R P and Stassen, P and Tierney, J and Tripati, A and Wade, B and Westerhold, T and Witkowski, C and Zachos, J C and Zhang, Y G and Huber, M and Lunt, D J},
doi = {10.5194/gmd-12-3149-2019},
journal = {Geoscientific Model Development},
number = {7},
pages = {3149--3206},
title = {{The DeepMIP contribution to PMIP4: methodologies for selection, compilation and analysis of latest Paleocene and early Eocene climate proxy data, incorporating version 0.1 of the DeepMIP database}},
url = {https://www.geosci-model-dev.net/12/3149/2019/},
volume = {12},
year = {2019}
}
@article{Hopcroft2017,
abstract = {During the Quaternary, the Sahara desert was periodically colonized by vegetation, likely because of orbitally induced rainfall increases. However, the estimated hydrological change is not reproduced in climate model simulations, undermining confidence in projections of future rainfall. We evaluated the relationship between the qualitative information on past vegetation coverage and climate for the mid-Holocene using three different dynamic vegetation models. Compared with two available vegetation reconstructions, the models require 500–800 mm of rainfall over 20°–25°N, which is significantly larger than inferred from pollen but largely in agreement with more recent leaf wax biomarker reconstructions. The magnitude of the response also suggests that required rainfall regime of the early to middle Holocene is far from being correctly represented in general circulation models. However, intermodel differences related to moisture stress parameterizations, biases in simulated present-day vegetation, and uncertainties about paleosoil distributions introduce uncertainties, and these are also relevant to Earth system model simulations of African humid periods. {\textcopyright}2017. The Authors.},
author = {Hopcroft, Peter O. and Valdes, Paul J. and Harper, Anna B. and Beerling, David J.},
doi = {10.1002/2017GL073740},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {jul},
number = {13},
pages = {6804--6813},
title = {{Multi vegetation model evaluation of the Green Sahara climate regime}},
url = {http://doi.wiley.com/10.1002/2017GL073740},
volume = {44},
year = {2017}
}
@article{Hope2017,
abstract = {The characteristics of El Nino–Southern Oscillation (ENSO) spectra over the Last Millennium are examined to characterise variability over past centuries. Seven published palaeo-ENSO reconstructions and Nino3.4 from six Coupled Model Intercomparison Project-Phase 5 and Paleoclimate Modelling Intercomparison Project-Phase 3 (CMIP5–PMIP3) Last Millennium simulations were analysed. The corresponding Historical and pre-industrial Control CMIP5–PMIP3 simulations were also considered. The post-1850 spectrum of each modelled or reconstructed ENSO series captures aspects of the observed spectrum to varying degrees. We note that no single model or ENSO reconstruction completely reproduces the instrumental spectral characteristics. The spectral power across the 2–3 years (near biennial), 3–8 years (classical ENSO) and 8–25 years (decadal) periodicity bands was calculated in a sliding 50 year window, revealing temporal variability in the spectra. There was strong temporal variability in the spectral power of each periodicity band in observed Nino3.4 and SOI and for all reconstructions and simulations of ENSO. Significant peaks in spectral power such as observed in recent decades also occur in some of the reconstructed palaeo-ENSO (around 1600, the early 1700s and 1900) and modelled series (around the major volcanic eruptions of 1258 and 1452). While the recent increase in spectral power might be in response to enhanced greenhouse gas levels, the increase lies within the range of variability across the suite of ENSO reconstructions and simulations examined here. This study demonstrates that the analysis of a suite of ENSO reconstructions and model simulations can build a broader understanding of the time-varying nature of ENSO spectra, and how the nature of the past spectra of ENSO is to some extent dependant on the climate model or palaeo-ENSO reconstruction chosen.},
author = {Hope, Pandora and Henley, Benjamin J. and Gergis, Joelle and Brown, Josephine and Ye, Hua},
doi = {10.1007/s00382-016-3393-z},
issn = {14320894},
journal = {Climate Dynamics},
keywords = {CMIP5,Climate model simulations,Decadal variability,ENSO,El Ni{\~{n}}o–Southern Oscillation,Last Millennium,Nino3.4,PMIP,SOI,Spectra},
number = {5-6},
pages = {1705--1727},
publisher = {Springer Berlin Heidelberg},
title = {{Time-varying spectral characteristics of ENSO over the Last Millennium}},
volume = {49},
year = {2017}
}
@article{Horel1981,
abstract = {Abstract Atmospheric phenomena associated with the Southern Oscillation are examined, with emphasis on vertical structure and teleconnections to middle latitudes. This paper is specifically concerned with the interannual variability of seasonal means for the Northern Hemisphere winter during the period 1951?78. Among the variables considered are sea surface temperature in the equatorial Pacific, precipitation at selected equatorial Pacific stations, a ?Southern Oscillation Index? of sea level pressure, 200 mb height and tropospheric mean temperature at stations throughout the tropics, and Northern Hemisphere geopotential height fields. Selected statistics derived from surface data also are examined for the period 1910?45. Results are presented in the form of time series and correlation statistics for the variables listed above. Results concerning the relationships between sea surface temperature, sea level pressure and rainfall are consistent with the major conclusions of previous studies by J. Bjerknes and others. Fluctuations in mean tropospheric temperature and 200 mb height are shown to vary simultaneously with equatorial Pacific sea surface temperature fluctuations, not only in the Pacific sector, but at stations throughout the tropics. The zonally symmetric component of these 200 mb height fluctuations is considerably larger than the Southern Oscillation in 1000 mb height, and the corresponding fluctuations in the mean temperature of the tropical troposphere are on the order of nearly 1 K. The correlations between the tropical time series and Northern Hemisphere geopotential height fields exhibit well-defined teleconnection patterns. Warm episodes in equatorial Pacific sea surface temperature tend to be accompanied by below-normal heights in the North Pacific and the south?eastern United States and above-normal heights over western Canada. Recent theoretical work by Opsteegh and Van den Dool (1980), Hoskins and Karoly (1981) and Webster (1981) on Rossby wave propagation on a sphere provides a basis for understanding the teleconnection in terms of the distribution of sea surface temperature and rainfall in the equatorial Pacific. The theory successfully explains several characteristics of the observed teleconnection patterns, including their horizontal scale and shape, their vertical structure and their seasonal dependence.},
annote = {doi: 10.1175/1520-0493(1981)1092.0.CO;2},
author = {Horel, John D and Wallace, John M},
doi = {10.1175/1520-0493(1981)109<0813:PSAPAW>2.0.CO;2},
issn = {0027-0644},
journal = {Monthly Weather Review},
month = {apr},
number = {4},
pages = {813--829},
publisher = {American Meteorological Society},
title = {{Planetary-Scale Atmospheric Phenomena Associated with the Southern Oscillation}},
url = {https://doi.org/10.1175/1520-0493(1981)109{\%}3C0813:PSAPAW{\%}3E2.0.CO http://0.0.0.2},
volume = {109},
year = {1981}
}
@article{Hoskins1981,
abstract = {Abstract Motivated by some results from barotropic models, a linearized steady-state five-layer baroclinic model is used to study the response of a spherical atmosphere to thermal and orographic forcing. At low levels the significant perturbations are confined to the neighborhood of the source and for midlatitude thermal forcing these perturbations are crucially dependent on the vertical distribution of the source. In the upper troposphere the sources generate wavetrains which are very similar to those given by barotropic models. For a low-latitude source, long wavelengths propagate strongly polewards as well as eastwards. Shorter wavelengths are trapped equatorward of the poleward flank of the jet, resulting in a split of the wave-trains at this latitude. Using reasonable dissipation magnitudes, the easiest way to produce an appreciable response in middle and high latitudes is by subtropical forcing. These results suggest an explanation for the shapes of patterns described in observational studies. The theory for waves propagating in a slowly varying medium is applied to Rossby waves propagating in a barotropic atmosphere. The slow variation of the medium is associated with the sphericity of the domain and the latitudinal structure of the zonal wind. Rays along which wave activity propagates, the speeds of propagation, and the amplitudes and phases along these rays are determined for a constant angular velocity basic flow as well as a more realistic jet flow. They agree well with the observational and numerical model results and give a simple interpretation of them.},
annote = {doi: 10.1175/1520-0469(1981)0382.0.CO;2},
author = {Hoskins, Brian J and Karoly, David J},
doi = {10.1175/1520-0469(1981)038<1179:TSLROA>2.0.CO;2},
issn = {0022-4928},
journal = {Journal of the Atmospheric Sciences},
month = {jun},
number = {6},
pages = {1179--1196},
publisher = {American Meteorological Society},
title = {{The Steady Linear Response of a Spherical Atmosphere to Thermal and Orographic Forcing}},
url = {https://doi.org/10.1175/1520-0469(1981)038{\%}3C1179:TSLROA{\%}3E2.0.CO http://0.0.0.2},
volume = {38},
year = {1981}
}
@article{Hourdin2017,
abstract = {{\textcopyright} 2017 American Meteorological Society. We survey the rationale and diversity of approaches for tuning, a fundamental aspect of climate modeling, which should be more systematically documented and taken into account in multimodel analysis.},
author = {Hourdin, F. and Mauritsen, T. and Gettelman, A. and Golaz, J.-C. and Balaji, V. and Duan, Q. and Folini, D. and Ji, D. and Klocke, D. and Qian, Y. and Rauser, F. and Rio, C. and Tomassini, L. and Watanabe, M. and Williamson, D.},
doi = {10.1175/BAMS-D-15-00135.1},
journal = {Bulletin of the American Meteorological Society},
number = {3},
pages = {589--602},
title = {{The art and science of climate model tuning}},
volume = {98},
year = {2017}
}
@article{Hourdin2015,
author = {Hourdin, Fr{\'{e}}d{\'{e}}ric and Găinusă-Bogdan, Alina and Braconnot, Pascale and Dufresne, Jean-Louis and Traore, Aboul-Khadre and Rio, Catherine},
doi = {10.1002/2015GL066764},
issn = {00948276},
journal = {Geophysical Research Letters},
keywords = {climate,coupling,modeling,warm bias},
month = {dec},
number = {24},
pages = {10885--10893},
publisher = {Wiley-Blackwell},
title = {{Air moisture control on ocean surface temperature, hidden key to the warm bias enigma}},
url = {http://doi.wiley.com/10.1002/2015GL066764},
volume = {42},
year = {2015}
}
@article{Hu2014,
author = {Hu, Kaiming and Huang, Gang and Zheng, Xiao-Tong and Xie, Shang-Ping and Qu, Xia and Du, Yan and Liu, Lin},
doi = {10.1175/JCLI-D-13-00268.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {aug},
number = {15},
pages = {5982--5998},
title = {{Interdecadal Variations in ENSO Influences on Northwest Pacific–East Asian Early Summertime Climate Simulated in CMIP5 Models}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-13-00268.1},
volume = {27},
year = {2014}
}
@article{Hu2017,
author = {Hu, Shineng and Fedorov, Alexey V.},
doi = {10.1002/2017GL072908},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {apr},
number = {8},
pages = {3816--3824},
title = {{The extreme El Ni{\~{n}}o of 2015–2016 and the end of global warming hiatus}},
url = {http://doi.wiley.com/10.1002/2017GL072908},
volume = {44},
year = {2017}
}
@article{Hu2020,
abstract = {We investigate the influence of external forcings on the frequency of temperature extremes over land at the global and continental scales by comparing HadEX3 observations and simulations from the Coupled Model Intercomparison Programme Phase 6 (CMIP6) project. We consider four metrics including warm days and nights (TX90p and TN90p) and cold days and nights (TX10p and TN10p). The observational dataset during 1951-2018 shows continued increases in the warm days and nights and decreases in the cold days and nights in most land areas in the years after 2010. The area of the so-called 'warming hole' in North America is much reduced in 1951-2018 compared with that in 1951-2010. The comparison between observation and simulations based on an optimal fingerprinting method shows that the anthropogenic forcing, dominated by greenhouse gases, plays the most important role in the changes of the frequency indices. Changes in CMIP6 multi-model mean response to all forcing need to be scaled down to best match the observations, indicating that the multi-model ensemble mean may have overestimated the observed changes. Analyses that involve signals from anthropogenic and natural external forcings confirm that the anthropogenic signal can be detected over global land as a whole and for most continents in all temperature indices. Analyses that include signals from greenhouse gas (GHG), anthropogenic aerosol (AA) and natural external (NAT) forcings show that the GHG signal is detected in all indices over the globe and most continents while the AA signal can be detected mainly in the warm extremes but not the cold extremes over the globe and most continents. The effect of NAT is negligible in most land areas. GHG's warming effect is offset partially by AA's cooling effect. The combined effects from both explain most of the observed changes over the globe and continents.},
author = {Hu, Ting and Sun, Ying and Zhang, Xuebin and Min, Seung-Ki and Kim, Yeon-Hee},
doi = {10.1088/1748-9326/ab8497},
issn = {1748-9326},
journal = {Environmental Research Letters},
keywords = {CMIP6 models,HadEX3 dataset,anthropogenic forcing,detection and attribution,natural forcing,temperature extremes},
month = {jun},
number = {6},
pages = {064014},
title = {{Human influence on frequency of temperature extremes}},
url = {https://iopscience.iop.org/article/10.1088/1748-9326/ab8497},
volume = {15},
year = {2020}
}
@article{doi:10.1029/2018GL079033,
abstract = {Abstract There is substantial uncertainty in the relative contributions of internal variability and external forcing to the recent Pacific decadal variability, especially regarding their linkage with the Interdecadal Pacific Oscillation. By analyzing observations and large ensembles of coupled climate model simulations, here we show that observed Pacific decadal variations since 1920 resulted primarily from internal variability, although greenhouse gas (GHG) and other external forcing did modulate decadal variations in Pacific sea surface temperatures (SSTs) significantly, especially for the period since the early 1990s. Specifically, the GHG-induced warming and the recovery from the volcanic cooling caused by the 1991 Pinatubo eruption led to large warming in the tropical Pacific during 1993–2012, while recent anthropogenic aerosols contributed to Pacific regional SST variations on multiyear to decadal scales, causing a La Ni{\~{n}}a-like cooling pattern in the Pacific since 1998 in some of the models. Our results provide new evidence that both internal variability and external forcing have contributed to the recent decadal variations in Pacific SSTs since the early 1990s, although large uncertainties exist among the model-simulated effects of anthropogenic aerosols.},
author = {Hua, Wenjian and Dai, Aiguo and Qin, Minhua},
doi = {10.1029/2018GL079033},
journal = {Geophysical Research Letters},
keywords = {Interdecadal Pacific Oscillation,Pacific decadal variations,external forcing,internal variability},
number = {14},
pages = {7084--7092},
title = {{Contributions of Internal Variability and External Forcing to the Recent Pacific Decadal Variations}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL079033},
volume = {45},
year = {2018}
}
@article{Huber2014,
author = {Huber, Markus and Knutti, Reto},
doi = {10.1038/ngeo2228},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {sep},
number = {9},
pages = {651--656},
publisher = {Nature Publishing Group},
title = {{Natural variability, radiative forcing and climate response in the recent hiatus reconciled}},
url = {http://www.nature.com/articles/ngeo2228},
volume = {7},
year = {2014}
}
@article{Humphrey2018a,
abstract = {Land ecosystems absorb on average 30 per cent of anthropogenic carbon dioxide (CO 2 ) emissions, thereby slowing the increase of CO 2 concentration in the atmosphere 1 . Year-to-year variations in the atmospheric CO 2 growth rate are mostly due to fluctuating carbon uptake by land ecosystems 1 . The sensitivity of these fluctuations to changes in tropical temperature has been well documented 2–6 , but identifying the role of global water availability has proved to be elusive. So far, the only usable proxies for water availability have been time-lagged precipitation anomalies and drought indices 3–5 , owing to a lack of direct observations. Here, we use recent observations of terrestrial water storage changes derived from satellite gravimetry 7 to investigate terrestrial water effects on carbon cycle variability at global to regional scales. We show that the CO 2 growth rate is strongly sensitive to observed changes in terrestrial water storage, drier years being associated with faster atmospheric CO 2 growth. We demonstrate that this global relationship is independent of known temperature effects and is underestimated in current carbon cycle models. Our results indicate that interannual fluctuations in terrestrial water storage strongly affect the terrestrial carbon sink and highlight the importance of the interactions between the water and carbon cycles.},
author = {Humphrey, Vincent and Zscheischler, Jakob and Ciais, Philippe and Gudmundsson, Lukas and Sitch, Stephen and Seneviratne, Sonia I.},
doi = {10.1038/s41586-018-0424-4},
issn = {0028-0836},
journal = {Nature},
month = {aug},
number = {7720},
pages = {628--631},
title = {{Sensitivity of atmospheric CO2 growth rate to observed changes in terrestrial water storage}},
url = {http://www.nature.com/articles/s41586-018-0424-4},
volume = {560},
year = {2018}
}
@article{Huntingford2006b,
abstract = {Optimal detection analyses have been used to determine the causes of past global warming, leading to the conclusion by the Third Assessment Report of the IPCC that “most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations”. To date however, these analyses have not taken full account of uncertainty in the modelled patterns of climate response due to differences in basic model formulation. To address this current “perfect model” assumption, we extend the optimal detection method to include, simultaneously, output from more than one GCM by introducing inter-model variance as an extra uncertainty. Applying the new analysis to three climate models we find that the effects of both anthropogenic and natural factors are detected. We find that greenhouse gas forcing would very likely have resulted in greater warming than observed during the past half century if there had not been an offsetting cooling from aerosols and other forcings.},
author = {Huntingford, Chris and Stott, Peter A and Allen, Myles R and Lambert, F Hugo},
doi = {10.1029/2005GL024831},
journal = {Geophysical Research Letters},
number = {5},
pages = {L05710},
title = {{Incorporating model uncertainty into attribution of observed temperature change}},
volume = {33},
year = {2006}
}
@article{Huntingford2017,
abstract = {Land-atmosphere exchanges influence atmospheric CO2. Emphasis has been on describing photosynthetic CO2 uptake, but less on respiration losses. New global datasets describe upper canopy dark respiration (Rd) and temperature dependencies. This allows characterisation of baseline Rd, instantaneous temperature responses and longer-term thermal acclimation effects. Here we show the global implications of these parameterisations with a global gridded land model. This model aggregates Rd to whole-plant respiration Rp, driven with meteorological forcings spanning uncertainty across climate change models. For pre-industrial estimates, new baseline Rd increases Rp and especially in the tropics. Compared to new baseline, revised instantaneous response decreases Rp for mid-latitudes, while acclimation lowers this for the tropics with increases elsewhere. Under global warming, new Rd estimates amplify modelled respiration increases, although partially lowered by acclimation. Future measurements will refine how Rd aggregates to whole-plant respiration. Our analysis suggests Rp could be around 30{\%} higher than existing estimates.},
author = {Huntingford, Chris and Atkin, Owen K and {Martinez-de la Torre}, Alberto and Mercado, Lina M and Heskel, Mary A and Harper, Anna B and Bloomfield, Keith J and O'Sullivan, Odhran S and Reich, Peter B and Wythers, Kirk R and Butler, Ethan E and Chen, Ming and Griffin, Kevin L and Meir, Patrick and Tjoelker, Mark G and Turnbull, Matthew H and Sitch, Stephen and Wiltshire, Andy and Malhi, Yadvinder},
doi = {10.1038/s41467-017-01774-z},
issn = {2041-1723},
journal = {Nature Communications},
number = {1},
pages = {1602},
title = {{Implications of improved representations of plant respiration in a changing climate}},
url = {https://doi.org/10.1038/s41467-017-01774-z},
volume = {8},
year = {2017}
}
@article{Hyder2018e,
abstract = {The Southern Ocean is a pivotal component of the global climate system yet it is poorly represented in climate models, with significant biases in upper-ocean temperatures, clouds and winds. Combining Atmospheric and Coupled Model Inter-comparison Project (AMIP5/CMIP5) simulations, with observations and equilibrium heat budget theory, we show that across the CMIP5 ensemble variations in sea surface temperature biases in the 40–60°S Southern Ocean are primarily caused by AMIP5 atmospheric model net surface flux bias variations, linked to cloud-related short-wave errors. Equilibration of the biases involves local coupled sea surface temperature bias feedbacks onto the surface heat flux components. In combination with wind feedbacks, these biases adversely modify upper-ocean thermal structure. Most AMIP5 atmospheric models that exhibit small net heat flux biases appear to achieve this through compensating errors. We demonstrate that targeted developments to cloud-related parameterisations provide a route to better represent the Southern Ocean in climate models and projections.},
author = {Hyder, Patrick and Edwards, John M and Allan, Richard P and Hewitt, Helene T and Bracegirdle, Thomas J and Gregory, Jonathan M and Wood, Richard A and Meijers, Andrew J S and Mulcahy, Jane and Field, Paul and Furtado, Kalli and Bodas-Salcedo, Alejandro and Williams, Keith D and Copsey, Dan and Josey, Simon A and Liu, Chunlei and Roberts, Chris D and Sanchez, Claudio and Ridley, Jeff and Thorpe, Livia and Hardiman, Steven C and Mayer, Michael and Berry, David I and Belcher, Stephen E},
doi = {10.1038/s41467-018-05634-2},
issn = {2041-1723},
journal = {Nature Communications},
number = {1},
pages = {3625},
title = {{Critical Southern Ocean climate model biases traced to atmospheric model cloud errors}},
volume = {9},
year = {2018}
}
@article{Ibarra2018a,
author = {Ibarra, Daniel E. and Oster, Jessica L. and Winnick, Matthew J. and {Caves Rugenstein}, Jeremy K. and Byrne, Michael P. and Chamberlain, C. Page},
doi = {10.1130/G39962.1},
issn = {0091-7613},
journal = {Geology},
month = {apr},
number = {4},
pages = {355--358},
title = {{Warm and cold wet states in the western United States during the Pliocene–Pleistocene}},
url = {https://pubs.geoscienceworld.org/gsa/geology/article/46/4/355/528314/Warm-and-cold-wet-states-in-the-western-United},
volume = {46},
year = {2018}
}
@article{ISI:000371283900022,
abstract = {Stratospheric ozone and associated climate impacts in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) simulations are evaluated in the recent past (1980-2000), and examined in the longterm (1850-2100) using the Representative Concentration Pathways (RCPs) low- and high-emission scenarios (RCP2.6 and RCP8.5, respectively) for the period 2000-2100. ACCMIP multi-model mean total column ozone (TCO) trends compare favourably, within uncertainty estimates, against observations. Particularly good agreement is seen in the Antarctic austral spring (11.9{\%} dec(-1) compared to observed similar to -13.9 +/- 10.4{\%} dec(-1)), although larger deviations are found in the Arctic's boreal spring (-2.1{\%} dec(-1) compared to observed similar to -5.3 +/- 3.3{\%} dec(-1)). The simulated ozone hole has cooled the lower stratosphere during austral spring in the last few decades (-2.2Kdec(-1)). This cooling results in Southern Hemisphere summertime tropospheric circulation changes captured by an increase in the Southern Annular Mode (SAM) index (1.3 hPa dec(-1) ). In the future, the interplay between the ozone hole recovery and greenhouse gases (GHGs) concentrations may result in the SAM index returning to pre-ozone hole levels or even with a more positive phase from around the second half of the century (-0.4 and 0.3 hPa dec(-1) for the RCP2.6 and RCP8.5, respectively). By 2100, stratospheric ozone sensitivity to GHG concentrations is greatest in the Arctic and Northern Hemisphere midlatitudes (37.7 and 16.1DU difference between the RCP2.6 and RCP8.5, respectively), and smallest over the tropics and Antarctica continent (2.5 and 8.1DU respectively). Future TCO changes in the tropics are mainly determined by the upper stratospheric ozone sensitivity to GHG concentrations, due to a large compensation between tropospheric and lower stratospheric column ozone changes in the two RCP scenarios. These results demonstrate how changes in stratospheric ozone are tightly linked to climate and show the benefit of including the processes interactively in climate models.},
address = {BAHNHOFSALLEE 1E, GOTTINGEN, 37081, GERMANY},
author = {Iglesias-Suarez, F and Young, P J and Wild, O},
doi = {10.5194/acp-16-343-2016},
issn = {1680-7316},
journal = {Atmospheric Chemistry and Physics},
number = {1},
pages = {343--363},
publisher = {COPERNICUS GESELLSCHAFT MBH},
title = {{Stratospheric ozone change and related climate impacts over 1850–2100 as modelled by the ACCMIP ensemble}},
type = {Article},
volume = {16},
year = {2016}
}
@article{Iles2017,
author = {Iles, Carley E and Hegerl, Gabriele c},
doi = {10.1088/1748-9326/aa9152},
issn = {1748-9326},
journal = {Environmental Research Letters},
month = {nov},
number = {11},
pages = {114010},
title = {{Role of the North Atlantic Oscillation in decadal temperature trends}},
volume = {12},
year = {2017}
}
@article{Iles2015a,
author = {Iles, Carley E. and Hegerl, Gabriele C.},
doi = {10.1038/ngeo2545},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {nov},
number = {11},
pages = {838--842},
title = {{Systematic change in global patterns of streamflow following volcanic eruptions}},
url = {http://www.nature.com/articles/ngeo2545},
volume = {8},
year = {2015}
}
@article{Iles2014a,
abstract = {We examine the precipitation response to volcanic eruptions in the Coupled Model Intercomparison Project Phase 5 (CMIP5) historical simulations compared to three observational datasets, including one with ocean coverage. Global precipitation decreases significantly following eruptions in CMIP5 models, with the largest decrease in wet tropical regions. This also occurs in observational land data, and ocean data in the boreal cold season. Monsoon rainfall decreases following eruptions in both models and observations. In response to individual eruptions, the ITCZ shifts away from the hemisphere with the greater concentration of aerosols in CMIP5. Models undergo a longer-lasting ocean precipitation response than over land, but the response in the short satellite record is too noisy to confirm this. We detect the influence of volcanism on precipitation in all three datasets in the cold season, although the models underestimate the size of the response. In the warm season the volcanic influence is only marginally detectable.},
author = {Iles, Carley E and Hegerl, Gabriele C},
doi = {10.1088/1748-9326/9/10/104012},
issn = {1748-9326},
journal = {Environmental Research Letters},
number = {10},
pages = {104012},
publisher = {IOP Publishing},
title = {{The global precipitation response to volcanic eruptions in the CMIP5 models}},
url = {http://dx.doi.org/10.1088/1748-9326/9/10/104012},
volume = {9},
year = {2014}
}
@article{atmos8030057,
abstract = {Since the late 1990s, land surface temperatures over Japan have increased during the summer and autumn, while global mean temperatures have not risen in this duration (i.e., the global warming hiatus). In contrast, winter and spring temperatures in Japan have decreased. To assess the impact of both global warming and global-scale decadal variability on this enhanced seasonal temperature contrast, we analyzed the outputs of 100 ensemble simulations of historical and counterfactual non-warming climate simulations conducted using a high-resolution atmospheric general circulation model (AGCM). Our simulations showed that atmospheric fields impacted by the La Nina-like conditions associated with Interdecadal Pacific Oscillation (IPO) have predominantly contributed to the seasonal temperature contrast over Japan. Compared with the impact of negative IPO, the influence of global warming on seasonal temperature contrasts in Japan was small. In addition, atmospheric variability has also had a large impact on temperatures in Japan over a decadal timescale. The results of this study suggest a future increase in heatwave risk during the summer and autumn when La Nina-like decadal phenomena and atmospheric perturbations coincide over a background of global warming.},
author = {Imada, Yukiko and Maeda, Shuhei and Watanabe, Masahiro and Shiogama, Hideo and Mizuta, Ryo and Ishii, Masayoshi and Kimoto, Masahide},
doi = {10.3390/atmos8030057},
issn = {2073-4433},
journal = {Atmosphere},
month = {mar},
number = {12},
pages = {57},
title = {{Recent Enhanced Seasonal Temperature Contrast in Japan from Large Ensemble High-Resolution Climate Simulations}},
url = {http://www.mdpi.com/2073-4433/8/3/57},
volume = {8},
year = {2017}
}
@article{doi:10.1175/JCLI-D-12-00622.1,
abstract = { AbstractThe Intergovernmental Panel on Climate Change's (IPCC) “very likely” statement that anthropogenic emissions are affecting climate is based on a statistical detection and attribution methodology that strongly depends on the characterization of internal climate variability. In this paper, the authors test the robustness of this statement in the case of global mean surface air temperature, under different representations of such variability. The contributions of the different natural and anthropogenic forcings to the global mean surface air temperature response are computed using a box diffusion model. Representations of internal climate variability are explored using simple stochastic models that nevertheless span a representative range of plausible temporal autocorrelation structures, including the short-memory first-order autoregressive [AR(1)] process and the long-memory fractionally differencing process. The authors find that, independently of the representation chosen, the greenhouse gas signal remains statistically significant under the detection model employed in this paper. The results support the robustness of the IPCC detection and attribution statement for global mean temperature change under different characterizations of internal variability, but they also suggest that a wider variety of robustness tests, other than simple comparisons of residual variance, should be performed when dealing with other climate variables and/or different spatial scales. },
author = {Imbers, Jara and Lopez, Ana and Huntingford, Chris and Allen, Myles},
doi = {10.1175/JCLI-D-12-00622.1},
journal = {Journal of Climate},
number = {10},
pages = {3477--3491},
title = {{Sensitivity of Climate Change Detection and Attribution to the Characterization of Internal Climate Variability}},
url = {https://doi.org/10.1175/JCLI-D-12-00622.1},
volume = {27},
year = {2014}
}
@article{Iovino2016,
abstract = {{\textless}p{\textgreater}Abstract. Analysis of a global eddy-resolving simulation using the NEMO general circulation model is presented. The model has 1/16° horizontal spacing at the Equator, employs two displaced poles in the Northern Hemisphere, and uses 98 vertical levels. The simulation was spun up from rest and integrated for 11 model years, using ERA-Interim reanalysis as surface forcing. Primary intent of this hindcast is to test how the model represents upper ocean characteristics and sea ice properties. Analysis of the zonal averaged temperature and salinity, and the mixed layer depth indicate that the model average state is in good agreement with observed fields and that the model successfully represents the variability in the upper ocean and at intermediate depths. Comparisons against observational estimates of mass transports through key straits indicate that most aspects of the model circulation are realistic. As expected, the simulation exhibits turbulent behaviour and the spatial distribution of the sea surface height (SSH) variability from the model is close to the observed pattern. The distribution and volume of the sea ice are, to a large extent, comparable to observed values. Compared with a corresponding eddy-permitting configuration, the performance of the model is significantly improved: reduced temperature and salinity biases, in particular at intermediate depths, improved mass and heat transports, better representation of fluxes through narrow and shallow straits, and increased global-mean eddy kinetic energy (by ∼ 40 {\%}). However, relatively minor weaknesses still exist such as a lower than observed magnitude of the SSH variability. We conclude that the model output is suitable for broader analysis to better understand upper ocean dynamics and ocean variability at global scales. This simulation represents a major step forward in the global ocean modelling at the Euro-Mediterranean Centre on Climate Change and constitutes the groundwork for future applications to short-range ocean forecasting.{\textless}/p{\textgreater}},
author = {Iovino, Doroteaciro and Masina, Simona and Storto, Andrea and Cipollone, Andrea and Stepanov, Vladimir N.},
doi = {10.5194/gmd-9-2665-2016},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {aug},
number = {8},
pages = {2665--2684},
title = {{A 1/16° eddying simulation of the global NEMO sea-ice–ocean system}},
url = {https://www.geosci-model-dev.net/9/2665/2016/},
volume = {9},
year = {2016}
}
@techreport{IPCC2018,
author = {IPCC},
doi = {https://www.ipcc.ch/sr15},
editor = {Masson-Delmotte, V. and Zhai, P. and P{\"{o}}rtner, H.-O. and Roberts, D. and Skea, J. and Shukla, P.R. and Pirani, A. and Moufouma-Okia, W. and P{\'{e}}an, C. and Pidcock, R. and Connors, S. and Matthews, J.B.R. and Chen, Y. and Zhou, X. and Gomis, M.I. and Lonnoy, E. and Maycock, T. and Tignor, M. and Waterfield, T.},
pages = {616},
publisher = {In Press},
title = {{Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change,}},
url = {https://www.ipcc.ch/sr15},
year = {2018}
}
@incollection{IPCC2013,
address = {Cambridge, United Kingdom and New York, NY, USA},
author = {IPCC},
booktitle = {Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change},
doi = {10.1017/CBO9781107415324.004},
editor = {Stocker, T F and Qin, D and Plattner, G K and Tignor, M and Allen, S K and Boschung, J and Nauels, A and Xia, Y and Bex, V and Midgley, P M},
isbn = {9781107661820},
keywords = {a184},
pages = {3--29},
publisher = {Cambridge University Press},
title = {{Summary for Policymakers}},
url = {https://www.ipcc.ch/report/ar5/wg1},
year = {2013}
}
@techreport{IPCC2019d,
author = {IPCC},
doi = {https://www.ipcc.ch/report/srocc},
editor = {Pörtner, H.-O. and Roberts, D.C. and Masson-Delmotte, V. and Zhai, P. and Tignor, M. and Poloczanska, E. and Mintenbeck, K. and Alegría, A. and Nicolai, M. and Okem, A. and Petzold, J. and Rama, B. and Weyer, N.M.},
pages = {755},
publisher = {In Press},
title = {{IPCC Special Report on the Ocean and Cryosphere in a Changing Climate}},
url = {https://www.ipcc.ch/report/srocc},
year = {2019}
}
@techreport{IPCC2019c,
author = {IPCC},
doi = {https://www.ipcc.ch/srccl},
editor = {Shukla, P.R. and Skea, J. and Buendia, E. Calvo and Masson-Delmotte, V. and P{\"{o}}rtner, H.-O. and Roberts, D.C. and Zhai, P. and Slade, R. and Connors, S. and van Diemen, R. and Ferrat, M. and Haughey, E. and Luz, S. and Neogi, S. and Pathak, M. and Petzold, J. and Pereira, J. Portugal and Vyas, P. and Huntley, E. and Kissick, K. and Belkacemi, M. and Malley, J.},
pages = {896},
publisher = {In Press},
title = {{Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems}},
url = {https://www.ipcc.ch/srccl},
year = {2019}
}
@article{doi:10.1175/JCLI-D-15-0843.1,
abstract = { AbstractThe Pacific–South American (PSA) pattern is an important mode of climate variability in the mid-to-high southern latitudes. It is widely recognized as the primary mechanism by which El Ni{\~{n}}o–Southern Oscillation (ENSO) influences the southeast Pacific and southwest Atlantic and in recent years has also been suggested as a mechanism by which longer-term tropical sea surface temperature trends can influence the Antarctic climate. This study presents a novel methodology for objectively identifying the PSA pattern. By rotating the global coordinate system such that the equator (a great circle) traces the approximate path of the pattern, the identification algorithm utilizes Fourier analysis as opposed to a traditional empirical orthogonal function approach. The climatology arising from the application of this method to ERA-Interim reanalysis data reveals that the PSA pattern has a strong influence on temperature and precipitation variability over West Antarctica and the Antarctic Peninsula and on sea ice variability in the adjacent Amundsen, Bellingshausen, and Weddell Seas. Identified seasonal trends toward the negative phase of the PSA pattern are consistent with warming observed over the Antarctic Peninsula during autumn, but are inconsistent with observed winter warming over West Antarctica. Only a weak relationship is identified between the PSA pattern and ENSO, which suggests that the pattern might be better conceptualized as a preferred regional atmospheric response to various external (and internal) forcings. },
author = {Irving, Damien and Simmonds, Ian},
doi = {10.1175/JCLI-D-15-0843.1},
journal = {Journal of Climate},
number = {17},
pages = {6109--6125},
title = {{A New Method for Identifying the Pacific–South American Pattern and Its Influence on Regional Climate Variability}},
url = {https://doi.org/10.1175/JCLI-D-15-0843.1},
volume = {29},
year = {2016}
}
@article{Ishii2017,
author = {Ishii, Masayoshi and Fukuda, Yoshikazu and Hirahara, Shoji and Yasui, Soichiro and Suzuki, Toru and Sato, Kanako},
doi = {10.2151/sola.2017-030},
journal = {SOLA},
pages = {163--167},
title = {{Accuracy of Global Upper Ocean Heat Content Estimation Expected from Present Observational Data Sets}},
volume = {13},
year = {2017}
}
@article{Ito2017,
author = {Ito, Takamitsu and Minobe, Shoshiro and Long, Matthew C. and Deutsch, Curtis},
doi = {10.1002/2017GL073613},
issn = {00948276},
journal = {Geophysical Research Letters},
keywords = {biogeochemical cycling,climate change,climate impacts,data analysis,global warming,marine chemistry},
month = {may},
number = {9},
pages = {4214--4223},
publisher = {Wiley-Blackwell},
title = {{Upper ocean O2 trends: 1958–2015}},
url = {http://doi.wiley.com/10.1002/2017GL073613},
volume = {44},
year = {2017}
}
@article{Iturbide2020,
author = {Iturbide, Maialen and Guti{\'{e}}rrez, Jos{\'{e}} Manuel and Alves, Lincoln Muniz and Bedia, Joaqu{\'{i}}n and Cerezo-Mota, Ruth and Cimadevilla, Ezequiel and Cofi{\~{n}}o, Antonio S. and {Di Luca}, Alejandro and Faria, Sergio Henrique and Gorodetskaya, Irina V. and Hauser, Mathias and Herrera, Sixto and Hennessy, Kevin and Hewitt, Helene T. and Jones, Richard G. and Krakovska, Svitlana and Manzanas, Rodrigo and Mart{\'{i}}nez-Castro, Daniel and Narisma, Gemma Teressa and Nurhati, Intan S. and Pinto, Izidine and Seneviratne, Sonia I. and van den Hurk, Bart and Vera, Carolina S.},
doi = {10.5194/essd-12-2959-2020},
issn = {1866-3516},
journal = {Earth System Science Data},
keywords = {Climate change,Climate model,Climatology,Data definition language,Geology,Grid,Homogeneity (statistics),Python (programming language),Scatter plot,Shapefile},
month = {nov},
number = {4},
pages = {2959--2970},
title = {{An update of IPCC climate reference regions for subcontinental analysis of climate model data: definition and aggregated datasets}},
url = {https://essd.copernicus.org/articles/12/2959/2020/},
volume = {12},
year = {2020}
}
@article{Ivy2017,
abstract = {We present observational evidence for linkages between extreme Arctic stratospheric ozone anomalies in March and Northern Hemisphere tropospheric climate in spring (March-April). Springs characterized by low Arctic ozone anomalies in March are associated with a stronger, colder polar vortex and circulation anomalies consistent with the positive polarity of the Northern Annular Mode/North Atlantic Oscillation in March and April. The associated spring tropospheric circulation anomalies indicate a poleward shift of zonal winds at 500 hPa over the North Atlantic. Furthermore, correlations between March Arctic ozone and March-April surface temperatures reveal certain regions where a surprisingly large fraction of the interannual variability in spring surface temperatures is associated with interannual variability in ozone. We also find that years with low March Arctic ozone in the stratosphere display surface maximum daily temperatures in March-April that are colder than normal over southeastern Europe and southern Asia, but warmer than normal over northern Asia, adding to the warming from increasing well-mixed greenhouse gases in those locations. The results shown here do not establish causality, but nevertheless suggest that March stratospheric ozone is a useful indicator of spring averaged (March-April) tropospheric climate in certain Northern Hemispheric regions.},
address = {TEMPLE CIRCUS},
author = {Ivy, Diane J and Solomon, Susan and Calvo, Natalia and Thompson, David W J},
doi = {10.1088/1748-9326/aa57a4},
issn = {1748-9326},
journal = {Environmental Research Letters},
month = {feb},
number = {2},
pages = {024004},
publisher = {IOP PUBLISHING LTD},
title = {{Observed connections of Arctic stratospheric ozone extremes to Northern Hemisphere surface climate}},
url = {https://iopscience.iop.org/article/10.1088/1748-9326/aa57a4},
volume = {12},
year = {2017}
}
@article{Jackson2019,
abstract = {Abstract The observational network around the North Atlantic has improved significantly over the last few decades with subsurface profiling floats and satellite observations and the recent efforts to monitor the Atlantic Meridional Overturning Circulation (AMOC). These have shown decadal time scale changes across the North Atlantic including in heat content, heat transport, and the circulation. However, there are still significant gaps in the observational coverage. Ocean reanalyses integrate the observations with a dynamically consistent ocean model and can be used to understand the observed changes. However, the ability of the reanalyses to represent the dynamics must also be assessed. We use an ensemble of global ocean reanalyses to examine the time mean state and interannual-decadal variability of the North Atlantic ocean since 1993. We assess how well the reanalyses are able to capture processes and whether any understanding can be gained. In particular, we examine aspects of the circulation including convection, AMOC and gyre strengths, and transports. We find that reanalyses show some consistency, in particular showing a weakening of the subpolar gyre and AMOC at 50°N from the mid-1990s until at least 2009 (related to decadal variability in previous studies), a strengthening and then weakening of the AMOC at 26.5°N since 2000, and impacts of circulation changes on transports. These results agree with model studies and the AMOC observations at 26.5°N since 2005. We also see less spread across the ensemble in AMOC strength and mixed layer depth, suggesting improvements as the observational coverage has improved.},
annote = {doi: 10.1029/2019JC015210},
author = {Jackson, L C and Dubois, C and Forget, G and Haines, K and Harrison, M and Iovino, D and K{\"{o}}hl, A and Mignac, D and Masina, S and Peterson, K A and Piecuch, C G and Roberts, C D and Robson, J and Storto, A and Toyoda, T and Valdivieso, M and Wilson, C and Wang, Y and Zuo, H},
doi = {10.1029/2019JC015210},
issn = {2169-9275},
journal = {Journal of Geophysical Research: Oceans},
month = {dec},
number = {12},
pages = {9141--9170},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{The Mean State and Variability of the North Atlantic Circulation: A Perspective From Ocean Reanalyses}},
url = {https://doi.org/10.1029/2019JC015210 https://onlinelibrary.wiley.com/doi/10.1029/2019JC015210},
volume = {124},
year = {2019}
}
@article{Jebri2020a,
abstract = {In a warming world context, sea surface temperature (SST) off central-south Peru, northern Chile, and farther offshore increases at a slower rate than the global average since several decades (i.e., cools, relative to the global average). This tendency is synchronous with an interdecadal Pacific oscillation (IPO) negative trend since {\~{}}1980, which has a cooling signature in the southeastern Pacific. Here, we use a large ensemble of historical coupled model simulations to investigate the relative roles of internal variability (and in particular the IPO) and external forcing in driving this relative regional cooling, and the associated mechanisms. The ensemble mean reproduces the relative cooling, in response to an externally forced southerly wind anomaly, which strengthens the upwelling off Chile in recent decades. This southerly wind anomaly results from the poleward expansion of the Southern Hemisphere Hadley cell. Attribution experiments reveal that this poleward expansion and the resulting enhanced upwelling mostly occur in response to increasing greenhouse gases and stratospheric ozone depletion since {\~{}}1980. An oceanic heat budget confirms that the wind-forced upwelling enhancement dominates the relative cooling near the coast. In contrast, a wind-forced deepening of the mixed layer drives the offshore cooling. While internal variability contributes to the spread of tendencies, the ensemble-mean relative cooling in the southeastern Pacific is consistent with observations and occurs irrespectively of the IPO phase, hence, indicating the preeminent role of external forcing.},
author = {Jebri, Beyrem and Khodri, Myriam and Echevin, Vincent and Gastineau, Guillaume and Thiria, Sylvie and Vialard, J{\'{e}}r{\^{o}}me and Lebas, Nicolas},
doi = {10.1175/JCLI-D-19-0304.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {dec},
number = {24},
pages = {10555--10578},
title = {{Contributions of Internal Variability and External Forcing to the Recent Trends in the Southeastern Pacific and Peru–Chile Upwelling System}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-19-0304.1},
volume = {33},
year = {2020}
}
@article{Jeffers2015,
abstract = {Summary: The question of the relative importance of biotic interactions versus abiotic drivers for structuring plant communities is highly debated but largely unresolved. Here, we investigate the relative importance of mean July air temperature, nitrogen (N) availability and direct plant interactions in determining the millennial-scale population dynamics through the Holocene (10 700-5200 cal. years bp) for four temperate tree taxa in the Scottish Highlands. A variety of dynamic population models were fitted to our palaeoecological time-series data to determine the mechanism(s) by which each driver affected the population biomass dynamics of Betula (birch), Pinus (pine), Alnus (alder) and Quercus (oak). Akaike information criterion weights identified the best model(s) for describing the relationship between each population and driver. The relative importance of these drivers was then assessed by the ability of each model to predict the observed population biomass dynamics. We also measured the change in goodness-of-fit of each model over time. We found that models of intra- and interspecific plant interactions described the plant population dynamics better than temperature- or N-dependent population growth models over the 5000-year study period. The best-fitting models were constant over time for pine, alder and oak. However, the plant-N availability and plant-temperature models provided a progressively better fit to the birch data when temperatures rose and N availability declined, suggesting increasing importance of these abiotic factors coincident with changing conditions. Synthesis. Multiple mechanistic models were applied to palaeoecological data to infer the most likely processes driving millennial-scale plant biomass dynamics in a woodland ecosystem. Direct plant interactions provided a better explanation for population biomass dynamics than growing season temperature or N availability over the full study period. The relative importance of all drivers we assessed here varied by species and - in the case of birch - over time in response to warming and reduced N availability. Multiple mechanistic models were applied to palaeoecological data to infer the most likely processes driving millennial-scale plant biomass dynamics in a woodland ecosystem, and how the importance of each driver changed over time. Here, importance is measured in terms of the goodness of fit of each population dynamic model for predicting the observed biomass dynamics for each of the study taxa. This is measured as the root mean square error (RMSE) between the predicted and observed pollen accumulation rates, which was calculated over a moving window of ca. 500 years. The lowest RMSE value indicates the best fitting model(s). Direct plant interactions provided a better explanation for population biomass dynamics than growing season temperature or N availability over the full study period. The relative importance of all drivers we assessed here varied by species and - in the case of birch - over time in response to warming and reduced N availability.},
author = {Jeffers, Elizabeth S. and Bonsall, Michael B. and Froyd, Cynthia A. and Brooks, Stephen J. and Willis, Katherine J.},
doi = {10.1111/1365-2745.12365},
editor = {McGlone, Matt},
issn = {00220477},
journal = {Journal of Ecology},
keywords = {Climate change,Competition,Determinants of plant community diversity and stru,Drivers of change,Facilitation,Native pine woodland,Palaeoecology,Population and community dynamics,Stable isotopes of nitrogen},
month = {mar},
number = {2},
pages = {459--472},
title = {{The relative importance of biotic and abiotic processes for structuring plant communities through time}},
url = {https://onlinelibrary.wiley.com/doi/10.1111/1365-2745.12365},
volume = {103},
year = {2015}
}
@article{Jenkins2018a,
abstract = {Mass loss from the Amundsen Sea sector of the West Antarctic Ice Sheet has increased in recent decades, suggestive of sustained ocean forcing or an ongoing, possibly unstable, response to a past climate anomaly. Lengthening satellite records appear to be incompatible with either process, however, revealing both periodic hiatuses in acceleration and intermittent episodes of thinning. Here we use ocean temperature, salinity, dissolved-oxygen and current measurements taken from 2000 to 2016 near the Dotson Ice Shelf to determine temporal changes in net basal melting. A decadal cycle dominates the ocean record, with melt changing by a factor of about four between cool and warm extremes via a nonlinear relationship with ocean temperature. A warm phase that peaked around 2009 coincided with ice-shelf thinning and retreat of the grounding line, which re-advanced during a post-2011 cool phase. These observations demonstrate how discontinuous ice retreat is linked with ocean variability, and that the strength and timing of decadal extremes is more influential than changes in the longer-term mean state. The nonlinear response of melting to temperature change heightens the sensitivity of Amundsen Sea ice shelves to such variability, possibly explaining the vulnerability of the ice sheet in that sector, where subsurface ocean temperatures are relatively high.},
author = {Jenkins, Adrian and Shoosmith, Deb and Dutrieux, Pierre and Jacobs, Stan and Kim, Tae Wan and Lee, Sang Hoon and Ha, Ho Kyung and Stammerjohn, Sharon},
doi = {10.1038/s41561-018-0207-4},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {oct},
number = {10},
pages = {733--738},
title = {{West Antarctic Ice Sheet retreat in the Amundsen Sea driven by decadal oceanic variability}},
url = {http://www.nature.com/articles/s41561-018-0207-4},
volume = {11},
year = {2018}
}
@article{Jeong2017,
abstract = {Snow is an important component of the cryosphere and it has a direct and important influence on water storage and supply in snowmelt-dominated regions. This study evaluates the temporal evolution of snow water equivalent (SWE) for the February--April spring period using the GlobSnow observation dataset for the 1980--2012 period. The analysis is performed for different regions of hemispherical to sub-continental scales for the Northern Hemisphere. The detection--attribution analysis is then performed to demonstrate anthropogenic and natural effects on spring SWE changes for different regions, by comparing observations with six CMIP5 model simulations for three different external forcings: all major anthropogenic and natural (ALL) forcings, greenhouse gas (GHG) forcing only, and natural forcing only. The observed spring SWE generally displays a decreasing trend, due to increasing spring temperatures. However, it exhibits a remarkable increasing trend for the southern parts of East Eurasia. The six CMIP5 models with ALL forcings reproduce well the observed spring SWE decreases at the hemispherical scale and continental scales, whereas important differences are noted for smaller regions such as southern and northern parts of East Eurasia and northern part of North America. The effects of ALL and GHG forcings are clearly detected for the spring SWE decline at the hemispherical scale, based on multi-model ensemble signals. The effects of ALL and GHG forcings, however, are less clear for the smaller regions or with single-model signals, indicating the large uncertainty in regional SWE changes, possibly due to stronger influence of natural climate variability.},
author = {Jeong, Dae Il and Sushama, Laxmi and {Naveed Khaliq}, M},
doi = {10.1007/s00382-016-3291-4},
issn = {1432-0894},
journal = {Climate Dynamics},
month = {jun},
number = {11},
pages = {3645--3658},
title = {{Attribution of spring snow water equivalent (SWE) changes over the northern hemisphere to anthropogenic effects}},
url = {https://doi.org/10.1007/s00382-016-3291-4},
volume = {48},
year = {2017}
}
@article{Jeong2020b,
abstract = {The Southern Ocean overturning circulation is driven by winds, heat fluxes, and freshwater sources. Among these sources of freshwater, Antarctic sea ice formation and melting play the dominant role. Even though ice-shelf melt is relatively small in magnitude, it is located close to regions of convection, where it may influence dense water formation. Here, we explore the impacts of ice-shelf melting on Southern Ocean water-mass transformation (WMT) using simulations from the Energy Exascale Earth System Model (E3SM) both with and without the explicit representation of melt fluxes from beneath Antarctic ice shelves. We find that ice-shelf melting enhances transformation of Upper Circumpolar Deep Water, converting it to lower density values. While the overall differences in Southern Ocean WMT between the two simulations are moderate, freshwater fluxes produced by ice-shelf melting have a further, indirect impact on the Southern Ocean overturning circulation through their interaction with sea ice formation and melting, which also cause considerable upwelling. We further find that surface freshening and cooling by ice-shelf melting cause increased Antarctic sea ice production and stronger density stratification near the Antarctic coast. In addition, ice-shelf melting causes decreasing air temperature, which may be directly related to sea ice expansion. The increased stratification reduces vertical heat transport from the deeper ocean. Although the addition of ice-shelf melting processes leads to no significant changes in Southern Ocean WMT, the simulations and analysis conducted here point to a relationship between increased Antarctic ice-shelf melting and the increased role of sea ice in Southern Ocean overturning.},
author = {Jeong, Hyein and Asay-Davis, Xylar S and Turner, Adrian K and Comeau, Darin S and Price, Stephen F and Abernathey, Ryan P and Veneziani, Milena and Petersen, Mark R and Hoffman, Matthew J and Mazloff, Matthew R and Ringler, Todd D},
doi = {10.1175/JCLI-D-19-0683.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jun},
number = {13},
pages = {5787--5807},
title = {{Impacts of Ice-Shelf Melting on Water-Mass Transformation in the Southern Ocean from E3SM Simulations}},
volume = {33},
year = {2020}
}
@article{doi:10.1175/JCLI-D-11-00434.1,
abstract = { AbstractThis paper proposes an optimal method for estimating time-dependent climate change signals from general circulation models. The basic idea is to identify vectors that maximize the mean-square detection statistic derived from optimal fingerprinting techniques. The method also provides an objective and systematic procedure for identifying the limit to which a signal can be restricted in space and time without losing detectability. As an illustration, the method is applied to the Coupled Model Intercomparison Project, phase 3 multimodel dataset to determine the continental seasonal-mean anomaly in surface air temperature and precipitation that is most detectable, on average, in these models. Anomalies in seasonal-mean surface air temperature are detectable in all seasons by almost all models on all continents but Europe; seasonal-mean anomalies over Europe are undetectable for some models, though this does not preclude other expressions of the signal, such as those that include longer time averages or time-lag information, from being detectable. Detectability in seasonal-mean temperature is found not only for multidecadal warming trends but also for cooling after major volcanic eruptions. In contrast, seasonal-mean precipitation anomalies are detectable in only a few models for averages over 5 yr or more, suggesting that the signal should include more spatiotemporal detail to be detectable across more models. Nevertheless, of the precipitation anomalies that are detectable, the signal appears to be of two characters: a systematic trend and enhanced frequency of extreme values. These results derived from twentieth-century simulations appear to be consistent with previous studies based on twenty-first-century simulations with larger signal-to-noise ratios. },
author = {Jia, Liwei and DelSole, Timothy},
doi = {10.1175/JCLI-D-11-00434.1},
journal = {Journal of Climate},
number = {20},
pages = {7122--7137},
title = {{Optimal Determination of Time-Varying Climate Change Signals}},
url = {https://doi.org/10.1175/JCLI-D-11-00434.1},
volume = {25},
year = {2012}
}
@incollection{Jia2019,
author = {Jia, G. and {E. Shevliakova} and Artaxo, P. and Noblet-Ducoudr{\'{e}}, N. De and Houghton, R. and House, J. and Kitajima, K. and Lennard, C. and Popp, A. and Sirin, A. and Sukumar, R. and Verchot, L.},
booktitle = {Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems},
doi = {https://www.ipcc.ch/srccl/chapter/chapter-2},
editor = {{P.R. Shukla} and Skea, J. and {E. Calvo Buendia} and Masson-Delmotte, V. and P{\"{o}}rtner, H.-O. and Roberts, D.C. and Zhai, P. and Slade, R. and Connors, S. and van Diemen, R. and Ferrat, M. and Haughey, E. and Luz, S. and Neogi, S. and Pathak, M. and Petzold, J. and Pereira, J. Portugal and Vyas, P. and Huntley, E. and Kissick, K. and Belkacemi, M. and Malley, J.},
pages = {131--248},
publisher = {In Press},
title = {{Land–climate interactions}},
url = {https://www.ipcc.ch/srccl/chapter/chapter-2},
year = {2019}
}
@article{Jiang2015,
author = {Jiang, Dabang and Tian, Zhiping and Lang, Xianmei},
doi = {10.1007/s00382-014-2175-8},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {may},
number = {9-10},
pages = {2493--2512},
title = {{Mid-Holocene global monsoon area and precipitation from PMIP simulations}},
url = {http://link.springer.com/10.1007/s00382-014-2175-8},
volume = {44},
year = {2015}
}
@article{Jiang2012a,
author = {Jiang, Jonathan H. and Su, Hui and Zhai, Chengxing and Perun, Vincent S. and {Del Genio}, Anthony and Nazarenko, Larissa S. and Donner, Leo J. and Horowitz, Larry and Seman, Charles and Cole, Jason and Gettelman, Andrew and Ringer, Mark A. and Rotstayn, Leon and Jeffrey, Stephen and Wu, Tongwen and Brient, Florent and Dufresne, Jean-Louis and Kawai, Hideaki and Koshiro, Tsuyoshi and Watanabe, Masahiro and L{\'{E}}cuyer, Tristan S. and Volodin, Evgeny M. and Iversen, Trond and Drange, Helge and Mesquita, Michel D. S. and Read, William G. and Waters, Joe W. and Tian, Baijun and Teixeira, Joao and Stephens, Graeme L.},
doi = {10.1029/2011JD017237},
issn = {01480227},
journal = {Journal of Geophysical Research: Atmospheres},
month = {jul},
number = {D14},
pages = {D14105},
title = {{Evaluation of cloud and water vapor simulations in CMIP5 climate models using NASA “A-Train” satellite observations}},
url = {http://doi.wiley.com/10.1029/2011JD017237},
volume = {117},
year = {2012}
}
@article{Jiang2019,
abstract = {The effects of sea salt aerosols (SSA) on cloud microphysical processes, precipitation, and upper troposphere/lower stratosphere water vapour in tropical cyclones were studied with the Weather Research and Forecasting with Chemistry model. Two numerical experiments were conducted: a control experiment (CTL) and an experiment with sea salt emission intensity one-tenth of that in the CTL experiment (CLEAN). Results show increased SSA concentrations, increased production rates of auto-conversion of cloud water to form rain, and increased accretion of cloud water by rain in the CTL experiment, leading to an increase in the precipitation amount. The peak value of precipitation is {\~{}}17 mm/h in the CTL experiment and {\~{}}13 mm/h in the CLEAN experiment, a difference of {\~{}}30{\%}. The CTL experiment has more intense vertical movement in the eyewall and thus more water vapour is transported to the upper atmosphere, which promotes cloud ice deposition. This process consumes more water vapour, which makes the CTL experiment drier in the upper troposphere/lower stratosphere layer (altitude above 17 km). At 18–20 km altitude, the domain-averaged water vapour mixing ratio of the CTL experiment is {\~{}}0.02 ppmv lower than that of the CLEAN experiment. SSA have the effect of strengthening tropical cyclones and increasing precipitation.},
author = {Jiang, Baolin and Wang, Dongdong and Shen, Xiaodian and Chen, Junwen and Lin, Wenshi},
doi = {10.1038/s41598-019-51757-x},
issn = {2045-2322},
journal = {Scientific Reports},
month = {dec},
number = {1},
pages = {15105},
publisher = {Nature Publishing Group},
title = {{Effects of sea salt aerosols on precipitation and upper troposphere/lower stratosphere water vapour in tropical cyclone systems}},
url = {http://www.nature.com/articles/s41598-019-51757-x},
volume = {9},
year = {2019}
}
@article{Jiang2019a,
abstract = {Multidecadal variations in the global land monsoon were observed during the twentieth century, with an overall increasing trend from 1901 to 1955 that was followed by a decreasing trend up to 1990, but the mechanisms governing the above changes remain inconclusive. Based on the outputs of two atmospheric general circulation models (AGCMs) forced by historical sea surface temperature (SST) covering the twentieth century, supplemented with AGCM simulations forced by idealized SST anomalies representing different conditions of the North Atlantic and tropical Pacific, evidence shows that the observed changes can be partly reproduced, particularly over the Northern Hemisphere summer monsoon (NHSM) domain, demonstrating the modulation of decadal SST changes on the long-term variations in monsoon precipitation. Moisture budget analysis is performed to understand the interdecadal changes in monsoon precipitation, and the dynamic term associated with atmospheric circulation changes is found to be prominent, while the contribution of the thermodynamic term associated with humidity changes can lead to coincident wetting over the NHSM domain. The increase (decrease) in NHSM land precipitation during 1901–55 (1956–90) is associated with the strengthening (weakening) of NHSM circulation and Walker circulation. The multidecadal scale changes in atmospheric circulation are driven by SST anomalies over the North Atlantic and the Pacific. A warmer North Atlantic together with a colder eastern tropical Pacific and a warmer western subtropical Pacific can lead to a strengthened meridional gradient in mid-to-upper-tropospheric thickness and strengthened trade winds, which transport more water vapor into monsoon regions, leading to an increase in monsoon precipitation.},
author = {Jiang, Jie and Zhou, Tianjun},
doi = {10.1175/JCLI-D-18-0890.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {nov},
number = {22},
pages = {7675--7695},
title = {{Global Monsoon Responses to Decadal Sea Surface Temperature Variations during the Twentieth Century: Evidence from AGCM Simulations}},
url = {https://journals.ametsoc.org/jcli/article/32/22/7675/344009/Global-Monsoon-Responses-to-Decadal-Sea-Surface},
volume = {32},
year = {2019}
}
@article{Jianping2003b,
author = {Jianping, Li and Wang, Julian X. L.},
doi = {10.1007/BF02915394},
issn = {0256-1530},
journal = {Advances in Atmospheric Sciences},
month = {sep},
number = {5},
pages = {661--676},
title = {{A new North Atlantic Oscillation index and its variability}},
url = {http://link.springer.com/10.1007/BF02915394},
volume = {20},
year = {2003}
}
@article{Gao,
abstract = {Bomb cyclones are explosively intensifying extratropical cyclones that can cause severe damage to life and property. However, the poor ability of coarse-resolution climate models to simulate bomb cyclones, including underestimation of the frequency of bomb cyclones, remains a problem. In this study, the dependence of bomb cyclone characteristics on horizontal resolution from 135 to 18 km is investigated by analyzing the outputs of HighResMIP historical simulations of atmospheric general circulation models and four reanalysis datasets. Robust resolution dependence of bomb cyclone characteristics is identified for both the models and the reanalyses. Finer horizontal resolution significantly increases the frequency of bomb cyclones and reduces their average horizontal size. A regression analysis indicates that bomb cyclone frequency is roughly doubled from 140 km to 25 km resolution. The overall increase in bomb cyclone number is associated with a large increase in small bomb cyclones and a moderate decrease in large ones. Bomb cyclones in higher-resolution models are also accompanied by a higher maximum wind speed and more extreme wind events, which is probably related to the increased pressure gradients due to the smaller size of the bomb cyclones. These results imply that high-resolution models should be used for evaluating the impacts of bomb cyclones.},
author = {Jiaxiang, Gao and Shoshiro, Minobe and Roberts, Malcolm J. and Haarsma, Rein and Putrasahan, Dian and Roberts, Christopher D. and Scoccimarro, Enrico and Terray, Laurent and Vanniere, Benoit and Vidale, Pier Luigi},
doi = {10.1088/1748-9326/ab88fa},
issn = {17489326},
journal = {Environmental Research Letters},
keywords = {cyclone size,explosive cyclones,high-resolution AGCMs,maximum wind speed,multi-model analysis},
number = {8},
pages = {084001},
title = {{Influence of model resolution on bomb cyclones revealed by HighResMIP-PRIMAVERA simulations}},
volume = {15},
year = {2020}
}
@article{Jin2006,
author = {Jin, Fei-Fei and Kim, Seon Tae and Bejarano, Luis},
doi = {10.1029/2006GL027221},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {dec},
number = {23},
pages = {L23708},
title = {{A coupled-stability index for ENSO}},
type = {Journal Article},
url = {http://doi.wiley.com/10.1029/2006GL027221},
volume = {33},
year = {2006}
}
@article{Johnson2016,
author = {Johnson, Stephanie J. and Levine, Richard C. and Turner, Andrew G. and Martin, Gill M. and Woolnough, Steven J. and Schiemann, Reinhard and Mizielinski, Matthew S. and Roberts, Malcolm J. and Vidale, Pier Luigi and Demory, Marie-Estelle and Strachan, Jane},
doi = {10.1007/s00382-015-2614-1},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {feb},
number = {3-4},
pages = {807--831},
title = {{The resolution sensitivity of the South Asian monsoon and Indo-Pacific in a global 0.35° AGCM}},
url = {http://link.springer.com/10.1007/s00382-015-2614-1},
volume = {46},
year = {2016}
}
@article{Jones_2020,
abstract = {To achieve the goals of the Paris Agreement requires deep and rapid reductions in anthropogenic CO2 emissions, but uncertainty surrounds the magnitude and depth of reductions. Earth system models provide a means to quantify the link from emissions to global climate change. Using the concept of TCRE—the transient climate response to cumulative carbon emissions—we can estimate the remaining carbon budget to achieve 1.5 or 2 °C. But the uncertainty is large, and this hinders the usefulness of the concept. Uncertainty in carbon budgets associated with a given global temperature rise is determined by the physical Earth system, and therefore Earth system modelling has a clear and high priority remit to address and reduce this uncertainty. Here we explore multi-model carbon cycle simulations across three generations of Earth system models to quantitatively assess the sources of uncertainty which propagate through to TCRE. Our analysis brings new insights which will allow us to determine how we can better direct our research priorities in order to reduce this uncertainty. We emphasise that uses of carbon budget estimates must bear in mind the uncertainty stemming from the biogeophysical Earth system, and we recommend specific areas where the carbon cycle research community needs to re-focus activity in order to try to reduce this uncertainty. We conclude that we should revise focus from the climate feedback on the carbon cycle to place more emphasis on CO2 as the main driver of carbon sinks and their long-term behaviour. Our proposed framework will enable multiple constraints on components of the carbon cycle to propagate to constraints on remaining carbon budgets.},
author = {Jones, Chris D and Friedlingstein, Pierre},
doi = {10.1088/1748-9326/ab858a},
journal = {Environmental Research Letters},
month = {jun},
number = {7},
pages = {74019},
publisher = {{\{}IOP{\}} Publishing},
title = {{Quantifying process-level uncertainty contributions to TCRE and carbon budgets for meeting Paris Agreement climate targets}},
url = {https://doi.org/10.1088/1748-9326/ab858a},
volume = {15},
year = {2020}
}
@article{Jones2016e,
abstract = {{\textcopyright} 2016. Crown copyright. Using optimal detection techniques with climate model simulations, most of the observed increase of near-surface temperatures over the second half of the twentieth century is attributed to anthropogenic influences. However, the partitioning of the anthropogenic influence to individual factors, such as greenhouse gases and aerosols, is much less robust. Differences in how forcing factors are applied, in their radiative influence and in models' climate sensitivities, substantially influence the response patterns. We find that standard optimal detection methodologies cannot fully reconcile this response diversity. By selecting a set of experiments to enable the diagnosing of greenhouse gases and the combined influence of other anthropogenic and natural factors, we find robust detections of well-mixed greenhouse gases across a large ensemble of models. Of the observed warming over the twentieth century of 0.65 K/century we find, using a multimodel mean not incorporating pattern uncertainty, a well-mixed greenhouse gas warming of 0.87 to 1.22 K/century. This is partially offset by cooling from other anthropogenic and natural influences of-0.54 to-0.22 K/century. Although better constrained than recent studies, the attributable trends across climate models are still wide, with implications for observational constrained estimates of transient climate response. Some of the uncertainties could be reduced in future by having more model data to better quantify the simulated estimates of the signals and natural variability, by designing model experiments more effectively and better quantification of the climate model radiative influences. Most importantly, how model pattern uncertainties are incorporated into the optimal detection methodology should be improved.},
author = {Jones, G.S. and Stott, P.A. and Mitchell, J.F.B.},
doi = {10.1002/2015JD024337},
journal = {Journal of Geophysical Research},
number = {12},
pages = {6969--6992},
title = {{Uncertainties in the attribution of greenhouse gas warming and implications for climate prediction}},
volume = {121},
year = {2016}
}
@article{Jones2013a,
abstract = {We have carried out an investigation into the causes of changes in near-surface temperatures from 1860 to 2010. We analyze the HadCRUT4 observational data set which has the most comprehensive set of adjustments available to date for systematic biases in sea surface temperatures and the CMIP5 ensemble of coupled models which represents the most sophisticated multi-model climate modeling exercise yet carried out. Simulations that incorporate both anthropogenic and natural factors span changes in observed temperatures between 1860 and 2010, while simulations of natural factors do not warm as much as observed. As a result of sampling a much wider range of structural modeling uncertainty, we find a wider spread of historic temperature changes in CMIP5 than was simulated by the previous multi-model ensemble, CMIP3. However, calculations of attributable temperature trends based on optimal detection support previous conclusions that human-induced greenhouse gases dominate observed global warming since the mid-20th century. With a much wider exploration of model uncertainty than previously carried out, we find that individually the models give a wide range of possible counteracting cooling from the direct and indirect effects of aerosols and other non-greenhouse gas anthropogenic forcings. Analyzing the multi-model mean over 1951-2010 (focusing on the most robust result), we estimate a range of possible contributions to the observed warming of approximately 0.6 K from greenhouse gases of between 0.6 and 1.2 K, balanced by a counteracting cooling from other anthropogenic forcings of between 0 and -0.5 K. Key PointsLatest dataset of historic temperatures compared with multi model ensembleCMIP5 models have wider range of global mean warming than CMIP3 modelsMultimodel attribution analysis shows greenhouse gases dominate warming {\textcopyright}2013. Crown copyright. This article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.},
author = {Jones, Gareth S. and Stott, Peter A. and Christidis, Nikolaos},
doi = {10.1002/jgrd.50239},
isbn = {2169-8996},
issn = {21698996},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {climate change,climate models,observational datasets,temperature change},
number = {10},
pages = {4001--4024},
title = {{Attribution of observed historical near-surface temperature variations to anthropogenic and natural causes using CMIP5 simulations}},
volume = {118},
year = {2013}
}
@article{Jones2017,
abstract = {The impact of including comprehensive estimates of observational uncertainties on a detection and attri-bution analysis of twentieth-century near-surface temperature variations is investigated. The error model of HadCRUT4, a dataset of land near-surface air temperatures and sea surface temperatures, provides estimates of measurement, sampling, and bias adjustment uncertainties. These uncertainties are incorporated into an optimal detection analysis that regresses simulated large-scale temporal and spatial variations in near-surface temperatures, driven by well-mixed greenhouse gas variations and other anthropogenic and natural factors, against observed changes. The inclusion of bias adjustment uncertainties increases the variance of the re-gression scaling factors and the range of attributed warming from well-mixed greenhouse gases by less than 20{\%}. Including estimates of measurement and sampling errors has a much smaller impact on the results. The range of attributable greenhouse gas warming is larger across analyses exploring dataset structural un-certainty. The impact of observational uncertainties on the detection analysis is found to be small compared to other sources of uncertainty, such as model variability and methodological choices, but it cannot be ruled out that on different spatial and temporal scales this source of uncertainty may be more important. The results support previous conclusions that there is a dominant anthropogenic greenhouse gas influence on twentieth-century near-surface temperature increases.},
author = {Jones, Gareth S. and Kennedy, John J.},
doi = {10.1175/JCLI-D-16-0628.1},
isbn = {0894-8755},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Anthropogenic effects,Climate change,Climate models,Statistical techniques,Surface observations,Surface temperature},
month = {jun},
number = {12},
pages = {4677--4691},
title = {{Sensitivity of attribution of anthropogenic near-surface warming to observational uncertainty}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-16-0628.1},
volume = {30},
year = {2017}
}
@article{Jones2016c,
abstract = {The purpose of this review article is to discuss the development and associated estimation of uncertainties in the global and hemispheric surface temperature records. The review begins by detailing the groups that produce surface temperature datasets. After discussing the reasons for similarities and differences between the various products, the main issues that must be addressed when deriving accurate estimates, particularly for hemispheric and global averages, are then considered. These issues are discussed in the order of their importance for temperature records at these spatial scales: biases in SST data, particularly before the 1940s; the exposure of land-based thermometers before the development of louvred screens in the late 19th century; and urbanization effects in some regions in recent decades. The homogeneity of land-based records is also discussed; however, at these large scales it is relatively unimportant. The article concludes by illustrating hemispheric and global temperature records from the four groups that produce series in near-real time.},
author = {Jones, Philip},
doi = {10.1007/s00376-015-5194-4},
issn = {0256-1530},
journal = {Advances in Atmospheric Sciences},
month = {mar},
number = {3},
pages = {269--282},
title = {{The reliability of global and hemispheric surface temperature records}},
url = {http://link.springer.com/10.1007/s00376-015-5194-4},
volume = {33},
year = {2016}
}
@article{Joshi2017,
author = {Joshi, Manish K. and Kucharski, Fred},
doi = {10.1007/s00382-016-3210-8},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {apr},
number = {7-8},
pages = {2375--2391},
title = {{Impact of Interdecadal Pacific Oscillation on Indian summer monsoon rainfall: an assessment from CMIP5 climate models}},
url = {http://link.springer.com/10.1007/s00382-016-3210-8},
volume = {48},
year = {2017}
}
@article{Jouanno2017c,
abstract = {Abstract. The contributions of the dynamic and thermodynamic forcing to the interannual variability of the equatorial Atlantic sea surface temperature (SST) are investigated using a set of interannual regional simulations of the tropical Atlantic Ocean. The ocean model is forced with an interactive atmospheric boundary layer, avoiding damping toward prescribed air temperature as is usually the case in forced ocean models. The model successfully reproduces a large fraction (R2 = 0.55) of the observed interannual variability in the equatorial Atlantic. In agreement with leading theories, our results confirm that the interannual variations of the dynamical forcing largely contributes to this variability. We show that mean and seasonal upper ocean temperature biases, commonly found in fully coupled models, strongly favor an unrealistic thermodynamic control of the equatorial Atlantic interannual variability.},
author = {Jouanno, Julien and Hernandez, Olga and Sanchez-Gomez, Emilia},
doi = {10.5194/esd-8-1061-2017},
issn = {2190-4987},
journal = {Earth System Dynamics},
month = {nov},
number = {4},
pages = {1061--1069},
title = {{Equatorial Atlantic interannual variability and its relation to dynamic and thermodynamic processes}},
volume = {8},
year = {2017}
}
@article{Jung2017b,
abstract = {Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO 2) originate primarily from fluctuations in carbon uptake by land ecosystems. It remains uncertain, however, to what extent temperature and water availability control the carbon balance of land ecosystems across spatial and temporal scales. Here we use empirical models based on eddy covariance data and process-based models to investigate the effect of changes in temperature and water availability on gross primary productivity (GPP), terrestrial ecosystem respiration (TER) and net ecosystem exchange (NEE) at local and global scales. We find that water availability is the dominant driver of the local interannual variability in GPP and TER. To a lesser extent this is true also for NEE at the local scale, but when integrated globally, temporal NEE variability is mostly driven by temperature fluctuations. We suggest that this apparent paradox can be explained by two compensatory water effects. Temporal water-driven GPP and TER variations compensate locally, dampening water-driven NEE variability. Spatial water availability anomalies also compensate, leaving a dominant temperature signal in the year-to-year fluctuations of the land carbon sink. These findings help to reconcile seemingly contradictory reports regarding the importance of temperature and water in controlling the interannual variability of the terrestrial carbon balance. Our study indicates that spatial climate covariation drives the global carbon cycle response.},
author = {Jung, Martin and Reichstein, Markus and Schwalm, Christopher R. and Huntingford, Chris and Sitch, Stephen and Ahlstr{\"{o}}m, Anders and Arneth, Almut and Camps-Valls, Gustau and Ciais, Philippe and Friedlingstein, Pierre and Gans, Fabian and Ichii, Kazuhito and Jain, Atul K. and Kato, Etsushi and Papale, Dario and Poulter, Ben and Raduly, Botond and R{\"{o}}denbeck, Christian and Tramontana, Gianluca and Viovy, Nicolas and Wang, Ying-Ping and Weber, Ulrich and Zaehle, S{\"{o}}nke and Zeng, Ning},
doi = {10.1038/nature20780},
issn = {0028-0836},
journal = {Nature},
month = {jan},
number = {7638},
pages = {516--520},
title = {{Compensatory water effects link yearly global land CO2 sink changes to temperature}},
url = {http://www.nature.com/articles/nature20780},
volume = {541},
year = {2017}
}
@article{Kadow2020,
author = {Kadow, Christopher and Hall, David Matthew and Ulbrich, Uwe},
doi = {10.1038/s41561-020-0582-5},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {jun},
number = {6},
pages = {408--413},
title = {{Artificial intelligence reconstructs missing climate information}},
url = {http://www.nature.com/articles/s41561-020-0582-5},
volume = {13},
year = {2020}
}
@article{gmd-10-4035-2017,
author = {Kageyama, M and Albani, S and Braconnot, P and Harrison, S P and Hopcroft, P O and Ivanovic, R F and Lambert, F and Marti, O and Peltier, W R and Peterschmitt, J.-Y. and Roche, D M and Tarasov, L and Zhang, X and Brady, E C and Haywood, A M and LeGrande, A N and Lunt, D J and Mahowald, N M and Mikolajewicz, U and Nisancioglu, K H and Otto-Bliesner, B L and Renssen, H and Tomas, R A and Zhang, Q and Abe-Ouchi, A and Bartlein, P J and Cao, J and Li, Q and Lohmann, G and Ohgaito, R and Shi, X and Volodin, E and Yoshida, K and Zhang, X and Zheng, W},
doi = {10.5194/gmd-10-4035-2017},
journal = {Geoscientific Model Development},
number = {11},
pages = {4035--4055},
title = {{The PMIP4 contribution to CMIP6 – Part 4: Scientific objectives and experimental design of the PMIP4-CMIP6 Last Glacial Maximum experiments and PMIP4 sensitivity experiments}},
url = {https://www.geosci-model-dev.net/10/4035/2017/},
volume = {10},
year = {2017}
}
@article{cp-17-37-2021,
author = {Kageyama, M and Sime, L C and Sicard, M and Guarino, M.-V. and de Vernal, A and Stein, R and Schroeder, D and Malmierca-Vallet, I and Abe-Ouchi, A and Bitz, C and Braconnot, P and Brady, E C and Cao, J and Chamberlain, M A and Feltham, D and Guo, C and LeGrande, A N and Lohmann, G and Meissner, K J and Menviel, L and Morozova, P and Nisancioglu, K H and Otto-Bliesner, B L and O'ishi, R and {Ramos Buarque}, S and y Melia, D and Sherriff-Tadano, S and Stroeve, J and Shi, X and Sun, B and Tomas, R A and Volodin, E and Yeung, N K H and Zhang, Q and Zhang, Z and Zheng, W and Ziehn, T},
doi = {10.5194/cp-17-37-2021},
journal = {Climate of the Past},
number = {1},
pages = {37--62},
title = {{A multi-model CMIP6-PMIP4 study of Arctic sea ice at 127 ka: sea ice data compilation and model differences}},
url = {https://cp.copernicus.org/articles/17/37/2021/},
volume = {17},
year = {2021}
}
@article{cp-2019-169,
author = {Kageyama, Masa and Harrison, Sandy P and Kapsch, Marie-L. and Lofverstrom, Marcus and Lora, Juan M and Mikolajewicz, Uwe and Sherriff-Tadano, Sam and Vadsaria, Tristan and Abe-Ouchi, Ayako and Bouttes, Nathaelle and Chandan, Deepak and Gregoire, Lauren J. and Ivanovic, Ruza F. and Izumi, Kenji and LeGrande, Allegra N and Lhardy, Fanny and Lohmann, Gerrit and Morozova, Polina A and Ohgaito, Rumi and Paul, Andr{\'{e}} and Peltier, W Richard and Poulsen, Christopher J. and Quiquet, Aur{\'{e}}lien and Roche, Didier M and Shi, Xiaoxu and Tierney, Jessica E and Valdes, Paul J. and Volodin, Evgeny and Zhu, Jiang},
doi = {10.5194/cp-17-1065-2021},
issn = {1814-9332},
journal = {Climate of the Past},
month = {may},
number = {3},
pages = {1065--1089},
title = {{The PMIP4 Last Glacial Maximum experiments: preliminary results and comparison with the PMIP3 simulations}},
url = {https://cp.copernicus.org/articles/17/1065/2021/},
volume = {17},
year = {2021}
}
@article{Kageyama2018b,
author = {Kageyama, M and Braconnot, P and Harrison, S P and Haywood, A M and Jungclaus, J H and Otto-Bliesner, B L and Peterschmitt, J.-Y. and Abe-Ouchi, A and Albani, S and Bartlein, P J and Brierley, C and Crucifix, M and Dolan, A and Fernandez-Donado, L and Fischer, H and Hopcroft, P O and Ivanovic, R F and Lambert, F and Lunt, D J and Mahowald, N M and Peltier, W R and Phipps, S J and Roche, D M and Schmidt, G A and Tarasov, L and Valdes, P J and Zhang, Q and Zhou, T},
doi = {10.5194/gmd-11-1033-2018},
journal = {Geoscientific Model Development},
number = {3},
pages = {1033--1057},
title = {{The PMIP4 contribution to CMIP6 – Part 1: Overview and over-arching analysis plan}},
url = {https://www.geosci-model-dev.net/11/1033/2018/},
volume = {11},
year = {2018}
}
@article{Kam2018a,
abstract = {Over regions where snowmelt runoff substantially contributes to winter–spring streamflows, warming can accelerate snowmelt and reduce dry-season streamflows. However, conclusive detection of changes and attribution to anthropogenic forcing is hindered by the brevity of observational records, model uncertainty, and uncertainty concerning internal variability. In this study, the detection/attribution of changes in midlatitude North American winter–spring streamflow timing is examined using nine global climate models under multiple forcing scenarios. Robustness across models, start/end dates for trends, and assumptions about internal variability are evaluated. Marginal evidence for an emerging detectable anthropogenic influence (according to four or five of nine models) is found in the north-central United States, where winter–spring streamflows have been starting earlier. Weaker indications of detectable anthropogenic influence (three of nine models) are found in the mountainous western United States/southwestern Canada and in the extreme northeastern United States/Canadian Maritimes. In the former region, a recent shift toward later streamflows has rendered the full-record trend toward earlier streamflows only marginally significant, with possible implications for previously published climate change detection findings for streamflow timing in this region. In the latter region, no forced model shows as large a shift toward earlier streamflow timing as the detectable observed shift. In other (including warm, snow free) regions, observed trends are typically not detectable, although in the U.S. central plains we find detectable delays in streamflow, which are inconsistent with forced model experiments.},
author = {Kam, Jonghun and Knutson, Thomas R. and Milly, P. C. D.},
doi = {10.1175/JCLI-D-17-0813.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jul},
number = {14},
pages = {5581--5593},
title = {{Climate Model Assessment of Changes in Winter–Spring Streamflow Timing over North America}},
url = {https://journals.ametsoc.org/doi/10.1175/JCLI-D-17-0813.1},
volume = {31},
year = {2018}
}
@article{doi:10.1002/2014GL061062,
abstract = {Abstract Anomalously high summertime temperatures have occurred with increasing frequency since the late 20th century. It is not clear why hot summers are becoming more frequent despite the recent slowdown in the rise in global surface air temperature. To examine factors affecting the historical variation in the frequency of hot summers over the Northern Hemisphere (NH), we conducted three sets of ensemble simulations with an atmospheric general circulation model. The model accurately reproduced interannual variation and long-term increase in the occurrence of hot summers. Decadal variabilities in the Pacific and Atlantic Oceans accounted for 43 ± 27{\%} of the recent increase over the NH middle latitudes. In addition, direct influence of anthropogenic forcing also contributes to increasing the frequency since the late 20th century. The results suggest that the heat extremes can become more frequent in the coming decade even with the persistent slowdown in the global-mean surface warming.},
author = {Kamae, Youichi and Shiogama, Hideo and Watanabe, Masahiro and Kimoto, Masahide},
doi = {10.1002/2014GL061062},
journal = {Geophysical Research Letters},
keywords = {AMO,PDO,climate hiatus,hot summers},
number = {14},
pages = {5192--5199},
title = {{Attributing the increase in Northern Hemisphere hot summers since the late 20th century}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2014GL061062},
volume = {41},
year = {2014}
}
@article{Kamae2017a,
author = {Kamae, Youichi and Li, Xichen and Xie, Shang-Ping and Ueda, Hiroaki},
doi = {10.1007/s00382-017-3522-3},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {nov},
number = {9-10},
pages = {3443--3455},
title = {{Atlantic effects on recent decadal trends in global monsoon}},
url = {http://link.springer.com/10.1007/s00382-017-3522-3},
volume = {49},
year = {2017}
}
@article{Kang2011a,
abstract = {Over the past half-century, the ozone hole has caused a poleward shift of the extratropical westerly jet in the Southern Hemisphere. Here, we argue that these extratropical circulation changes, resulting from ozone depletion, have substantially contributed to subtropical precipitation changes. Specifically, we show that precipitation in the southern subtropics in austral summer increases significantly when climate models are integrated with reduced polar ozone concentrations. Furthermore, the observed patterns of subtropical precipitation change, from 1979 to 2000, are very similar to those in our model integrations, where ozone depletion alone is prescribed. In both climate models and observations, the subtropical moistening is linked to a poleward shift of the extratropical westerly jet. Our results highlight the importance of polar regions for the subtropical hydrological cycle.},
address = {1200 NEW YORK AVE},
author = {Kang, S M and Polvani, L M and Fyfe, J C and Sigmond, M},
doi = {10.1126/science.1202131},
issn = {0036-8075},
journal = {Science},
month = {may},
number = {6032},
pages = {951--954},
publisher = {AMER ASSOC ADVANCEMENT SCIENCE},
title = {{Impact of Polar Ozone Depletion on Subtropical Precipitation}},
volume = {332},
year = {2011}
}
@article{Karl1469,
abstract = {Previous analyses of global temperature trends during the first decade of the 21st century seemed to indicate that warming had stalled. This allowed critics of the idea of global warming to claim that concern about climate change was misplaced. Karl et al. now show that temperatures did not plateau as thought and that the supposed warming {\{}$\backslash$textquotedblleft{\}}hiatus{\{}$\backslash$textquotedblright{\}} is just an artifact of earlier analyses. Warming has continued at a pace similar to that of the last half of the 20th century, and the slowdown was just an illusion.Science, this issue p. 1469Much study has been devoted to the possible causes of an apparent decrease in the upward trend of global surface temperatures since 1998, a phenomenon that has been dubbed the global warming {\{}$\backslash$textquotedblleft{\}}hiatus.{\{}$\backslash$textquotedblright{\}} Here, we present an updated global surface temperature analysis that reveals that global trends are higher than those reported by the Intergovernmental Panel on Climate Change, especially in recent decades, and that the central estimate for the rate of warming during the first 15 years of the 21st century is at least as great as the last half of the 20th century. These results do not support the notion of a {\{}$\backslash$textquotedblleft{\}}slowdown{\{}$\backslash$textquotedblright{\}} in the increase of global surface temperature.},
author = {Karl, Thomas R and Arguez, Anthony and Huang, Boyin and Lawrimore, Jay H and McMahon, James R and Menne, Matthew J and Peterson, Thomas C and Vose, Russell S and Zhang, Huai-Min},
doi = {10.1126/science.aaa5632},
issn = {0036-8075},
journal = {Science},
number = {6242},
pages = {1469--1472},
publisher = {American Association for the Advancement of Science},
title = {{Possible artifacts of data biases in the recent global surface warming hiatus}},
url = {http://science.sciencemag.org/content/348/6242/1469},
volume = {348},
year = {2015}
}
@article{Karoly1989,
abstract = {[Composite seasonal mean and anomaly fields prepared from operational numerical analyses have been used to describe the Southern Hemisphere (SH) circulation features associated with El Ni{\~{n}}o–Southern Oscillation (ENSO) events. The period of analyses available (1972–83) has limited the composites to include only three ENSO events. The reliability and stability of the composites has been tested using multiple permutation methods and by comparison with the results obtained using a longer period (1950–79) of SH rawinsonde station data. In the SH winter, a weak equivalent–barotropic wavetrain pattern of anomalies extends over Australia and the South Pacific Ocean to South America. This wavetrain pattern is quite variable in amplitude and location between ENSO events, although it is more stable over the subtropical Pacific. In the SH summer, the circulation anomalies are more zonally symmetric, with increased height at low and high latitudes and decreased height in middle latitudes. The circulation anomalies in the SH summer are more stable than in winter, with similar patterns of anomalies in the subtropics and middle latitudes in all events.]},
author = {Karoly, David J},
doi = {10.1175/1520-0442(1989)002<1239:SHCFAW>2.0.CO;2},
issn = {0894-8755},
journal = {Journal of Climate},
month = {nov},
number = {11},
pages = {1239--1252},
publisher = {American Meteorological Society},
title = {{Southern Hemisphere Circulation Features Associated with El Ni{\~{n}}o-Southern Oscillation Events}},
url = {http://journals.ametsoc.org/doi/10.1175/1520-0442(1989)002{\%}3C1239:SHCFAW{\%}3E2.0.CO;2},
volume = {2},
year = {1989}
}
@incollection{Maycock2018,
address = {Geneva, Switzerland},
author = {Karpechko, A. Yu. and {Maycock (Lead Authors)}, A.C. and Abalos, M. and Akiyoshi, H. and Arblaster, J.M. and Garfinkel, C.I. and Rosenlof, K.H. and Sigmond, M.},
booktitle = {Scientific Assessment of Ozone Depletion: 2018},
doi = {https://csl.noaa.gov/assessments/ozone/2018/downloads/},
organization = {WMO},
pages = {5.1--5.69},
publisher = {World Meteorological Organization (WMO)},
series = {Global Ozone Research and Monitoring Project – Report No. 58},
title = {{Stratospheric Ozone Changes and Climate}},
url = {https://csl.noaa.gov/assessments/ozone/2018/downloads/},
year = {2018}
}
@article{Karpechko2017,
author = {Karpechko, Alexey Yu. and Hitchcock, Peter and Peters, Dieter H. W. and Schneidereit, Andrea},
doi = {10.1002/qj.3017},
issn = {00359009},
journal = {Quarterly Journal of the Royal Meteorological Society},
month = {apr},
number = {704},
pages = {1459--1470},
title = {{Predictability of downward propagation of major sudden stratospheric warmings}},
url = {http://doi.wiley.com/10.1002/qj.3017},
volume = {143},
year = {2017}
}
@article{karset2018strong,
author = {Karset, Inger Helene Hafsahl and Berntsen, Terje Koren and Storelvmo, Trude and Alterskj{\ae}r, Kari and Grini, Alf and Olivi{\'{e}}, Dirk and Kirkev{\aa}g, Alf and Seland, {\O}yvind and Iversen, Trond and Schulz, Michael},
doi = {10.5194/acp-18-7669-2018},
issn = {1680-7324},
journal = {Atmospheric Chemistry and Physics},
month = {jun},
number = {10},
pages = {7669--7690},
publisher = {Copernicus GmbH},
title = {{Strong impacts on aerosol indirect effects from historical oxidant changes}},
url = {https://acp.copernicus.org/articles/18/7669/2018/},
volume = {18},
year = {2018}
}
@article{Katzfuss2017,
abstract = {{\textcopyright}2017. American Geophysical Union. All Rights Reserved. Regression-based detection and attribution methods continue to take a central role in the study of climate change and its causes. Here we propose a novel Bayesian hierarchical approach to this problem, which allows us to address several open methodological questions. Specifically, we take into account the uncertainties in the true temperature change due to imperfect measurements, the uncertainty in the true climate signal under different forcing scenarios due to the availability of only a small number of climate model simulations, and the uncertainty associated with estimating the climate variability covariance matrix, including the truncation of the number of empirical orthogonal functions (EOFs) in this covariance matrix. We apply Bayesian model averaging to assign optimal probabilistic weights to different possible truncations and incorporate all uncertainties into the inference on the regression coefficients. We provide an efficient implementation of our method in a software package and illustrate its use with a realistic application.},
author = {Katzfuss, M. and Hammerling, D. and Smith, R.L.},
doi = {10.1002/2017GL073688},
journal = {Geophysical Research Letters},
number = {11},
pages = {5720--5728},
title = {{A Bayesian hierarchical model for climate change detection and attribution}},
volume = {44},
year = {2017}
}
@article{Kaufman,
abstract = {An extensive new multi-proxy database of paleo-temperature time series (Temperature 12k) enables a more robust analysis of global mean surface temperature (GMST) and associated uncertainties than was previously available. We applied five different statistical methods to reconstruct the GMST of the past 12,000 years (Holocene). Each method used different approaches to averaging the globally distributed time series and to characterizing various sources of uncertainty, including proxy temperature, chronology and methodological choices. The results were aggregated to generate a multi-method ensemble of plausible GMST and latitudinal-zone temperature reconstructions with a realistic range of uncertainties. The warmest 200-year-long interval took place around 6500 years ago when GMST was 0.7 °C (0.3, 1.8) warmer than the 19 th Century (median, 5 th , 95 th percentiles). Following the Holocene global thermal maximum, GMST cooled at an average rate −0.08 °C per 1000 years (−0.24, −0.05). The multi-method ensembles and the code used to generate them highlight the utility of the Temperature 12k database, and they are now available for future use by studies aimed at understanding Holocene evolution of the Earth system.},
author = {Kaufman, Darrell and McKay, Nicholas and Routson, Cody and Erb, Michael and D{\"{a}}twyler, Christoph and Sommer, Philipp S. and Heiri, Oliver and Davis, Basil},
doi = {10.1038/s41597-020-0530-7},
issn = {2052-4463},
journal = {Scientific Data},
month = {dec},
number = {1},
pages = {201},
pmid = {32606396},
title = {{Holocene global mean surface temperature, a multi-method reconstruction approach}},
url = {http://www.nature.com/articles/s41597-020-0530-7},
volume = {7},
year = {2020}
}
@article{Kay2015,
abstract = {While internal climate variability is known to affect climate projections, its influence is often underappreciated and confused with model error. Why? In general, modeling centers contribute a small number of realizations to international climate model assessments [e.g., phase 5 of the Coupled Model Intercomparison Project (CMIP5)]. As a result, model error and internal climate variability are difficult, and at times impossible, to disentangle. In response, the Community Earth System Model (CESM) community designed the CESM Large Ensemble (CESM-LE) with the explicit goal of enabling assessment of climate change in the presence of internal climate variability. All CESM-LE simulations use a single CMIP5 model (CESM with the Community Atmosphere Model, version 5). The core simulations replay the twenty to twenty-first century (1920–2100) 30 times under historical and representative concentration pathway 8.5 external forcing with small initial condition differences. Two companion 1000+-yr-long preindustrial control simulations (fully coupled, prognostic atmosphere and land only) allow assessment of internal climate variability in the absence of climate change. Comprehensive outputs, including many daily fields, are available as single-variable time series on the Earth System Grid for anyone to use. Early results demonstrate the substantial influence of internal climate variability on twentieth- to twenty-first-century climate trajectories. Global warming hiatus decades occur, similar to those recently observed. Internal climate variability alone can produce projection spread comparable to that in CMIP5. Scientists and stakeholders can use CESM-LE outputs to help interpret the observational record, to understand projection spread and to plan for a range of possible futures influenced by both internal climate variability and forced climate change.},
author = {Kay, J. E. and Deser, C. and Phillips, A. and Mai, A. and Hannay, C. and Strand, G. and Arblaster, J. M. and Bates, S. C. and Danabasoglu, G. and Edwards, J. and Holland, M. and Kushner, P. and Lamarque, J.-F. and Lawrence, D. and Lindsay, K. and Middleton, A. and Munoz, E. and Neale, R. and Oleson, K. and Polvani, L. and Vertenstein, M.},
doi = {10.1175/BAMS-D-13-00255.1},
issn = {0003-0007},
journal = {Bulletin of the American Meteorological Society},
month = {aug},
number = {8},
pages = {1333--1349},
title = {{The Community Earth System Model (CESM) Large Ensemble Project: A Community Resource for Studying Climate Change in the Presence of Internal Climate Variability}},
url = {https://journals.ametsoc.org/doi/10.1175/BAMS-D-13-00255.1},
volume = {96},
year = {2015}
}
@article{doi:10.1029/2011GL048008,
abstract = {A climate model (CCSM4) is used to investigate the influence of anthropogenic forcing on late 20th century and early 21st century Arctic sea ice extent trends. On all timescales examined (2–50+ years), the most extreme negative observed late 20th century trends cannot be explained by modeled natural variability alone. Modeled late 20th century ice extent loss also cannot be explained by natural causes alone, but the six available CCSM4 ensemble members exhibit a large spread in their late 20th century ice extent loss. Comparing trends from the CCSM4 ensemble to observed trends suggests that internal variability explains approximately half of the observed 1979–2005 September Arctic sea ice extent loss. In a warming world, CCSM4 shows that multi-decadal negative trends increase in frequency and magnitude, and that trend variability on 2–10 year timescales increases. Furthermore, when internal variability counteracts anthropogenic forcing, positive trends on 2–20 year timescales occur until the middle of the 21st century.},
author = {Kay, Jennifer E and Holland, Marika M and Jahn, Alexandra},
doi = {10.1029/2011GL048008},
journal = {Geophysical Research Letters},
keywords = {Arctic sea ice,anthropogenic forcing,climate models,natural variability},
number = {15},
pages = {L15708},
title = {{Inter-annual to multi-decadal Arctic sea ice extent trends in a warming world}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2011GL048008},
volume = {38},
year = {2011}
}
@article{Keeling1996b,
author = {Keeling, C D and Chin, J F S and Whorf, T P},
doi = {10.1038/382146a0},
issn = {0028-0836},
journal = {Nature},
month = {jul},
number = {6587},
pages = {146--149},
publisher = {Nature Publishing Group},
title = {{Increased activity of northern vegetation inferred from atmospheric CO2 measurements}},
url = {http://www.nature.com/articles/382146a0},
volume = {382},
year = {1996}
}
@article{Kharin2018a,
abstract = {Parties to the United Nations Framework Convention on Climate Change have agreed to hold the “increase in global average temperature to well below 2°C above preindustrial levels and to pursue efforts to limit the temperature increase to 1.5°C.” Comparison of the costs and benefits for different warming limits requires an understanding of how risks vary between warming limits. As changes in risk are often associated with changes in exposure due to projected changes in local or regional climate extremes, we analyze differences in the risks of extreme daily temperatures and extreme daily precipitation amounts under different warming limits. We show that global warming of 2°C would result in substantially larger changes in the probabilities of the extreme events than global warming of 1.5°C. For example, over the global land area, the probability of a warm extreme that occurs once every 20 years on average in the current climate is projected to increase 130{\%} and 340{\%} at the 1.5°C and 2.0°C warming levels, respectively (median values). Moreover, the relative changes in probability are larger for rarer, more extreme events, implying that risk assessments need to carefully consider the extreme event thresholds at which vulnerabilities occur.},
author = {Kharin, V. V. and Flato, G. M. and Zhang, X. and Gillett, N. P. and Zwiers, F. and Anderson, K. J.},
doi = {10.1002/2018EF000813},
issn = {23284277},
journal = {Earth's Future},
month = {may},
number = {5},
pages = {704--715},
title = {{Risks from Climate Extremes Change Differently from 1.5°C to 2.0°C Depending on Rarity}},
url = {https://onlinelibrary.wiley.com/doi/10.1002/2018EF000813},
volume = {6},
year = {2018}
}
@article{Kidston2015c,
author = {Kidston, Joseph and Scaife, Adam A. and Hardiman, Steven C. and Mitchell, Daniel M. and Butchart, Neal and Baldwin, Mark P. and Gray, Lesley J.},
doi = {10.1038/ngeo2424},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {jun},
number = {6},
pages = {433--440},
title = {{Stratospheric influence on tropospheric jet streams, storm tracks and surface weather}},
volume = {8},
year = {2015}
}
@article{Kim2017,
abstract = {This study conducts an attribution analysis of long-term changes in the southern edge of the local Hadley cell (HC) during austral summer for the past three decades (1979–2009). The southern edges of the local overturning circulations (local HC) are defined as the latitudes of maximum sea level pressure in the Southern Hemisphere subtropics, and the long-term variations of local HC edges from multireanalyses are compared with those from Coupled Model Intercomparison Project Phase 5 (CMIP5) multimodel simulations by using the optimal fingerprinting technique. The observed local HC exhibits a poleward expansion in the Atlantic and Indian Ocean regions, which is successfully reproduced by the CMIP5 models including anthropogenic forcing (ANT) but with a weaker amplitude. The detection analyses further show that ANT signals are detected robustly in both Atlantic and Indian HC trends. More importantly, anthropogenic forcings other than greenhouse gas forcing are found to be clearly detected in isolation, indicating a possible attribution of the observed local HC widening over these regions to stratospheric ozone depletion.},
annote = {Zonal mean and basin Hadley cell, SH, DJF
8 reanalyses
CMIP5 historical+RCP4.5, historicalGHG, historicalNat, piControl
dSLP/dy = 0 in zonal mean, Atlantic, Indian Ocean and Eastern Pacific
Optimal fingerprinting

- Poleward shift of the Hadley cell edge is detected in Atl, and in IO widening is comparable with piControl internal variability range
- Zonal mean edge shift is close to (but within) 95 percentile of internal variability
- Historical forcing show poleward shift, with weak contribution from GHG  suggesting importance of ozone forcing
- The overall underestimation suggest model bias as well as contribution from internal variability},
author = {Kim, Yeon Hee and Min, Seung Ki and Son, Seok Woo and Choi, Jung},
doi = {10.1002/2016GL072353},
issn = {19448007},
journal = {Geophysical Research Letters},
keywords = {Southern Hemisphere,detection and attribution,local Hadley cell,tropical expansion},
number = {2},
pages = {1015--1024},
title = {{Attribution of the local Hadley cell widening in the Southern Hemisphere}},
volume = {44},
year = {2017}
}
@article{Kim2017a,
abstract = { AbstractA sudden stratospheric warming (SSW) is often defined as zonal-mean zonal wind reversal at 10 hPa and 60°N. This simple definition has been applied not only to the reanalysis data but also to climate model output. In the present study, it is shown that the application of this definition to models can be significantly influenced by model mean biases (i.e., more frequent SSWs appear to occur in models with a weaker climatological polar vortex). To overcome this deficiency, a tendency-based definition is proposed and applied to the multimodel datasets archived for phase 5 of the Coupled Model Intercomparison Project (CMIP5). In this definition, SSW-like events are defined by sufficiently strong vortex deceleration. This approach removes a linear relationship between SSW frequency and intensity of the climatological polar vortex in the CMIP5 models. The models' SSW frequency instead becomes significantly correlated with the climatological upward wave flux at 100 hPa, a measure of interaction between the troposphere and stratosphere. Lower stratospheric wave activity and downward propagation of stratospheric anomalies to the troposphere are also reasonably well captured. However, in both definitions, the high-top models generally exhibit more frequent SSWs than the low-top models. Moreover, a hint of more frequent SSWs in a warm climate is found in both definitions. },
author = {Kim, Junsu and Son, Seok-Woo and Gerber, Edwin P and Park, Hyo-Seok},
doi = {10.1175/JCLI-D-16-0465.1},
journal = {Journal of Climate},
number = {14},
pages = {5529--5546},
title = {{Defining Sudden Stratospheric Warming in Climate Models: Accounting for Biases in Model Climatologies}},
volume = {30},
year = {2017}
}
@article{Kim2014,
abstract = {Successive cold winters of severely low temperatures in recent years have had critical social and economic impacts on the mid-latitude continents in the Northern Hemisphere. Although these cold winters are thought to be partly driven by dramatic losses of Arctic sea-ice, the mechanism that links sea-ice loss to cold winters remains a subject of debate. Here, by conducting observational analyses and model experiments, we show how Arctic sea-ice loss and cold winters in extra-polar regions are dynamically connected through the polar stratosphere. We find that decreased sea-ice cover during early winter months (November-December), especially over the Barents-Kara seas, enhances the upward propagation of planetary-scale waves with wavenumbers of 1 and 2, subsequently weakening the stratospheric polar vortex in mid-winter (January-February). The weakened polar vortex preferentially induces a negative phase of Arctic Oscillation at the surface, resulting in low temperatures in mid-latitudes.},
annote = {Obs composite based on Barents-Kara SIC
Low SIC is associated with
- Early winter tropospheric wave pattern
- Upward propagation
- More SSW
- Downward influence, negative AO

- CAM5, CAM3
- 40 member, control: forced by climatological SST and SIC
- 40 member, perturbed: composited SST and SIC in the Arctic
- Captures the SSW, stratospheric signal, downwarld influence},
author = {Kim, Baek Min and Son, Seok Woo and Min, Seung Ki and Jeong, Jee Hoon and Kim, Seong Joong and Zhang, Xiangdong and Shim, Taehyoun and Yoon, Jin Ho},
doi = {10.1038/ncomms5646},
journal = {Nature Communications},
number = {1},
pages = {4646},
publisher = {Nature Publishing Group},
title = {{Weakening of the stratospheric polar vortex by Arctic sea-ice loss}},
url = {http://dx.doi.org/10.1038/ncomms5646},
volume = {5},
year = {2014}
}
@article{Kim2018,
abstract = {AbstractThere is observational and modeling evidence that low-frequency variability in the North Atlantic has significant implications for the global climate, particularly for the climate of the Northern Hemisphere. This study explores the representation of low-frequency variability in the Atlantic region in historical large ensemble and preindustrial control simulations performed with the Community Earth System Model (CESM). Compared to available observational estimates, it is found that the simulated variability in Atlantic meridional overturning circulation (AMOC), North Atlantic sea surface temperature (NASST), and Sahel rainfall is underestimated on multidecadal time scales but comparable on interannual to decadal time scales. The weak multidecadal North Atlantic variability appears to be closely related to weaker-than-observed multidecadal variations in the simulated North Atlantic Oscillation (NAO), as the AMOC and consequent NASST variability is impacted, to a great degree, by the NAO. Possible reasons for this weak multidecadal NAO variability are explored with reference to solutions from two atmosphere-only simulations with different lower boundary conditions and vertical resolution. Both simulations consistently reveal weaker-than-observed multidecadal NAO variability despite more realistic boundary conditions and better resolved dynamics than coupled simulations. The authors thus conjecture that the weak multidecadal NAO variability in CESM is likely due to deficiencies in air?sea coupling, resulting from shortcomings in the atmospheric model or coupling details.},
annote = {doi: 10.1175/JCLI-D-17-0193.1},
author = {Kim, Who M and Yeager, Stephen and Chang, Ping and Danabasoglu, Gokhan},
doi = {10.1175/JCLI-D-17-0193.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {oct},
number = {2},
pages = {787--813},
publisher = {American Meteorological Society},
title = {{Low-Frequency North Atlantic Climate Variability in the Community Earth System Model Large Ensemble}},
url = {https://doi.org/10.1175/JCLI-D-17-0193.1},
volume = {31},
year = {2018}
}
@article{Kim2014a,
abstract = {In this study, using the Bjerknes stability (BJ) index analysis, we estimate the overall linear El Nin ˜o- Southern Oscillation (ENSO) stability and the relative contribution of positive feedbacks and damping processes to the stability in historical simulations of Coupled Model Intercomparison Project Phase 5 (CMIP5) models. When compared with CMIP3 models, the ENSO amplitudes and the ENSO stability as estimated by the BJ index in the CMIP5 models are more converged around the observed, estimated from the atmosphere and ocean reanalysis data sets. The reduced diversity among models in the simulated ENSO stability can be partly attributed to the reduced spread of the thermocline feedback and Ekman feedback terms among the models. However, a systematic bias per- sists from CMIP3 to CMIP5. In other words, the majority of the CMIP5 models analyzed in this study still underes- timate the zonal advective feedback, thermocline feedback and thermodynamic damping terms, when compared with those estimated from reanalysis. This discrepancy turns out to be related with a cold tongue bias in coupled models that causes a weaker atmospheric thermodynamical response to sea surface temperature changes and a weaker oceanic response (zonal currents and zonal thermocline slope) to wind changes.},
author = {Kim, Seon Tae and Cai, Wenju and Jin, Fei Fei and Yu, Jin Yi},
doi = {10.1007/s00382-013-1833-6},
isbn = {0930-7575},
issn = {14320894},
journal = {Climate Dynamics},
keywords = {BJ index,CMIP5,ENSO,ENSO feedback,ENSO stability},
number = {11-12},
pages = {3313--3321},
title = {{ENSO stability in coupled climate models and its association with mean state}},
volume = {42},
year = {2014}
}
@article{Kim2012,
abstract = {In this study, we evaluate the intensity of the Central- Pacific (CP) and Eastern-Pacific (EP) types of El Ni{\~{n}}o- Southern Oscillation (ENSO) simulated in the pre-industrial, historical, and the Representative Concentration Pathways (RCP) 4.5 experiments of the Coupled Model Intercom- parison Project Phase 5 (CMIP5). Compared to the CMIP3 models, the pre-industrial simulations of the CMIP5 models are found to (1) better simulate the observed spatial patterns of the two types of ENSO and (2) have a significantly smaller inter-model diversity in ENSO intensities. The decrease in the CMIP5 model discrepancies is particularly obvious in the simulation of the EP ENSO intensity, although it is still more difficult for the models to reproduce the observed EP ENSO intensity than the observed CP ENSO intensity. Ensemble means of the CMIP5 models indicate that the intensity of the CP ENSO increases steadily from the pre-industrial to the historical and the RCP4.5 simulations, but the intensity of the EP ENSO increases from the pre-industrial to the historical simulations and then decreases in the RCP4.5 projections. The CP-to-EP ENSO intensity ratio, as a result, is almost the same in the pre-industrial and historical simulations but increases in the RCP4.5 simulation.},
author = {Kim, Seon Tae and Yu, Jin Yi},
doi = {10.1029/2012GL052006},
isbn = {0094-8276},
issn = {00948276},
journal = {Geophysical Research Letters},
number = {11},
pages = {1--6},
title = {{The two types of ENSO in CMIP5 models}},
volume = {39},
year = {2012}
}
@article{Kim2019a,
abstract = {The sea surface temperature (SST) signature of Atlantic multidecadal variability (AMV) is a key driver of climate variability in surrounding regions. Low-frequency Atlantic meridional overturning circulation (AMOC) variability is often invoked as a key driving mechanism of AMV-related SST anomalies. However, the origins of both AMV and multidecadal AMOC variability remain areas of active research and debate. Here, using coupled ensemble experiments designed to isolate the climate response to buoyancy forcing associated with the North Atlantic Oscillation in the Labrador Sea, we show that ocean dynamical changes are the essential drivers of AMV and related climate impacts. Atmospheric teleconnections also play an important role in rendering the full AMV pattern by transmitting the ocean-driven subpolar SST signal into the rest of the basin, including the tropical North Atlantic. As such, the atmosphere response to the tropical AMV in our experiments is limited to a relatively small area in the Atlantic sector in summertime, suggesting that it could be overestimated in widely adopted protocols for AMV pacemaker experiments.},
author = {Kim, Who M. and Yeager, Stephen and Danabasoglu, Gokhan},
doi = {10.1175/JCLI-D-19-0530.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {feb},
number = {4},
pages = {1317--1334},
title = {{Atlantic Multidecadal Variability and Associated Climate Impacts Initiated by Ocean Thermohaline Dynamics}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-19-0530.1},
volume = {33},
year = {2020}
}
@article{Kim2018a,
author = {Kim, Who M. and Yeager, Stephen G. and Danabasoglu, Gokhan},
doi = {10.1029/2018GL080474},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {dec},
number = {24},
pages = {13449--13457},
title = {{Key Role of Internal Ocean Dynamics in Atlantic Multidecadal Variability During the Last Half Century}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GL080474},
volume = {45},
year = {2018}
}
@article{doi:10.1175/JCLI-D-16-0412.1,
abstract = { AbstractArctic sea ice extent (SIE) has decreased over recent decades, with record-setting minimum events in 2007 and again in 2012. A question of interest across many disciplines concerns the extent to which such extreme events can be attributed to anthropogenic influences. First, a detection and attribution analysis is performed for trends in SIE anomalies over the observed period. The main objective of this study is an event attribution analysis for extreme minimum events in Arctic SIE. Although focus is placed on the 2012 event, the results are generalized to extreme events of other magnitudes, including both past and potential future extremes. Several ensembles of model responses are used, including two single-model large ensembles. Using several different metrics to define the events in question, it is shown that an extreme SIE minimum of the magnitude seen in 2012 is consistent with a scenario including anthropogenic influence and is extremely unlikely in a scenario excluding anthropogenic influence. Hence, the 2012 Arctic sea ice minimum provides a counterexample to the often-quoted idea that individual extreme events cannot be attributed to human influence. },
author = {Kirchmeier-Young, Megan C and Zwiers, Francis W and Gillett, Nathan P},
doi = {10.1175/JCLI-D-16-0412.1},
journal = {Journal of Climate},
number = {2},
pages = {553--571},
title = {{Attribution of Extreme Events in Arctic Sea Ice Extent}},
url = {https://doi.org/10.1175/JCLI-D-16-0412.1},
volume = {30},
year = {2017}
}
@article{Kjeldsen2015a,
abstract = {The response of the Greenland Ice Sheet (GIS) to changes in temperature during the twentieth century remains contentious, largely owing to difficulties in estimating the spatial and temporal distribution of ice mass changes before 1992, when Greenland-wide observations first became available. The only previous estimates of change during the twentieth century are based on empirical modelling and energy balance modelling. Consequently, no observation-based estimates of the contribution from the GIS to the global-mean sea level budget before 1990 are included in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Here we calculate spatial ice mass loss around the entire GIS from 1900 to the present using aerial imagery from the 1980s. This allows accurate high-resolution mapping of geomorphic features related to the maximum extent of the GIS during the Little Ice Age at the end of the nineteenth century. We estimate the total ice mass loss and its spatial distribution for three periods: 1900-1983 (75.1±29.4 gigatonnes per year), 1983-2003 (73.8±40.5 gigatonnes per year), and 2003-2010 (186.4±18.9 gigatonnes per year). Furthermore, using two surface mass balance models we partition the mass balance into a term for surface mass balance (that is, total precipitation minus total sublimation minus runoff) and a dynamic term. We find that many areas currently undergoing change are identical to those that experienced considerable thinning throughout the twentieth century. We also reveal that the surface mass balance term shows a considerable decrease since 2003, whereas the dynamic term is constant over the past 110 years. Overall, our observation-based findings show that during the twentieth century the GIS contributed at least 25.0±9.4millimetres of global-mean sea level rise. Our result will help to close the twentieth-century sea level budget, which remains crucial for evaluating the reliability of models used to predict global sea level rise.},
author = {Kjeldsen, Kristian K. and Korsgaard, Niels J. and Bj{\o}rk, Anders A. and Khan, Shfaqat A. and Box, Jason E. and Funder, Svend and Larsen, Nicolaj K. and Bamber, Jonathan L. and Colgan, William and van den Broeke, Michiel and Siggaard-Andersen, Marie-Louise and Nuth, Christopher and Schomacker, Anders and Andresen, Camilla S. and Willerslev, Eske and Kj{\ae}r, Kurt H.},
doi = {10.1038/nature16183},
issn = {0028-0836},
journal = {Nature},
month = {dec},
number = {7582},
pages = {396--400},
publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.},
title = {{Spatial and temporal distribution of mass loss from the Greenland Ice Sheet since AD 1900}},
url = {http://dx.doi.org/10.1038/nature16183 http://10.0.4.14/nature16183 http://www.nature.com/articles/nature16183},
volume = {528},
year = {2015}
}
@article{Knudsen2014,
author = {Knudsen, Mads Faurschou and Jacobsen, Bo Holm and Seidenkrantz, Marit-Solveig and Olsen, Jesper},
doi = {10.1038/ncomms4323},
issn = {2041-1723},
journal = {Nature Communications},
month = {may},
number = {1},
pages = {3323},
title = {{Evidence for external forcing of the Atlantic Multidecadal Oscillation since termination of the Little Ice Age}},
url = {http://www.nature.com/articles/ncomms4323},
volume = {5},
year = {2014}
}
@article{Knutson2018a,
author = {Knutson, T. R. and Zeng, F},
doi = {10.1175/JCLI-D-17-0672.1},
journal = {Journal of Climate},
number = {12},
pages = {4617--4637},
title = {{Model Assessment of observed precipitation trends over land regions: Detectable human influences and possible low bias in model trends}},
volume = {31},
year = {2018}
}
@article{Knutti2013a,
abstract = {A new ensemble of climate models is becoming available and provides the basis for climate change projections. Here, we show a first analysis indicating that the models in the new ensemble agree better with observations than those in older ones and that the poorest models have been eliminated. Most models are strongly tied to their predecessors, and some also exchange ideas and code with other models, thus supporting an earlier hypothesis that the models in the new ensemble are neither independent of each other nor independent of the earlier generation. On the basis of one atmosphere model, we show how statistical methods can identify similarities between model versions and complement process understanding in characterizing how and why a model has changed. We argue that the interdependence of models complicates the interpretation of multimodel ensembles but largely goes unnoticed.},
author = {Knutti, Reto and Masson, David and Gettelman, Andrew},
doi = {10.1002/grl.50256},
isbn = {1944-8007},
issn = {00948276},
journal = {Geophysical Research Letters},
number = {6},
pages = {1194--1199},
title = {{Climate model genealogy: Generation CMIP5 and how we got there}},
volume = {40},
year = {2013}
}
@article{Kociuba2015,
abstract = {This paper examines changes in the strength of the Walker circulation (WC) using the pressure difference between the western and eastern equatorial Pacific. Changes in observations and in 35 climate models from the Coupled Model Intercomparison Project (CMIP) phase 5 (CMIP5) are determined. On the one hand, 78{\%} of the models show a weakening of the WC over the twentieth century, consistent with the observations and previous studies using CMIP phase 3 (CMIP3) models. However, the observations also exhibit a strengthening in the last three decades (i.e., from 1980 to 2012) that is statistically significant at the 95{\%} level. The models, on the other hand, show no consensus on the sign of change, and none of the models shows a statistically significant strengthening over the same period. While the reasons for the inconsistency between models and observations is not fully understood, it is shown that the ability of the models to generate trends as large as the observed from internal variability is reduced because most models have weaker than observed levels of both multidecadal variability and persistence of interannual variability in WC strength. In the twenty-first-century future projections, the WC weakens in 25 out of 35 models, under representative concentration pathway (RCP) 8.5, 9 out of 11 models under RCP6.0, 16 out of 18 models under RCP4.5, and 12 out of 15 models under RCP2.6. The projected decrease is also consistent with results obtained previously using models from CMIP3. However, as the reasons for the inconsistency between modeled and observed trends in the last three decades are not fully understood, confidence in the model projections is reduced.},
annote = {Pacific Walker circulation
$\Delta$SLP
CMIP5 historical + RCP8.5
SOI, HadSLP2r (variance-adjusted)
Past 1900-2012, 1980-2012, future 2013-2100

- Most of models agree with the sign of 1900-2012 trend (weakening), consistent with observations, although a bit weaker (but not in order)
- Observations show significant strengthening for 1980-2012, while models don't agree even in sign
- Decadal-multidecadal variability is underestimated in models in relation to too oscillatory ENSO},
author = {Kociuba, Greg and Power, Scott B.},
doi = {10.1175/JCLI-D-13-00752.1},
isbn = {10.1175/JCLI-D-13-00752.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Climate variability,Decadal variability,Interannual variability},
number = {1},
pages = {20--35},
title = {{Inability of CMIP5 models to simulate recent strengthening of the walker circulation: Implications for projections}},
volume = {28},
year = {2015}
}
@article{gmd-2019-369,
author = {Kodama, Chihiro and Ohno, Tomoki and Seiki, Tatsuya and Yashiro, Hisashi and Noda, Akira T and Nakano, Masuo and Yamada, Yohei and Roh, Woosub and Satoh, Masaki and Nitta, Tomoko and Goto, Daisuke and Miura, Hiroaki and Nasuno, Tomoe and Miyakawa, Tomoki and Chen, Ying-Wen and Sugi, Masato},
doi = {10.5194/gmd-14-795-2021},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {feb},
number = {2},
pages = {795--820},
title = {{The Nonhydrostatic ICosahedral Atmospheric Model for CMIP6 HighResMIP simulations (NICAM16-S): experimental design, model description, and impacts of model updates}},
url = {https://gmd.copernicus.org/articles/14/795/2021/},
volume = {14},
year = {2021}
}
@article{kok2018global,
author = {Kok, Jasper F and Ward, Daniel S and Mahowald, Natalie M and Evan, Amato T},
doi = {10.1038/s41467-017-02620-y},
journal = {Nature communications},
number = {1},
pages = {241},
publisher = {Nature Publishing Group},
title = {{Global and regional importance of the direct dust–climate feedback}},
volume = {9},
year = {2018}
}
@article{Kopp2016c,
abstract = {We assess the relationship between temperature and global sealevel (GSL) variability over the Common Era through a statistical metaanalysis of proxy relative sea-level reconstructions and tidegauge data. GSL rose at 0.1 ± 0.1 mm/y (2$\sigma$) over 0-700 CE. A GSL fall of 0.2 ± 0.2 mm/y over 1000-1400 CE is associated with {\~{}}0.2 °C global mean cooling. A significant GSL acceleration began in the 19th century and yielded a 20th century rise that is extremely likely (probability P ≥0.95) faster than during any of the previous 27 centuries. A semiempirical model calibrated against the GSL reconstruction indicates that, in the absence of anthropogenic climate change, it is extremely likely (P =0.95) that 20th century GSL would have risen by less than 51{\%} of the observed 13.8±1.5 cm. The new semiempirical model largely reconciles previous differences between semiempirical 21st century GSL projections and the process model-based projections summarized in the Intergovernmental Panel on Climate Change¡¯s Fifth Assessment Report.},
author = {Kopp, Robert E. and Kemp, Andrew C. and Bittermann, Klaus and Horton, Benjamin P. and Donnelly, Jeffrey P. and Gehrels, W. Roland and Hay, Carling C. and Mitrovica, Jerry X. and Morrow, Eric D. and Rahmstorf, Stefan},
doi = {10.1073/pnas.1517056113},
issn = {10916490},
journal = {Proceedings of the National Academy of Sciences},
keywords = {Climate,Common Era,Late Holocene,Ocean,Sea level},
month = {mar},
number = {11},
pages = {E1434--E1441},
publisher = {National Academy of Sciences},
title = {{Temperature-driven global sea-level variability in the Common Era}},
volume = {113},
year = {2016}
}
@article{Kosaka2013,
abstract = {Despite the continued increase in atmospheric greenhouse gas concentrations, the annual-mean global temperature has not risen in the twenty-first century, challenging the prevailing view that anthropogenic forcing causes climate warming. Various mechanisms have been proposed for this hiatus in global warming, but their relative importance has not been quantified, hampering observational estimates of climate sensitivity. Here we show that accounting for recent cooling in the eastern equatorial Pacific reconciles climate simulations and observations. We present a novel method of uncovering mechanisms for global temperature change by prescribing, in addition to radiative forcing, the observed history of sea surface temperature over the central to eastern tropical Pacific in a climate model. Although the surface temperature prescription is limited to only 8.2{\%} of the global surface, our model reproduces the annual-mean global temperature remarkably well with correlation coefficient r = 0.97 for 1970-2012 (which includes the current hiatus and a period of accelerated global warming). Moreover, our simulation captures major seasonal and regional characteristics of the hiatus, including the intensified Walker circulation, the winter cooling in northwestern North America and the prolonged drought in the southern USA. Our results show that the current hiatus is part of natural climate variability, tied specifically to a La-Ni{\~{n}}a-like decadal cooling. Although similar decadal hiatus events may occur in the future, the multi-decadal warming trend is very likely to continue with greenhouse gas increase.},
author = {Kosaka, Y. and Xie, S.-P.},
doi = {10.1038/nature12534},
journal = {Nature},
number = {7467},
pages = {403--407},
title = {{Recent global-warming hiatus tied to equatorial Pacific surface cooling}},
volume = {501},
year = {2013}
}
@article{Kosaka2016,
abstract = {{\textcopyright} 2016 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. Global mean surface temperature change over the past 120 years resembles a rising staircase: The overall warming trend was interrupted by the mid-Twentieth-century big hiatus and the warming slowdown since about 1998. The Interdecadal Pacific Oscillation has been implicated in modulations of global mean surface temperatures, but which part of the mode drives the variability in warming rates is unclear. Here we present a successful simulation of the global warming staircase since 1900 with a global ocean-Atmosphere coupled model where tropical Pacific sea surface temperatures are forced to follow the observed evolution. Without prescribed tropical Pacific variability, the same model, on average, produces a continual warming trend that accelerates after the 1960s. We identify four events where the tropical Pacific decadal cooling markedly slowed down the warming trend. Matching the observed spatial and seasonal fingerprints we identify the tropical Pacific as a key pacemaker of the warming staircase, with radiative forcing driving the overall warming trend. Specifically, tropical Pacific variability amplifies the first warming epoch of the 1910s-1940s and determines the timing when the big hiatus starts and ends. Our method of removing internal variability from the observed record can be used for real-Time monitoring of anthropogenic warming.},
author = {Kosaka, Yu and Xie, Shang-Ping},
doi = {10.1038/ngeo2770},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {sep},
number = {9},
pages = {669--673},
title = {{The tropical Pacific as a key pacemaker of the variable rates of global warming}},
url = {http://www.nature.com/articles/ngeo2770},
volume = {9},
year = {2016}
}
@article{Kostov2017,
abstract = {We investigate how sea surface temperatures (SSTs) around Antarctica respond to the Southern Annular Mode (SAM) on multiple timescales. To that end we examine the relationship between SAM and SST within unperturbed preindustrial control simulations of coupled general circulation models (GCMs) included in the Climate Modeling Intercomparison Project phase 5 (CMIP5). We develop a technique to extract the response of the Southern Ocean SST (55{\{}$\backslash$textdegree{\}}S--70{\{}$\backslash$textdegree{\}}S) to a hypothetical step increase in the SAM index. We demonstrate that in many GCMs, the expected SST step response function is nonmonotonic in time. Following a shift to a positive SAM anomaly, an initial cooling regime can transition into surface warming around Antarctica. However, there are large differences across the CMIP5 ensemble. In some models the step response function never changes sign and cooling persists, while in other GCMs the SST anomaly crosses over from negative to positive values only 3 years after a step increase in the SAM. This intermodel diversity can be related to differences in the models' climatological thermal ocean stratification in the region of seasonal sea ice around Antarctica. Exploiting this relationship, we use observational data for the time-mean meridional and vertical temperature gradients to constrain the real Southern Ocean response to SAM on fast and slow timescales.},
author = {Kostov, Yavor and Marshall, John and Hausmann, Ute and Armour, Kyle C and Ferreira, David and Holland, Marika M},
doi = {10.1007/s00382-016-3162-z},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {5},
pages = {1595--1609},
title = {{Fast and slow responses of Southern Ocean sea surface temperature to SAM in coupled climate models}},
url = {https://doi.org/10.1007/s00382-016-3162-z},
volume = {48},
year = {2017}
}
@article{Kucharski2016,
abstract = {This paper investigates the Atlantic Ocean influence on equatorial Pacific decadal variability. Using an ensemble of simulations, where the ICTPAGCM (``SPEEDY'') is coupled to the NEMO/OPA ocean model in the Indo-Pacific region and forced by observed sea surface temperatures in the Atlantic region, it is shown that the Atlantic Multidecadal Oscillation (AMO) has had a substantial influence on the equatorial Pacific decadal variability. According to AMO phases we have identified three periods with strong Atlantic forcing of equatorial Pacific changes, namely (1) 1931--1950 minus 1910--1929, (2) 1970--1989 minus 1931--1950 and (3) 1994--2013 minus 1970--1989. Both observations and the model show easterly surface wind anomalies in the central Pacific, cooling in the central-eastern Pacific and warming in the western Pacific/Indian Ocean region in events (1) and (3) and the opposite signals in event (2). The physical mechanism for these responses is related to a modification of the Walker circulation because a positive (negative) AMO leads to an overall warmer (cooler) tropical Atlantic. The warmer (cooler) tropical Atlantic modifies the Walker circulation, leading to rising (sinking) and upper-level divergence (convergence) motion in the Atlantic region and sinking (rising) motion and upper-level convergence (divergence) in the central Pacific region.},
author = {Kucharski, Fred and Ikram, Farah and Molteni, Franco and Farneti, Riccardo and Kang, In-Sik and No, Hyun-Ho and King, Martin P and Giuliani, Graziano and Mogensen, Kristian},
doi = {10.1007/s00382-015-2705-z},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {7},
pages = {2337--2351},
title = {{Atlantic forcing of Pacific decadal variability}},
url = {https://doi.org/10.1007/s00382-015-2705-z},
volume = {46},
year = {2016}
}
@article{Kuhlbrodt2018a,
abstract = {A new climate model, HadGEM3 N96ORCA1, is presented that is part of the GC3.1 configuration of HadGEM3. N96ORCA1 has a horizontal resolution of {\~{}}135 km in the atmosphere and 1° in the ocean and requires an order of magnitude less computing power than its medium-resolution counterpart, N216ORCA025, while retaining a high degree of performance traceability. Scientific performance is compared to both observations and the N216ORCA025 model. N96ORCA1 reproduces observed climate mean and variability almost as well as N216ORCA025. Patterns of biases are similar across the two models. In the northwest Atlantic, N96ORCA1 shows a cold surface bias of up to 6 K, typical of ocean models of this resolution. The strength of the Atlantic meridional overturning circulation (16 to 17 Sv) matches observations. In the Southern Ocean, a warm surface bias (up to 2 K) is smaller than in N216ORCA025 and linked to improved ocean circulation. Model El Ni{\~{n}}o/Southern Oscillation and Atlantic Multidecadal Variability are close to observations. Both the cold bias in the Northern Hemisphere (N96ORCA1) and the warm bias in the Southern Hemisphere (N216ORCA025) develop in the first few decades of the simulations. As in many comparable climate models, simulated interhemispheric gradients of top-of-atmosphere radiation are larger than observations suggest, with contributions from both hemispheres. HadGEM3 GC3.1 N96ORCA1 constitutes the physical core of the UK Earth System Model (UKESM1) and will be used extensively in the Coupled Model Intercomparison Project 6 (CMIP6), both as part of the UK Earth System Model and as a stand-alone coupled climate model.},
author = {Kuhlbrodt, Till and Jones, Colin G. and Sellar, Alistair and Storkey, Dave and Blockley, Ed and Stringer, Marc and Hill, Richard and Graham, Tim and Ridley, Jeff and Blaker, Adam and Calvert, Daley and Copsey, Dan and Ellis, Richard and Hewitt, Helene and Hyder, Patrick and Ineson, Sarah and Mulcahy, Jane and Siahaan, Antony and Walton, Jeremy},
doi = {10.1029/2018MS001370},
issn = {19422466},
journal = {Journal of Advances in Modeling Earth Systems},
keywords = {CMIP6,Earth system model,HadGEM,coupled climate model,model evaluation},
month = {nov},
number = {11},
pages = {2865--2888},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{The Low-Resolution Version of HadGEM3 GC3.1: Development and Evaluation for Global Climate}},
volume = {10},
year = {2018}
}
@article{Kuhlbrodt2012,
author = {Kuhlbrodt, T and Smith, R S and Wang, Z and Gregory, J M},
doi = {10.1016/j.ocemod.2012.04.006},
issn = {1463-5003},
journal = {Ocean Modelling},
pages = {1--8},
title = {{The influence of eddy parameterizations on the transport of the Antarctic Circumpolar Current in coupled climate models}},
volume = {52-53},
year = {2012}
}
@article{Kumar2014,
abstract = {Based on a novel design of coupled model simulations where sea surface temperature (SST) variability in the equatorial tropical Pacific was constrained to follow the observed El Ni{\~{n}}o-Southern Oscillation (ENSO) variability, while rest of the global oceans were free to evolve, the ENSO response in SSTs over the other ocean basins was analyzed. Conceptually the experimental setup was similar to discerning the contribution of ENSO variability to interannual variations in atmospheric anomalies. A unique feature of the analysis was that it was not constrained by a priori assumptions on the nature of the teleconnected response in SSTs. The analysis demonstrated that the time lag between ENSO SST and SSTs in other ocean basins was about 6 months. A signal-to-noise analysis indicated that between 25 and 50 {\%} of monthly mean SST variance over certain ocean basins can be attributed to SST variability over the equatorial tropical Pacific. The experimental setup provides a basis for (a) attribution of SST variability in global oceans to ENSO variability, (b) a method for separating the ENSO influence in SST variations, and (c) understanding the contribution from other external factors responsible for variations in SSTs, for example, changes in atmospheric composition, volcanic aerosols, etc. {\textcopyright} 2013 Springer-Verlag (outside the USA).},
author = {Kumar, A. and Jha, B. and Wang, H.},
doi = {10.1007/s00382-013-1865-y},
journal = {Climate Dynamics},
number = {1-2},
pages = {209--220},
title = {{Attribution of SST variability in global oceans and the role of ENSO}},
volume = {43},
year = {2014}
}
@article{Kumar2015c,
author = {Kumar, S and Allan, R. P. and Zwiers, F.W. and Lawrence, D. M. and Dirmeyer, P A},
doi = {10.1002/2015GL066858},
journal = {Geophysical Research Letters},
pages = {10867--10875},
title = {{Revisiting trends in wetness and dryness in the presence of internal climate variability and water limitations over land}},
volume = {42},
year = {2015}
}
@article{Kuntz2016,
author = {Kuntz, L. B. and Schrag, D. P.},
doi = {10.1002/2016JD025430},
issn = {2169897X},
journal = {Journal of Geophysical Research: Atmospheres},
month = {dec},
number = {24},
pages = {14,403--14,413},
title = {{Impact of Asian aerosol forcing on tropical Pacific circulation and the relationship to global temperature trends}},
url = {http://doi.wiley.com/10.1002/2016JD025430},
volume = {121},
year = {2016}
}
@article{LHeureux2013a,
abstract = {The Pacific Walker circulation is a large overturning cell that spans the tropical Pacific Ocean, characterized by rising motion (lower sea-level pressure) over Indonesia and sinking motion (higher sea level-pressure) over the eastern Pacific1,2. Fluctuations in the Walker circulation reflect changes in the location and strength of tropical heating, so related circulation anomalies have global impacts3,4. On interannual timescales, the El Ni{\~{n}}o/Southern Oscillation accounts for much of the variability in the Walker circulation, but there is considerable interest in longer-term trends and their drivers, including anthropogenic climate change5–12. Here, we examine sea-level pressure trends in ten different data sets drawn from reanalysis, reconstructions and in situ measurements for 1900–2011. We show that periods with fewer in situ measurements result in lower signal-to-noise ratios, making assessments of sea-level pressure trends largely unsuitable before about the 1950s. Multidecadal trends evaluated since 1950 reveal statistically significant, negative values over the Indonesian region, with weaker, positive trends over the eastern Pacific. The overall trend towards a stronger, La Ni{\~{n}}alike Walker circulation is nearly concurrent with the observed increase in global average temperatures, thereby justifying closer scrutiny of how the Pacific climate system has changed in the historical record},
author = {L'Heureux, Michelle L. and Lee, Sukyoung and Lyon, Bradfield},
doi = {10.1038/nclimate1840},
isbn = {1758-6798},
issn = {1758678X},
journal = {Nature Climate Change},
month = {mar},
number = {6},
pages = {571--576},
publisher = {Springer Nature},
title = {{Recent multidecadal strengthening of the Walker circulation across the tropical Pacific}},
volume = {3},
year = {2013}
}
@article{doi:10.1002/wcc.527,
abstract = {Sea surface temperature (SST) variability in the tropical Atlantic Ocean strongly impacts the climate on the surrounding continents. On interannual time scales, highest SST variability occurs in the eastern equatorial region and off the coast of southwestern Africa. The pattern of SST variability resembles the Pacific El Ni{\~{n}}o, but features notable differences, and has been discussed in the context of various climate modes, that is, reoccurring patterns resulting from particular interactions in the climate system. Here, we attempt to reconcile those different definitions, concluding that almost all of them are essentially describing the same mode that we refer to as the “Atlantic Ni{\~{n}}o.” We give an overview of the mechanisms that have been proposed to underlie this mode, and we discuss its interaction with other climate modes within and outside the tropical Atlantic. The impact of Atlantic Ni{\~{n}}o-related SST variability on rainfall, in particular over the Gulf of Guinea and north eastern South America is also described. An important aspect we highlight is that the Atlantic Ni{\~{n}}o and its teleconnections are not stationary, but subject to multidecadal modulations. Simulating the Atlantic Ni{\~{n}}o proves a challenge for state-of-the-art climate models, and this may be partly due to the large mean state biases in the region. Potential reasons for these model biases and implications for seasonal prediction are discussed. This article is categorized under: Climate Models and Modeling {\textgreater} Knowledge Generation with Models},
author = {L{\"{u}}bbecke, Joke F and Rodr{\'{i}}guez-Fonseca, Belen and Richter, Ingo and Mart{\'{i}}n-Rey, Marta and Losada, Teresa and Polo, Irene and Keenlyside, Noel S},
doi = {10.1002/wcc.527},
journal = {WIREs Climate Change},
keywords = {Atlantic Ni{\~{n}}o,climate models,climate variability,tropical Atlantic},
number = {4},
pages = {e527},
title = {{Equatorial Atlantic variability – Modes, mechanisms, and global teleconnections}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/wcc.527},
volume = {9},
year = {2018}
}
@article{Lucke2019,
abstract = {Quantifying past climate variation and attributing its causes improves our understanding of the natural variability of the climate system. Tree-ring-based proxies have provided skillful and highly resolved reconstructions of temperature and hydroclimate of the last millennium. However, like all proxies, they are subject to uncertainties arising from varying data quality, coverage, and reconstruction methodology. Previous studies have suggested that biological-based memory processes could cause spectral biases in climate reconstructions. This study determines the effects of such biases on reconstructed temperature variability and the resultant implications for detection and attribution studies. We find that introducing persistent memory, reflecting the spectral properties of tree-ring data, can change the variability of pseudoproxy reconstructions compared to the surrogate climate and resolve certain model–proxy discrepancies. This is especially the case for proxies based on ring-width data. Such memory inflates the difference between the Medieval Climate Anomaly and the Little Ice Age and suppresses and extends the cooling in response to volcanic eruptions. When accounting for memory effects, climate model data can reproduce long-term cooling after volcanic eruptions, as seen in proxy reconstructions. Results of detection and attribution studies show that signals in reconstructions as well as residual unforced variability are consistent with those in climate models when the model fingerprints are adjusted to reflect autoregressive memory as found in tree rings.},
address = {Boston MA, USA},
author = {L{\"{u}}cke, Lucie J. and Hegerl, Gabriele C. and Schurer, Andrew P. and Wilson, Rob},
doi = {10.1175/JCLI-D-19-0184.1},
issn = {08948755},
journal = {Journal of Climate},
language = {English},
number = {24},
pages = {8713--8731},
publisher = {American Meteorological Society},
title = {{Effects of memory biases on variability of temperature reconstructions}},
url = {https://journals.ametsoc.org/view/journals/clim/32/24/jcli-d-19-0184.1.xml},
volume = {32},
year = {2019}
}
@article{Ludecke2020,
author = {L{\"{u}}decke, Horst-Joachim and Cina, Richard and Dammschneider, Hans-Joachim and L{\"{u}}ning, Sebastian},
doi = {10.1016/j.jastp.2020.105294},
issn = {13646826},
journal = {Journal of Atmospheric and Solar-Terrestrial Physics},
month = {sep},
pages = {105294},
title = {{Decadal and multidecadal natural variability in European temperature}},
url = {https://linkinghub.elsevier.com/retrieve/pii/S1364682620301115},
volume = {205},
year = {2020}
}
@article{Laepple2014,
abstract = {The variability of sea surface temperatures (SSTs) at multidecadal and longer timescales is poorly constrained, primarily because instrumental records are short and proxy records are noisy. Through applying a new noise filtering technique to a global network of late Holocene SST proxies, we estimate SST variability between annual and millennial timescales. Filtered estimates of SST variability obtained from coral, foraminifer, and alkenone records are shown to be consistent with one another and with instrumental records in the frequency bands at which they overlap. General circulation models, however, simulate SST variability that is systematically smaller than instrumental and proxy-based estimates. Discrepancies in variability are largest at low latitudes and increase with timescale, reaching two orders of magnitude for tropical variability at millennial timescales. This result implies major deficiencies in observational estimates or model simulations, or both, and has implications for the attribution of past variations and prediction of future change.},
author = {Laepple, Thomas and Huybers, Peter},
doi = {10.1073/pnas.1412077111},
issn = {10916490},
journal = {Proceedings of the National Academy of Sciences},
keywords = {Climate variability,Multiproxy synthesis,Proxy data reconstruction,Sea surface temperature},
number = {47},
pages = {16682--16687},
publisher = {National Academy of Sciences},
title = {{Ocean surface temperature variability: Large model-data differences at decadal and longer periods}},
url = {https://www.pnas.org/content/111/47/16682},
volume = {111},
year = {2014}
}
@article{Lago2016,
abstract = {The ocean's surface salinity field has changed over the observed record, driven by an intensification of the water cycle in response to global warming. However, the origin and causes of the coincident subsurface salinity changes are not fully understood. The relationship between imposed surface salinity and temperature changes and their corresponding subsurface changes is investigated using idealized ocean model experiments. The ocean's surface has warmed by about 0.58C (50 yr)-1 while the surface salinity pattern has amplified by about 8{\%} per 50 years. The idealized experiments are constructed for a 50-yr period, allowing a qualitative comparison to the observed salinity and temperature changes previously reported. The comparison suggests that changes in both modeled surface salinity and temperature are required to replicate the three-dimensional pattern of observed salinity change. The results also show that the effects of surface changes in temperature and salinity act linearly on the changes in subsurface salinity. Surface salinity pattern amplification appears to be the leading driver of subsurface salinity change on depth surfaces; however, surface warming is also required to replicate the observed patterns of change on density surfaces. This is the result of isopycnal migration modified by the ocean surface warming, which produces significant salinity changes on density surfaces.},
author = {Lago, V{\'{e}}ronique and Wijffels, Susan E. and Durack, Paul J. and Church, John A. and Bindoff, Nathaniel L. and Marsland, Simon J.},
doi = {10.1175/JCLI-D-15-0519.1},
issn = {08948755},
journal = {Journal of Climate},
month = {dec},
number = {15},
pages = {5575--5588},
publisher = {American Meteorological Society},
title = {{Simulating the role of surface forcing on observed multidecadal upper-ocean salinity changes}},
volume = {29},
year = {2016}
}
@article{Lago2019,
abstract = { AbstractThe sinking and recirculation of Antarctic Bottom Water (AABW) are a major regulator of the storage of heat, carbon, and nutrients in the ocean. This sinking is sensitive to changes in surface buoyancy, in particular because of freshening since salinity plays a greater role in determining density at cold temperatures. Acceleration in Antarctic ice-shelf and land-ice melt could thus significantly impact the ventilation of the world's oceans, yet future projections do not usually include this effect in models. Here we use an ocean–sea ice model to investigate the potential long-term impact of Antarctic meltwater on ocean circulation and heat storage. The freshwater forcing is derived from present-day estimates of meltwater input from drifting icebergs and basal melt, combined with RCP2.6, RCP4.5, and RCP8.5 scenarios of projected amplification of Antarctic meltwater. We find that the additional freshwater induces a substantial slowdown in the formation rate of AABW, reducing ventilation of the abyssal ocean. Under both the RCP4.5 and RCP8.5 meltwater scenarios, there is a near-complete shutdown of AABW formation within just 50 years, something that is not captured by climate model projections. The abyssal overturning at {\~{}}30°S also weakens, with an {\~{}}20-yr delay relative to the onset of AABW slowdown. After 200 years, up to {\~{}}50{\%} of the original volume of AABW has disappeared as a result of abyssal warming, induced by vertical mixing in the absence of AABW ventilation. This result suggests that climate change could induce the disappearance of present-day abyssal water masses, with implications for the global distribution of heat, carbon, and nutrients. },
author = {Lago, V{\'{e}}ronique and England, Matthew H},
doi = {10.1175/JCLI-D-18-0622.1},
journal = {Journal of Climate},
number = {19},
pages = {6319--6335},
title = {{Projected Slowdown of Antarctic Bottom Water Formation in Response to Amplified Meltwater Contributions}},
volume = {32},
year = {2019}
}
@article{doi:10.1002/2017GL075618,
abstract = {Abstract It has been suggested that recent regional trends in Antarctic sea ice might have been caused by the formation of the ozone hole in the late twentieth century. Here we explore this by examining two ensembles of a climate model over the ozone hole formation period (1955–2005). One ensemble includes all known historical forcings; the other is identical except for ozone levels, which are fixed at 1955 levels. We demonstrate that the model is able to capture, on interannual and decadal timescales, the observed statistical relationship between summer Amundsen Sea Low strength (when ozone loss causes a robust deepening) and fall sea ice concentrations (when observed trends are largest). In spite of this, the modeled regional trends caused by ozone depletion are found to be almost exactly opposite to the observed ones. We deduce that the regional character of observed sea ice trends is likely not caused by ozone depletion.},
author = {Landrum, Laura L and Holland, Marika M and Raphael, Marilyn N and Polvani, Lorenzo M},
doi = {10.1002/2017GL075618},
journal = {Geophysical Research Letters},
keywords = {Amundsen Sea Low,Antarctic sea ice trends,stratrospheric ozone depletion},
number = {21},
pages = {11062--11070},
title = {{Stratospheric Ozone Depletion: An Unlikely Driver of the Regional Trends in Antarctic Sea Ice in Austral Fall in the Late Twentieth Century}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2017GL075618},
volume = {44},
year = {2017}
}
@article{Landrum2013,
abstract = {An overview of a simulation referred to as the “Last Millennium” (LM) simulation of the Community Climate System Model, version 4 (CCSM4), is presented. The CCSM4 LM simulation reproduces many large-scale climate patterns suggested by historical and proxy-data records, with Northern Hemisphere (NH) and Southern Hemisphere (SH) surface temperatures cooling to the early 1800s Common Era by {\~{}}0.5°C (NH) and {\~{}}0.3°C (SH), followed by warming to the present. High latitudes of both hemispheres show polar amplification of the cooling from the Medieval Climate Anomaly (MCA) to the Little Ice Age (LIA) associated with sea ice increases. The LM simulation does not reproduce La Ni{\~{n}}a–like cooling in the eastern Pacific Ocean during the MCA relative to the LIA, as has been suggested by proxy reconstructions. Still, dry medieval conditions over the southwestern and central United States are simulated in agreement with proxy indicators for these regions. Strong global cooling is associated with large volcanic eruptions, with indications of multidecadal colder climate in response to larger eruptions. The CCSM4's response to large volcanic eruptions captures some reconstructed patterns of temperature changes over Europe and North America, but not those of precipitation in the Asian monsoon region. The Atlantic multidecadal oscillation (AMO) has higher variance at centennial periods in the LM simulation compared to the 1850 nontransient run, suggesting a long-term Atlantic Ocean response to natural forcings. The North Atlantic Oscillation (NAO), Pacific decadal oscillation (PDO), and El Ni{\~{n}}o–Southern Oscillation (ENSO) variability modes show little or no change. CCSM4 does not simulate a persistent positive NAO or a prolonged period of negative PDO during the MCA, as suggested by some proxy reconstructions.},
author = {Landrum, Laura L. and Otto-Bliesner, Bette L. and Wahl, Eugene R. and Conley, Andrew and Lawrence, Peter J. and Rosenbloom, Nan and Teng, Haiyan},
doi = {10.1175/JCLI-D-11-00326.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {feb},
number = {4},
pages = {1085--1111},
title = {{Last Millennium Climate and Its Variability in CCSM4}},
url = {https://journals.ametsoc.org/jcli/article/26/4/1085/34276/Last-Millennium-Climate-and-Its-Variability-in},
volume = {26},
year = {2013}
}
@article{Landschutzer2016,
author = {Landsch{\"{u}}tzer, Peter and Gruber, Nicolas and Bakker, Dorothee C. E.},
doi = {10.1002/2015GB005359},
issn = {08866236},
journal = {Global Biogeochemical Cycles},
keywords = {carbon sink variability,climate change,global carbon budget,global carbon cycle,ocean biogeochemistry},
month = {oct},
number = {10},
pages = {1396--1417},
publisher = {Wiley-Blackwell},
title = {{Decadal variations and trends of the global ocean carbon sink}},
url = {http://doi.wiley.com/10.1002/2015GB005359},
volume = {30},
year = {2016}
}
@article{Langenbrunner2013a,
abstract = {The accurate representation of precipitation is a recurring issue in climate models. El Ni{\~{}} no–Southern Os- cillation (ENSO) precipitation teleconnections provide a test bed for comparison of modeled to observed precipitation. The simulation quality for the atmospheric component of models in the Coupled Model In- tercomparisonProject (CMIP) phase 5 (CMIP5) is assessed here, using the ensembleof runs driven by observed sea surface temperatures (SSTs). Simulated seasonal precipitation teleconnection patterns are compared to observations during 1979–2005 and to the ensemble of CMIP phase 3 (CMIP3).Within regions of strong ob- served teleconnections (equatorial South America, the western equatorial Pacific, and a southern section of NorthAmerica), there is little improvement in theCMIP5 ensemble relative toCMIP3 in amplitude and spatial correlation metrics of precipitation. Spatial patterns within each region exhibit substantial departures from observations, with spatial correlation coefficients typically less than 0.5. However, the atmospheric models do considerably better in other measures. First, the amplitude of the precipitation response (root-mean-square deviation over each region) is well estimated by themean of the amplitudes fromthe individualmodels. This is in contrast with the amplitude of the multimodel ensemble mean, which is systematically smaller (by about 30{\%}–40{\%}) in the selected teleconnection regions. Second, high intermodel agreement on teleconnection sign provides a good predictor for high model agreement with observed teleconnections. The ability of the model ensemble to yield amplitude and sign measures that agree with the observed signal for ENSO precipitation teleconnections lends supporting evidence for the use of correspondingmeasures in globalwarming projections.},
author = {Langenbrunner, Baird and Neelin, J. David},
doi = {10.1175/JCLI-D-12-00542.1},
isbn = {0894-8755 1520-0442},
issn = {08948755},
journal = {Journal of Climate},
number = {13},
pages = {4431--4446},
title = {{Analyzing ENSO Teleconnections in CMIP Models as a Measure of Model Fidelity in Simulating Precipitation}},
volume = {26},
year = {2013}
}
@article{Lapointe2020,
abstract = {Global warming due to anthropogenic factors can be amplified or dampened by natural climate oscillations, especially those involving sea surface temperatures (SSTs) in the North Atlantic which vary on a multidecadal scale (Atlantic multidecadal variability, AMV). Because the instrumental record of AMV is short, long-term behavior of AMV is unknown, but climatic teleconnections to regions beyond the North Atlantic offer the prospect of reconstructing AMV from high-resolution records elsewhere. Annually resolved titanium from an annually laminated sedimentary record from Ellesmere Island, Canada, shows that the record is strongly influenced by AMV via atmospheric circulation anomalies. Significant correlations between this High-Arctic proxy and other highly resolved Atlantic SST proxies demonstrate that it shares the multidecadal variability seen in the Atlantic. Our record provides a reconstruction of AMV for the past ∼3 millennia at an unprecedented time resolution, indicating North Atlantic SSTs were coldest from ∼1400–1800 CE, while current SSTs are the warmest in the past ∼2,900 y.},
author = {Lapointe, Francois and Bradley, Raymond S. and Francus, Pierre and Balascio, Nicholas L. and Abbott, Mark B. and Stoner, Joseph S. and St-Onge, Guillaume and {De Coninck}, Arnaud and Labarre, Thibault},
doi = {10.1073/pnas.2014166117},
issn = {0027-8424},
journal = {Proceedings of the National Academy of Sciences},
month = {nov},
number = {44},
pages = {27171--27178},
title = {{Annually resolved Atlantic sea surface temperature variability over the past 2,900 y}},
url = {http://www.pnas.org/lookup/doi/10.1073/pnas.2014166117},
volume = {117},
year = {2020}
}
@article{Larkin2002,
abstract = {(El Nin Previous studies by the authors have described the composite global marine surface anomalies of ENSO warm ˜o) events and cold (La Nin ˜a) events. Here the similarities and differences in these life cycles are examined. Qualitatively different behavior between warm events and cold events exists in the tropical Indian and Atlantic Oceans and in the extratropical Pacific. Even in the tropical Pacific statistically significantly different behavior is found in some variables for particular regions and phases of the life cycles. A single-mode regression analysis of the ENSO signal is done; the patterns are very similar to those of previously published ENSO EOF and regression analyses. The authors describe how the regression patterns obscure many of the interesting life cycles and life cycle differences of cold events and warm events. Most of the regression structures outside of the tropical Pacific are not statistically significant because of such differences. ENSO models should be evaluated against their ability to reproduce the observed cold event and warm event life cycles and not just single EOF or regression mode patterns.},
author = {Larkin, Narasimhan K. and Harrison, D. E.},
doi = {10.1175/1520-0442(2002)015<1118:EWENOA>2.0.CO;2},
isbn = {0894-8755},
issn = {08948755},
journal = {Journal of Climate},
number = {10},
pages = {1118--1140},
title = {{ENSO warm (El Ni{\~{n}}o) and cold (La Ni{\~{n}}a) event life cycles: Ocean surface anomaly patterns, their symmetries, asymmetries, and implications}},
volume = {15},
year = {2002}
}
@article{Latif2013,
abstract = {Evidence is presented for the notion that some contribution to the recent decadal trends observed in the Southern Hemisphere, including the lack of a strong Southern Ocean surface warming, may have originated from longer-term internal centennial variability originating in the Southern Ocean. The existence of such centennial variability is supported by the instrumental sea surface temperatures (SSTs), a multimillennial reconstruction of Tasmanian summer temperatures from tree rings, and a millennial control integration of the Kiel Climate Model (KCM). The model variability was previously shown to be linked to changes in Weddell Sea deep convection. During phases of deep convection the surface Southern Ocean warms, the abyssal Southern Ocean cools, Antarctic sea ice extent retreats, and the low-level atmospheric circulation over the Southern Ocean weakens. After the halt of deep convection the surface Southern Ocean cools, the abyssal Southern Ocean warms, Antarctic sea ice expands, and the low-level atmospheric circulation over the Southern Ocean intensifies, consistent with what has been observed during the recent decades. A strong sensitivity of the time scale to model formulation is noted. In theKCM,the centennial variability is associated with global-average surface air temperature (SAT) changes of the order of a few tenths of a degree per century. The model results thus suggest that internal centennial variability originating in the Southern Ocean should be considered in addition to other internal variability and external forcing when discussing the climate of the twentieth century and projecting that of the twenty-first century.},
author = {Latif, Mojib and Martin, Torge and Park, Wonsun},
doi = {10.1175/JCLI-D-12-00281.1},
isbn = {0894-8755},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Atmosphere-ocean interaction,Climate variability,Decadal variability},
month = {may},
number = {19},
pages = {7767--7782},
publisher = {American Meteorological Society},
title = {{Southern ocean sector centennial climate variability and recent decadal trends}},
volume = {26},
year = {2013}
}
@article{Lau2015a,
abstract = {In this paper, we investigate changes in the Hadley Circulation (HC) and their connections to increased global dryness (suppressed rainfall and reduced tropospheric relative humidity) under CO 2 warming from Coupled Model Intercomparison Project Phase 5 (CMIP5) model projections. We find a strengthening of the HC manifested in a “deep-tropics squeeze” (DTS), i.e., a deepening and narrowing of the convective zone, enhanced ascent, increased high clouds, suppressed low clouds, and a rise of the level of maximum meridional mass outflow in the upper troposphere (200−100 hPa) of the deep tropics. The DTS induces atmospheric moisture divergence and reduces tropospheric relative humidity in the tropics and subtropics, in conjunction with a widening of the subsiding branches of the HC, resulting in increased frequency of dry events in preferred geographic locations worldwide. Among various water-cycle parameters examined, global dryness is found to have the highest signal-to-noise ratio. Our results provide a physical basis for inferring that greenhouse warming is likely to contribute to the observed prolonged droughts worldwide in recent decades.},
author = {Lau, William K M and Kim, Kyu-Myong},
doi = {10.1073/pnas.1418682112},
issn = {0027-8424},
journal = {Proceedings of the National Academy of Sciences},
month = {mar},
number = {12},
pages = {3630--3635},
title = {{Robust Hadley Circulation changes and increasing global dryness due to CO2 warming from CMIP5 model projections}},
url = {http://www.pnas.org/lookup/doi/10.1073/pnas.1418682112},
volume = {112},
year = {2015}
}
@article{gmd-13-4205-2020,
author = {Lauer, A and Eyring, V and Bellprat, O and Bock, L and Gier, B K and Hunter, A and Lorenz, R and P{\'{e}}rez-Zan{\'{o}}n, N and Righi, M and Schlund, M and Senftleben, D and Weigel, K and Zechlau, S},
doi = {10.5194/gmd-13-4205-2020},
journal = {Geoscientific Model Development},
number = {9},
pages = {4205--4228},
title = {{Earth System Model Evaluation Tool (ESMValTool) v2.0 – diagnostics for emergent constraints and future projections from Earth system models in CMIP}},
url = {https://gmd.copernicus.org/articles/13/4205/2020/},
volume = {13},
year = {2020}
}
@article{Lauer2018,
abstract = {The performance of updated versions of the four earth system models (ESMs) CNRM, EC-Earth, HadGEM, and MPI-ESM is assessed in comparison to their predecessor versions used in Phase 5 of the Coupled Model Intercomparison Project. The Earth System Model Evaluation Tool (ESMValTool) is applied to evaluate selected climate phenomena in the models against observations. This is the first systematic application of the ESMValTool to assess and document the progress made during an extensive model development and improvement project. This study focuses on the South Asian monsoon (SAM) and the West African monsoon (WAM), the coupled equatorial climate, and Southern Ocean clouds and radiation, which are known to exhibit systematic biases in present-day ESMs. The analysis shows that the tropical precipitation in three out of four models is clearly improved. Two of three updated coupled models show an improved representation of tropical sea surface temperatures with one coupled model not exhibiting a double Intertropical Convergence Zone (ITCZ). Simulated cloud amounts and cloud-radiation interactions are improved over the Southern Ocean. Improvements are also seen in the simulation of the SAM and WAM, although systematic biases remain in regional details and the timing of monsoon rainfall. Analysis of simulations with EC-Earth at different horizontal resolutions from T159 up to T1279 shows that the synoptic-scale variability in precipitation over the SAM and WAM regions improves with higher model resolution. The results suggest that the reasonably good agreement of modeled and observed mean WAM and SAM rainfall in lower-resolution models may be a result of unrealistic intensity distributions.},
author = {Lauer, A. and Jones, C. and Eyring, V. and Evaldsson, M. and Hagemann, S. and M{\"{a}}kel{\"{a}}, J. and Martin, G. and Roehrig, R. and Wang, S.},
doi = {10.5194/esd-9-33-2018},
journal = {Earth System Dynamics},
number = {1},
pages = {33--67},
title = {{Process-level improvements in CMIP5 models and their impact on tropical variability, the Southern Ocean, and monsoons}},
volume = {9},
year = {2018}
}
@article{Lean2018,
abstract = {Climate change detection and attribution have proven unexpectedly challenging during the 21st century. Earth's global surface temperature increased less rapidly from 2000 to 2015 than during the last half of the 20th century, even though greenhouse gas concentrations continued to increase. A probable explanation is the mitigation of anthropogenic warming by La Ni{\~{n}}a cooling and declining solar irradiance. Physical climate models overestimated recent global warming because they did not generate the observed phase of La Ni{\~{n}}a cooling and may also have underestimated cooling by declining solar irradiance. Ongoing scientific investigations continue to seek alternative explanations to account for the divergence of simulated and observed climate change in the early 21st century, which IPCC termed a “global warming hiatus.” Amplified by media commentary, the suggestions by these studies that “missing” mechanisms may be influencing climate exacerbates confusion among policy makers, the public and other stakeholders about the causes and reality of modern climate change. Understanding and communicating the causes of climate change in the next 20 years may be equally challenging. Predictions of the modulation of projected anthropogenic warming by natural processes have limited skill. The rapid warming at the end of 2015, for example, is not a resumption of anthropogenic warming but rather an amplification of ongoing warming by El Ni{\~{n}}o. Furthermore, emerging feedbacks and tipping points precipitated by, for example, melting summer Arctic sea ice may alter Earth's global temperature in ways that even the most sophisticated physical climate models do not yet replicate. This article is categorized under: Paleoclimates and Current Trends {\textgreater} Climate Forcing.},
author = {Lean, J.L.},
doi = {10.1002/wcc.511},
journal = {WIREs Climate Change},
number = {2},
pages = {e511},
title = {{Observation-based detection and attribution of 21st century climate change}},
volume = {9},
year = {2018}
}
@article{Lee2018,
abstract = {Using historical simulations of the Coupled Model Intercomparison Project-5 (CMIP5) and multiple observationally-based datasets, we employ skill metrics to analyze the fidelity of the simulated Northern Annular Mode, the North Atlantic Oscillation, the Pacific North America pattern, the Southern Annular Mode, the Pacific Decadal Oscillation, the North Pacific Oscillation, and the North Pacific Gyre Oscillation. We assess the benefits of a unified approach to evaluate these modes of variability, which we call the common basis function (CBF) approach, based on projecting model anomalies onto observed empirical orthogonal functions (EOFs). The CBF approach circumvents issues with conventional EOF analysis, eliminating, for example, corrections of arbitrarily assigned, but inconsistent, signs of the EOF's/PC's being compared. It also avoids the problem that sometimes the first observed EOF is more similar to a higher order model EOF, particularly if the simulated EOFs are not well separated. Compared to conventional EOF analysis of models, the CBF approach indicates that models compare significantly better with observations in terms of pattern correlation and root-mean-squared-error (RMSE) than heretofore suggested. In many cases, models are doing a credible job at capturing the observationally-based estimates of patterns; however, errors in simulated amplitudes can be large and more egregious than pattern errors. In the context of the broad distribution of errors in the CMIP5 ensemble, sensitivity tests demonstrate that our results are relatively insensitive to methodological considerations (CBF vs. conventional approach), observational uncertainties in pattern (as determined by using multiple datasets), and internal variability (when multiple realizations from the same model are compared). The skill metrics proposed in this study can provide a useful summary of the ability of models to reproduce the observed EOF patterns and amplitudes. Additionally, the skill metrics can be used as a tool to objectively highlight where potential model improvements might be made. We advocate more systematic and objective testing of simulated extratropical variability, especially during the non-dominant seasons of each mode, when many models are performing relatively poorly.},
author = {Lee, Jiwoo and Sperber, Kenneth R and Gleckler, Peter J and Bonfils, C{\'{e}}line J W and Taylor, Karl E},
doi = {10.1007/s00382-018-4355-4},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {apr},
number = {7-8},
pages = {4057--4089},
title = {{Quantifying the agreement between observed and simulated extratropical modes of interannual variability}},
url = {https://doi.org/10.1007/s00382-018-4355-4 http://link.springer.com/10.1007/s00382-018-4355-4},
volume = {52},
year = {2019}
}
@article{Lee2014a,
abstract = {This study investigates future changes of Global Monsoon (GM) under anthropogenic global warming using 20 coupled models that participated in the phase five of Coupled Model Intercomparison Project (CMIP5) by comparing two runs: the historical run for 1850–2005 and the Representative Concentration Pathway (RCP) 4.5 run for 2006–2100. A metrics for evaluation of models' performance on GM is designed to document performance for 1980–2005 and best four models are selected. The four best models' multi-model ensemble (B4MME) projects the following changes in the twenty-first century under the RCP4.5 scenario. (1) Monsoon domain will not change appreciably but land monsoon domain over Asia tends to expand westward by 10.6 {\%}. (2) The annual mean and range of GM precipitation and the percentage of local summer rainfall will all amplify at a significant level over most of the global region, both over land and over ocean. (3) There will be a more prominent northern-southern hemispheric asymmetry and eastern-western hemispheric asymmetry. (4) Northern Hemisphere (NH) monsoon onset will be advanced and withdrawal will be delayed. (5) Changes in monsoon precipitation exhibits huge differences between the NH and the Southern hemisphere (SH). The NH monsoon precipitation will increase significantly due to increase in temperature difference between the NH and SH, significant enhancement of the Hadley circulation, and atmospheric moistening, against stabilization of troposphere. There is a slight decrease of the Walker circulation but not significant against the inter-model spread. There are important differences between the CMIP 3 and CMIP5 results which are discussed in detail.},
author = {Lee, J-Y and Wang, B},
doi = {10.1007/s00382-012-1564-0},
issn = {1432-0894},
journal = {Climate Dynamics},
month = {jan},
number = {1},
pages = {101--119},
title = {{Future change of global monsoon in the CMIP5}},
url = {https://doi.org/10.1007/s00382-012-1564-0},
volume = {42},
year = {2014}
}
@article{doi:10.1175/JCLI-D-12-00591.1,
abstract = { AbstractWind stress measurements from the Quick Scatterometer (QuikSCAT) satellite and two atmospheric reanalysis products are used to evaluate the annual mean and seasonal cycle of wind stress simulated by phases 3 and 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5). The ensemble CMIP3 and CMIP5 wind stresses are very similar to each other. Generally speaking, there is no significant improvement of CMIP5 over CMIP3. The CMIP ensemble–average zonal wind stress has eastward biases at midlatitude westerly wind regions (30°–50°N and 30°–50°S, with CMIP being too strong by as much as 55{\%}), westward biases in subtropical–tropical easterly wind regions (15°–25°N and 15°–25°S), and westward biases at high-latitude regions (poleward of 55°S and 55°N). These biases correspond to too strong anticyclonic (cyclonic) wind stress curl over the subtropical (subpolar) ocean gyres, which would strengthen these gyres and influence oceanic meridional heat transport. In the equatorial zone, significant biases of CMIP wind exist in individual basins. In the equatorial Atlantic and Indian Oceans, CMIP ensemble zonal wind stresses are too weak and result in too small of an east–west gradient of sea level. In the equatorial Pacific Ocean, CMIP zonal wind stresses are too weak in the central and too strong in the western Pacific. These biases have important implications for the simulation of various modes of climate variability originating in the tropics. The CMIP as a whole overestimate the magnitude of seasonal variability by almost 50{\%} when averaged over the entire global ocean. The biased wind stress climatologies in CMIP not only have implications for the simulated ocean circulation and climate variability but other air–sea fluxes as well. },
author = {Lee, Tong and Waliser, Duane E and Li, Jui-Lin F and Landerer, Felix W and Gierach, Michelle M},
doi = {10.1175/JCLI-D-12-00591.1},
journal = {Journal of Climate},
number = {16},
pages = {5810--5826},
title = {{Evaluation of CMIP3 and CMIP5 Wind Stress Climatology Using Satellite Measurements and Atmospheric Reanalysis Products}},
url = {https://doi.org/10.1175/JCLI-D-12-00591.1},
volume = {26},
year = {2013}
}
@article{Lee2015,
abstract = {AbstractThe structure and dynamics of stratospheric northern annular mode (SNAM) events in CMIP5 simulations are studied, emphasizing (i) stratosphere?troposphere coupling and (ii) disparities between high-top (HT) and low-top (LT) models. Compared to HT models, LT models generally underrepresent SNAM amplitude in stratosphere, consistent with weaker polar vortex variability, as demonstrated by Charlton-Perez et al. Interestingly, however, this difference does not carry over to the associated zonal-mean SNAM signature in troposphere, which closely resembles observations in both HT and LT models. Nonetheless, a regional analysis illustrates that both HT and LT models exhibit anomalously weak and eastward shifted (compared to observations) storm track and sea level pressure anomaly patterns in association with SNAM events.Dynamical analyses of stratosphere?troposphere coupling are performed to further examine the distinction between HT and LT models. Variability in stratospheric planetary wave activity is reduced in LT models despite robust concomitant tropospheric variability. A meridional heat flux analysis indicates relatively weak vertical Rossby wave coupling in LT models consistent with the excessive damping events discussed by Shaw et al. Eliassen?Palm flux cross sections reveal that Rossby wave propagation is anomalously weak above the tropopause in LT models, suggesting that weak polar vortex variability in LT models is due, at least in part, to the inability of tropospheric planetary wave activity to enter the stratosphere. Although the results are consistent with anomalously weak vertical dynamical coupling in LT models during SNAM events, there is little impact upon attendant tropospheric variability. The physical reason behind this apparent paradox represents an important topic for future study.},
annote = {Stratospheric NAM in CMIP5 models {\ldots} high-top vs low-top models
- CMIP5 historical, 1950-2005
- NCEP/NCAR
- EOF1 of JFMA daily zonal-mean zonal wind over 45-90N, 100-10hPa

- High-top models slightly overestimate the intensity of stratospheric zonal wind anomalies while low-top models strongly underestimate
- Underestimation of associated tropospheric NAM in low-top models is not as serious as in the stratosphere 
- Stratospheric NAM events are too frequent and less persistent},
author = {Lee, Yun-Young and Black, Robert X},
doi = {10.1175/JCLI-D-13-00570.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {oct},
number = {1},
pages = {86--107},
publisher = {American Meteorological Society},
title = {{The Structure and Dynamics of the Stratospheric Northern Annular Mode in CMIP5 Simulations}},
url = {https://doi.org/10.1175/JCLI-D-13-00570.1},
volume = {28},
year = {2015}
}
@article{doi:10.1002/jgrd.50493,
abstract = {AbstractThis study assesses the capability of CMIP5 models in representing primary modes of boreal winter extratropical low-frequency variability. Rotated principal component analysis is applied to monthly mean output from historical simulations of 14 plus two variants models and National Centers for Environmental Prediction–National Center for Atmospheric Research reanalyses (NNR) to isolate the leading patterns of variability in 500 hPa height. For each model data set, North Atlantic Oscillation (NAO)-like and Pacific-North American (PNA)-like patterns are identified using pattern correlation analysis (against NNR patterns). The relative pattern correspondence among CMIP5 models and reanalyses is further quantified via cluster analyses of the rotated empirical orthogonal function, NAO-like, and PNA-like patterns, respectively. For both NAO and PNA, 18.8{\%} of the model patterns lie within the same cluster as NNR. Composite structural differences among clusters chiefly consist of (a) spatial displacements of or (b) regional magnitude disparities in the primary anomaly features. While all models replicate the basic aspects of PNA, a small minority of models fails to replicate NAO pattern. Overall, the best performing model is the “GFDL-ESM2G.” Interestingly, models having a well-resolved stratosphere generally perform more poorly than those without. Model biases in low-frequency mode structure have important consequences for the representation of associated regional anomalies in surface air temperature and storm track behavior. Those differences among clusters are linked to variations in dynamical structures and their relation to the climatological-mean flow. It is concluded that some state-of-the-art models have important deficiencies in representing low-frequency variability and some of these deficiencies are associated with the failure of models to adequately replicate the observed climatological stationary waves.},
annote = {CMIP5 evaluation in reproducing NAO and PNA
- In comparison to NCEP/NCAR
- EOF of z500 over 20-87.5N for DJF 1950-2005
- REOF -{\textgreater} NAO-like and PNA-like patterns
- Intermodel cluster analysis of NAO-like and PNA-like patterns

- NAO reproduction is poorer than PNA
- In some model (cluster {\#}4 especially) NAO is very unrealistic, while PNA is overall well reproduced
- Associated energy conversion and eddy feedback are accordingly biased
- Low-top models performs better than high-top models for NAO
- Better model in terms of one mode does not necessarily fall into better model in the other mode {\ldots} performance in region-dependent},
author = {Lee, Yun-Young and Black, Robert X},
doi = {10.1002/jgrd.50493},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {Boreal extratropical low-frequency variability,Climatological stationary waves,North Atlantic Oscillation,Pacific-North American pattern,Performance of GCMs in CMIP5,Relation of low-frequency variability with climat},
number = {13},
pages = {6891--6904},
title = {{Boreal winter low-frequency variability in CMIP5 models}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/jgrd.50493},
volume = {118},
year = {2013}
}
@article{Lee2015a,
abstract = {Global mean surface warming has stalled since the end of the twentieth century1, 2, but the net radiation imbalance at the top of the atmosphere continues to suggest an increasingly warming planet. This apparent contradiction has been reconciled by an anomalous heat flux into the ocean3, 4, 5, 6, 7, 8, induced by a shift towards a La Ni{\~{n}}a-like state with cold sea surface temperatures in the eastern tropical Pacific over the past decade or so. A significant portion of the heat missing from the atmosphere is therefore expected to be stored in the Pacific Ocean. However, in situ hydrographic records indicate that Pacific Ocean heat content has been decreasing9. Here, we analyse observations along with simulations from a global ocean–sea ice model to track the pathway of heat. We find that the enhanced heat uptake by the Pacific Ocean has been compensated by an increased heat transport from the Pacific Ocean to the Indian Ocean, carried by the Indonesian throughflow. As a result, Indian Ocean heat content has increased abruptly, which accounts for more than 70{\%} of the global ocean heat gain in the upper 700 m during the past decade. We conclude that the Indian Ocean has become increasingly important in modulating global climate variability.},
author = {Lee, Sang Ki and Park, Wonsun and Baringer, Molly O. and Gordon, Arnold L. and Huber, Bruce and Liu, Yanyun},
doi = {10.1038/NGEO2438},
isbn = {1752-0894},
issn = {17520908},
journal = {Nature Geoscience},
number = {6},
pages = {445--449},
title = {{Pacific origin of the abrupt increase in Indian Ocean heat content during the warming hiatus}},
volume = {8},
year = {2015}
}
@article{Lehner2016,
abstract = {{\textcopyright}2016. American Geophysical Union. All Rights Reserved. Comparisons of the observed global-scale cooling following recent volcanic eruptions to that simulated by climate models from the Coupled Model Intercomparison Project 5 (CMIP5) indicate that the models overestimate the magnitude of the global temperature response to volcanic eruptions. Here we show that this overestimation can be explained as a sampling issue, arising because all large eruptions since 1951 coincided with El Ni{\~{n}}o events, which cause global-scale warming that partially counteracts the volcanically induced cooling. By subsampling the CMIP5 models according to the observed El Ni{\~{n}}o-Southern Oscillation (ENSO) phase during each eruption, we find that the simulated global temperature response to volcanic forcing is consistent with observations. Volcanic eruptions pose a particular challenge for the detection and attribution methodology, as their surface impacts are short-lived and hence can be confounded by ENSO. Our results imply that detection and attribution studies must carefully consider sampling biases due to internal climate variability.},
author = {Lehner, F. and Schurer, A.P. and Hegerl, G.C. and Deser, C. and Fr{\"{o}}licher, T.L.},
doi = {10.1002/2016GL067935},
journal = {Geophysical Research Letters},
number = {6},
pages = {2851--2858},
title = {{The importance of ENSO phase during volcanic eruptions for detection and attribution}},
volume = {43},
year = {2016}
}
@article{Lehner2012,
author = {Lehner, Flavio and Raible, Christoph C. and Stocker, Thomas F.},
doi = {10.1016/j.quascirev.2012.04.025},
issn = {02773791},
journal = {Quaternary Science Reviews},
month = {jun},
pages = {85--94},
title = {{Testing the robustness of a precipitation proxy-based North Atlantic Oscillation reconstruction}},
url = {https://linkinghub.elsevier.com/retrieve/pii/S0277379112001722},
volume = {45},
year = {2012}
}
@article{Leroux2018,
abstract = {This study investigates the origin and features of interannual–decadal Atlantic meridional overturning circulation (AMOC) variability from several ocean simulations, including a large (50 member) ensemble of global, eddy-permitting (1/4°) ocean–sea ice hindcasts. After an initial stochastic perturbation, each member is driven by the same realistic atmospheric forcing over 1960–2015. The magnitude, spatiotemporal scales, and patterns of both the atmospherically forced and intrinsic–chaotic interannual AMOC variability are then characterized from the ensemble mean and ensemble spread, respectively. The analysis of the ensemble-mean variability shows that the AMOC fluctuations north of 40°N are largely driven by the atmospheric variability, which forces meridionally coherent fluctuations reaching decadal time scales. The amplitude of the intrinsic interannual AMOC variability never exceeds the atmospherically forced contribution in the Atlantic basin, but it reaches up to 100{\%} of the latter around 35°S and 60{\%} in the Northern Hemisphere midlatitudes. The intrinsic AMOC variability exhibits a large-scale meridional coherence, especially south of 25°N. An EOF analysis over the basin shows two large-scale leading modes that together explain 60{\%} of the interannual intrinsic variability. The first mode is likely excited by intrinsic oceanic processes at the southern end of the basin and affects latitudes up to 40°N; the second mode is mostly restricted to, and excited within, the Northern Hemisphere midlatitudes. These features of the intrinsic, chaotic variability (intensity, patterns, and random phase) are barely sensitive to the atmospheric evolution, and they strongly resemble the “pure intrinsic” interannual AMOC variability that emerges in climatological simulations under repeated seasonal-cycle forcing. These results raise questions about the attribution of observed and simulated AMOC signals and about the possible impact of intrinsic signals on the atmosphere.},
author = {Leroux, Stephanie and Penduff, Thierry and Bessi{\`{e}}res, Laurent and Molines, Jean-Marc and Brankart, Jean-Michel and S{\'{e}}razin, Guillaume and Barnier, Bernard and Terray, Laurent},
doi = {10.1175/JCLI-D-17-0168.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {feb},
number = {3},
pages = {1183--1203},
title = {{Intrinsic and Atmospherically Forced Variability of the AMOC: Insights from a Large-Ensemble Ocean Hindcast}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-17-0168.1},
volume = {31},
year = {2018}
}
@article{Levang2015,
abstract = {AbstractThe global water cycle is predicted to intensify under various greenhouse gas emissions scenarios. Here we assess the nature and strength of the expected changes for the ocean in the coming century by examining the output of several CMIP5 model runs for the periods 1990-2000 and 2090-2100 and comparing them to a dataset built from modern observations. Key elements of the water cycle, such as the atmospheric vapor transport, the evaporation minus precipitation over the ocean and the surface salinity, show significant changes over the coming century. The intensification of the water cycle leads to increased salinity contrasts in the ocean, both within and between basins. Regional projections for several areas important to large-scale ocean circulation are presented, including the export of atmospheric moisture across the tropical Americas from Atlantic to Pacific, the freshwater gain of high latitude deepwater formation sites, and the basin averaged evaporation minus precipitation with implications for interbasin mass transports.},
author = {Levang, Samuel J. and Schmitt, Raymond W.},
doi = {10.1175/JCLI-D-15-0143.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Climate change,Climate prediction,Hydrologic cycle,Salinity,Water budget,Water vapor},
month = {aug},
number = {16},
pages = {6489--6502},
title = {{Centennial changes of the global water cycle in CMIP5 models}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-15-0143.1},
volume = {28},
year = {2015}
}
@article{Levitus2012,
abstract = {We provide updated estimates of the change of ocean heat content and the thermosteric component of sea level change of the 0-700 and 0-2000m layers of the World Ocean for 1955-2010. Our estimates are based on historical data not previously available, additional modern data, and bathythermograph data corrected for instrumental biases. We have also used Argo data corrected by the Argo DAC if available and used uncorrected Argo data if no corrections were available at the time we downloaded the Argo data. The heat content of the World Ocean for the 0-2000m layer increased by 24.01.9 ? 1022 J (2S.E.) corresponding to a rate of 0.39Wm-2 (per unit area of the World Ocean) and a volume mean warming of 0.09C. This warming corresponds to a rate of 0.27Wm-2 per unit area of earth's surface. The heat content of the World Ocean for the 0-700m layer increased by 16.71.6 ? 10 22 J corresponding to a rate of 0.27Wm-2 (per unit area of the World Ocean) and a volume mean warming of 0.18C. The World Ocean accounts for approximately 93{\%} of the warming of the earth system that has occurred since 1955. The 700-2000m ocean layer accounted for approximately one-third of the warming of the 0-2000m layer of the World Ocean. The thermosteric component of sea level trend was 0.54.05mmyr-1 for the 0-2000m layer and 0.41.04mmyr-1 for the 0-700m layer of the World Ocean for 1955-2010. ? Copyright 2012 by the American Geophysical Union.},
author = {Levitus, S. and Antonov, J.I. and Boyer, T.P. and Baranova, O.K. and Garcia, H.E. and Locarnini, R.A. and Mishonov, A.V. and Reagan, J.R. and Seidov, D. and Yarosh, E.S. and Zweng, M.M.},
doi = {10.1029/2012GL051106},
issn = {00948276},
journal = {Geophysical Research Letters},
number = {10},
pages = {L10603},
publisher = {Wiley Online Library},
title = {{World ocean heat content and thermosteric sea level change (0–2000m), 1955–2010}},
volume = {39},
year = {2012}
}
@article{doi:10.1002/2016JD024774,
abstract = {Land surface albedo is a key parameter affecting energy balance and near-surface climate. In this study, we used satellite data to evaluate simulated surface albedo in 37 models participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5). There was a systematic overestimation in the simulated seasonal cycle of albedo with the highest bias occurring during the Northern Hemisphere's winter months. The bias in surface albedo during the snow-covered season was classified into that in snow cover fraction (SCF) and albedo contrast ($\beta$1). There was a general overestimation of $\beta$1 due to the simulated snow-covered albedo being brighter than the observed value; negative biases in SCF were not always related to negative albedo biases, highlighting the need for realistic representation of snow-covered albedo in models. In addition, models with a lower leaf area index (LAI) tend to produce a higher surface albedo over the boreal forests during the winter, which emphasizes the necessity of improving LAI simulations in CMIP5 models. Insolation weighting showed that spring albedo biases were of greater importance for climate. The removal of albedo biases is expected to improve temperature simulations particularly over high-elevation regions. {\textcopyright}2016. American Geophysical Union. All Rights Reserved.},
author = {Li, Yue and Wang, Tao and Zeng, Zhenzhong and Peng, Shushi and Lian, Xu and Piao, Shilong},
doi = {10.1002/2016JD024774},
issn = {21562202},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {CMIP5,albedo,climate,land surface,model biases,snow},
number = {11},
pages = {6178--6190},
title = {{Evaluating biases in simulated land surface albedo from CMIP5 global climate models}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2016JD024774},
volume = {121},
year = {2016}
}
@article{doi:10.1175/JCLI-D-14-00740.1,
abstract = { AbstractLong-standing biases of climate models limit the skills of climate prediction and projection. Overlooked are tropical Indian Ocean (IO) errors. Based on the phase 5 of the Coupled Model Intercomparison Project (CMIP5) multimodel ensemble, the present study identifies a common error pattern in climate models that resembles the IO dipole (IOD) mode of interannual variability in nature, with a strong equatorial easterly wind bias during boreal autumn accompanied by physically consistent biases in precipitation, sea surface temperature (SST), and subsurface ocean temperature. The analyses show that such IOD-like biases can be traced back to errors in the South Asian summer monsoon. A southwest summer monsoon that is too weak over the Arabian Sea generates a warm SST bias over the western equatorial IO. In boreal autumn, Bjerknes feedback helps amplify the error into an IOD-like bias pattern in wind, precipitation, SST, and subsurface ocean temperature. Such mean state biases result in an interannual IOD variability that is too strong. Most models project an IOD-like future change for the boreal autumn mean state in the global warming scenario, which would result in more frequent occurrences of extreme positive IOD events in the future with important consequences to Indonesia and East Africa. The Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) characterizes this future IOD-like projection in the mean state as robust based on consistency among models, but the authors' results cast doubts on this conclusion since models with larger IOD amplitude biases tend to produce stronger IOD-like projected changes in the future. },
annote = {Indian Ocean biases in SST, thermocline, wind and convection in CMIP5 models
- CMIP5 historical, 1950-1999
- GPCP, ERA-40, HadISST, SODA

i) Annual mean bias
- Equatorial westerly bias is weak in annual mean
- Excessive (slighyly insufficient) precipitation in western (eastern) Eq IO
ii) Seasonality
- Extremely warm (slightly cool) SST bias in the western (eastern) IO in JJA and SON
- Eq easterly wind bias in SON {\ldots} "IOD-like"
(In summer, pressure gradient and meridional momentum flux biases cancel one another)
- Too weak South Asian monsoon in JJA (Boos {\&} Hurley 2013) yields a warm bias in the Arabian Sea, which persists until fall and initiates the Bjerkness feedback and induces the IOD-like bias in fall
- The unrealistically steep equatorial thermocline in fall helps developing excessively strong IOD ({\~{}}2x in MME) through too strong thermocline feedback
- Implications for future change (callibration with the present climatology -{\textgreater} IOD-like future change pattern would be much weaker)},
author = {Li, Gen and Xie, Shang-Ping and Du, Yan},
doi = {10.1175/JCLI-D-14-00740.1},
journal = {Journal of Climate},
number = {8},
pages = {3058--3072},
title = {{Monsoon-Induced Biases of Climate Models over the Tropical Indian Ocean}},
url = {https://doi.org/10.1175/JCLI-D-14-00740.1},
volume = {28},
year = {2015}
}
@article{doi:10.1175/JCLI-D-14-00810.1,
abstract = { AbstractAn open-ocean thermocline dome south of the equator is a striking feature of the Indian Ocean (IO) as a result of equatorial westerly winds. Over the thermocline dome, the El Ni{\~{n}}o–forced Rossby waves help sustain the IO basin (IOB) mode and offer climate predictability for the IO and surrounding countries. This study shows that a common equatorial easterly wind bias, by forcing a westward-propagating downwelling Rossby wave in the southern IO, induces too deep a thermocline dome over the southwestern IO (SWIO) in state-of-the-art climate models. Such a deep SWIO thermocline weakens the influence of subsurface variability on sea surface temperature (SST), reducing the IOB amplitude and possibly limiting the models' skill of regional climate prediction. To the extent that the equatorial easterly wind bias originates from errors of the South Asian summer monsoon, improving the monsoon simulation can lead to substantial improvements in simulating and predicting interannual variability in the IO. },
annote = {Too deep SIO thermocline dome in the CMIP5 models and the IOBM
- CMIP5 historical vs HadISST, SODA, GPCP, ERA-40 
- 1950-2005
- MME mean of 14 out of 19 models (excl those with no eq easterly wind bias)

- The MME shows overly deep thermocline dome in the SWIO
- The bias is year-round but slightly weaker in boreal summer
- Climatologically, the eq IO surface westerlies forms the dome, and consistently, easterly wind bias in the models causes deeper dome in the form of seasonal Rossby-wave propagation seen in El Ni{\~{n}}o event
- Models with stronger easterly wind bias tend to have weak IOBM (in Feb-Aug) with lower persistence following ENSO
- The easterly bias may originate in Indian monsoon representation {\ldots} another study},
author = {Li, Gen and Xie, Shang-Ping and Du, Yan},
doi = {10.1175/JCLI-D-14-00810.1},
journal = {Journal of Climate},
number = {8},
pages = {3093--3098},
title = {{Climate Model Errors over the South Indian Ocean Thermocline Dome and Their Effect on the Basin Mode of Interannual Variability}},
url = {https://doi.org/10.1175/JCLI-D-14-00810.1},
volume = {28},
year = {2015}
}
@article{Li2015a,
abstract = {We investigate the relative magnitudes of the contributions of surface temperature trends from different latitude bands to the recent warming hiatus. We confirm from five different global data sets that the global-mean surface temperature trend in the period 1998–2012 is strongly influenced by a pronounced Eurasian winter cooling trend. To understand the drivers of this winter cooling trend, we perform three 20-member ensembles of simulations with different prescribed sea surface temperature and sea ice in the atmospheric model ECHAM6. Our experimental results suggest that the Arctic sea ice loss does not drive systematic changes in the Northern Hemisphere large-scale circulation in the past decades. The observed Eurasian winter cooling trend over 1998–2012 arises essentially from atmospheric internal variability and constitutes an extreme climate event. However, the observed reduction in Arctic sea ice enhances the variability of Eurasian winter climate and thus increases the probability of an extreme Eurasian winter cooling trend.},
annote = {Observed SAT trend for 1998-2012 vs 1984-1998
- Winter NH midlatitude cooling -{\textgreater} contributed to the hiatus
Especially the Eurasian winter cooling trend
- ECHAM6 experiments
i) AMIP, ii) ACLI: SST and SIC north of 60N fixed to climatology, iii) GCLI: SST and SIC climatology globally
Each 20 members
All forced by historical and RCP4.5
-{\textgreater} AO index in AMIP is well reproduced by ACLI at r = 0.87
PNA index at r = 0.58},
author = {Li, Chao and Stevens, Bjorn and Marotzke, Jochem},
doi = {10.1002/2015GL065327},
isbn = {1944-8007},
issn = {19448007},
journal = {Geophysical Research Letters},
keywords = {warming hiatus,winter cooling},
number = {19},
pages = {8131--8139},
title = {{Eurasian winter cooling in the warming hiatus of 1998-2012}},
volume = {42},
year = {2015}
}
@article{Li2015b,
abstract = {During the past three decades, tropical sea surface temperature (SST) has shown dipole-like trends, with warming over the tropical Atlantic and Indo-western Pacific but cooling over the eastern Pacific. Competing hypotheses relate this cooling, identified as a driver of the global warming hiatus 1,2 , to the warming trends in either the Atlantic 3,4 or Indian Ocean 5 . However, the mechanisms, the relative importance and the interactions between these teleconnections remain unclear. Using a state-of-the-art climate model, we show that the Atlantic plays a key role in initiating the tropical-wide teleconnection, and the Atlantic-induced anomalies contribute ∼55–75{\%} of the tropical SST and circulation changes during the satellite era. The Atlantic warming drives easterly wind anomalies over the Indo-western Pacific as Kelvin waves and westerly anomalies over the eastern Pacific as Rossby waves. The wind changes induce an Indo-western Pacific warming through the wind–evaporation–SST eeect 6,7 , and this warming intensifies the La Ni{\~{n}}a-type response in the tropical Pacific by enhancing the easterly trade winds and through the Bjerknes ocean dynamical processes 8 . The teleconnection develops into a tropical-wide SST dipole pattern. This mechanism, supported by observations and a hierarchy of climate models, reveals that the tropical ocean basins are more tightly connected than previously thought. The tropics have experienced marked climate change since 1979 when the era of global satellite observations began. SST trends exhibit a pan-tropical dipole-like pattern (Fig. 1a), with extensive warming from the tropical Atlantic to the Indo-western Pacific, and a triangular cooling pattern in the central–eastern Pacific. This tropical-wide gradient in the SST trend interacts with the atmo-spheric and oceanic circulation throughout the tropics (Fig. 1c,e), with an enhanced Walker circulation 9–11 and a La Ni{\~{n}}a-like Pacific subsurface response. These changes further contribute to global cli-mate change 1,12,13 through multiple atmospheric teleconnections 8,14 . The tropical ocean basins are connected through an atmospheric bridge 15 into an interactive system. On interannual timescales, El Ni{\~{n}}o/Southern Oscillation (ENSO) dominates the tropical inter-basin teleconnections 15,16 , although the Indian 17,18 and Atlantic 19–21},
author = {Li, Xichen and Xie, Shang-Ping and Gille, Sarah T. and Yoo, Changhyun},
doi = {10.1038/nclimate2840},
isbn = {1758-678X},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {mar},
number = {3},
pages = {275--279},
title = {{Atlantic-induced pan-tropical climate change over the past three decades}},
url = {http://www.nature.com/articles/nclimate2840},
volume = {6},
year = {2016}
}
@article{Li2013,
abstract = {Predicting how the El Ni{\~{n}}o/Southern Oscillation (ENSO) will change with global warming is of enormous importance to society. ENSO exhibits considerable natural variability at interdecadal–centennial timescales. Instrumental records are too short to determine whether ENSO has changed and existing reconstructions are often developed without adequate tropical records. Here we present a seven-century-long ENSO reconstruction based on 2,222 tree-ring chronologies from both the tropics and mid-latitudes in both hemispheres. The inclusion of tropical records enables us to achieve unprecedented accuracy, as attested by high correlations with equatorial Pacific corals and coherent modulation of global teleconnections that are consistent with an independent Northern Hemisphere temperature reconstruction9. Our data indicate that ENSO activity in the late twentieth century was anomalously high over the past seven centuries, suggestive of a response to continuing global warming. Climate models disagree on the ENSO response to global warming, suggesting that many models underestimate the sensitivity to radiative perturbations. Illustrating the radiative effect, our reconstruction reveals a robust ENSO response to large tropical eruptions, with anomalous cooling in the east-central tropical Pacific in the year of eruption, followed by anomalous warming one year after. Our observations provide crucial constraints for improving climate models and their future projections.},
author = {Li, Jinbao and Xie, Shang Ping and Cook, Edward R. and Morales, Mariano S. and Christie, Duncan A. and Johnson, Nathaniel C. and Chen, Fahu and D'Arrigo, Rosanne and Fowler, Anthony M. and Gou, Xiaohua and Fang, Keyan},
doi = {10.1038/nclimate1936},
isbn = {1758-6798},
issn = {1758678X},
journal = {Nature Climate Change},
number = {9},
pages = {822--826},
publisher = {Nature Publishing Group},
title = {{El Ni{\~{n}}o modulations over the past seven centuries}},
url = {http://dx.doi.org/10.1038/nclimate1936},
volume = {3},
year = {2013}
}
@article{Li2018b,
author = {Li, Hongmei and Ilyina, Tatiana},
doi = {10.1002/2017GL075370},
issn = {00948276},
journal = {Geophysical Research Letters},
keywords = {Earth system models,decadal trends,forced signal,internal variability,large ensemble simulations,oceanic carbon uptake},
month = {jan},
number = {2},
pages = {916--925},
publisher = {Wiley-Blackwell},
title = {{Current and Future Decadal Trends in the Oceanic Carbon Uptake Are Dominated by Internal Variability}},
url = {http://doi.wiley.com/10.1002/2017GL075370},
volume = {45},
year = {2018}
}
@article{Li2016c,
abstract = {Predictability of variations in the ocean carbon sink has remained unexplored in previous decadal prediction studies based on modern Earth system models. Here, the authors show that potential predictive skill of the ocean CO2 uptake in the North Atlantic western subpolar gyre region is up to 4–7 years.},
author = {Li, Hongmei and Ilyina, Tatiana and M{\"{u}}ller, Wolfgang A. and Sienz, Frank},
doi = {10.1038/ncomms11076},
issn = {2041-1723},
journal = {Nature Communications},
keywords = {Marine chemistry,Physical oceanography},
month = {mar},
pages = {11076},
publisher = {Nature Publishing Group},
title = {{Decadal predictions of the North Atlantic CO2 uptake}},
url = {http://www.nature.com/doifinder/10.1038/ncomms11076},
volume = {7},
year = {2016}
}
@article{Li2018d,
abstract = {The enhanced vegetation growth by climate warming plays a pivotal role in amplifying the seasonal cycle of atmospheric CO2 at northern lands ({\textgreater}50° N) since 1960s. However, the correlation between vegetation growth, temperature and seasonal amplitude of atmospheric CO2 concentration have become elusive with the slowed increasing trend of vegetation growth and weakened temperature control on CO2 uptake since late 1990s. Here, based on in situ atmospheric CO2 concentration records from the Barrow observatory site, we found a slowdown in the increasing trend of the atmospheric CO2 amplitude from 1990s to mid-2000s. This phenomenon was associated with the paused decrease in the minimum CO2 concentration ([CO2]min), which was significantly correlated with the slowdown of vegetation greening and growing-season length extension. We then showed that both the vegetation greenness and growing-season length were positively correlated with spring but not autumn temperature over the northern lands. Furthermore, such asymmetric dependences of vegetation growth upon spring and autumn temperature cannot be captured by the state-of-art terrestrial biosphere models. These findings indicate that the responses of vegetation growth to spring and autumn warming are asymmetric, and highlight the need of improving autumn phenology in the models for predicting seasonal cycle of atmospheric CO2 concentration.},
author = {Li, Zhao and Xia, Jianyang and Ahlstr{\"{o}}m, Anders and Rinke, Annette and Koven, Charles and Hayes, Daniel J and Ji, Duoying and Zhang, Geli and Krinner, Gerhard and Chen, Guangsheng and Cheng, Wanying and Dong, Jinwei and Liang, Junyi and Moore, John C and Jiang, Lifen and Yan, Liming and Ciais, Philippe and Peng, Shushi and Wang, Ying-Ping and Xiao, Xiangming and Shi, Zheng and McGuire, A David and Luo, Yiqi},
doi = {10.1088/1748-9326/aae9ad},
issn = {1748-9326},
journal = {Environmental Research Letters},
number = {12},
pages = {124008},
publisher = {IOP Publishing},
title = {{Non-uniform seasonal warming regulates vegetation greening and atmospheric CO2 amplification over northern lands}},
url = {http://dx.doi.org/10.1088/1748-9326/aae9ad},
volume = {13},
year = {2018}
}
@article{Li2016d,
abstract = {In this study, we examined the annual precipitation amounts, the seasonality over global land and their linear trends, as well as the uncertainties in two observations (precipitation reconstruction and Global Precipitation Climatology Centre), and then compared them with historical runs by multiple models. Overall, the large-scale patterns of both the climatology of the annual precipitation amount and the seasonality are consistent between the two observations. Nevertheless, some noticeable differences existed, particularly in the regions with fewer gauge observations, such as northern Africa and the Tibetan Plateau. For long-term changes, significant drying trends during 1948–2005 were observed in the tropical areas of northern Africa, accompanied by significant wetting trends in the polar region of Canada. The seasonality change during the period was dominated by a decreasing trend in precipitation, especially in the western portion of Russia. The model simulations of the Coupled Model Intercomparison Project, Phase 5 (CMIP5) reproduced the climatological mean state of annual precipitation and its seasonality in the observations, as well as to some extent the zonal mean trends of precipitation amounts, but did not reproduce the zonal mean trends of seasonality. The two-dimensional distribution of linear trends of annual precipitation and seasonality simulated by CMIP5 models showed little consistency with their observational counterparts. One possibility for the inconsistencies was that they were largely determined by internal variations of the climate system rather than external forcings. In contrast, it might also suggest a challenge for state-of-the-art climate models to correctly simulate the spatial distribution of responses of annual precipitation amounts and seasonality to the evolution of external forcings. Our results suggest that, in addition to the precipitation amount, seasonality should be used as a metric to assess the ability of a climate model to simulate current climate conditions and project future climate change.},
author = {Li, Xiaofan and Hu, Zeng Zhen and Jiang, Xingwen and Li, Yueqing and Gao, Zongting and Yang, Song and Zhu, Jieshun and Jha, Bhaskar},
doi = {10.1002/joc.4592},
issn = {10970088},
journal = {International Journal of Climatology},
keywords = {climatology and trend,land precipitation,mean and seasonality,observations and CMIP5},
number = {11},
pages = {3781--3793},
title = {{Trend and seasonality of land precipitation in observations and CMIP5 model simulations}},
volume = {36},
year = {2016}
}
@article{Li2018g,
author = {Li, Xiangyu and Jiang, Dabang and Tian, Zhiping and Yang, Yibo},
doi = {10.1016/j.palaeo.2018.06.027},
issn = {00310182},
journal = {Palaeogeography, Palaeoclimatology, Palaeoecology},
month = {dec},
pages = {56--70},
title = {{Mid-Pliocene global land monsoon from PlioMIP1 simulations}},
url = {https://linkinghub.elsevier.com/retrieve/pii/S0031018218302256},
volume = {512},
year = {2018}
}
@article{Li2020c,
author = {Li, Zhiyu and Zhang, Wenjun and Jin, Fei-Fei and Stuecker, Malte F. and Sun, Cheng and Levine, Aaron F. Z. and Xu, Haiming and Liu, Chao},
doi = {10.1007/s00382-020-05362-8},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {oct},
number = {7-8},
pages = {1945--1959},
title = {{A robust relationship between multidecadal global warming rate variations and the Atlantic Multidecadal Variability}},
url = {http://link.springer.com/10.1007/s00382-020-05362-8},
volume = {55},
year = {2020}
}
@article{Li2014,
abstract = {AbstractErrors of coupled general circulation models (CGCMs) limit their utility for climate prediction and projection. Origins of and feedback for tropical biases are investigated in the historical climate simulations of 18 CGCMs from phase 5 of the Coupled Model Intercomparison Project (CMIP5), together with the available Atmospheric Model Intercomparison Project (AMIP) simulations. Based on an intermodel empirical orthogonal function (EOF) analysis of tropical Pacific precipitation, the excessive equatorial Pacific cold tongue and double intertropical convergence zone (ITCZ) stand out as the most prominent errors of the current generation of CGCMs. The comparison of CMIP–AMIP pairs enables us to identify whether a given type of errors originates from atmospheric models. The equatorial Pacific cold tongue bias is associated with deficient precipitation and surface easterly wind biases in the western half of the basin in CGCMs, but these errors are absent in atmosphere-only models, indicating that the er...},
author = {Li, Gen and Xie, Shang-Ping and Li, Gen and Xie, Shang-Ping},
doi = {10.1175/JCLI-D-13-00337.1},
issn = {0894-8755},
journal = {Journal of Climate},
keywords = {Atmosphere-ocean interaction,Climatology,General circulation models,Model errors,Precipitation,Tropics},
month = {feb},
number = {4},
pages = {1765--1780},
title = {{Tropical Biases in CMIP5 Multimodel Ensemble: The Excessive Equatorial Pacific Cold Tongue and Double ITCZ Problems}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-13-00337.1},
volume = {27},
year = {2014}
}
@article{Liang2020,
abstract = {The Coupled Model Intercomparison Project Phase 6 (CMIP6) archive includes larger ensembles, longer historical simulations, and models with a broader range of climate sensitivity than CMIP5. These features favor the application of observationally constrained climate projections. The 1970–2014 trend in global mean temperature is well-correlated with projected future warming across the CMIP6 multimodel ensemble. We first evaluate an approach that weights simulations based on the realism and degree of independence of their 1970–2014 trends, by treating each historical simulation in turn as pseudo-observations, and using the other models and weighting method to predict 21st century warming in the model concerned. The method performs well based on correlation and probabilistic measures. Applying the method using the observed 1970–2014 warming trend results in only small changes in the mean and lower bound of CMIP6 projected warming but substantially reduces the upper bound of projected early-, mid- and late-21st century warming under all SSP scenarios.},
author = {Liang, Yongxiao and Gillett, Nathan P. and Monahan, Adam H.},
doi = {10.1029/2019GL086757},
issn = {19448007},
journal = {Geophysical Research Letters},
number = {12},
pages = {e2019GL086757},
title = {{Climate Model Projections of 21st Century Global Warming Constrained Using the Observed Warming Trend}},
volume = {47},
year = {2020}
}
@article{Liguori2020,
abstract = {Despite the observed monotonic increase in greenhouse-gas concentrations, global mean temperature displays important decadal fluctuations typically attributed to both external forcing and internal variability. Here, we provide a robust quantification of the relative contributions of anthropogenic, natural, and internally-driven decadal variability of global mean sea surface temperature (GMSST) by using a unique dataset consisting of 30-member large initial-condition ensembles with five Earth System Models (ESM-LE). We present evidence that a large fraction ({\~{}}29–53{\%}) of the simulated decadal-scale variance in individual timeseries of GMSST over 1950–2010 is externally forced and largely linked to the representation of volcanic aerosols. Comparison with the future (2010–2070) period suggests that external forcing provides a source of additional decadal-scale variability in the historical period. Given the unpredictable nature of future volcanic aerosol forcing, it is suggested that a large portion of decadal GMSST variability might not be predictable.},
author = {Liguori, Giovanni and McGregor, Shayne and Arblaster, Julie M. and Singh, Martin S. and Meehl, Gerald A.},
doi = {10.1038/s41467-020-17683-7},
issn = {20411723},
journal = {Nature Communications},
number = {1},
pages = {3827},
pmid = {32737325},
title = {{A joint role for forced and internally-driven variability in the decadal modulation of global warming}},
volume = {11},
year = {2020}
}
@article{Lim2019,
author = {Lim, Young-Kwon and Cullather, Richard I. and Nowicki, Sophie M. J. and Kim, Kyu-Myong},
doi = {10.1038/s41598-019-39896-7},
issn = {2045-2322},
journal = {Scientific Reports},
month = {dec},
number = {1},
pages = {3481},
title = {{Inter-relationship between subtropical Pacific sea surface temperature, Arctic sea ice concentration, and North Atlantic Oscillation in recent summers}},
url = {http://www.nature.com/articles/s41598-019-39896-7},
volume = {9},
year = {2019}
}
@article{doi:10.1002/2016GL069453,
abstract = {Abstract A robust positive trend in the Southern Annular Mode (SAM) is projected for the end of the 21st century under the Representative Concentration Pathway 8.5 scenario, which results in rainfall decreases in the midlatitudes and increases in the high latitudes in the Southern Hemisphere (SH). We find that this SAM trend also increases rainfall over the SH subtropics in austral summer but not in winter, leading to a pronounced wintertime poleward expansion of the subtropical dry zone. These dynamically driven rainfall changes by the SAM appear to oppose the thermodynamically driven projected rainfall changes in the SH subtropics and midlatitudes, whereas the two components reinforce each other in the high latitudes. However, we show that most climate models fall short in capturing the observed SAM component driven by the El Ni{\~{n}}o–Southern Oscillation and associated rainfall in the austral warm seasons, which limits our confidence in quantifying the contribution of the SAM to projected rainfall changes.},
author = {Lim, Eun-Pa and Hendon, Harry H and Arblaster, Julie M and Delage, Francois and Nguyen, Hanh and Min, Seung-Ki and Wheeler, Matthew C},
doi = {10.1002/2016GL069453},
journal = {Geophysical Research Letters},
keywords = {CMIP5,RCP8.5,Souther Hemisphere rainfall,Southern Annular Mode},
number = {13},
pages = {7160--7167},
title = {{The impact of the Southern Annular Mode on future changes in Southern Hemisphere rainfall}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2016GL069453},
volume = {43},
year = {2016}
}
@misc{LIN2019,
annote = {10.12006/j.issn.1673-1719.2019.166},
author = {Lin, Yan-Luan and Liang, Yi-Shuang and {Yi Qin}, Shi-Ming and Xu, Wen-Yu and Huang, Fang-Hua and Xu, Li and Liu, Yong and Wang, Yi-Ran and Peng, Lan-Ning and Wang, Wei and Xue, Hao-Huan and Fu, Guang-Jun and Zhang, Bin and Wang, Rui-Zhe and Li, Cheng and Zhang, Hui and Lu, Kun and Yang, Yong and LUO, Yu-Qi and BAI, Zhen-Ya and SONG, Min-Qi and WANG, Wen-Jie and ZHAO, Feng and ZHANG, Jing-Heng and XU and ZHAO, Xi and LU, Chun-Song and LUO, Yi-Qi and CHEN, Yi-Zhao and HU, Yong and TANG, Qiang and CHEN, De-Xun and YANG, Guang-Wen and GONG, Peng and HUANG, Xiao-Meng},
booktitle = {Advances in Climate Change Research},
doi = {10.12006/j.issn.1673-1719.2019.166},
number = {5},
pages = {545--550},
title = {{The Community Integrated Earth System Model (CIESM) from Tsinghua University and its plan for CMIP6 experiments}},
volume = {15},
year = {2019}
}
@article{Liu2014,
abstract = {The performance of 21 Coupled Model Intercomparison Project Phase 5 (CMIP5) models in the simulation of the Indian Ocean Dipole (IOD) mode is evaluated. Compared to CMIP3, CMIP5 models exhibit a similar spread in IOD intensity. A detailed diagnosis was carried out to understand whether CMIP5 models have shown improvement in their representation of the important dynamical and thermodynamical feedbacks in the tropical Indian Ocean. These include the Bjerknes dynamic air-sea feedback, which includes the equatorial zonal wind response to sea surface temperature (SST) anomaly, the thermocline response to equatorial zonal wind forcing, the ocean subsurface temperature response to the thermocline variations, and the thermodynamic air-sea coupling that includes the wind-evaporation-SST and cloud-radiation-SST feedback. Compared to CMIP3, the CMIP5 ensemble produces a more realistic positive wind-evaporation-SST feedback during the IOD developing phase, while the simulation of Bjerknes dynamic feedback is more unrealistic especially with regard to the wind response to SST forcing and the thermocline response to surface wind forcing. The overall CMIP5 performance in the IOD simulation does not show remarkable improvements compared to CMIP3. It is further noted that the El Ni{\~{n}}o-Southern Oscillation (ENSO) and IOD amplitudes are closely related, if a model generates a strong ENSO, it is likely that this model also simulates a strong IOD.},
annote = {IOD in CMIP5 models
- CMIP3 versus CMIP5
- 1950-1999
- NCEP/NCAR, ERA-40, SODA, Ishii {\&} Kimoto, HadISST, ERSST

- Like CMIP3, CMIP5 models on average overestimate SST anomaly magnitude associated with the IOD
- Seasonality is reproduced in CMIP5 as in CMIP3 models 
- Slightly better in magnitude in fall with narrower ensemble spread in CMIP5 than CMIP3
- Bjerkness and thermodynamic (cloud-radiation-SST and WES) feedback efficiency
-- CMIP5 is better in WES feedback than CMIP3
-- Bjerkness feedback is worse in CMIP5, especially wind response to SST forcing and thermocline response to wind forcing
→ In terms of individual processes, the representation of IOD is not remarkably improved from CMIP3
- ENSO amplitude affects IOD amplitude
- Magnitude bias of the IOD is not fully attributable to thermocline bias},
author = {Liu, Lin and Xie, Shang-Ping and Zheng, Xiao-Tong and Li, Tim and Du, Yan and Huang, Gang and Yu, Wei-Dong},
doi = {10.1007/s00382-013-2000-9},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {5},
pages = {1715--1730},
title = {{Indian Ocean variability in the CMIP5 multi-model ensemble: the zonal dipole mode}},
url = {https://doi.org/10.1007/s00382-013-2000-9},
volume = {43},
year = {2014}
}
@article{doi:10.1175/JCLI-D-12-00556.1,
abstract = { AbstractThis study investigates Atlantic warm pool (AWP) variability in the historical run of 19 coupled general circulation models (CGCMs) submitted to phase 5 of the Coupled Model Intercomparison Project (CMIP5). As with the CGCMs in phase 3 (CMIP3), most models suffer from the cold SST bias in the AWP region and also show very weak AWP variability as represented by the AWP area index. However, for the seasonal cycle the AWP SST bias of model ensemble and model sensitivities are decreased compared with CMIP3, indicating that the CGCMs are improved. The origin of the cold SST bias in the AWP region remains unknown, but among the CGCMs in CMIP5 excess (insufficient) high-level cloud simulation decreases (enhances) the cold SST bias in the AWP region through the warming effect of the high-level cloud radiative forcing. Thus, the AWP SST bias in CMIP5 is more modulated by an erroneous radiation balance due to misrepresentation of high-level clouds rather than low-level clouds as in CMIP3. AWP variability is assessed as in the authors' previous study in the aspects of spectral analysis, interannual variability, multidecadal variability, and comparison of the remote connections with ENSO and the North Atlantic Oscillation (NAO) against observations. In observations the maximum influences of the NAO and ENSO on the AWP take place in boreal spring. For some CGCMs these influences erroneously last to late summer. The effect of this overestimated remote forcing can be seen in the variability statistics as shown in the rotated EOF patterns from the models. It is concluded that the NCAR Community Climate System Model, version 4 (CCSM4), the Goddard Institute for Space Studies (GISS) Model E, version 2, coupled with the Hybrid Coordinate Ocean Model (HYCOM) ocean model (GISS-E2H), and the GISS Model E, version 2, coupled with the Russell ocean model (GISS-E2R) are the best three models of CMIP5 in simulating AWP variability. },
author = {Liu, Hailong and Wang, Chunzai and Lee, Sang-Ki and Enfield, David},
doi = {10.1175/JCLI-D-12-00556.1},
journal = {Journal of Climate},
number = {15},
pages = {5315--5336},
title = {{Atlantic Warm Pool Variability in the CMIP5 Simulations}},
url = {https://doi.org/10.1175/JCLI-D-12-00556.1},
volume = {26},
year = {2013}
}
@article{Liu2016a,
abstract = {Ocean heat uptake is observed to penetrate deep into the Atlantic and Southern Oceans during the recent hiatus of global warming. Here we show that the deep heat penetration in these two basins is not unique to the hiatus but is characteristic of anthropogenic warming and merely reflects the depth of the mean meridional overturning circulation in the basin. We find, however, that heat redistribution in the upper 350 m between the Pacific and Indian Oceans is closely tied to the surface warming hiatus. The Indian Ocean shows an anomalous warming below 50 m during hiatus events due to an enhanced heat transport by the Indonesian throughflow in response to the intensified trade winds in the equatorial Pacific. Thus, the Pacific and Indian Oceans are the key regions to track ocean heat uptake during the surface warming hiatus.},
author = {Liu, Wei and Xie, Shang Ping and Lu, Jian},
doi = {10.1038/ncomms10926},
isbn = {2041-1723 (Electronic)$\backslash$r2041-1723 (Linking)},
issn = {20411723},
journal = {Nature Communications},
pages = {1--9},
pmid = {27025666},
publisher = {Nature Publishing Group},
title = {{Tracking ocean heat uptake during the surface warming hiatus}},
url = {http://dx.doi.org/10.1038/ncomms10926},
volume = {7},
year = {2016}
}
@article{Liu2016e,
abstract = {Climate variation of global monsoon (GM) precipitation involves both internal feedback and external forcing. Here, we focus on strong volcanic forcing since large eruptions are known to be a dominant mechanism in natural climate change. It is not known whether large volcanoes erupted at different latitudes have distinctive effects on the monsoon in the Northern Hemisphere (NH) and the Southern Hemisphere (SH). We address this issue using a 1500-year volcanic sensitivity simulation by the Community Earth System Model version 1.0 (CESM1). Volcanoes are classified into three types based on their meridional aerosol distributions: NH volcanoes, SH volcanoes and equatorial volcanoes. Using the model simulation, we discover that the GM precipitation in one hemisphere is enhanced significantly by the remote volcanic forcing occurring in the other hemisphere. This remote volcanic forcing-induced intensification is mainly through circulation change rather than moisture content change. In addition, the NH volcanic eruptions are more efficient in reducing the NH monsoon precipitation than the equatorial ones, and so do the SH eruptions in weakening the SH monsoon, because the equatorial eruptions, despite reducing moisture content, have weaker effects in weakening the off-equatorial monsoon circulation than the subtropical-extratropical volcanoes do.},
author = {Liu, Fei and Chai, Jing and Wang, Bin and Liu, Jian and Zhang, Xiao and Wang, Zhiyuan},
doi = {10.1038/srep24331},
issn = {20452322},
journal = {Scientific Reports},
month = {jul},
number = {1},
pages = {24331},
title = {{Global monsoon precipitation responses to large volcanic eruptions}},
volume = {6},
year = {2016}
}
@article{Liu2012b,
author = {Liu, Jian and Wang, Bin and Yim, So-Young and Lee, June-Yi and Jhun, Jong-Ghap and Ha, Kyung-Ja},
doi = {10.1007/s00382-012-1360-x},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {sep},
number = {5},
pages = {1063--1072},
title = {{What drives the global summer monsoon over the past millennium?}},
volume = {39},
year = {2012}
}
@article{Liu2017e,
abstract = {The far-reaching impacts of central Pacific El Ni{\~{n}}o events on global climate differ appreciably from those associated with eastern Pacific El Ni{\~{n}}o events. Central Pacific El Ni{\~{n}}o events may become more frequent in coming decades as atmospheric greenhouse gas concentrations rise, but the instrumental record of central Pacific sea-surface temperatures is too short to detect potential trends. Here we present an annually resolved reconstruction of NI{\~{N}}O4 sea-surface temperature, located in the central equatorial Pacific, based on oxygen isotopic time series from Taiwan tree cellulose that span from 1190 AD to 2007 AD. Our reconstruction indicates that relatively warm Ni{\~{n}}o4 sea-surface temperature values over the late twentieth century are accompanied by higher levels of interannual variability than observed in other intervals of the 818-year-long reconstruction. Our results imply that anthropogenic greenhouse forcing may be driving an increase in central Pacific El Ni{\~{n}}o-Southern Oscillation variability and/or its hydrological impacts, consistent with recent modelling studies.},
author = {Liu, Yu and Cobb, Kim M and Song, Huiming and Li, Qiang and Li, Ching-Yao and Nakatsuka, Takeshi and An, Zhisheng and Zhou, Weijian and Cai, Qiufang and Li, Jinbao and Leavitt, Steven W and Sun, Changfeng and Mei, Ruochen and Shen, Chuan-Chou and Chan, Ming-Hsun and Sun, Junyan and Yan, Libin and Lei, Ying and Ma, Yongyong and Li, Xuxiang and Chen, Deliang and Linderholm, Hans W},
doi = {10.1038/ncomms15386},
issn = {2041-1723},
journal = {Nature Communications},
number = {1},
pages = {15386},
title = {{Recent enhancement of central Pacific El Ni{\~{n}}o variability relative to last eight centuries}},
url = {https://doi.org/10.1038/ncomms15386},
volume = {8},
year = {2017}
}
@article{Liu2017a,
abstract = {Changes in the Atlantic Meridional Overturning Circulation (AMOC) are moderate in most climate model projections under increasing greenhouse gas forcing. This intermodel consensus may be an artifact of common model biases that favor a stable AMOC. Observationally based freshwater budget analyses suggest that the AMOC is in an unstable regime susceptible for large changes in response to perturbations. By correcting the model biases, we show that the AMOC collapses 300 years after the atmospheric CO2 concentration is abruptly doubled from the 1990 level. Compared to an uncorrected model, the AMOC collapse brings about large, markedly different climate responses: a prominent cooling over the northern North Atlantic and neighboring areas, sea ice increases over the Greenland-Iceland-Norwegian seas and to the south of Greenland, and a significant southward rain-belt migration over the tropical Atlantic. Our results highlight the need to develop dynamical metrics to constrain models and the importance of reducing model biases in long-term climate projection.},
author = {Liu, Wei and Xie, Shang-Ping and Liu, Zhengyu and Zhu, Jiang},
doi = {10.1126/sciadv.1601666},
journal = {Science Advances},
month = {jan},
number = {1},
pages = {e1601666},
title = {{Overlooked possibility of a collapsed Atlantic Meridional Overturning Circulation in warming climate}},
url = {http://advances.sciencemag.org/content/3/1/e1601666.abstract},
volume = {3},
year = {2017}
}
@article{Liu2018d,
author = {Liu, Shanshan and Jiang, Dabang and Lang, Xianmei},
doi = {10.1016/j.quascirev.2018.05.029},
issn = {02773791},
journal = {Quaternary Science Reviews},
month = {jul},
pages = {363--377},
title = {{A multi-model analysis of moisture changes during the last glacial maximum}},
url = {https://linkinghub.elsevier.com/retrieve/pii/S0277379118301185},
volume = {191},
year = {2018}
}
@article{Ljungqvist2019,
abstract = {Systematic comparisons of proxy-based reconstructions and climate model simulations of past millennium temperature variability offer insights into climate sensitivity and feedback mechanisms, besides allowing model evaluation independently from the period covered by instrumental data. Such simulation-reconstruction comparisons can help to distinguish more skillful models from less skillful ones, which may subsequently help to develop more reliable future projections. This study evaluates the low-frequency simulation-reconstruction agreement within the past millennium through assessing the amplitude of temperature change between the Medieval Climate Anomaly (here, 950-1250 CE) and the Little Ice Age (here, 1450-1850 CE) in PMIP3 model simulations compared to proxy-based local and continental-scale reconstructions. The simulations consistently show a smaller temperature change than the reconstructions for most regions in the Northern Hemisphere, but not in the Southern Hemisphere, as well as a partly different spatial pattern. A cost function analysis assesses how well the various simulations agree with reconstructions. Disregarding spatial correlation, significant differences are seen in the agreement with the local temperature reconstructions between groups of models, but insignificant differences are noted when compared to continental-scale reconstructions. This result points toward a limited possibility to "rank" models by means of their low-frequency temperature variability alone. The systematically lower amplitude of simulated versus reconstructed temperature change indicates either too-small simulated internal variability or that the analyzed models lack some critical forcing or have missing or too-weak feedback mechanisms. We hypothesize that too-cold initial ocean conditions in the models-in combination with too-weak internal variability and slow feedbacks over longer time scales-could account for much of the simulation-reconstruction disagreement.},
address = {Boston MA, USA},
author = {Ljungqvist, Fredrik Charpentier and Zhang, Qiong and Brattstr{\"{o}}m, Gudrun and Krusic, Paul J. and Seim, Andrea and Li, Qiang and Zhang, Qiang and Moberg, Anders},
doi = {10.1175/JCLI-D-18-0525.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Climate models,Model comparison,Paleoclimate,Ranking methods,Surface temperature},
language = {English},
number = {9},
pages = {2441--2482},
publisher = {American Meteorological Society},
title = {{Centennial-scale temperature change in last millennium simulations and proxy-based reconstructions}},
url = {https://journals.ametsoc.org/view/journals/clim/32/9/jcli-d-18-0525.1.xml},
volume = {32},
year = {2019}
}
@article{Long2020,
abstract = {Previous studies reveal that the last generation of coupled general circulation models (CGCMs) commonly suffer from the so-called Indian Ocean dipole (IOD)-like biases, lowering the models' ability in climate prediction and projection. The present study shows that such IOD-like biases are reduced insignificantly or even worsen in CGCMs from phase 5 to phase 6 of the Coupled Model Intercomparison Project (CMIP). The origins of the IOD-like biases in CGCMs are further investigated by comparing model outputs from CMIP and the Atmospheric Model Intercomparison Project (AMIP). The CGCMs' errors are divided into the biases from the AMIP simulation (AMIP biases) and ocean–atmosphere coupling (coupling biases). For the multimodel ensemble mean, the AMIP (coupling) biases account for about two-thirds (one-third) of the IOD-like CMIP biases. In AMIP simulations, the South Asian summer monsoon (SASM) is overly strong; therefore, it could advect overly large easterly momentum from the south Indian Ocean (IO) to the equator. The resultant equatorial easterly wind bias would initiate the convection–circulation feedback and develop large IOD-like AMIP biases. In contrast, the coupling biases weaken the SASM and hence generate warm SST error over the western IO during boreal summer. Such SST error persists to boreal autumn and triggers the Bjerknes feedback, developing the IOD-like coupling biases. Furthermore, the intermodel spread in the IOD-like CMIP biases is largely explained by the intermodel differences in the coupling biases rather than the AMIP biases. The results imply that substantial efforts should be respectively made on reducing the atmospheric models' intrinsic monsoon biases as well as advancing the simulations of ocean–atmosphere coupling processes.},
author = {Long, Shang-Min and Li, Gen and Hu, Kaiming and Ying, Jun},
doi = {10.1175/JCLI-D-20-0459.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {dec},
number = {24},
pages = {10437--10453},
title = {{Origins of the IOD-like Biases in CMIP Multimodel Ensembles: The Atmospheric Component and Ocean–Atmosphere Coupling}},
url = {https://journals.ametsoc.org/doi/10.1175/JCLI-D-20-0459.1},
volume = {33},
year = {2020}
}
@article{Lora2018a,
abstract = {AbstractThis study examines the differences in the moisture budget over North America between the Last Glacial Maximum (LGM) and modern, as simulated by nine models from phase 3 of the Paleoclimate Modelling Intercomparison Project. The results help elucidate the components and mechanisms of the LGM hydrologic cycle. The models predict substantial increases in winter precipitation minus evaporation (P–E) over the ice-free parts of western North America with respect to modern, primarily due to increases in moisture convergence by the mean flow. In summer, they predict P–E increases from the Great Plains to the southeastern margin of the ice sheet—driven by large decreases in E—that are due to a combination of increased convergence by the mean flow and transient eddies. In both seasons, the LGM–modern changes in P–E are dominated by changes in the circulation, rather than by changes in atmospheric water vapor. Compared to a proxy reconstruction of LGM–modern changes in P, the simulated P responses show mode...},
author = {Lora, Juan M.},
doi = {10.1175/JCLI-D-17-0544.1},
issn = {08948755},
journal = {Journal of Climate},
month = {jun},
number = {17},
pages = {7035--7051},
publisher = {American Meteorological Society},
title = {{Components and mechanisms of hydrologic cycle changes over North America at the Last Glacial Maximum}},
volume = {31},
year = {2018}
}
@article{Lovejoy2014,
author = {Lovejoy, S.},
doi = {10.1002/2014GL060478},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {jul},
number = {13},
pages = {4704--4710},
title = {{Return periods of global climate fluctuations and the pause}},
url = {http://doi.wiley.com/10.1002/2014GL060478},
volume = {41},
year = {2014}
}
@article{Lovenduski2016,
author = {Lovenduski, Nicole S. and McKinley, Galen A. and Fay, Amanda R. and Lindsay, Keith and Long, Matthew C.},
doi = {10.1002/2016GB005426},
issn = {08866236},
journal = {Global Biogeochemical Cycles},
keywords = {carbon,climate,model,ocean,projection,uncertainty},
month = {sep},
number = {9},
pages = {1276--1287},
publisher = {Wiley-Blackwell},
title = {{Partitioning uncertainty in ocean carbon uptake projections: Internal variability, emission scenario, and model structure}},
url = {http://doi.wiley.com/10.1002/2016GB005426},
volume = {30},
year = {2016}
}
@article{Lovenduski2008,
author = {Lovenduski, Nicole S. and Gruber, Nicolas and Doney, Scott C.},
doi = {10.1029/2007GB003139},
issn = {08866236},
journal = {Global Biogeochemical Cycles},
keywords = {Southern Annular Mode,Southern Ocean,ocean carbon sink},
month = {sep},
number = {3},
pages = {GB3016},
publisher = {Wiley-Blackwell},
title = {{Toward a mechanistic understanding of the decadal trends in the Southern Ocean carbon sink}},
url = {http://doi.wiley.com/10.1029/2007GB003139},
volume = {22},
year = {2008}
}
@article{Lu2016,
author = {Lu, Xuefei and Wang, Lixin and McCabe, Matthew F},
doi = {10.1038/srep20716},
issn = {2045-2322},
journal = {Scientific Reports},
month = {aug},
number = {1},
pages = {20716},
publisher = {The Author(s)},
title = {{Elevated CO2 as a driver of global dryland greening}},
url = {http://www.nature.com/articles/srep20716},
volume = {6},
year = {2016}
}
@article{gmd-10-889-2017,
author = {Lunt, D J and Huber, M and Anagnostou, E and Baatsen, M L J and Caballero, R and DeConto, R and Dijkstra, H A and Donnadieu, Y and Evans, D and Feng, R and Foster, G L and Gasson, E and von der Heydt, A S and Hollis, C J and Inglis, G N and Jones, S M and Kiehl, J and {Kirtland Turner}, S and Korty, R L and Kozdon, R and Krishnan, S and Ladant, J.-B. and Langebroek, P and Lear, C H and LeGrande, A N and Littler, K and Markwick, P and Otto-Bliesner, B and Pearson, P and Poulsen, C J and Salzmann, U and Shields, C and Snell, K and St{\"{a}}rz, M and Super, J and Tabor, C and Tierney, J E and Tourte, G J L and Tripati, A and Upchurch, G R and Wade, B S and Wing, S L and Winguth, A M E and Wright, N M and Zachos, J C and Zeebe, R E},
doi = {10.5194/gmd-10-889-2017},
journal = {Geoscientific Model Development},
number = {2},
pages = {889--901},
title = {{The DeepMIP contribution to PMIP4: experimental designfor model simulations of the EECO, PETM, and pre-PETM (version 1.0)}},
url = {https://www.geosci-model-dev.net/10/889/2017/},
volume = {10},
year = {2017}
}
@article{cp-17-203-2021,
author = {Lunt, D J and Bragg, F and Chan, W.-L. and Hutchinson, D K and Ladant, J.-B. and Morozova, P and Niezgodzki, I and Steinig, S and Zhang, Z and Zhu, J and Abe-Ouchi, A and Anagnostou, E and de Boer, A M and Coxall, H K and Donnadieu, Y and Foster, G and Inglis, G N and Knorr, G and Langebroek, P M and Lear, C H and Lohmann, G and Poulsen, C J and Sepulchre, P and Tierney, J E and Valdes, P J and Volodin, E M and {Dunkley Jones}, T and Hollis, C J and Huber, M and Otto-Bliesner, B L},
doi = {10.5194/cp-17-203-2021},
journal = {Climate of the Past},
number = {1},
pages = {203--227},
title = {{DeepMIP: model intercomparison of early Eocene climatic optimum (EECO) large-scale climate features and comparison with proxy data}},
url = {https://cp.copernicus.org/articles/17/203/2021/},
volume = {17},
year = {2021}
}
@article{Luo18701,
abstract = {It has been widely believed that the tropical Pacific trade winds weakened in the last century and would further decrease under a warmer climate in the 21st century. Recent high-quality observations, however, suggest that the tropical Pacific winds have actually strengthened in the past two decades. Precise causes of the recent Pacific climate shift are uncertain. Here we explore how the enhanced tropical Indian Ocean warming in recent decades favors stronger trade winds in the western Pacific via the atmosphere and hence is likely to have contributed to the La Ni{\~{n}}a-like state (with enhanced east{\{}$\backslash$textendash{\}}west Walker circulation) through the Pacific ocean{\{}$\backslash$textendash{\}}atmosphere interactions. Further analysis, based on 163 climate model simulations with centennial historical and projected external radiative forcing, suggests that the Indian Ocean warming relative to the Pacific{\{}$\backslash$textquoteright{\}}s could play an important role in modulating the Pacific climate changes in the 20th and 21st centuries.},
author = {Luo, Jing-Jia and Sasaki, Wataru and Masumoto, Yukio},
doi = {10.1073/pnas.1210239109},
issn = {0027-8424},
journal = {Proceedings of the National Academy of Sciences},
number = {46},
pages = {18701--18706},
publisher = {National Academy of Sciences},
title = {{Indian Ocean warming modulates Pacific climate change}},
url = {http://www.pnas.org/content/109/46/18701},
volume = {109},
year = {2012}
}
@misc{Luo2018a,
author = {Luo, B.},
language = {Refcheck: Does the ftp weblink work?},
title = {{Aerosol Radiative Forcing and SAD version v4.0.0 1850–2016}},
url = {ftp://iacftp.ethz.ch/pub{\_}read/luo/CMIP6{\_}SAD{\_}radForcing{\_}v4.0.0/},
year = {2018}
}
@article{Lyu2016,
abstract = {With significant impacts on the regional weather and climate, interdecadal climate variability is of great importance in understanding historical observations and predicting the climate in the near future....},
author = {Lyu, Kewei and Zhang, Xuebin and Church, John A. and Hu, Jianyu},
doi = {10.1002/joc.4587},
issn = {10970088},
journal = {International Journal of Climatology},
number = {11},
pages = {3723--3740},
title = {{Evaluation of the interdecadal variability of sea surface temperature and sea level in the Pacific in CMIP3 and CMIP5 models}},
volume = {36},
year = {2016}
}
@article{Muller2015,
author = {M{\"{u}}ller, W. A. and Matei, D. and Bersch, M. and Jungclaus, J. H. and Haak, H. and Lohmann, K. and Compo, G. P. and Sardeshmukh, P. D. and Marotzke, J.},
doi = {10.1007/s00382-014-2267-5},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {apr},
number = {7-8},
pages = {1935--1955},
title = {{A twentieth-century reanalysis forced ocean model to reconstruct the North Atlantic climate variation during the 1920s}},
url = {http://link.springer.com/10.1007/s00382-014-2267-5},
volume = {44},
year = {2015}
}
@article{Menegoz2018,
author = {M{\'{e}}n{\'{e}}goz, Martin and Cassou, Christophe and Swingedouw, Didier and Ruprich-Robert, Yohan and Bretonni{\`{e}}re, Pierre-Antoine and Doblas-Reyes, Francisco},
doi = {10.1007/s00382-017-3986-1},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {sep},
number = {5-6},
pages = {1863--1883},
title = {{Role of the Atlantic Multidecadal Variability in modulating the climate response to a Pinatubo-like volcanic eruption}},
url = {http://link.springer.com/10.1007/s00382-017-3986-1},
volume = {51},
year = {2018}
}
@article{Ma2015a,
abstract = {AbstractIn this study, the zonal mass streamfunction ?, which depicts intuitively the tropical Pacific Walker circulation (PWC) structure characterized by an enclosed and clockwise rotation cell in the zonal?vertical section over the equatorial Pacific, was used to study the changes of PWC spatial structure during 1979?2012. To examine the robustness of changes in PWC characteristics, the linear trends of PWC were evaluated and compared among the current seven sets of reanalysis data, along with a comparison to the trends of surface climate variables. The spatial pattern of ? trend exhibited a strengthening and westward-shifting trend of PWC in all reanalysis datasets, with the significantly positive ? dominating the western Pacific and negative ? controlling the eastern Pacific. This kind of change is physically in agreement with the changes of the sea level pressure (SLP), surface winds, and precipitation derived from both the reanalyses and independent observations. Quantitative analyses of the changes in the PWC intensity and western edge, defined based on the zonal mass streamfunction, also revealed a robust strengthening and westward-shifting trend among all reanalysis datasets, with a trend of 15.08{\%} decade?1 and 3.70° longitude decade?1 in the ensemble mean of seven sets of reanalysis data, with the strongest (weakest) intensification of 17.53{\%} decade?1 (7.96{\%} decade?1) in the Twentieth Century Reanalysis (NCEP-2) and largest (smallest) westward shift of ?4.68° longitude decade?1 (?2.55° longitude decade?1) in JRA-55 (JRA-25). In response to the recent observed La Ni{\~{n}}a?like anomalous SST forcing, the ensemble simulations from phase 5 of the Coupled Model Intercomparison Project (CMIP5), with 26 models in the ensemble, reasonably reproduced the observed strengthening and westward-shifting trend of PWC, implying the dominant forcing of the La Ni{\~{n}}a?like SST anomalies to the recent PWC change.},
author = {Ma, Shuangmei and Zhou, Tianjun},
doi = {10.1175/JCLI-D-15-0398.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {may},
number = {9},
pages = {3097--3118},
publisher = {American Meteorological Society},
title = {{Robust Strengthening and Westward Shift of the Tropical Pacific Walker Circulation during 1979–2012: A Comparison of 7 Sets of Reanalysis Data and 26 CMIP5 Models}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-15-0398.1 https://doi.org/10.1175/JCLI-D-15-0398.1},
volume = {29},
year = {2016}
}
@article{doi:10.1002/2014GL060527,
abstract = {AbstractThe latest generation of climate model simulations are used to investigate the occurrence of hiatus periods in global surface air temperature in the past and under two future warming scenarios. Hiatus periods are identified in three categories: (i) those due to volcanic eruptions, (ii) those associated with negative phases of the Interdecadal Pacific Oscillation (IPO), and (iii) those affected by anthropogenically released aerosols in the mid-twentieth century. The likelihood of future hiatus periods is found to be sensitive to the rate of change of anthropogenic forcing. Under high rates of greenhouse gas emissions there is little chance of a hiatus decade occurring beyond 2030, even in the event of a large volcanic eruption. We further demonstrate that most nonvolcanic hiatuses across Coupled Model Intercomparison Project 5 (CMIP5) models are associated with enhanced cooling in the equatorial Pacific linked to the transition to a negative IPO phase.},
author = {Maher, Nicola and Gupta, Alexander Sen and England, Matthew H},
doi = {10.1002/2014GL060527},
journal = {Geophysical Research Letters},
keywords = {CMIP5,Pacific Ocean,aerosols,eruption,hiatus,volcanic},
number = {16},
pages = {5978--5986},
title = {{Drivers of decadal hiatus periods in the 20th and 21st centuries}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2014GL060527},
volume = {41},
year = {2014}
}
@article{Maher2018a,
author = {Maher, Nicola and England, Matthew H. and Gupta, Alex Sen and Spence, Paul},
doi = {10.1007/s00382-017-3923-3},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jul},
number = {1-2},
pages = {321--336},
title = {{Role of Pacific trade winds in driving ocean temperatures during the recent slowdown and projections under a wind trend reversal}},
url = {http://link.springer.com/10.1007/s00382-017-3923-3},
volume = {51},
year = {2018}
}
@article{Maher2018c,
author = {Maher, N. and Matei, D. and Milinski, S. and Marotzke, J.},
doi = {10.1029/2018GL079764},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {oct},
number = {20},
pages = {11390--11398},
title = {{ENSO Change in Climate Projections: Forced Response or Internal Variability?}},
url = {https://onlinelibrary.wiley.com/doi/10.1029/2018GL079764},
volume = {45},
year = {2018}
}
@article{doi:10.1175/2010JCLI3713.1,
abstract = { Abstract The Arctic climate is governed by complex interactions and feedback mechanisms between the atmosphere, ocean, and solar radiation. One of its characteristic features, the Arctic sea ice, is very vulnerable to anthropogenically caused warming. Production and melting of sea ice is influenced by several physical processes. The authors show that the northward ocean heat transport is an important factor in the simulation of the sea ice extent in the current general circulation models. Those models that transport more energy to the Arctic show a stronger future warming, in the Arctic as well as globally. Larger heat transport to the Arctic, in particular in the Barents Sea, reduces the sea ice cover in this area. More radiation is then absorbed during summer months and is radiated back to the atmosphere in winter months. This process leads to an increase in the surface temperature and therefore to a stronger polar amplification. The models that show a larger global warming agree better with the observed sea ice extent in the Arctic. In general, these models also have a higher spatial resolution. These results suggest that higher resolution and greater complexity are beneficial in simulating the processes relevant in the Arctic and that future warming in the high northern latitudes is likely to be near the upper range of model projections, consistent with recent evidence that many climate models underestimate Arctic sea ice decline. },
author = {Mahlstein, Irina and Knutti, Reto},
doi = {10.1175/2010JCLI3713.1},
journal = {Journal of Climate},
number = {5},
pages = {1451--1460},
title = {{Ocean Heat Transport as a Cause for Model Uncertainty in Projected Arctic Warming}},
url = {https://doi.org/10.1175/2010JCLI3713.1},
volume = {24},
year = {2011}
}
@article{doi:10.1002/jgrd.50443,
abstract = {In contrast to Arctic sea ice, average Antarctic sea ice area is not retreating but has slowly increased since satellite measurements began in 1979. While most climate models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) archive simulate a decrease in Antarctic sea ice area over the recent past, whether these models can be dismissed as being wrong depends on more than just the sign of change compared to observations. We show that internal sea ice variability is large in the Antarctic region, and both the observed and modeled trends may represent natural variations along with external forcing. While several models show a negative trend, only a few of them actually show a trend that is significant compared to their internal variability on the time scales of available observational data. Furthermore, the ability of the models to simulate the mean state of sea ice is also important. The representations of Antarctic sea ice in CMIP5 models have not improved compared to CMIP3 and show an unrealistic spread in the mean state that may influence future sea ice behavior. Finally, Antarctic climate and sea ice area will be affected not only by ocean and air temperature changes but also by changes in the winds. The majority of the CMIP5 models simulate a shift that is too weak compared to observations. Thus, this study identifies several foci for consideration in evaluating and improving the modeling of climate and climate change in the Antarctic region.},
author = {Mahlstein, Irina and Gent, Peter R and Solomon, Susan},
doi = {10.1002/jgrd.50443},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {Antarctic sea ice,CMIP5},
number = {11},
pages = {5105--5110},
title = {{Historical Antarctic mean sea ice area, sea ice trends, and winds in CMIP5 simulations}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/jgrd.50443},
volume = {118},
year = {2013}
}
@article{doi:10.1029/2011JD016709,
abstract = {The decline of Arctic sea ice is one of the most visible signs of climate change over the past several decades. Arctic sea ice area shows large interannual variability due to the numerous factors, but on longer time scales the total sea ice area is approximately linearly related to Arctic surface air temperature in models and observations. Overall, models however strongly underestimate the recent sea ice decline. Here we show that this can be explained with two interlinked biases. Most climate models simulate a smaller sea ice area reduction per degree local surface warming. Arctic polar amplification, the ratio between Arctic and global temperature, is also underestimated but a number of models are within the uncertainty estimated from natural variability. A recalibration of an ensemble of global climate models using observations over 28 years provides a scenario independent relationship and yields about 2°C change in annual mean global surface temperature above present as the most likely global temperature threshold for September sea ice to disappear, but with substantial associated uncertainty. Natural variability in the Arctic is large and needs to be considered both for such recalibrations as well as for model evaluation, in particular when observed trends are relatively short.},
author = {Mahlstein, Irina and Knutti, Reto},
doi = {10.1029/2011JD016709},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {Arctic sea ice,model recalibration},
number = {D6},
pages = {D06104},
title = {{September Arctic sea ice predicted to disappear near 2°C global warming above present}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2011JD016709},
volume = {117},
year = {2012}
}
@article{mahowald2017interactions,
author = {Mahowald, Natalie M and Randerson, James T and Lindsay, Keith and Munoz, Ernesto and Doney, Scott C and Lawrence, Peter and Schlunegger, Sarah and Ward, Daniel S and Lawrence, David and Hoffman, Forrest M},
doi = {10.1002/2016GB005374},
journal = {Global Biogeochemical Cycles},
number = {1},
pages = {96--113},
publisher = {Wiley Online Library},
title = {{Interactions between land use change and carbon cycle feedbacks}},
volume = {31},
year = {2017}
}
@article{https://doi.org/10.1111/j.1600-0889.2010.00488.x,
abstract = {We have developed a new observational screening technique for inverse model. This technique was applied to our transport models with re-analysed meteorological data and the inverse model to estimate the global distribution of CO2 concentrations and fluxes. During the 1990s, we estimated a total CO2 uptake by the biosphere of 1.4-1.5 PgC yr-1 and a total CO2 uptake by the oceans of 1.7-1.8 PgC yr-1. The uncertainty of global CO2 flux estimation is about 0.3 PgC yr-1. We also obtained monthly surface CO2 concentrations in the marine boundary layer to precisions of 0.5-1.0 ppm. To utilize non-processed (statistical monthly mean) observational data in our analysis, we developed a quality control procedure for such observational data including a repetition of inversion. This technique is suitable for other inversion setups. Observational data by ships were placed into grids and used in our analysis to add to the available data from fixed stations. The estimated global distributions are updated and extended every year. {\textcopyright} 2010 The Authors Tellus B {\textcopyright} 2010 International Meteorological Institute in Stockholm.},
author = {Maki, T. and Ikegami, M. and Fujita, T. and Hirahara, T. and Yamada, K. and Mori, K. and Takeuchi, A. and Tsutsumi, Y. and Suda, K. and Conway, T. J.},
doi = {10.1111/j.1600-0889.2010.00488.x},
issn = {02806509},
journal = {Tellus B: Chemical and Physical Meteorology},
number = {5},
pages = {797--809},
title = {{New technique to analyse global distributions of CO2 concentrations and fluxes from non-processed observational data}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-0889.2010.00488.x},
volume = {62},
year = {2010}
}
@article{Malik2018,
author = {Malik, Abdul and Br{\"{o}}nnimann, Stefan and Perona, Paolo},
doi = {10.1007/s00382-017-3832-5},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {may},
number = {9-10},
pages = {3649--3670},
title = {{Statistical link between external climate forcings and modes of ocean variability}},
url = {http://link.springer.com/10.1007/s00382-017-3832-5},
volume = {50},
year = {2018}
}
@article{Mann2020a,
author = {Mann, Michael E. and Steinman, Byron A. and Miller, Sonya K.},
doi = {10.1038/s41467-019-13823-w},
issn = {2041-1723},
journal = {Nature Communications},
month = {dec},
number = {1},
pages = {49},
title = {{Absence of internal multidecadal and interdecadal oscillations in climate model simulations}},
url = {http://www.nature.com/articles/s41467-019-13823-w},
volume = {11},
year = {2020}
}
@article{Mann2014,
abstract = {We estimate the low-frequency internal variability of Northern Hemisphere (NH) mean temperature using observed temperature variations, which include both forced and internal variability components, and several alternative model simulations of the (natural+anthropogenic) forced component alone. We then generate an ensemble of alternative historical temperature histories based on the statistics of the estimated internal variability. Using this ensemble, we show, first, that recent NH mean temperatures fall within the range of expected multidecadal variability. Using the synthetic temperature histories, we also show that certain procedures used in past studies to estimate internal variability, and in particular, an internal multidecadal oscillation termed the "Atlantic Multidecadal Oscillation" or "AMO", fail to isolate the true internal variability when it is a priori known. Such procedures yield an AMO signal with an inflated amplitude and biased phase, attributing some of the recent NH mean temperature rise to the AMO. The true AMO signal, instead, appears likely to have been in a cooling phase in recent decades, offsetting some of the anthropogenic warming. Claims of multidecadal "stadium wave" patterns of variation across multiple climate indices are also shown to likely be an artifact of this flawed procedure for isolating putative climate oscillations. Key Points Certain common procedures fail to isolate internal variability in climate AMO appears to have been in a cool phase in recent decades 'Stadium wave' patterns are likely an artifact of flawed assessment procedures {\textcopyright} 2014. American Geophysical Union. All Rights Reserved.},
author = {Mann, Michael E. and Steinman, Byron A. and Miller, Sonya K.},
doi = {10.1002/2014GL059233},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {may},
number = {9},
pages = {3211--3219},
title = {{On forced temperature changes, internal variability, and the AMO}},
url = {http://doi.wiley.com/10.1002/2014GL059233},
volume = {41},
year = {2014}
}
@article{Mann2021,
abstract = {The Atlantic Multidecadal Oscillation (AMO), a 50- to 70-year quasiperiodic variation of climate centered in the North Atlantic region, was long thought to be an internal oscillation of the climate system. Mann et al. now show that this variation is forced externally by episodes of high-amplitude explosive volcanism. They used an ensemble of climate models to evaluate the causes of the AMO, finding that volcanos are the most important influence, and that there is no evidence to show that it has been internally generated during the last millennium.Science, this issue p. 1014Past research argues for an internal multidecadal (40- to 60-year) oscillation distinct from climate noise. Recent studies have claimed that this so-termed Atlantic Multidecadal Oscillation is instead a manifestation of competing time-varying effects of anthropogenic greenhouse gases and sulfate aerosols. That conclusion is bolstered by the absence of robust multidecadal climate oscillations in control simulations of current-generation models. Paleoclimate data, however, do demonstrate multidecadal oscillatory behavior during the preindustrial era. By comparing control and forced “Last Millennium” simulations, we show that these apparent multidecadal oscillations are an artifact of pulses of volcanic activity during the preindustrial era that project markedly onto the multidecadal (50- to 70-year) frequency band. We conclude that there is no compelling evidence for internal multidecadal oscillations in the climate system.},
author = {Mann, Michael E and Steinman, Byron A and Brouillette, Daniel J and Miller, Sonya K},
doi = {10.1126/science.abc5810},
issn = {0036-8075},
journal = {Science},
month = {mar},
number = {6533},
pages = {1014--1019},
title = {{Multidecadal climate oscillations during the past millennium driven by volcanic forcing}},
url = {http://science.sciencemag.org/content/371/6533/1014.abstract https://www.science.org/doi/10.1126/science.abc5810},
volume = {371},
year = {2021}
}
@article{Mantsis2017,
author = {Mantsis, Damianos F. and Sherwood, Steven and Allen, Robert and Shi, Lei},
doi = {10.1002/2016GL072097},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {apr},
number = {8},
pages = {3825--3832},
title = {{Natural variations of tropical width and recent trends}},
url = {http://doi.wiley.com/10.1002/2016GL072097},
volume = {44},
year = {2017}
}
@article{Mantua2002,
abstract = {The Pacific Decadal Oscillation (PDO) has been described by some as a long-lived El Ni{\~{n}}o-like pattern of Pacific climate variability, and by others as a blend of two sometimes independent modes having distinct spatial and temporal characteristics of North Pacific sea surface temperature (SST) variability. A growing body of evidence highlights a strong tendency for PDO impacts in the Southern Hemisphere, with important surface climate anomalies over the mid-latitude South Pacific Ocean, Australia and South America. Several independent studies find evidence for just two full PDO cycles in the past century: ``cool'' PDO regimes prevailed from 1890--1924 and again from 1947--1976, while ``warm'' PDO regimes dominated from 1925--1946 and from 1977 through (at least) the mid-1990's. Interdecadal changes in Pacific climate have widespread impacts on natural systems, including water resources in the Americas and many marine fisheries in the North Pacific. Tree-ring and Pacific coral based climate reconstructions suggest that PDO variations---at a range of varying time scales---can be traced back to at least 1600, although there are important differences between different proxy reconstructions. While 20th Century PDO fluctuations were most energetic in two general periodicities---one from 15-to-25 years, and the other from 50-to-70 years---the mechanisms causing PDO variability remain unclear. To date, there is little in the way of observational evidence to support a mid-latitude coupled air-sea interaction for PDO, though there are several well-understood mechanisms that promote multi-year persistence in North Pacific upper ocean temperature anomalies.},
author = {Mantua, Nathan J and Hare, Steven R},
doi = {10.1023/A:1015820616384},
issn = {1573-868X},
journal = {Journal of Oceanography},
number = {1},
pages = {35--44},
title = {{The Pacific Decadal Oscillation}},
url = {https://doi.org/10.1023/A:1015820616384},
volume = {58},
year = {2002}
}
@article{Mantua1997,
abstract = {Evidence gleaned from the instrumental record of climate data identifies a robust, recurring pattern of ocean?atmosphere climate variability centered over the midlatitude North Pacific basin. Over the past century, the amplitude of this climate pattern has varied irregularly at interannual-to-interdecadal timescales. There is evidence of reversals in the prevailing polarity of the oscillation occurring around 1925, 1947, and 1977; the last two reversals correspond to dramatic shifts in salmon production regimes in the North Pacific Ocean. This climate pattern also affects coastal sea and continental surface air temperatures, as well as streamflow in major west coast river systems, from Alaska to California.},
annote = {doi: 10.1175/1520-0477(1997)0782.0.CO;2},
author = {Mantua, Nathan J and Hare, Steven R and Zhang, Yuan and Wallace, John M and Francis, Robert C},
doi = {10.1175/1520-0477(1997)078<1069:APICOW>2.0.CO;2},
issn = {0003-0007},
journal = {Bulletin of the American Meteorological Society},
month = {jun},
number = {6},
pages = {1069--1080},
publisher = {American Meteorological Society},
title = {{A Pacific Interdecadal Climate Oscillation with Impacts on Salmon Production}},
url = {https://doi.org/10.1175/1520-0477(1997)078{\%}3C1069:APICOW{\%}3E2.0.CO http://0.0.0.2},
volume = {78},
year = {1997}
}
@article{Mao2016b,
author = {Mao, Jiafu and Ribes, Aur{\'{e}}lien and Yan, Binyan and Shi, Xiaoying and Thornton, Peter E and S{\'{e}}f{\'{e}}rian, Roland and Ciais, Philippe and Myneni, Ranga B and Douville, Herv{\'{e}} and Piao, Shilong and Zhu, Zaichun and Dickinson, Robert E and Dai, Yongjiu and Ricciuto, Daniel M and Jin, Mingzhou and Hoffman, Forrest M and Wang, Bin and Huang, Mengtian and Lian, Xu},
doi = {10.1038/nclimate3056},
journal = {Nature Climate Change},
month = {jun},
pages = {959},
publisher = {Nature Publishing Group},
title = {{Human-induced greening of the northern extratropical land surface}},
url = {https://doi.org/10.1038/nclimate3056 http://10.0.4.14/nclimate3056 https://www.nature.com/articles/nclimate3056{\#}supplementary-information},
volume = {6},
year = {2016}
}
@article{Mao2013,
abstract = {Using a recent Leaf Area Index (LAI) dataset and the Community Land Model version 4 (CLM4), we investigated percent changes and controlling factors of global vegetation growth for the period 1982 to 2009. Over that 28-year period, both the remote-sensing estimate and model simulation show a significant increasing trend in annual vegetation growth. Latitudinal asymmetry appeared in both products, with small increases in the Southern Hemisphere (SH) and larger increases at high latitudes in the Northern Hemisphere (NH). The south-to-north asymmetric land surface warming was assessed to be the principal driver of this latitudinal asymmetry of LAI trend. Heterogeneous precipitation functioned to decrease this latitudinal LAI gradient, and considerably regulated the local LAI change. A series of factorial experiments were specially-designed to isolate and quantify contributions to LAI trend from different external forcings such as climate variation, CO2, nitrogen deposition and land use and land cover change. The climate-only simulation confirms that climate change, particularly the asymmetry of land temperature variation, can explain the latitudinal pattern of LAI change. CO2 fertilization during the last three decades was simulated to be the dominant cause for the enhanced vegetation growth. Our study, though limited by observational and modeling uncertainties, adds further insight into vegetation growth trends and environmental correlations. These validation exercises also provide new quantitative and objective metrics for evaluation of land ecosystem process models at multiple spatio-temporal scales. {\textcopyright} 2013 by the authors; licensee MDPI, Basel, Switzerland.},
author = {Mao, Jiafu and Shi, Xiaoying and Thornton, Peter and Hoffman, Forrest and Zhu, Zaichun and Myneni, Ranga},
doi = {10.3390/rs5031484},
issn = {2072-4292},
journal = {Remote Sensing},
keywords = {CLM4,Detection and attribution study,Evaluation,Factorial simulation,Global vegetation growth trend,LAI},
month = {mar},
number = {3},
pages = {1484--1497},
title = {{Global Latitudinal-Asymmetric Vegetation Growth Trends and Their Driving Mechanisms: 1982–2009}},
url = {http://www.mdpi.com/2072-4292/5/3/1484},
volume = {5},
year = {2013}
}
@article{Marcos2014,
abstract = {Changes in thermosteric sea level at decadal and longer time scales respond to anthropogenic forcing and natural variability of the climate system. Disentangling these contributions is essential to quantify the impact of human activity in the past and to anticipate thermosteric sea level rise under global warming. Climate models, fed with radiative forcing, display a large spread of outputs with limited correspondencewith the observationally based estimates of thermosteric sea level during the last decades of the twentieth century. Here we extract the common signal of climate models from Coupled Model Intercomparison Project Phase 5 using a signal-to-noise maximizing empirical orthogonal function technique for the period 1950–2005. Our results match the observed trends, improving the widely used approach of multimodel ensemble averaging. We then compute the fraction of the observed thermosteric sea level rise of anthropogenic origin and conclude that 87{\%} of the observed trend in the upper 700m since 1970 is induced by human activity.},
author = {Marcos, Marta and Amores, Angel},
doi = {10.1002/2014GL059766},
isbn = {0094-8276},
issn = {19448007},
journal = {Geophysical Research Letters},
keywords = {CMIP5,anthropogenic forcing,climate models,thermosteric sea level},
month = {apr},
number = {7},
pages = {2502--2507},
publisher = {Wiley-Blackwell},
title = {{Quantifying anthropogenic and natural contributions to thermosteric sea level rise}},
url = {http://doi.wiley.com/10.1002/2014GL059766},
volume = {41},
year = {2014}
}
@article{marshall2003residual,
author = {Marshall, John and Radko, Timour},
doi = {10.1175/1520-0485(2003)033<2341:RSFTAC>2.0.CO;2},
journal = {Journal of Physical Oceanography},
number = {11},
pages = {2341--2354},
title = {{Residual-mean solutions for the Antarctic Circumpolar Current and its associated overturning circulation}},
volume = {33},
year = {2003}
}
@article{doi:10.1175/JCLI-D-16-0459.1,
abstract = { AbstractThe Atlantic multidecadal oscillation (AMO) is the leading mode of Atlantic sea surface temperature (SST) variability at multidecadal time scales. Previous studies have shown that the AMO could modulate El Ni{\~{n}}o–Southern Oscillation (ENSO) variance. However, the role played by the AMO in the tropical Atlantic variability (TAV) is still uncertain. Here, it is demonstrated that during negative AMO phases, associated with a shallower thermocline, the eastern equatorial Atlantic SST variability is enhanced by more than 150{\%} in boreal summer. Consequently, the interannual TAV modes are modified. During negative AMO, the Atlantic Ni{\~{n}}o displays larger amplitude and a westward extension and it is preceded by a simultaneous weakening of both subtropical highs in winter and spring. In contrast, a meridional seesaw SLP pattern evolving into a zonal gradient leads the Atlantic Ni{\~{n}}o during positive AMO. The north tropical Atlantic (NTA) mode is related to a Scandinavian blocking pattern during winter and spring in negative AMO, while under positive AMO it is part of the SST tripole associated with the North Atlantic Oscillation. Interestingly, the emergence of an overlooked variability mode, here called the horseshoe (HS) pattern on account of its shape, is favored during negative AMO. This anomalous warm (cool) HS surrounding an eastern equatorial cooling (warming) is remotely forced by an ENSO phenomenon. During negative AMO, the tropical–extratropical teleconnections are enhanced and the Walker circulation is altered. This, together with the increased equatorial SST variability, could promote the ENSO impacts on TAV. The results herein give a step forward in the better understanding of TAV, which is essential to improving its modeling, impacts, and predictability. },
author = {Mart{\'{i}}n-Rey, Marta and Polo, Irene and Rodr{\'{i}}guez-Fonseca, Bel{\'{e}}n and Losada, Teresa and Lazar, Alban},
doi = {10.1175/JCLI-D-16-0459.1},
journal = {Journal of Climate},
number = {2},
pages = {515--536},
title = {{Is There Evidence of Changes in Tropical Atlantic Variability Modes under AMO Phases in the Observational Record?}},
url = {https://doi.org/10.1175/JCLI-D-16-0459.1},
volume = {31},
year = {2018}
}
@article{Martin2013a,
abstract = {This study uses models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) to evaluate and investigate Sahel rainfall multidecadal variability and teleconnections with global sea surface temperatures (SSTs). Multidecadal variability is lower than observed in all historical simulations evaluated. Focus is on teleconnections with North Atlantic SST [Atlantic multidecadal variability (AMV)] as it is more successfully simulated than the Indian Ocean teleconnection. To investigate why some models successfully simulated this teleconnection and others did not, despite having similarly large AMV, two groups of models were selected. Models with large AMV were highlighted as good (or poor) by their ability to simulate relatively high (low) Sahel multidecadal variability and have significant (not significant) correlation between multidecadal Sahel rainfall and an AMV index. Poor models fail to capture the teleconnection between the AMV and Sahel rainfall because the spatial distribution of SST multidecadal variability across the North Atlantic is incorrect. A lack of SST signal in the tropical North Atlantic and Mediterranean reduces the interhemispheric SST gradient and, through circulation changes, the rainfall variability in the Sahel. This pattern was also evident in the control simulations, where SST and Sahel rainfall variability were significantly weaker than historical simulations. Errors in SST variability were suggested to result from a combination of weak wind–evaporation–SST feedbacks, poorly simulated cloud amounts and feedbacks in the stratocumulus regions of the eastern Atlantic, dust–SST–rainfall feedbacks, and sulfate aerosol interactions with clouds. By understanding the deficits and successes of CMIP5 historical simulations, future projections and decadal hindcasts can be examined with additional confidence.},
annote = {doi: 10.1175/JCLI-D-13-00242.1},
author = {Martin, Elinor R and Thorncroft, Chris and Booth, Ben B B},
doi = {10.1175/JCLI-D-13-00242.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jan},
number = {2},
pages = {784--806},
publisher = {American Meteorological Society},
title = {{The Multidecadal Atlantic SST—Sahel Rainfall Teleconnection in CMIP5 Simulations}},
url = {https://doi.org/10.1175/JCLI-D-13-00242.1 http://journals.ametsoc.org/doi/10.1175/JCLI-D-13-00242.1},
volume = {27},
year = {2014}
}
@article{Marvel2017,
abstract = {Anthropogenic climate change is predicted to cause spatial and temporal shifts in precipitation patterns. These may be apparent in changes to the annual cycle of zonal mean precipitation P. Trends in the amplitude and phase of the P annual cycle in two long-term, global satellite datasets are broadly similar. Model-derived fingerprints of externally forced changes to the amplitude and phase of the P seasonal cycle, combined with these observations, enable a formal detection and attribution analysis. Observed amplitude changes are inconsistent with model estimates of internal variability but not attributable to the model-predicted response to external forcing. This mismatch between observed and predicted amplitude changes is consistent with the sustained La Ni{\~{n}}a–like conditions that characterize the recent slowdown in the rise of the global mean temperature. However, observed changes to the annual cycle phase do not seem to be driven by this recent hiatus. These changes are consistent with model estimates of forced changes, are inconsistent (in one observational dataset) with estimates of internal variability, and may suggest the emergence of an externally forced signal.},
author = {Marvel, Kate and Biasutti, Michela and Bonfils, C{\'{e}}line and Taylor, Karl E. and Kushnir, Yochanan and Cook, Benjamin I.},
doi = {10.1175/JCLI-D-16-0572.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jul},
number = {13},
pages = {4983--4995},
title = {{Observed and Projected Changes to the Precipitation Annual Cycle}},
url = {https://journals.ametsoc.org/doi/10.1175/JCLI-D-16-0572.1},
volume = {30},
year = {2017}
}
@article{Marvel2013,
author = {Marvel, K. and Bonfils, C.},
doi = {10.1073/pnas.1314382110},
issn = {0027-8424},
journal = {Proceedings of the National Academy of Sciences},
month = {nov},
number = {48},
pages = {19301--19306},
title = {{Identifying external influences on global precipitation}},
url = {http://www.pnas.org/cgi/doi/10.1073/pnas.1314382110},
volume = {110},
year = {2013}
}
@article{Marvel2019,
abstract = {Although anthropogenic climate change is expected to have caused large shifts in temperature and rainfall, the detection of human influence on global drought has been complicated by large internal variability and the brevity of observational records. Here we address these challenges using reconstructions of the Palmer drought severity index obtained with data from tree rings that span the past millennium. We show that three distinct periods are identifiable in climate models, observations and reconstructions during the twentieth century. In recent decades (1981 to present), the signal of greenhouse gas forcing is present but not yet detectable at high confidence. Observations and reconstructions differ significantly from an expected pattern of greenhouse gas forcing around mid-century (1950–1975), coinciding with a global increase in aerosol forcing. In the first half of the century (1900–1949), however, a signal of greenhouse-gas-forced change is robustly detectable. Multiple observational datasets and reconstructions using data from tree rings confirm that human activities were probably affecting the worldwide risk of droughts as early as the beginning of the twentieth century.},
author = {Marvel, Kate and Cook, Benjamin I. and Bonfils, C{\'{e}}line J.W. and Durack, Paul J. and Smerdon, Jason E. and Williams, A. Park},
doi = {10.1038/s41586-019-1149-8},
issn = {14764687},
journal = {Nature},
keywords = {Attribution,Climate and Earth system modelling,Palaeoclimate,Projection and prediction},
month = {may},
number = {7754},
pages = {59--65},
publisher = {Nature Publishing Group},
title = {{Twentieth-century hydroclimate changes consistent with human influence}},
url = {http://www.nature.com/articles/s41586-019-1149-8},
volume = {569},
year = {2019}
}
@article{Marzeion2014,
abstract = {The ongoing global glacier retreat is affecting human societies by causing sea-level rise, changing seasonal water availability, and increasing geohazards. Melting glaciers are an icon of anthropogenic climate change. However, glacier response times are typically decades or longer, which implies that the present-day glacier retreat is a mixed response to past and current natural climate variability and current anthropogenic forcing. Here we show that only 25 ± 35{\%} of the global glacier mass loss during the period from 1851 to 2010 is attributable to anthropogenic causes. Nevertheless, the anthropogenic signal is detectable with high confidence in glacier mass balance observations during 1991 to 2010, and the anthropogenic fraction of global glacier mass loss during that period has increased to 69 ± 24{\%}. Copyright {\textcopyright} 2014, American Association for the Advancement of Science.},
author = {Marzeion, Ben and Cogley, J. Graham and Richter, Kristin and Parkes, David},
doi = {10.1126/science.1254702},
isbn = {1853467960},
issn = {0036-8075},
journal = {Science},
month = {aug},
number = {6199},
pages = {919--921},
pmid = {25123485},
publisher = {American Association for the Advancement of Science},
title = {{Attribution of global glacier mass loss to anthropogenic and natural causes}},
url = {https://www.science.org/doi/10.1126/science.1254702},
volume = {345},
year = {2014}
}
@article{Marzeion2020,
abstract = {Glacier mass loss is recognized as a major contributor to current sea level rise. However, large uncertainties remain in projections of glacier mass loss on global and regional scales. We present an ensemble of 288 glacier mass and area change projections for the 21st century based on 11 glacier models using up to 10 general circulation models and four Representative Concentration Pathways (RCPs) as boundary conditions. We partition the total uncertainty into the individual contributions caused by glacier models, general circulation models, RCPs, and natural variability. We find that emission scenario uncertainty is growing throughout the 21st century and is the largest source of uncertainty by 2100. The relative importance of glacier model uncertainty decreases over time, but it is the greatest source of uncertainty until the middle of this century. The projection uncertainty associated with natural variability is small on the global scale but can be large on regional scales. The projected global mass loss by 2100 relative to 2015 (79 ± 56 mm sea level equivalent for RCP2.6, 159 ± 86 mm sea level equivalent for RCP8.5) is lower than, but well within, the uncertainty range of previous projections.},
author = {Marzeion, Ben and Hock, Regine and Anderson, Brian and Bliss, Andrew and Champollion, Nicolas and Fujita, Koji and Huss, Matthias and Immerzeel, Walter W. and Kraaijenbrink, Philip and Malles, Jan Hendrik and Maussion, Fabien and Radi{\'{c}}, Valentina and Rounce, David R. and Sakai, Akiko and Shannon, Sarah and van de Wal, Roderik and Zekollari, Harry},
doi = {10.1029/2019EF001470},
issn = {23284277},
journal = {Earth's Future},
keywords = {glacier,modeling,projections,sea level rise,uncertainties},
number = {7},
pages = {e2019EF001470},
title = {{Partitioning the Uncertainty of Ensemble Projections of Global Glacier Mass Change}},
volume = {8},
year = {2020}
}
@article{doi:10.1002/2017GL073936,
abstract = {Abstract Antarctic sea-ice formation plays a key role in shaping the abyssal overturning circulation and stratification in all ocean basins, by driving surface buoyancy loss through the associated brine rejection. Changes in Antarctic sea ice have therefore been suggested as drivers of major glacial-interglacial ocean circulation rearrangements. Here, the relationship between Antarctic sea ice, buoyancy loss, deep-ocean stratification, and overturning circulation is investigated in Last Glacial Maximum and preindustrial simulations from the Paleoclimate Modelling Intercomparison Project (PMIP). The simulations show substantial intermodel differences in their representation of the glacial deep-ocean state and circulation, which is often at odds with the geological evidence. We argue that these apparent inconsistencies can largely be attributed to differing (and likely insufficient) Antarctic sea-ice formation. Discrepancies can be further amplified by short integration times. Deep-ocean equilibration and sea-ice representation should, therefore, be carefully evaluated in the forthcoming PMIP4 simulations.},
author = {Marzocchi, Alice and Jansen, Malte F},
doi = {10.1002/2017GL073936},
journal = {Geophysical Research Letters},
keywords = {AMOC,Antarctic,LGM,PMIP,sea ice,stratification},
number = {12},
pages = {6286--6295},
title = {{Connecting Antarctic sea ice to deep-ocean circulation in modern and glacial climate simulations}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2017GL073936},
volume = {44},
year = {2017}
}
@incollection{Masson-Delmotte2013b,
address = {Cambridge, United Kingdom and New York, NY, USA},
author = {Masson-Delmotte, V and Schulz, M. and Abe-Ouchi, A. and Beer, J. and Ganopolski, A. and Rouco, J.F. Gonz{\'{a}}lez and Jansen, E. and Lambeck, K. and Luterbacher, J. and Naish, T. and Osborn, T. and Otto-Bliesner, B. and Quinn, T. and Ramesh, R. and Rojas, M. and Shao, X. and Timmermann, A.},
booktitle = {Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change},
chapter = {5},
doi = {10.1017/CBO9781107415324.013},
editor = {Stocker, T.F and Qin, D. and Plattner, G.-K. and Tignor, M. and Allen, S.K. and Boschung, J. and Nauels, A. and Xia, Y. and Bex, V. and Midgley, P.M.},
isbn = {9781107661820},
pages = {383--464},
publisher = {Cambridge University Press},
title = {{Information from Paleoclimate Archives}},
url = {https://www.ipcc.ch/report/ar5/wg1},
year = {2013}
}
@article{Massonnet2018d,
abstract = {One of the clearest manifestations of ongoing global climate change is the dramatic retreat and thinning of the Arctic sea-ice cover1. While all state-of-the-art climate models consistently reproduce the sign of these changes, they largely disagree on their magnitude1–4, the reasons for which remain contentious3,5–7. As such, consensual methods to reduce uncertainty in projections are lacking7. Here, using the CMIP5 ensemble, we propose a process-oriented approach to revisit this issue. We show that intermodel differences in sea-ice loss and, more generally, in simulated sea-ice variability, can be traced to differences in the simulation of seasonal growth and melt. The way these processes are simulated is relatively independent of the complexity of the sea-ice model used, but rather a strong function of the background thickness. The larger role played by thermodynamic processes as sea ice thins8,9 further suggests that the recent10 and projected11 reductions in sea-ice thickness induce a transition of the Arctic towards a state with enhanced volume seasonality but reduced interannual volume variability and persistence, before summer ice-free conditions eventually occur. These results prompt modelling groups to focus their priorities on the reduction of sea-ice thickness biases.},
author = {Massonnet, Fran{\c{c}}ois and Vancoppenolle, Martin and Goosse, Hugues and Docquier, David and Fichefet, Thierry and Blanchard-Wrigglesworth, Edward},
doi = {10.1038/s41558-018-0204-z},
issn = {1758-6798},
journal = {Nature Climate Change},
number = {7},
pages = {599--603},
title = {{Arctic sea-ice change tied to its mean state through thermodynamic processes}},
volume = {8},
year = {2018}
}
@article{Massonnet2012,
author = {Massonnet, F and Fichefet, T and Goosse, H and Bitz, C M and Philippon-Berthier, G and Holland, M M and Barriat, P.-Y.},
doi = {10.5194/tc-6-1383-2012},
issn = {1994-0424},
journal = {The Cryosphere},
month = {nov},
number = {6},
pages = {1383--1394},
publisher = {Copernicus Publications},
title = {{Constraining projections of summer Arctic sea ice}},
url = {https://www.the-cryosphere.net/6/1383/2012/ https://www.the-cryosphere.net/6/1383/2012/tc-6-1383-2012.pdf},
volume = {6},
year = {2012}
}
@article{Mauritsen2020,
abstract = {A climate model's ability to reproduce observed historical warming is sometimes viewed as a measure of quality. Yet, for practical reasons it cannot be considered a purely empirical result of the modeling efforts because the desired result is known in advance and so is a potential target of tuning. Here we report how the latest edition of the Max Planck Institute for Meteorology Earth System Models (MPI-ESM1.2) atmospheric component (ECHAM6.3) had its sensitivity systematically tuned in order to improve the modeled match with the instrumental record. In practice, this was done by targeting an equilibrium climate sensitivity of about 3 K, slightly lower than in the previous model generation (MPI-ESM), which warmed more than observed, and in particular by addressing a climate sensitivity of about 7 K in an intermediate version of the model. In the process we identified several controls on cloud feedback, some of which confirm recently proposed hypotheses. We find the model exhibits excellent fidelity with the observed centennial global warming. We further find that an alternative approach with high climate sensitivity compensated by strong aerosol cooling instead would yield colder than observed results in the second half of the twentieth century.},
author = {Mauritsen, Thorsten and Roeckner, Erich},
doi = {10.1029/2019MS002037},
issn = {19422466},
journal = {Journal of Advances in Modeling Earth Systems},
number = {5},
pages = {e2019MS002037},
title = {{Tuning the MPI-ESM1.2 Global Climate Model to Improve the Match With Instrumental Record Warming by Lowering Its Climate Sensitivity}},
volume = {12},
year = {2020}
}
@article{Mauritsen2019,
abstract = {A new release of the Max Planck Institute for Meteorology Earth System Model version 1.2 (MPI-ESM1.2) is presented. The development focused on correcting errors in and improving the physical processes representation, as well as improving the computational performance, versatility, and overall user friendliness. In addition to new radiation and aerosol parameterizations of the atmosphere, several relatively large, but partly compensating, coding errors in the model's cloud, convection, and turbulence parameterizations were corrected. The representation of land processes was refined by introducing a multilayer soil hydrology scheme, extending the land biogeochemistry to include the nitrogen cycle, replacing the soil and litter decomposition model and improving the representation of wildfires. The ocean biogeochemistry now represents cyanobacteria prognostically in order to capture the response of nitrogen fixation to changing climate conditions and further includes improved detritus settling and numerous other refinements. As something new, in addition to limiting drift and minimizing certain biases, the instrumental record warming was explicitly taken into account during the tuning process. To this end, a very high climate sensitivity of around 7 K caused by low-level clouds in the tropics as found in an intermediate model version was addressed, as it was not deemed possible to match observed warming otherwise. As a result, the model has a climate sensitivity to a doubling of CO2 over preindustrial conditions of 2.77 K, maintaining the previously identified highly nonlinear global mean response to increasing CO2 forcing, which nonetheless can be represented by a simple two-layer model.},
author = {Mauritsen, Thorsten and Bader, J{\"{u}}rgen and Becker, Tobias and Behrens, J{\"{o}}rg and Bittner, Matthias and Brokopf, Renate and Brovkin, Victor and Claussen, Martin and Crueger, Traute and Esch, Monika and Fast, Irina and Fiedler, Stephanie and Fl{\"{a}}schner, Dagmar and Gayler, Veronika and Giorgetta, Marco and Goll, Daniel S. and Haak, Helmuth and Hagemann, Stefan and Hedemann, Christopher and Hohenegger, Cathy and Ilyina, Tatiana and Jahns, Thomas and Jimen{\'{e}}z-de-la-Cuesta, Diego and Jungclaus, Johann and Kleinen, Thomas and Kloster, Silvia and Kracher, Daniela and Kinne, Stefan and Kleberg, Deike and Lasslop, Gitta and Kornblueh, Luis and Marotzke, Jochem and Matei, Daniela and Meraner, Katharina and Mikolajewicz, Uwe and Modali, Kameswarrao and M{\"{o}}bis, Benjamin and M{\"{u}}ller, Wolfgang A. and Nabel, Julia E.M.S. and Nam, Christine C.W. and Notz, Dirk and Nyawira, Sarah Sylvia and Paulsen, Hanna and Peters, Karsten and Pincus, Robert and Pohlmann, Holger and Pongratz, Julia and Popp, Max and Raddatz, Thomas J{\"{u}}rgen and Rast, Sebastian and Redler, Rene and Reick, Christian H. and Rohrschneider, Tim and Schemann, Vera and Schmidt, Hauke and Schnur, Reiner and Schulzweida, Uwe and Six, Katharina D. and Stein, Lukas and Stemmler, Irene and Stevens, Bjorn and von Storch, Jin Song and Tian, Fangxing and Voigt, Aiko and Vrese, Philipp and Wieners, Karl Hermann and Wilkenskjeld, Stiig and Winkler, Alexander and Roeckner, Erich},
doi = {10.1029/2018MS001400},
issn = {19422466},
journal = {Journal of Advances in Modeling Earth Systems},
number = {4},
pages = {998--1038},
title = {{Developments in the MPI-M Earth System Model version 1.2 (MPI-ESM1.2) and Its Response to Increasing CO2}},
volume = {11},
year = {2019}
}
@article{Mauritsen2015,
abstract = {An iris effect in tropical cloud-cover was controversially proposed as a negative climate change feedback that is not represented in climate models. If such an effect exists, it could go some way to reconciling climate models and observations.},
author = {Mauritsen, Thorsten and Stevens, Bjorn},
doi = {10.1038/ngeo2414},
issn = {1752-0908},
journal = {Nature Geoscience},
number = {5},
pages = {346--351},
title = {{Missing iris effect as a possible cause of muted hydrological change and high climate sensitivity in models}},
url = {https://doi.org/10.1038/ngeo2414},
volume = {8},
year = {2015}
}
@article{Maycock2018b,
abstract = {Abstract Simulated stratospheric temperatures over the period 1979-2016 in models from the Chemistry-Climate Model Initiative (CCMI) are compared with recently updated and extended satellite observations. The multi-model mean global temperature trends over 1979-2005 are -0.88 ± 0.23, -0.70 ± 0.16, and -0.50 ± 0.12 K decade-1 for the Stratospheric Sounding Unit (SSU) channels 3 ({\~{}}40-50 km), 2 ({\~{}}35-45 km), and 1 ({\~{}}25-35 km), respectively. These are within the uncertainty bounds of the observed temperature trends from two reprocessed satellite datasets. In the lower stratosphere, the multi-model mean trend in global temperature for the Microwave Sounding Unit channel 4 ({\~{}}13-22 km) is -0.25 ± 0.12 K decade-1 over 1979-2005, consistent with estimates from three versions of this satellite record. The simulated stratospheric temperature trends in CCMI models over 1979-2005 agree with the previous generation of chemistry-climate models. The models and an extended satellite dataset of SSU with the Advanced Microwave Sounding Unit-A show weaker global stratospheric cooling over 1998-2016 compared to the period of intensive ozone depletion (1979-1997). This is due to the reduction in ozone-induced cooling from the slow-down of ozone trends and the onset of ozone recovery since the late 1990s. In summary, the results show much better consistency between simulated and satellite observed stratospheric temperature trends than was reported by Thompson et al. (2012) for the previous versions of the SSU record and chemistry-climate models. The improved agreement mainly comes from updates to the satellite records; the range of simulated trends is comparable to the previous generation of models.},
author = {Maycock, Amanda C. and Randel, William J. and Steiner, Andrea K. and Karpechko, Alexey Yu and Christy, John and Saunders, Roger and Thompson, David W. J. and Zou, Cheng-Zhi and Chrysanthou, Andreas and {Luke Abraham}, N. and Akiyoshi, Hideharu and Archibald, Alex T. and Butchart, Neal and Chipperfield, Martyn and Dameris, Martin and Deushi, Makoto and Dhomse, Sandip and {Di Genova}, Glauco and J{\"{o}}ckel, Patrick and Kinnison, Douglas E. and Kirner, Oliver and Ladst{\"{a}}dter, Florian and Michou, Martine and Morgenstern, Olaf and O'Connor, Fiona and Oman, Luke and Pitari, Giovanni and Plummer, David A. and Revell, Laura E. and Rozanov, Eugene and Stenke, Andrea and Visioni, Daniele and Yamashita, Yousuke and Zeng, Guang},
doi = {10.1029/2018GL078035},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {sep},
number = {18},
pages = {9919--9933},
title = {{Revisiting the Mystery of Recent Stratospheric Temperature Trends}},
url = {https://onlinelibrary.wiley.com/doi/10.1029/2018GL078035},
volume = {45},
year = {2018}
}
@article{McClymont2020,
abstract = {A range of future climate scenarios are projected for high atmospheric CO2 concentrations, given uncertainties over future human actions as well as potential environmental and climatic feedbacks. The geological record offers an opportunity to understand climate system response to a range of forcings and feedbacks which operate over multiple temporal and spatial scales. Here, we examine a single interglacial during the late Pliocene (KM5c, ca. 3:205{\_}0:01 Ma) when atmospheric CO2 exceeded pre-industrial concentrations, but were similar to today and to the lowest emission scenarios for this century. As orbital forcing and continental configurations were almost identical to today, we are able to focus on equilibrium climate system response to modern and near-future CO2. Using proxy data from 32 sites, we demonstrate that global mean sea-surface temperatures were warmer than pre-industrial values, by 2:3 C for the combined proxy data (foraminifera Mg=Ca and alkenones), or by 3:2 3.4 C (alkenones only). Compared to the preindustrial period, reduced meridional gradients and enhanced warming in the North Atlantic are consistently reconstructed. There is broad agreement between data and models at the global scale, with regional differences reflecting ocean circulation and/or proxy signals. An uneven distribution of proxy data in time and space does, however, add uncertainty to our anomaly calculations. The reconstructed global mean seasurface temperature anomaly for KM5c is warmer than all but three of the PlioMIP2 model outputs, and the reconstructed North Atlantic data tend to align with the warmest KM5c model values. Our results demonstrate that even under low-CO2 emission scenarios, surface ocean warming may be expected to exceed model projections and will be accentuated in the higher latitudes.},
author = {McClymont, Erin L. and Ford, Heather L. and {Ling Ho}, Sze and Tindall, Julia C. and Haywood, Alan M. and Alonso-Garcia, Montserrat and Bailey, Ian and Berke, Melissa A. and Littler, Kate and Patterson, Molly O. and Petrick, Benjamin and Peterse, Francien and {Christina Ravelo}, A. and Risebrobakken, Bjorg and {De Schepper}, Stijn and Swann, George E.A. and Thirumalai, Kaustubh and Tierney, Jessica E. and {Van Der Weijst}, Carolien and White, Sarah and Abe-Ouchi, Ayako and Baatsen, Michiel L.J. and Brady, Esther C. and Chan, Wing Le and Chandan, Deepak and Feng, Ran and Guo, Chuncheng and {Von Der Heydt}, Anna S. and Hunter, Stephen and Li, Xiangyi and Lohmann, Gerrit and Nisancioglu, Kerim H. and Otto-Bliesner, Bette L. and {Richard Peltier}, W. and Stepanek, Christian and Zhang, Zhongshi},
doi = {10.5194/cp-16-1599-2020},
issn = {18149332},
journal = {Climate of the Past},
number = {4},
title = {{Lessons from a high-CO2 world: An ocean view from ∼3 million years ago}},
volume = {16},
year = {2020}
}
@article{McGregor2015a,
abstract = {The oceans mediate the response of global climate to natural and anthropogenic forcings. Yet for the past 2,000 years-a key interval for understanding the present and future climate response to these forcings-global sea surface temperature changes and the underlying driving mechanisms are poorly constrained. Here we present a global synthesis of sea surface temperatures for the Common Era (ce) derived from 57 individual marine reconstructions that meet strict quality control criteria. We observe a cooling trend from 1 to 1800 ce that is robust against explicit tests for potential biases in the reconstructions. Between 801 and 1800 ce, the surface cooling trend is qualitatively consistent with an independent synthesis of terrestrial temperature reconstructions, and with a sea surface temperature composite derived from an ensemble of climate model simulations using best estimates of past external radiative forcings. Climate simulations using single and cumulative forcings suggest that the ocean surface cooling trend from 801 to 1800 ce is not primarily a response to orbital forcing but arises from a high frequency of explosive volcanism. Our results show that repeated clusters of volcanic eruptions can induce a net negative radiative forcing that results in a centennial and global scale cooling trend via a decline in mixed-layer oceanic heat content.},
author = {McGregor, H.V. and Evans, M.N. and Goosse, H. and Leduc, G. and Martrat, B. and Addison, J.A. and Mortyn, P.G. and Oppo, D.W. and Seidenkrantz, M.-S. and Sicre, M.-A. and Phipps, S.J. and Selvaraj, K. and Thirumalai, K. and Filipsson, H.L. and Ersek, V.},
doi = {10.1038/ngeo2510},
journal = {Nature Geoscience},
number = {9},
pages = {671--677},
title = {{Robust global ocean cooling trend for the pre-industrial Common Era}},
volume = {8},
year = {2015}
}
@article{McGregor2014,
abstract = {An unprecedented strengthening of Pacific trade winds since the late 1990s (ref. 1) has caused widespread climate perturbations, including rapid sea-level rise in the western tropical Pacific, strengthening of Indo-Pacific ocean currents, and an increased uptake of heat in the equatorial Pacific thermocline. The corresponding intensification of the atmospheric Walker circulation is also associated with sea surface cooling in the eastern Pacific, which has been identified as one of the contributors to the current pause in global surface warming. In spite of recent progress in determining the climatic impacts of the Pacific trade wind acceleration, the cause of this pronounced trend in atmospheric circulation remains unknown. Here we analyse a series of climate model experiments along with observational data to show that the recent warming trend in Atlantic sea surface temperature and the corresponding trans-basin displacements of the main atmospheric pressure centres were key drivers of the observed Walker circulation intensification, eastern Pacific cooling, North American rainfall trends and western Pacific sea-level rise. Our study suggests that global surface warming has been partly offset by the Pacific climate response to enhanced Atlantic warming since the early 1990s.},
author = {McGregor, Shayne and Timmermann, Axel and Stuecker, Malte F. and England, Matthew H. and Merrifield, Mark and Jin, Fei-Fei and Chikamoto, Yoshimitsu},
doi = {10.1038/nclimate2330},
isbn = {1758-678X, 1758-6798},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {oct},
number = {10},
pages = {888--892},
title = {{Recent Walker circulation strengthening and Pacific cooling amplified by Atlantic warming}},
url = {http://www.nature.com/articles/nclimate2330},
volume = {4},
year = {2014}
}
@article{McGregor2013a,
author = {McGregor, S and Timmermann, A and England, M H and {Elison Timm}, O and Wittenberg, A T},
doi = {10.5194/cp-9-2269-2013},
journal = {Climate of the Past},
number = {5},
pages = {2269--2284},
title = {{Inferred changes in El Ni{\~{n}}o–Southern Oscillation variance over the past six centuries}},
volume = {9},
year = {2013}
}
@article{McGregor2018a,
abstract = {Pacific trade winds have displayed unprecedented strengthening in recent decades 1 . This strengthening has been associated with east Pacific sea surface cooling 2 and the early twenty-first-century slowdown in global surface warming 2,3, amongst a host of other substantial impacts 4-9 . Although some climate models produce the timing of these recently observed trends 10, they all fail to produce the trend magnitude 2,11,12 . This may in part be related to the apparent model underrepresentation of low-frequency Pacific Ocean variability and decadal wind trends 2,11-13 or be due to a misrepresentation of a forced response 1,14-16 or a combination of both. An increasingly prominent connection between the Pacific and Atlantic basins has been identified as a key driver of this strengthening of the Pacific trade winds 12,17-20 . Here we use targeted climate model experiments to show that combining the recent Atlantic warming trend with the typical climate model bias leads to a substantially underestimated response for the Pacific Ocean wind and surface temperature. The underestimation largely stems from a reduction and eastward shift of the atmospheric heating response to the tropical Atlantic warming trend. This result suggests that the recent Pacific trends and model decadal variability may be better captured by models with improved mean-state climatologies.},
author = {McGregor, Shayne and Stuecker, Malte F. and Kajtar, Jules B. and England, Matthew H. and Collins, Mat},
doi = {10.1038/s41558-018-0163-4},
issn = {17586798},
journal = {Nature Climate Change},
month = {jun},
number = {6},
pages = {493--498},
title = {{Model tropical Atlantic biases underpin diminished Pacific decadal variability}},
volume = {8},
year = {2018}
}
@article{McKenna2020a,
author = {McKenna, Sebastian and Santoso, Agus and Gupta, Alexander Sen and Taschetto, Andr{\'{e}}a S. and Cai, Wenju},
doi = {10.1038/s41598-020-68268-9},
issn = {2045-2322},
journal = {Scientific Reports},
month = {dec},
number = {1},
pages = {11500},
title = {{Indian Ocean Dipole in CMIP5 and CMIP6: characteristics, biases, and links to ENSO}},
url = {http://www.nature.com/articles/s41598-020-68268-9},
volume = {10},
year = {2020}
}
@article{McKitrick2018,
abstract = {Abstract Overall climate sensitivity to CO2 doubling in a general circulation model results from a complex system of parameterizations in combination with the underlying model structure. We refer to this as the model's major hypothesis, and we assume it to be testable. We explain four criteria that a valid test should meet: measurability, specificity, independence, and uniqueness. We argue that temperature change in the tropical 200- to 300-hPa layer meets these criteria. Comparing modeled to observed trends over the past 60 years using a persistence-robust variance estimator shows that all models warm more rapidly than observations and in the majority of individual cases the discrepancy is statistically significant. We argue that this provides informative evidence against the major hypothesis in most current climate models.},
annote = {doi: 10.1029/2018EA000401},
author = {McKitrick, Ross and Christy, John},
doi = {10.1029/2018EA000401},
issn = {2333-5084},
journal = {Earth and Space Science},
keywords = {climate model testing,climate sensitivity,radiosondes,trend estimation,tropical troposphere},
month = {sep},
number = {9},
pages = {529--536},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{A Test of the Tropical 200- to 300-hPa Warming Rate in Climate Models}},
url = {https://doi.org/10.1029/2018EA000401},
volume = {5},
year = {2018}
}
@article{McKitrick2019,
abstract = {We estimate trends in US regional precipitation on multiple time spans and scales relevant to the detection of changes in climatic regimes. A large literature has shown that trend estimation in hydrological series may be affected by long-term persistence (LTP) and selection of sample length. We show that 2000-year proxy-based reconstructions of the Palmer Modified Drought Index for the US Southeast (SE) and Pacific Coast (PC) regions exhibit LTP and reveal post- 1900 changes to be within the range of longer-term natural fluctuations. We also use a new data base of daily precipitation records for 20 locations (10 PC and 10 SE) extending back in many cases to the 1870s. Over the 1901–2017 interval upward trends in some measures of average and extreme precipitation appear, but they are not consistently significant and in the full records back to 1872 they largely disappear. They also disappear or reverse in the post-1978 portion of the data set, which is inconsistent with them being responses to enhanced greenhouse gas forcing. We conclude that natural variability is likely the dominant driver of historical changes in precipitation and hence drought dynamics in the US SE and PC.},
author = {McKitrick, Ross and Christy, John},
doi = {10.1016/j.jhydrol.2019.124074},
issn = {00221694},
journal = {Journal of Hydrology},
keywords = {Extreme events,Long term persistence,Time scales,Twentieth century,US regional precipitation},
month = {nov},
pages = {124074},
title = {{Assessing changes in US regional precipitation on multiple time scales}},
url = {https://doi.org/10.1016/j.jhydrol.2019.124074 https://linkinghub.elsevier.com/retrieve/pii/S0022169419308091},
volume = {578},
year = {2019}
}
@article{McKitrick2020,
abstract = {The tendency of climate models to overstate warming in the tropical troposphere has long been noted. Here we examine individual runs from 38 newly released Coupled Model Intercomparison Project Version 6 (CMIP6) models and show that the warm bias is now observable globally as well. We compare CMIP6 runs against observational series drawn from satellites, weather balloons, and reanalysis products. We focus on the 1979–2014 interval, the maximum span for which all observational products are available and for which models were run using historically observed forcings. For lower-troposphere and midtroposphere layers both globally and in the tropics, all 38 models overpredict warming in every target observational analog, in most cases significantly so, and the average differences between models and observations are statistically significant. We present evidence that consistency with observed warming would require lower model Equilibrium Climate Sensitivity (ECS) values.},
author = {McKitrick, R. and Christy, J.},
doi = {10.1029/2020EA001281},
issn = {23335084},
journal = {Earth and Space Science},
keywords = {climate model testing,climate sensitivity,global warming,trend estimation,troposphere},
number = {9},
pages = {1--8},
title = {{Pervasive Warming Bias in CMIP6 Tropospheric Layers}},
volume = {7},
year = {2020}
}
@article{McPhaden2011a,
abstract = {[1]This paper addresses the question of whether the increased occurrence of central Pacific (CP) versus Eastern Pacific (EP) El Ni{\~{n}}os is consistent with greenhouse gas forced changes in the background state of the tropical Pacific as inferred from global climate change models. Our analysis uses high‐quality satellite and in situ ocean data combined with wind data from atmospheric reanalyses for the past 31 years (1980–2010). We find changes in back- ground conditions that are opposite to those expected from greenhouse gas forcing in climate models and opposite to what is expected if changes in the background state are mediating more frequent occurrences of CP El Ni{\~{n}}os. A plausible interpretation of these results is that the character of El Ni{\~{n}}o over the past 31 years has varied naturally and that these variations projected onto changes in the back- ground state because of the asymmetric spatial structures of CP and EP El Ni{\~{n}}os.},
author = {McPhaden, M. J. and Lee, T. and McClurg, D.},
doi = {10.1029/2011GL048275},
isbn = {0094-8276},
issn = {00948276},
journal = {Geophysical Research Letters},
number = {15},
pages = {2--5},
title = {{El Ni{\~{n}}o and its relationship to changing background conditions in the tropical Pacific Ocean}},
volume = {38},
year = {2011}
}
@article{McPhaden2006a,
abstract = {The El Ni{\~{n}}o-Southern Oscillation (ENSO) cycle of alternating warm El Ni{\~{n}}o and cold La Ni{\~{n}}a events is the dominant year-to-year climate signal on Earth. ENSO originates in the tropical Pacific through interactions between the ocean and the atmosphere, but its environmental and socioeconomic impacts are felt worldwide. Spurred on by the powerful 1997-1998 El Ni{\~{n}}o, efforts to understand the causes and consequences of ENSO have greatly expanded in the past few years. These efforts reveal the breadth of ENSO's influence on the Earth system and the potential to exploit its predictability for societal benefit. However, many intertwined issues regarding ENSO dynamics, impacts, forecasting, and applications remain unresolved. Research to address these issues will not only lead to progress across a broad range of scientific disciplines but also provide an opportunity to educate the public and policy makers about the importance of climate variability and change in the modern world.},
author = {McPhaden, Michael J. and Zebiak, Stephen E. and Glantz, Michael H.},
doi = {10.1126/science.1132588},
isbn = {0036807510959203},
issn = {0036-8075},
journal = {Science},
month = {dec},
number = {5806},
pages = {1740--1745},
pmid = {17170296},
title = {{ENSO as an Integrating Concept in Earth Science}},
url = {https://www.science.org/doi/10.1126/science.1132588},
volume = {314},
year = {2006}
}
@article{Mecking2017,
annote = {doi: 10.1080/16000870.2017.1299910},
author = {Mecking, J V and Drijfhout, S S and Jackson, L C and Andrews, M B},
doi = {10.1080/16000870.2017.1299910},
issn = {null},
journal = {Tellus A: Dynamic Meteorology and Oceanography},
month = {jan},
number = {1},
pages = {1299910},
publisher = {Taylor {\&} Francis},
title = {{The effect of model bias on Atlantic freshwater transport and implications for AMOC bi-stability}},
url = {https://doi.org/10.1080/16000870.2017.1299910},
volume = {69},
year = {2017}
}
@article{Medhaug2017,
author = {Medhaug, Iselin and Stolpe, Martin B and Fischer, Erich M and Knutti, Reto},
doi = {10.1038/nature22315},
journal = {Nature},
month = {may},
pages = {41},
publisher = {Macmillan Publishers Limited, part of Springer Nature. All rights reserved.},
title = {{Reconciling controversies about the ‘global warming hiatus'}},
url = {http://dx.doi.org/10.1038/nature22315 http://10.0.4.14/nature22315},
volume = {545},
year = {2017}
}
@article{Medhaug2016,
author = {Medhaug, Iselin and Drange, Helge},
doi = {10.1007/s00382-015-2811-y},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jun},
number = {11-12},
pages = {3899--3920},
title = {{Global and regional surface cooling in a warming climate: a multi-model analysis}},
url = {http://link.springer.com/10.1007/s00382-015-2811-y},
volume = {46},
year = {2016}
}
@article{Meehl2016,
abstract = {The negative phase of the Interdecadal Pacific Oscillation (IPO), a dominant mode of multi-decadal variability of sea surface temperatures (SSTs) in the Pacific, contributed to the reduced rate of global surface temperature warming in the early 2000s. A proposed mechanism for IPO multidecadal variability indicates that the presence of decadal timescale upper ocean heat content in the off-equatorial western tropical Pacific can provide conditions for an interannual El Nino/Southern Oscillation event to trigger a transition of tropical Pacific SSTs to the opposite IPO phase. Here we show that a decadal prediction initialized in 2013 simulates predicted Nino3.4 SSTs that have qualitatively tracked the observations through 2015. The year three to seven average prediction (2015-2019) from the 2013 initial state shows a transition to the positive phase of the IPO from the previous negative phase and a resumption of larger rates of global warming over the 2013-2022 period consistent with a positive IPO phase.},
author = {Meehl, Gerald A. and Hu, Aixue and Teng, Haiyan},
doi = {10.1038/ncomms11718},
isbn = {2041-1723 (Electronic) 2041-1723 (Linking)},
issn = {20411723},
journal = {Nature Communications},
number = {1},
pages = {11718},
pmid = {27251760},
publisher = {Nature Publishing Group},
title = {{Initialized decadal prediction for transition to positive phase of the Interdecadal Pacific Oscillation}},
url = {http://dx.doi.org/10.1038/ncomms11718},
volume = {7},
year = {2016}
}
@article{Meehl2014,
abstract = {The slowdown in the rate of global warming in the early 2000s is not evident in the multi-model ensemble average of traditional climate change projection simulations. However, a number of individual ensemble members from that set of models successfully simulate the early-2000s hiatus when naturally-occurring climate variability involving the Interdecadal Pacific Oscillation (IPO) coincided, by chance, with the observed negative phase of the IPO that contributed to the early-2000s hiatus. If the recent methodology of initialized decadal climate prediction could have been applied in the mid-1990s using the Coupled Model Intercomparison Project Phase 5 multi-models, both the negative phase of the IPO in the early 2000s as well as the hiatus could have been simulated, with the multi-model average performing better than most of the individual models. The loss of predictive skill for six initial years before the mid-1990s points to the need for consistent hindcast skill to establish reliability of an operational decadal climate prediction system.},
author = {Meehl, Gerald A. and Teng, Haiyan and Arblaster, Julie M.},
doi = {10.1038/nclimate2357},
isbn = {doi:10.1038/nclimate2357},
issn = {17586798},
journal = {Nature Climate Change},
number = {10},
pages = {898--902},
title = {{Climate model simulations of the observed early-2000s hiatus of global warming}},
volume = {4},
year = {2014}
}
@article{Meehl2016a,
abstract = {Longer-term externally forced trends in global mean surface temperatures (GMSTs) are embedded in the background noise of internally generated multidecadal variability1 . A key mode of internal variability is the Interdecadal Pacific Oscillation (IPO), which contributed to a reduced GMST trend during the early 2000s1–3 . We use a novel, physical phenomenon-based approach to quantify the contribution from a source of internally generated multidecadal variability—the IPO—to multidecadal GMST trends. Here we show that the largest IPO contributions occurred in its positive phase during the rapidwarming periods from1910–1941 and 1971–1995, with the IPO contributing 71{\%} and 75{\%}, respectively, to the difference between the median values of the externally forced trends and observed trends. The IPO transition from positive to negative in the late-1990s contributed 27{\%}of the discrepancy between model median estimates of the forced part of the GMST trend and the observed trend from 1995 to 2013, with additional contributions that are probably due to internal variability outside of the Pacific4 and an externally forced response fromsmall volcanic eruptions5 . Understanding and quantifying the contribution of a specific source of internally generated variability—the IPO—to GMST trends is necessary to improve decadal climate prediction skill.},
author = {Meehl, Gerald A. and Hu, Aixue and Santer, Benjamin D. and Xie, Shang Ping},
doi = {10.1038/nclimate3107},
isbn = {1758-678X},
issn = {17586798},
journal = {Nature Climate Change},
number = {11},
pages = {1005--1008},
title = {{Contribution of the Interdecadal Pacific Oscillation to twentieth-century global surface temperature trends}},
volume = {6},
year = {2016}
}
@article{Meehl2007,
abstract = {Abstract A coordinated set of global coupled climate model [atmosphere–ocean general circulation model (AOGCM)] experiments for twentieth- and twenty-first-century climate, as well as several climate change commitment and other experiments, was run by 16 modeling groups from 11 countries with 23 models for assessment in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). Since the assessment was completed, output from another model has been added to the dataset, so the participation is now 17 groups from 12 countries with 24 models. This effort, as well as the subsequent analysis phase, was organized by the World Climate Research Programme (WCRP) Climate Variability and Predictability (CLIVAR) Working Group on Coupled Models (WGCM) Climate Simulation Panel, and constitutes the third phase of the Coupled Model Intercomparison Project (CMIP3). The dataset is called the WCRP CMIP3 multimodel dataset, and represents the largest and most comprehensive international global coupl...},
author = {Meehl, Gerald A. and Covey, Curt and Delworth, Thomas and Latif, Mojib and McAvaney, Bryant and Mitchell, John F.B. and Stouffer, Ronald J. and Taylor, Karl E.},
doi = {10.1175/BAMS-88-9-1383},
isbn = {0003-0007},
issn = {00030007},
journal = {Bulletin of the American Meteorological Society},
month = {sep},
number = {9},
pages = {1383--1394},
publisher = {American Meteorological Society},
title = {{The WCRP CMIP3 multimodel dataset: A new era in climatic change research}},
url = {http://journals.ametsoc.org/doi/10.1175/BAMS-88-9-1383},
volume = {88},
year = {2007}
}
@article{Meehl2013,
abstract = {AbstractGlobally averaged surface air temperatures in some decades show rapid increases (accelerated warming decades), and in other decades there is no warming trend (hiatus decades). A previous study showed that the net energy imbalance at the top of the atmosphere of about 1 W m?2 is associated with greater increases of deep ocean heat content below 750 m during the hiatus decades, while there is little globally averaged surface temperature increase or warming in the upper ocean layers. Here the authors examine processes involved with accelerated warming decades and address the relative roles of external forcing from increasing greenhouse gases and internally generated decadal climate variability associated with interdecadal Pacific oscillation (IPO). Model results from the Community Climate System Model, version 4 (CCSM4), show that accelerated warming decades are characterized by rapid warming of globally averaged surface air temperature, greater increases of heat content in the upper ocean layers, and less heat content increase in the deep ocean, opposite to the hiatus decades. In addition to contributions from processes potentially linked to Antarctic Bottom Water (AABW) formation and the Atlantic meridional overturning circulation (AMOC), the positive phase of the IPO, adding to the response to external forcing, is usually associated with accelerated warming decades. Conversely, hiatus decades typically occur with the negative phase of the IPO, when warming from the external forcing is overwhelmed by internally generated cooling in the tropical Pacific. Internally generated hiatus periods of up to 15 years with zero global warming trend are present in the future climate simulations. This suggests that there is a chance that the current observed hiatus could extend for several more years.},
annote = {doi: 10.1175/JCLI-D-12-00548.1},
author = {Meehl, Gerald A and Hu, Aixue and Arblaster, Julie M and Fasullo, John and Trenberth, Kevin E},
doi = {10.1175/JCLI-D-12-00548.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {apr},
number = {18},
pages = {7298--7310},
publisher = {American Meteorological Society},
title = {{Externally Forced and Internally Generated Decadal Climate Variability Associated with the Interdecadal Pacific Oscillation}},
url = {https://doi.org/10.1175/JCLI-D-12-00548.1},
volume = {26},
year = {2013}
}
@article{Meehl2016e,
abstract = {Antarctic sea-ice extent has been slowly increasing in the satellite record that began in 1979. Since the late 1990s, the increase has accelerated, but the average of all climate models shows a decline. Meanwhile, the Interdecadal Pacific Oscillation, an internally generated mode of climate variability, transitioned from positive to negative, with an average cooling of tropical Pacific sea surface temperatures, a slowdown of the global warming trend and a deepening of the Amundsen Sea Low near Antarctica that has contributed to regional circulation changes in the Ross Sea region and expansion of sea ice. Here we show that the negative phase of the Interdecadal Pacific Oscillation in global coupled climate models is characterized by anomalies similar to the observed sea-level pressure and near-surface 850 hPa wind changes near Antarctica since 2000 that are conducive to expanding Antarctic sea-ice extent, particularly in the Ross Sea region in all seasons, involving a deepening of the Amundsen Sea Low. These atmospheric circulation changes are shown to be mainly driven by precipitation and convective heating anomalies related to the Interdecadal Pacific Oscillation in the equatorial eastern Pacific, with additional contributions from convective heating anomalies in the South Pacific convergence zone and tropical Atlantic regions.},
author = {Meehl, Gerald A and Arblaster, Julie M and Bitz, Cecilia M and Chung, Christine T.Y. and Teng, Haiyan},
doi = {10.1038/ngeo2751},
issn = {17520908},
journal = {Nature Geoscience},
month = {jul},
number = {8},
pages = {590--595},
publisher = {Nature Publishing Group},
title = {{Antarctic sea-ice expansion between 2000 and 2014 driven by tropical Pacific decadal climate variability}},
volume = {9},
year = {2016}
}
@article{Meehl2011b,
author = {Meehl, Gerald A. and Arblaster, Julie M. and Fasullo, John T. and Hu, Aixue and Trenberth, Kevin E.},
doi = {10.1038/nclimate1229},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {oct},
number = {7},
pages = {360--364},
title = {{Model-based evidence of deep-ocean heat uptake during surface-temperature hiatus periods}},
volume = {1},
year = {2011}
}
@article{doi:10.1029/2018GL079989,
abstract = {Abstract The trend for cold-season (November-December-January-February, NDJF) decreases in Arctic sea ice extent from 2000 to 2014 was about a factor of two larger than the 1979–2000 trend, and the warm-season (June-July-August-September, JJAS) trend was about a factor of three larger. Sensitivity experiments with an atmospheric model show that a negative convective heating anomaly in the tropical Pacific, associated with the negative Interdecadal Pacific Oscillation phase after 2000, produces an atmospheric teleconnection pattern over the Arctic comparable to the observations in NDJF but not JJAS. A positive convective heating anomaly over the tropical Atlantic, associated with warming sea surface temperatures there in the 2000–2014 period, produces a teleconnection pattern over the Arctic comparable to the observations in JJAS but not NDJF. Thus, the observed anomalously strong Arctic surface winds and sea ice drifts after 2000, which produced accelerated decreases in sea ice extent, likely had contributions from decadal-time scale variability in the tropical Pacific and Atlantic.},
author = {Meehl, Gerald A and Chung, Christine T Y and Arblaster, Julie M and Holland, Marika M and Bitz, Cecilia M},
doi = {10.1029/2018GL079989},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {oct},
number = {20},
pages = {11326--11333},
title = {{Tropical Decadal Variability and the Rate of Arctic Sea Ice Decrease}},
url = {https://onlinelibrary.wiley.com/doi/10.1029/2018GL079989},
volume = {45},
year = {2018}
}
@article{Meehl2019a,
abstract = {After nearly three decades of observed increasing trends of Antarctic sea ice extent, in September-October-November 2016, there was a dramatic decrease. Here we document factors that contributed to that decrease. An atmosphere-only model with a specified positive convective heating anomaly in the eastern Indian/western Pacific Ocean, representing the record positive precipitation anomalies there in September-October-November 2016, produces an anomalous atmospheric Rossby wave response with mid- and high latitude surface wind anomalies that contribute to the decrease of Antarctic sea ice extent. The sustained decreases of Antarctic sea ice extent after late 2016 are associated with a warmer upper Southern Ocean. This is the culmination of a negative decadal trend of wind stress curl with positive Southern Annular Mode and negative Interdecadal Pacific Oscillation, Ekman suction that results in warmer water being moved upward in the column closer to the surface, a transition to positive Interdecadal Pacific Oscillation around 2014–2016, and negative Southern Annular Mode in late 2016.},
author = {Meehl, Gerald A and Arblaster, Julie M and Chung, Christine T Y and Holland, Marika M and DuVivier, Alice and Thompson, LuAnne and Yang, Dongxia and Bitz, Cecilia M},
doi = {10.1038/s41467-018-07865-9},
issn = {2041-1723},
journal = {Nature Communications},
number = {1},
pages = {14},
title = {{Sustained ocean changes contributed to sudden Antarctic sea ice retreat in late 2016}},
url = {https://doi.org/10.1038/s41467-018-07865-9},
volume = {10},
year = {2019}
}
@article{Meehl2020b,
abstract = {For the current generation of earth system models participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6), the range of equilibrium climate sensitivity (ECS, a hypothetical value of global warming at equilibrium for a doubling of CO2) is 1.8°C to 5.6°C, the largest of any generation of models dating to the 1990s. Meanwhile, the range of transient climate response (TCR, the surface temperature warming around the time of CO2 doubling in a 1{\%} per year CO2 increase simulation) for the CMIP6 models of 1.7°C (1.3°C to 3.0°C) is only slightly larger than for the CMIP3 and CMIP5 models. Here we review and synthesize the latest developments in ECS and TCR values in CMIP, compile possible reasons for the current values as supplied by the modeling groups, and highlight future directions. Cloud feedbacks and cloud-aerosol interactions are the most likely contributors to the high values and increased range of ECS in CMIP6.},
author = {Meehl, Gerald A. and Senior, Catherine A. and Eyring, Veronika and Flato, Gregory and Lamarque, Jean-Francois and Stouffer, Ronald J. and Taylor, Karl E. and Schlund, Manuel},
doi = {10.1126/sciadv.aba1981},
issn = {2375-2548},
journal = {Science Advances},
month = {jun},
number = {26},
pages = {eaba1981},
pmid = {32637602},
title = {{Context for interpreting equilibrium climate sensitivity and transient climate response from the CMIP6 Earth system models}},
url = {https://www.science.org/doi/10.1126/sciadv.aba1981},
volume = {6},
year = {2020}
}
@article{Meijers2012a,
abstract = {The representation of the Antarctic Circumpolar Current (ACC) in the fifth Coupled Models Intercomparison Project (CMIP5) is generally improved over CMIP3. The range of modeled transports in the historical (1976–2006) scenario is reduced (90–264 Sv) compared with CMIP3 (33–337 Sv) with a mean of 155 ? 51 Sv. The large intermodel range is associated with significant differences in the ACC density structure. The ACC position is accurately represented at most longitudes, with a small (1.27?) standard deviation in mean latitude. The westerly wind jet driving the ACC is biased too strong and too far north on average. Unlike CMIP3 there is no correlation between modeled ACC latitude and the position of the westerly wind jet. Under future climate forcing scenarios (2070–2099 mean) the modeled ACC transport changes by between ?26 to +17 Sv and the ACC shifts polewards (equatorwards) in models where the transport increases (decreases). There is no significant correlation between the ACC position change and that of the westerly wind jet, which shifts polewards and strengthens. The subtropical gyres strengthen and expand southwards, while the change in subpolar gyre area varies between models. An increase in subpolar gyre area corresponds with a decreases in ACC transport and an equatorward shift in the ACC position, and vice versa for a contraction of the gyre area. There is a general decrease in density in the upper 1000 m, particularly equatorwards of the ACC core.},
author = {Meijers, A. J.S. and Shuckburgh, E and Bruneau, N and Sallee, J. B. and Bracegirdle, T J and Wang, Z},
doi = {10.1029/2012JC008412},
isbn = {2156-2202},
issn = {21699291},
journal = {Journal of Geophysical Research: Oceans},
number = {12},
pages = {C12008},
publisher = {American Geophysical Union},
title = {{Representation of the Antarctic Circumpolar Current in the CMIP5 climate models and future changes under warming scenarios}},
volume = {117},
year = {2012}
}
@article{Menary2013,
abstract = {AbstractMechanisms of sustained multidecadal changes in the strength of the Atlantic Meridional Overturning Circulation (AMOC) are investigated in a set of simulations with a new state-of-the-art Earth system model. Anthropogenic aerosols have previously been highlighted as a potential mitigator of AMOC weakening. In this study, we explain the oceanic mechanisms behind how anthropogenic aerosols force a strengthening of the AMOC by up to 20{\%} in our state-of-the-art Earth system model. This strengthening is driven via atmospheric circulation changes which subsequently modulate the salinity budget of the North Atlantic subpolar gyre. Gradual salinification occurs via increased evaporation and decreased fluxes of ice through the Fram Straits. A component of the salinification is a positive feedback from the AMOC bringing more saline water northwards from the subtropical Atlantic. Salinification of the subpolar gyre results in increased deep convection and a strengthening of the AMOC. Following a reduction in aerosol concentrations, the AMOC rapidly weakens, approximately 3 times faster than in the case where anthropogenic aerosol concentrations had never been increased. Similarities and differences with available observational records and long term reanalysis products are also discussed.},
annote = {doi: 10.1002/jgrc.20178},
author = {Menary, Matthew B and Roberts, Christopher D and Palmer, Matthew D and Halloran, Paul R and Jackson, Laura and Wood, Richard A and M{\"{u}}ller, Wolfgang A and Matei, Daniela and Lee, Sang-Ki},
doi = {10.1002/jgrc.20178},
issn = {2169-9275},
journal = {Journal of Geophysical Research: Oceans},
keywords = {aerosols,amoc,atlantic,circulation,cmip5,overturning},
month = {mar},
number = {4},
pages = {2087--2096},
publisher = {Wiley-Blackwell},
title = {{Mechanisms of aerosol-forced AMOC variability in a state of the art climate model}},
url = {https://doi.org/10.1002/jgrc.20178},
volume = {118},
year = {2013}
}
@article{Menary2014,
abstract = {The mechanisms by which natural forcing factors alone could drive simulated multidecadal variability in the Atlantic meridional overturning circulation (AMOC) are assessed in an ensemble of climate model simulations. It is shown for a new state-of-the-art general circulation model, HadGEM2-ES, that the most important of these natural forcings, in terms of the multidecadal response of the AMOC, is solar rather than volcanic forcing. AMOC strengthening occurs through a densification of the North Atlantic, driven by anomalous surface freshwater fluxes due to increased evaporation. These are related to persistent North Atlantic atmospheric circulation anomalies, driven by forced changes in the stratosphere, associated with anomalously weak solar irradiance during the late nineteenth and early twentieth centuries. Within a period of approximately 100 years the 11-year smoothed ensemble mean AMOC strengthens by 1.5 Sv and subsequently weakens by 1.9 Sv, representing respectively approximately 3 and 4 standard deviations of the 11-year smoothed control simulation. The solar-induced variability of the AMOC has various relevant climate impacts, such as a northward shift of the intertropical convergence zone, anomalous Amazonian rainfall, and a sustained increase in European temperatures. While this model has only a partial representation of the atmospheric response to solar variability, these results demonstrate the potential for solar variability to have a multidecadal impact on North Atlantic climate.},
author = {Menary, Matthew B and Scaife, Adam A},
doi = {10.1007/s00382-013-2028-x},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {5},
pages = {1347--1362},
title = {{Naturally forced multidecadal variability of the Atlantic meridional overturning circulation}},
url = {https://doi.org/10.1007/s00382-013-2028-x},
volume = {42},
year = {2014}
}
@article{Menary2015a,
author = {Menary, Matthew B. and Hodson, Daniel L. R. and Robson, Jon I. and Sutton, Rowan T. and Wood, Richard A. and Hunt, Jonathan A.},
doi = {10.1002/2015GL064360},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {jul},
number = {14},
pages = {5926--5934},
title = {{Exploring the impact of CMIP5 model biases on the simulation of North Atlantic decadal variability}},
url = {http://doi.wiley.com/10.1002/2015GL064360},
volume = {42},
year = {2015}
}
@article{Menary2020,
abstract = {The Atlantic Meridional Overturning Circulation (AMOC) has been, and will continue to be, a key factor in the modulation of climate change both locally and globally. However, there remains considerable uncertainty in recent AMOC evolution. Here, we show that the multimodel mean AMOC strengthened by approximately 10{\%} from 1850–1985 in new simulations from the 6th Coupled Model Intercomparison Project (CMIP6), a larger change than was seen in CMIP5. Across the models, the strength of the AMOC trend up to 1985 is related to a proxy for the strength of the aerosol forcing. Therefore, the multimodel difference is a result of stronger anthropogenic aerosol forcing on average in CMIP6 than CMIP5, which is primarily due to more models including aerosol-cloud interactions. However, observational constraints—including a historical sea surface temperature fingerprint and shortwave radiative forcing in recent decades—suggest that anthropogenic forcing and/or the AMOC response may be overestimated.},
author = {Menary, Matthew B. and Robson, Jon and Allan, Richard P. and Booth, Ben B.B. and Cassou, Christophe and Gastineau, Guillaume and Gregory, Jonathan and Hodson, Dan and Jones, Colin and Mignot, Juliette and Ringer, Mark and Sutton, Rowan and Wilcox, Laura and Zhang, Rong},
doi = {10.1029/2020GL088166},
issn = {19448007},
journal = {Geophysical Research Letters},
keywords = {AMOC,CMIP6,aerosols,climate change,historical simulations,strengthening},
number = {14},
pages = {e2020GL088166},
title = {{Aerosol-Forced AMOC Changes in CMIP6 Historical Simulations}},
volume = {47},
year = {2020}
}
@article{Menary2018b,
author = {Menary, Matthew B. and Kuhlbrodt, Till and Ridley, Jeff and Andrews, Martin B. and Dimdore‐Miles, Oscar B. and Deshayes, Julie and Eade, Rosie and Gray, Lesley and Ineson, Sarah and Mignot, Juliette and Roberts, Christopher D. and Robson, Jon and Wood, Richard A. and Xavier, Prince},
doi = {10.1029/2018MS001495},
issn = {1942-2466},
journal = {Journal of Advances in Modeling Earth Systems},
month = {dec},
number = {12},
pages = {3049--3075},
title = {{Preindustrial Control Simulations With HadGEM3‐GC3.1 for CMIP6}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018MS001495},
volume = {10},
year = {2018}
}
@incollection{Meredith2019,
author = {Meredith, M. and Sommerkorn, M. and Cassotta, S. and Derksen, C. and Ekaykin, A. and Hollowed, A. and Kofinas, G. and Mackintosh, A. and Melbourne-Thomas, J. and Muelbert, M.M.C. and Ottersen, G. and Pritchard, H. and Schuur, E.A.G.},
booktitle = {IPCC Special Report on the Ocean and Cryosphere in a Changing Climate},
chapter = {3},
doi = {https://www.ipcc.ch/srocc/chapter/chapter-3-2},
editor = {Pörtner, H.-O. and Roberts, D.C. and Masson-Delmotte, V. and Zhai, P. and Tignor, M. and Poloczanska, E. and Mintenbeck, K. and Alegría, A. and Nicolai, M. and Okem, A. and Petzold, J. and Rama, B. and Weyer, N.M.},
pages = {203--320},
publisher = {In Press},
title = {{Polar Regions}},
url = {https://www.ipcc.ch/srocc/chapter/chapter-3-2},
year = {2019}
}
@article{Meyerholt2020,
abstract = {The magnitude of the nitrogen (N) limitation of terrestrial carbon (C) storage over the 21st century is highly uncertain because of the complex interactions between the terrestrial C and N cycles. We use an ensemble approach to quantify and attribute process-level uncertainty in C-cycle projections by analysing a 30-member ensemble representing published alternative representations of key N cycle processes (stoichiometry, biological nitrogen fixation (BNF) and ecosystem N losses) within the framework of one terrestrial biosphere model. Despite large differences in the simulated present-day N cycle, primarily affecting simulated productivity north of 40°N, ensemble members generally conform with global C-cycle benchmarks for present-day conditions. Ensemble projections for two representative concentration pathways (RCP 2.6 and RCP 8.5) show that the increase in land C storage due to CO2 fertilization is reduced by 24 ± 15{\%} due to N constraints, whereas terrestrial C losses associated with climate change are attenuated by 19 ± 20{\%}. As a result, N cycling reduces projected land C uptake for the years 2006–2099 by 19{\%} (37{\%} decrease to 3{\%} increase) for RCP 2.6, and by 21{\%} (40{\%} decrease to 9{\%} increase) for RCP 8.5. Most of the ensemble spread results from uncertainty in temperate and boreal forests, and is dominated by uncertainty in BNF (10{\%} decrease to 50{\%} increase for RCP 2.6, 5{\%} decrease to 100{\%} increase for RCP 8.5). However, choices about the flexibility of ecosystem C:N ratios and processes controlling ecosystem N losses regionally also play important roles. The findings of this study demonstrate clearly the need for an ensemble approach to quantify likely future terrestrial C–N cycle trajectories. Present-day C-cycle observations only weakly constrain the future ensemble spread, highlighting the need for better observational constraints on large-scale N cycling, and N cycle process responses to global change.},
author = {Meyerholt, Johannes and Sickel, Kerstin and Zaehle, S{\"{o}}nke},
doi = {10.1111/gcb.15114},
issn = {13652486},
journal = {Global Change Biology},
number = {7},
title = {{Ensemble projections elucidate effects of uncertainty in terrestrial nitrogen limitation on future carbon uptake}},
volume = {26},
year = {2020}
}
@article{Meyssignac2017,
abstract = {AbstractTwentieth-century regional sea level changes are estimated from 12 climate models from phase 5 of the Climate Model Intercomparison Project (CMIP5). The output of the CMIP5 climate model simulations was used to calculate the global and regional sea level changes associated with dynamic sea level, atmospheric loading, glacier mass changes, and ice sheet surface mass balance contributions. The contribution from groundwater depletion, reservoir storage, and dynamic ice sheet mass changes are estimated from observations as they are not simulated by climate models. All contributions are summed, including the glacial isostatic adjustment (GIA) contribution, and compared to observational estimates from 27 tide gauge records over the twentieth century (1900–2015). A general agreement is found between the simulated sea level and tide gauge records in terms of interannual to multidecadal variability over 1900–2015. But climate models tend to systematically underestimate the observed sea level trends, partic...},
author = {Meyssignac, Benoit and Slangen, A. B.A. and Melet, A. and Church, J. A. and Fettweis, X. and Marzeion, B. and Agosta, C. and Ligtenberg, S. R.M. and Spada, G. and Richter, K. and Palmer, M. D. and Roberts, C. D. and Champollion, N.},
doi = {10.1175/JCLI-D-17-0112.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Climate change,Climate models,Sea level},
month = {nov},
number = {21},
pages = {8565--8593},
title = {{Evaluating model simulations of twentieth-century sea-level rise. Part II: Regional sea-level changes}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-17-0112.1},
volume = {30},
year = {2017}
}
@article{Michel2020,
abstract = {Abstract. Modes of climate variability strongly impact our climate and thus human society. Nevertheless, the statistical properties of these modes remain poorly known due to the short time frame of instrumental measurements. Reconstructing these modes further back in time using statistical learning methods applied to proxy records is useful for improving our understanding of their behaviour. For doing so, several statistical methods exist, among which principal component regression is one of the most widely used in paleoclimatology. Here, we provide the software ClimIndRec to the climate community; it is based on four regression methods (principal component regression, PCR; partial least squares, PLS; elastic net, Enet; random forest, RF) and cross-validation (CV) algorithms, and enables the systematic reconstruction of a given climate index. A prerequisite is that there are proxy records in the database that overlap in time with its observed variations. The relative efficiency of the methods can vary, according to the statistical properties of the mode and the proxy records used. Here, we assess the sensitivity to the reconstruction technique. ClimIndRec is modular as it allows different inputs like the proxy database or the regression method. As an example, it is here applied to the reconstruction of the North Atlantic Oscillation by using the PAGES 2k database. In order to identify the most reliable reconstruction among those given by the different methods, we use the modularity of ClimIndRec to investigate the sensitivity of the methodological setup to other properties such as the number and the nature of the proxy records used as predictors or the targeted reconstruction period. We obtain the best reconstruction of the North Atlantic Oscillation (NAO) using the random forest approach. It shows significant correlation with former reconstructions, but exhibits higher validation scores.},
author = {Michel, Simon and Swingedouw, Didier and Chavent, Marie and Ortega, Pablo and Mignot, Juliette and Khodri, Myriam},
doi = {10.5194/gmd-13-841-2020},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {mar},
number = {2},
pages = {841--858},
title = {{Reconstructing climatic modes of variability from proxy records using ClimIndRec version 1.0}},
url = {https://gmd.copernicus.org/articles/13/841/2020/},
volume = {13},
year = {2020}
}
@article{Middlemas2016b,
author = {Middlemas, Eleanor A. and Clement, Amy C.},
doi = {10.1175/JCLI-D-15-0609.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {sep},
number = {17},
pages = {6245--6257},
title = {{Spatial Patterns and Frequency of Unforced Decadal-Scale Changes in Global Mean Surface Temperature in Climate Models}},
volume = {29},
year = {2016}
}
@article{doi:10.1029/2008GL035725,
abstract = {Human influence has previously been identified in the observed loss of Arctic sea ice, but this hypothesis has not yet been tested with a formal optimal detection approach. By comparing observed and multi-model simulated changes in Arctic sea ice extent during 1953–2006 using an optimal fingerprinting method, we find that the anthropogenic signal first emerged in the early 1990s, indicating that human influence could have been detected even prior to the recent dramatic sea ice decline. The anthropogenic signal is also detectable for individual months from May to December, suggesting that human influence, strongest in late summer, now also extends into colder seasons.},
author = {Min, Seung-Ki and Zhang, Xuebin and Zwiers, Francis W and Agnew, Tom},
doi = {10.1029/2008GL035725},
journal = {Geophysical Research Letters},
keywords = {Arctic sea ice,climate change detection},
number = {21},
pages = {L21701},
title = {{Human influence on Arctic sea ice detectable from early 1990s onwards}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2008GL035725},
volume = {35},
year = {2008}
}
@article{Min518,
abstract = {The Arctic and northern subpolar regions are critical for climate change. Ice-albedo feedback amplifies warming in the Arctic, and fluctuations of regional fresh water inflow to the Arctic Ocean modulate the deep ocean circulation and thus exert a strong global influence. By comparing observations to simulations from 22 coupled climate models, we find influence from anthropogenic greenhouse gases and sulfate aerosols in the space-time pattern of precipitation change over high-latitude land areas north of 55°N during the second half of the 20th century. The human-induced Arctic moistening is consistent with observed increases in Arctic river discharge and freshening of Arctic water masses. This result provides new evidence that human activity has contributed to Arctic hydrological change.},
author = {Min, Seung-Ki and Zhang, Xuebin and Zwiers, Francis},
doi = {10.1126/science.1153468},
issn = {00368075},
journal = {Science},
number = {5875},
pages = {518--520},
pmid = {18440925},
publisher = {American Association for the Advancement of Science},
title = {{Human-induced Arctic moistening}},
url = {http://science.sciencemag.org/content/320/5875/518},
volume = {320},
year = {2008}
}
@article{Min2011,
author = {Min, Seung-Ki and Zhang, Xuebin and Zwiers, Francis W and Hegerl, Gabriele C},
doi = {10.1038/nature09763},
journal = {Nature},
month = {feb},
pages = {378--381},
publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.},
title = {{Human contribution to more-intense precipitation extremes}},
volume = {470},
year = {2011}
}
@article{ISI:000402122200026,
abstract = {Atmospheric modes of variability relevant for extreme temperature and precipitation events are evaluated in models currently being used for extreme event attribution. A 100 member initial condition ensemble of the global circulation model HadAM3P is compared with both the multi-model ensemble from the Coupled Model Inter-comparison Project, Phase 5 (CMIP5) and the CMIP5 atmosphere-only counterparts (AMIP5). The use of HadAM3P allows for huge ensembles to be computed relatively fast, thereby providing unique insights into the dynamics of extremes. The analysis focuses on mid Northern Latitudes (primarily Europe) during winter, and is compared with ERA-Interim reanalysis. The tri-modal Atlantic eddy-driven jet distribution is remarkably well captured in HadAM3P, but not so in the CMIP5 or AMIP5 multi-model mean, although individual models fare better. The well known underestimation of blocking in the Atlantic region is apparent in CMIP5 and AMIP5, and also, to a lesser extent, in HadAM3P. Pacific blocking features are well produced in all modeling initiatives. Blocking duration is biased towards models reproducing too many short-lived events in all three modelling systems. Associated storm tracks are too zonal over the Atlantic in the CMIP5 and AMIP5 ensembles, but better simulated in HadAM3P with the exception of being too weak over Western Europe. In all cases, the CMIP5 and AMIP5 performances were almost identical, suggesting that the biases in atmospheric modes considered here are not strongly coupled to SSTs, and perhaps other model characteristics such as resolution are more important. For event attribution studies, it is recommended that rather than taking statistics over the entire CMIP5 or AMIP5 available models, only models capable of producing the relevant dynamical phenomena be employed.},
address = {233 SPRING ST, NEW YORK, NY 10013 USA},
annote = {CMIP5 The multi-model mean of CMIP5 fares less well in simulating the relevant atmospheric modes for extreme events than HadAM3P. The tri-modal structure of the Atlantic jet is not reproduced in many of the models, and even then only vaguely resembles the ERA-I calculated distribution. Extreme blocking events (in terms of duration of winter blocked) over the European sector are notably absent, with the top 5 {\%} of blocking events from the CMIP5 models only matching the mean of ERA-I. Over the Pacific the CMIP5 models perform far better, and represent the variability and duration of winter blocking well (and more accurately than HadAM3P). Finally, on average, the CMIP5 models have too high a density of storm tracks over Western America and Canada, and too zonal a jet over the Euro-Atlantic region.},
author = {Mitchell, Daniel M. and Davini, Paolo and Harvey, Ben and Massey, Neil and Haustein, Karsten and Woollings, Tim and Jones, Richard and Otto, Fredi and Guillod, Benoit and Sparrow, Sarah and Wallom, David and Allen, Myles},
doi = {10.1007/s00382-016-3308-z},
issn = {0930-7575},
journal = {Climate Dynamics},
keywords = {Dynamics,Event attribution,Extrem,Mid-latitudes},
month = {jun},
number = {11-12},
pages = {3889--3901},
publisher = {SPRINGER},
title = {{Assessing mid-latitude dynamics in extreme event attribution systems}},
type = {Article},
url = {http://link.springer.com/10.1007/s00382-016-3308-z},
volume = {48},
year = {2017}
}
@article{Mitchell2013,
abstract = {Controversy remains over a discrepancy between modeled and observed tropical upper tropospheric temperature trends. This discrepancy is reassessed using simulations from the Coupled Climate Model Inter-comparison Project phase 5 (CMIP 5) together with radiosonde and surface observations that provide multiple realizations of possible "observed" temperatures given various methods of homogenizing the data. Over the 1979-2008 period, tropical temperature trends are not consistent with observations throughout the depth of the troposphere, and this primarily stems from a poor simulation of the surface temperature trends. This discrepancy is substantially reduced when (1) atmosphere-only simulations are examined or (2) the trends are considered as an amplification of the surface temperature trend with height. Using these approaches, it is shown that within observational uncertainty, the 5-95 percentile range of temperature trends from both coupled-ocean and atmosphere-only models are consistent with the analyzed observations at all but the upper most tropospheric level (150 hPa), and models with ultra-high horizontal resolution (≤ 0.5° × 0.5°) perform particularly well. Other than model resolution, it is hypothesized that this remaining discrepancy could be due to a poor representation of stratospheric ozone or remaining observational uncertainty. {\textcopyright} 2013 American Geophysical Union. All Rights Reserved.},
author = {Mitchell, D.M. and Thorne, P.W. and Stott, P.A. and Gray, L.J.},
doi = {10.1002/grl.50465},
journal = {Geophysical Research Letters},
number = {11},
pages = {2801--2806},
title = {{Revisiting the controversial issue of tropical tropospheric temperature trends}},
volume = {40},
year = {2013}
}
@article{Mitchell2016,
abstract = {{\textcopyright} 2016 Royal Meteorological Society. One of the largest anthropogenic fingerprints on climate is observed in stratospheric temperatures, but measurements in this region are uncertain. Here, regularised optimal fingerprinting techniques are used to attribute annual temperature variability in the mid-upper stratosphere to external forcing factors over the period 1979-2005. Specifically, the solar, volcanic, ozone and greenhouse gas (GHG) forced components are characterised. The analysis compares the two most recent reconstructions of the Stratospheric Sounding Unit (SSU) with each other and with six historically forced simulations taken from the Coupled Model Intercomparison Project, phase 5. In the uppermost stratospheric SSU channel, all individual forcings are detected. Solar and volcanic forcings are also detected in the middle and lower SSU channels, but at these levels the GHG and ozone signals are not detected separately from each other. The uncertainty in the global temperature response due to individual forcings is found to be dominated by observational uncertainty in the upper stratosphere, and the signal-to-noise ratio in the middle stratosphere. Estimates of the 11-year solar cycle amplitude are broadly consistent with reanalysis studies. The temperature response to volcanic eruptions is found to be larger than previously thought in the upper stratosphere (0.4-0.6 K for Mount Pinatubo), although is still dominated by the lower-stratospheric signal. Finally, the anthropogenic response in the upper stratosphere gives rise to a cooling of ∼2-3 K over the 27-year period, with two thirds of this attributed to GHGs, and one third to ozone depletion.},
author = {Mitchell, D.M.},
doi = {10.1002/qj.2707},
journal = {Quarterly Journal of the Royal Meteorological Society},
number = {695},
pages = {1041--1047},
title = {{Attributing the forced components of observed stratospheric temperature variability to external drivers}},
volume = {142},
year = {2016}
}
@article{mitchell2012effect,
abstract = {With extreme variability of the Arctic polar vortex being a key link for stratosphere–troposphere influences, its evolution into the twenty-first century is important for projections of changing surface climate in response to greenhouse gases. Variability of the stratospheric vortex is examined using a state-of-the-art climate model and a suite of specifically developed vortex diagnostics. The model has a fully coupled ocean and a fully resolved stratosphere. Analysis of the standard stratospheric zonal mean wind diagnostic shows no significant increase over the twenty-first century in the number of major sudden stratospheric warmings (SSWs) from its historical value of 0.7 events per decade, although the monthly distribution of SSWs does vary, with events becoming more evenly dispersed throughout the winter. However, further analyses using geometric-based vortex diagnostics show that the vortex mean state becomes weaker, and the vortex centroid is climatologically more equatorward by up to 2.5°, especially during early winter. The results using these diagnostics not only characterize the vortex structure and evolution but also emphasize the need for vortex-centric diagnostics over zonally averaged measures. Finally, vortex variability is subdivided into wave-1 (displaced) and -2 (split) components, and it is implied that vortex displacement events increase in frequency under climate change, whereas little change is observed in splitting events.},
author = {Mitchell, Daniel M and Osprey, Scott M and Gray, Lesley J and Butchart, Neal and Hardiman, Steven C and Charlton-Perez, Andrew J and Watson, Peter},
doi = {10.1175/JAS-D-12-021.1},
issn = {0022-4928},
journal = {Journal of the Atmospheric Sciences},
month = {aug},
number = {8},
pages = {2608--2618},
title = {{The Effect of Climate Change on the Variability of the Northern Hemisphere Stratospheric Polar Vortex}},
url = {https://journals.ametsoc.org/doi/10.1175/JAS-D-12-021.1},
volume = {69},
year = {2012}
}
@article{Mitchell_2020,
abstract = {Tropospheric and stratospheric tropical temperature trends in recent decades have been notoriously hard to simulate using climate models, particularly in the upper troposphere. Aside from the warming trend itself, this has broader implications, e.g. atmospheric circulation trends depend on latitudinal temperature gradients. In this study, tropical temperature trends in the CMIP6 models are examined, from 1979 to 2014, and contrasted with trends from the RICH/RAOBCORE radiosondes, and the ERA5/5.1 reanalysis. As in earlier studies, we find considerable warming biases in the CMIP6 modeled trends, and we show that these biases are linked to biases in surface temperature. We also uncover previously undocumented biases in the lower-middle stratosphere: the CMIP6 models appear unable to capture the time evolution of stratospheric cooling, which is non-monotonic owing to the Montreal Protocol. Finally, using models with large ensembles, we show that their standard deviation in tropospheric temperature trends, which is due to internal variability alone, explains ∼ 50{\%} (± 20{\%}) of that from the CMIP6 models.},
author = {Mitchell, Dann M and Lo, Y T Eunice and Seviour, William J M and Haimberger, Leopold and Polvani, Lorenzo M},
doi = {10.1088/1748-9326/ab9af7},
journal = {Environmental Research Letters},
number = {10},
pages = {1040b4},
publisher = {{\{}IOP{\}} Publishing},
title = {{The vertical profile of recent tropical temperature trends: Persistent model biases in the context of internal variability}},
url = {https://doi.org/10.1088{\%}2F1748-9326{\%}2Fab9af7},
volume = {15},
year = {2020}
}
@article{Mochizuki2016,
author = {Mochizuki, Takashi and Kimoto, Masahide and Watanabe, Masahiro and Chikamoto, Yoshimitsu and Ishii, Masayoshi},
doi = {10.1002/2016GL069940},
issn = {00948276},
journal = {Geophysical Research Letters},
keywords = {10.1002/2016GL069940 and interbasin connection,Indian Ocean warming,data assimilation,decadal climate variability,global warming,pacemaker experiment},
month = {jul},
number = {13},
pages = {7168--7175},
title = {{Interbasin effects of the Indian Ocean on Pacific decadal climate change}},
url = {http://doi.wiley.com/10.1002/2016GL069940},
volume = {43},
year = {2016}
}
@article{Moffa-Sanchez2014,
author = {Moffa-S{\'{a}}nchez, Paola and Born, Andreas and Hall, Ian R. and Thornalley, David J. R. and Barker, Stephen},
doi = {10.1038/ngeo2094},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {apr},
number = {4},
pages = {275--278},
title = {{Solar forcing of North Atlantic surface temperature and salinity over the past millennium}},
url = {http://www.nature.com/articles/ngeo2094},
volume = {7},
year = {2014}
}
@article{Mohtadi2016,
author = {Mohtadi, Mahyar and Prange, Matthias and Steinke, Stephan},
doi = {10.1038/nature17450},
issn = {0028-0836},
journal = {Nature},
month = {may},
number = {7602},
pages = {191--199},
title = {{Palaeoclimatic insights into forcing and response of monsoon rainfall}},
url = {http://www.nature.com/articles/nature17450},
volume = {533},
year = {2016}
}
@article{Molteni2017,
author = {Molteni, Franco and Farneti, Riccardo and Kucharski, Fred and Stockdale, Timothy N.},
doi = {10.1002/2016GL072298},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {feb},
number = {3},
pages = {1494--1502},
title = {{Modulation of air-sea fluxes by extratropical planetary waves and its impact during the recent surface warming slowdown}},
url = {http://doi.wiley.com/10.1002/2016GL072298},
volume = {44},
year = {2017}
}
@article{Monerie2019,
author = {Monerie, Paul-Arthur and Robson, Jon and Dong, Buwen and Hodson, Dan L. R. and Klingaman, Nicholas P.},
doi = {10.1029/2018GL080903},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {feb},
number = {3},
pages = {1765--1775},
title = {{Effect of the Atlantic Multidecadal Variability on the Global Monsoon}},
url = {http://doi.wiley.com/10.1029/2018GL080903},
volume = {46},
year = {2019}
}
@article{Mongwe2018,
abstract = {Abstract. The Southern Ocean forms an important component of the Earth system as a major sink of CO2 and heat. Recent studies based on the Coupled Model Intercomparison Project version 5 (CMIP5) Earth system models (ESMs) show that CMIP5 models disagree on the phasing of the seasonal cycle of the CO2 flux (FCO2) and compare poorly with available observation products for the Southern Ocean. Because the seasonal cycle is the dominant mode of CO2 variability in the Southern Ocean, its simulation is a rigorous test for models and their long-term projections. Here we examine the competing roles of temperature and dissolved inorganic carbon (DIC) as drivers of the seasonal cycle of pCO2 in the Southern Ocean to explain the mechanistic basis for the seasonal biases in CMIP5 models. We find that despite significant differences in the spatial characteristics of the mean annual fluxes, the intra-model homogeneity in the seasonal cycle of FCO2 is greater than observational products. FCO2 biases in CMIP5 models can be grouped into two main categories, i.e., group-SST and group-DIC. Group-SST models show an exaggeration of the seasonal rates of change of sea surface temperature (SST) in autumn and spring during the cooling and warming peaks. These higher-than-observed rates of change of SST tip the control of the seasonal cycle of pCO2 and FCO2 towards SST and result in a divergence between the observed and modeled seasonal cycles, particularly in the Sub-Antarctic Zone. While almost all analyzed models (9 out of 10) show these SST-driven biases, 3 out of 10 (namely NorESM1-ME, HadGEM-ES and MPI-ESM, collectively the group-DIC models) compensate for the solubility bias because of their overly exaggerated primary production, such that biologically driven DIC changes mainly regulate the seasonal cycle of FCO2.},
author = {Mongwe, N. Precious and Vichi, Marcello and Monteiro, Pedro M. S.},
doi = {10.5194/bg-15-2851-2018},
issn = {1726-4189},
journal = {Biogeosciences},
month = {may},
number = {9},
pages = {2851--2872},
title = {{The seasonal cycle of pCO2 and CO2 fluxes in the Southern Ocean: diagnosing anomalies in CMIP5 Earth system models}},
url = {https://www.biogeosciences.net/15/2851/2018/},
volume = {15},
year = {2018}
}
@article{MONGWE201690,
abstract = {The Southern Ocean forms a key component of the global carbon budget, taking up about 1.0 Pg C yr−1 of anthropogenic CO2 emitted annually (∼10.7±0.5 Pg C yr−1 for 2012). However, despite its importance, it still remains undersampled with respect to surface ocean carbon flux variability, resulting in weak constraints for ocean carbon and carbon – climate models. As a result, atmospheric inversion and coupled physics-biogeochemical ocean models still play a central role in constraining the air-sea CO2 fluxes in the Southern Ocean. A recent synthesis study (Lenton et al., 2013a), however, showed that although ocean biogeochemical models (OBGMs) agree on the mean annual flux of CO2 in the Southern Ocean, they disagree on both amplitude and phasing of the seasonal cycle and compare poorly to observations. In this study, we develop and present a methodological framework to diagnose the controls on the seasonal variability of sea-air CO2 fluxes in model outputs relative to observations. We test this framework by comparing the NEMO-PISCES ocean model ORCA2-LIM2-PISCES to the Takahashi 2009 (T09) CO2 dataset. Here we demonstrate that the seasonal cycle anomaly for CO2 fluxes in ORCA2LP is linked to an underestimation of winter convective CO2 entrainment as well as the impact of biological CO2 uptake during the spring-summer season, relative to T09 observations. This resulted in sea surface temperature (SST) becoming the dominant driver of seasonal scale of the partial pressure of CO2 (pCO2) variability and hence of the differences in the seasonality of CO2 sea-air flux between the model and observations.},
author = {Mongwe, N Precious and Chang, Nicolette and Monteiro, Pedro M S},
doi = {https://doi.org/10.1016/j.ocemod.2016.09.006},
issn = {1463-5003},
journal = {Ocean Modelling},
keywords = {CO air-sea fluxes,DIC-SST control of pCO,Model biases,Model-data comparison,Seasonal cycle,Southern Ocean},
pages = {90--103},
title = {{The seasonal cycle as a mode to diagnose biases in modelled CO2 fluxes in the Southern Ocean}},
url = {http://www.sciencedirect.com/science/article/pii/S1463500316300956},
volume = {106},
year = {2016}
}
@article{Monselesan2015,
abstract = {{\textcopyright}2015. American Geophysical Union. All Rights Reserved. Attribution of cause of climate change is hindered by our ability to separate internal low-frequency variability from the forced response in the climate system. We characterize the spatiotemporal characteristics of internal variability by comparing ensemble averages of in-band fractional variances in Coupled Model Intercomparison Project Phase 5 (CMIP5) preindustrial control simulations to estimates from observations and reanalyses. For sea surface temperature and sea level height anomalies both models and observations show that variability on time scales less than 5 years is predominantly in the tropics and has the spatial signature of El Ni{\~{n}}o-Southern Oscillation. On progressively longer time scales the variance moves to the extratropics and from middle to higher latitudes while displaying spatially coherent features. The CMIP5 models show good agreement in the spatial and temporal apportioning of in-band variance when the variances are normalized.},
author = {Monselesan, D.P. and O'Kane, T.J. and Risbey, J.S. and Church, J.},
doi = {10.1002/2014GL062765},
journal = {Geophysical Research Letters},
number = {4},
pages = {1232--1242},
title = {{Internal climate memory in observations and models}},
volume = {42},
year = {2015}
}
@article{Moorman2020,
abstract = {The response of near-Antarctic waters to freshening by increased glacial melt is investigated using a high-resolution (0.1°) global ocean–sea ice model with realistic Antarctic water-mass properties. Two meltwater perturbation experiments are conducted where the ocean model is forced with constant elevated glacial melt rates of 1.5 and 2.8 times the control rate. Within 10 years of the onset of enhanced meltwater forcing, the generation of Antarctic Bottom Water from Dense Shelf Water ceases, as shelf waters become increasingly buoyant. Increased ocean stratification triggers subsurface warming in Dense Shelf Water source regions, suggesting a localized positive feedback to melt. In a parallel response, meltwater forcing enhances the subsurface lateral density gradients of the Antarctic Slope Front that modulate the transport of warm Circumpolar Deep Water across the continental slope toward ice shelf grounding lines. Consequently, coastal freshening acts to isolate the Antarctic Ice Sheet from open ocean heat, suggesting a cooling response to melt that counteracts warming associated with stratification. Further, these strengthening density gradients accelerate westward geostrophic currents along the coast and shelf break, homogenizing shelf waters and amplifying remote feedbacks. The net effect on the continental shelf is transient warming, followed by cooling in both experiments; however, this signal is the aggregate of a complex pattern of regional warming and cooling responses. These results suggest coastal freshening by meltwater may alter the thermal forcing of the Antarctic ice sheet in ways that both accelerate and inhibit ice shelf melt at different locations along the Antarctic coastline.},
author = {Moorman, Ruth and Morrison, Adele K and {McC. Hogg}, Andrew},
doi = {10.1175/JCLI-D-19-0846.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jun},
number = {15},
pages = {6599--6620},
title = {{Thermal Responses to Antarctic Ice Shelf Melt in an Eddy-Rich Global Ocean–Sea Ice Model}},
volume = {33},
year = {2020}
}
@article{Morgenstern2020a,
abstract = {Abstract We assess the effective radiative forcing due to ozone-depleting substances using models participating in the Aerosols and Chemistry and Radiative Forcing Model Intercomparison Projects (AerChemMIP, RFMIP). A large intermodel spread in this globally averaged quantity necessitates an ?emergent constraint? approach whereby we link the radiative forcing to ozone declines measured and simulated during 1979?2000, excluding two volcanically perturbed periods. During this period, ozone-depleting substances were increasing, and several merged satellite-based climatologies document the ensuing decline of total-column ozone. Using these analyses, we find an effective radiative forcing of ?0.05 to 0.13 W m?2. Our best estimate (0.04 W m?2) is on the edge of the ?likely? range given by the Fifth Assessment Report of IPCC of 0.03 to 0.33 W m?2 but is in better agreement with two other literature results.},
annote = {https://doi.org/10.1029/2020GL088295},
author = {Morgenstern, Olaf and O'Connor, Fiona M and Johnson, Ben T and Zeng, Guang and Mulcahy, Jane P and Williams, Jonny and Teixeira, Jo{\~{a}}o and Michou, Martine and Nabat, Pierre and Horowitz, Larry W and Naik, Vaishali and Sentman, Lori T and Deushi, Makoto and Bauer, Susanne E and Tsigaridis, Kostas and Shindell, Drew T and Kinnison, Douglas E},
doi = {10.1029/2020GL088295},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {climate change,emergent constraint,ozone depletion,radiative forcing},
month = {oct},
number = {20},
pages = {e2020GL088295},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Reappraisal of the Climate Impacts of Ozone-Depleting Substances}},
url = {https://doi.org/10.1029/2020GL088295},
volume = {47},
year = {2020}
}
@article{Morgenstern2018,
author = {Morgenstern, O and Stone, K A and Schofield, R and Akiyoshi, H and Yamashita, Y and Kinnison, D E and Garcia, R R and Sudo, K and Plummer, D A and Scinocca, J and Oman, L D and Manyin, M E and Zeng, G and Rozanov, E and Stenke, A and Revell, L E and Pitari, G and Mancini, E and {Di Genova}, G and Visioni, D and Dhomse, S S and Chipperfield, M P},
doi = {10.5194/acp-18-1091-2018},
journal = {Atmospheric Chemistry and Physics},
number = {2},
pages = {1091--1114},
title = {{Ozone sensitivity to varying greenhouse gases and ozone-depleting substances in CCMI-1 simulations}},
volume = {18},
year = {2018}
}
@article{doi:10.1002/2014GL062140,
abstract = {Abstract We assess the roles of long-lived greenhouse gases and ozone depletion in driving meridional surface pressure gradients in the southern extratropics; these gradients are a defining feature of the Southern Annular Mode. Stratospheric ozone depletion is thought to have caused a strengthening of this mode during summer, with increasing long-lived greenhouse gases playing a secondary role. Using a coupled atmosphere-ocean chemistry-climate model, we show that there is cancelation between the direct, radiative effect of increasing greenhouse gases by the also substantial indirect—chemical and dynamical—feedbacks that greenhouse gases have via their impact on ozone. This sensitivity of the mode to greenhouse gas-induced ozone changes suggests that a consistent implementation of ozone changes due to long-lived greenhouse gases in climate models benefits the simulation of this important aspect of Southern Hemisphere climate.},
author = {Morgenstern, Olaf and Zeng, Guang and Dean, Sam M and Joshi, Manoj and Abraham, N Luke and Osprey, Annette},
doi = {10.1002/2014GL062140},
journal = {Geophysical Research Letters},
keywords = {Southern Hemisphere,climate change,greenhouse gas,ozone,regression,southern annular mode},
number = {24},
pages = {9050--9057},
title = {{Direct and ozone-mediated forcing of the Southern Annular Mode by greenhouse gases}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2014GL062140},
volume = {41},
year = {2014}
}
@article{https://doi.org/10.1029/2020JD034161,
abstract = {Abstract I analyze trends in the Southern Annular Mode (SAM) in CMIP6 simulations. For the period 1957–2014, simulated linear trends are generally consistent with two observational references but seasonally in disagreement with two other representations of the SAM. Using a regression analysis applied to model simulations with interactive ozone chemistry, a strengthening of the SAM in summer is attributed nearly completely to ozone depletion because a further strengthening influence due to long-lived greenhouse gases is almost fully counterbalanced by a weakening influence due to stratospheric ozone increases associated with these greenhouse gas increases. Ignoring such ozone feedbacks would yield comparable contributions from these two influences, an incorrect result. In winter, trends are smaller but an influence of greenhouse gas-mediated ozone feedbacks is also identified. The regression analysis furthermore yields significant differences in the attribution of SAM changes to the two influences between models with and without interactive ozone chemistry, with ozone depletion and GHG increases playing seasonally a stronger and weaker, respectively, role in the chemistry models versus the no-chemistry ones.},
annote = {e2020JD034161 2020JD034161},
author = {Morgenstern, O},
doi = {https://doi.org/10.1029/2020JD034161},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {CMIP6,SAM,Southern Annular Mode,attribution,greenhouse gases,ozone},
number = {5},
pages = {e2020JD034161},
title = {{The Southern Annular Mode in 6th Coupled Model Intercomparison Project Models}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020JD034161},
volume = {126},
year = {2021}
}
@article{morice2012quantifying,
author = {Morice, Colin P and Kennedy, John J and Rayner, Nick A and Jones, Phil D},
doi = {10.1029/2011JD017187},
journal = {Journal of Geophysical Research: Atmospheres},
number = {D8},
pages = {D08101},
publisher = {Wiley Online Library},
title = {{Quantifying uncertainties in global and regional temperature change using an ensemble of observational estimates: The HadCRUT4 data set}},
volume = {117},
year = {2012}
}
@article{Mouginot2019,
abstract = {We reconstruct the mass balance of the Greenland Ice Sheet using a comprehensive survey of thickness, surface elevation, velocity, and surface mass balance (SMB) of 260 glaciers from 1972 to 2018. We calculate mass discharge, D, into the ocean directly for 107 glaciers (85{\%} of D) and indirectly for 110 glaciers (15{\%}) using velocity-scaled reference fluxes. The decadal mass balance switched from a mass gain of +47 ± 21 Gt/y in 1972–1980 to a loss of 51 ± 17 Gt/y in 1980–1990. The mass loss increased from 41 ± 17 Gt/y in 1990–2000, to 187 ± 17 Gt/y in 2000–2010, to 286 ± 20 Gt/y in 2010–2018, or sixfold since the 1980s, or 80 ± 6 Gt/y per decade, on average. The acceleration in mass loss switched from positive in 2000–2010 to negative in 2010–2018 due to a series of cold summers, which illustrates the difficulty of extrapolating short records into longer-term trends. Cumulated since 1972, the largest contributions to global sea level rise are from northwest (4.4 ± 0.2 mm), southeast (3.0 ± 0.3 mm), and central west (2.0 ± 0.2 mm) Greenland, with a total 13.7 ± 1.1 mm for the ice sheet. The mass loss is controlled at 66 ± 8{\%} by glacier dynamics (9.1 mm) and 34 ± 8{\%} by SMB (4.6 mm). Even in years of high SMB, enhanced glacier discharge has remained sufficiently high above equilibrium to maintain an annual mass loss every year since 1998.},
author = {Mouginot, J{\'{e}}r{\'{e}}mie and Rignot, Eric and Bj{\o}rk, Anders A and van den Broeke, Michiel and Millan, Romain and Morlighem, Mathieu and No{\"{e}}l, Brice and Scheuchl, Bernd and Wood, Michael},
doi = {10.1073/pnas.1904242116},
issn = {0027-8424},
journal = {Proceedings of the National Academy of Sciences},
month = {may},
number = {19},
pages = {9239--9244},
title = {{Forty-six years of Greenland Ice Sheet mass balance from 1972 to 2018}},
url = {http://www.pnas.org/content/116/19/9239.abstract http://www.pnas.org/lookup/doi/10.1073/pnas.1904242116},
volume = {116},
year = {2019}
}
@article{Munoz2012,
abstract = {This study analyzes important aspects of the tropical Atlantic Ocean from simulations of the fourth version of the Community Climate System Model (CCSM4): the mean sea surface temperature (SST) and wind stress, the Atlantic warm pools, the principal modes of SST variability, and the heat budget in the Benguela region. Themain goal was to assess the similarities and differences between the CCSM4 simulations and observations. The results indicate that the tropical Atlantic overall is realistic in CCSM4. However, there are still significant biases in the CCSM4 Atlantic SSTs, with a colder tropical North Atlantic and a hotter tropical South Atlantic, that are related to biases in the wind stress. These are also reflected in the Atlantic warm pools in April and September, with its volume greater than in observations in April and smaller than in observations in September. The variability of SSTs in the tropicalAtlantic iswell represented inCCSM4.However, in the equatorial and tropical SouthAtlantic regions, CCSM4 has two distinct modes of variability, in contrast to observed behavior. A model heat budget analysis of the Benguela region indicates that the variability of the upper-ocean temperature is dominated by vertical advection, followed by meridional advection. {\textcopyright} 2012 American Meteorological Society.},
author = {Mu{\~{n}}oz, Ernesto and Weijer, Wilbert and Grodsky, Semyon A. and Bates, Susan C. and Wainer, Ilana},
doi = {10.1175/JCLI-D-11-00294.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Atlantic Ocean,Coupled models,Ensembles,Model evaluation/performance,Oceanic variability,Statistics},
month = {jul},
number = {14},
pages = {4860--4882},
title = {{Mean and variability of the tropical Atlantic Ocean in the CCSM4}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-11-00294.1},
volume = {25},
year = {2012}
}
@article{Mudryk2020,
abstract = {This paper presents an analysis of observed and simulated historical snow cover extent and snow mass, along with future snow cover projections from models participating in the World Climate Research Programme Coupled Model Intercomparison Project Phase 6 (CMIP6). Where appropriate, the CMIP6 output is compared to CMIP5 results in order to assess progress (or absence thereof) between successive model generations. An ensemble of six observation-based products is used to produce a new time series of historical Northern Hemisphere snow extent anomalies and trends; a subset of four of these products is used for snow mass. Trends in snow extent over 1981-2018 are negative in all months and exceed-50 × 103 km2 yr-1 during November, December, March, and May. Snow mass trends are approximately-5 Gtyr-1 or more for all months from December to May. Overall, the CMIP6 multi-model ensemble better represents the snow extent climatology over the 1981-2014 period for all months, correcting a low bias in CMIP5. Simulated snow extent and snow mass trends over the 1981-2014 period are stronger in CMIP6 than in CMIP5, although large inter-model spread remains in the simulated trends for both variables. There is a single linear relationship between projected spring snow extent and global surface air temperature (GSAT) changes, which is valid across all CMIP6 Shared Socioeconomic Pathways. This finding suggests that Northern Hemisphere spring snow extent will decrease by about 8 {\%} relative to the 1995-2014 level per degree Celsius of GSAT increase. The sensitivity of snow to temperature forcing largely explains the absence of any climate change pathway dependency, similar to other fast-response components of the cryosphere such as sea ice and near-surface permafrost extent.},
author = {Mudryk, Lawrence and Santolaria-Ot{\'{i}}n, Mar{\'{i}}a and Krinner, Gerhard and M{\'{e}}n{\'{e}}goz, Martin and Derksen, Chris and Brutel-Vuilmet, Claire and Brady, Mike and Essery, Richard},
doi = {10.5194/tc-14-2495-2020},
issn = {19940424},
journal = {Cryosphere},
number = {7},
pages = {2495--2514},
title = {{Historical Northern Hemisphere snow cover trends and projected changes in the CMIP6 multi-model ensemble}},
volume = {14},
year = {2020}
}
@article{Mueller2018b,
abstract = { AbstractThe paper presents results from a climate change detection and attribution study on the decline of Arctic sea ice extent in September for the 1953–2012 period. For this period three independently derived observational datasets and simulations from multiple climate models are available to attribute observed changes in the sea ice extent to known climate forcings. Here we direct our attention to the combined cooling effect from other anthropogenic forcing agents (mainly aerosols), which has potentially masked a fraction of greenhouse gas–induced Arctic sea ice decline. The presented detection and attribution framework consists of a regression model, namely, regularized optimal fingerprinting, where observations are regressed onto model-simulated climate response patterns (i.e., fingerprints). We show that fingerprints from greenhouse gas, natural, and other anthropogenic forcings are detected in the three observed records of Arctic sea ice extent. Beyond that, our findings indicate that for the 1953–2012 period roughly 23{\%} of the greenhouse gas–induced negative sea ice trend has been offset by a weak positive sea ice trend attributable to other anthropogenic forcing. We show that our detection and attribution results remain robust in the presence of emerging nonstationary internal climate variability acting upon sea ice using a perfect model experiment and data from two large ensembles of climate simulations. },
author = {Mueller, B L and Gillett, N P and Monahan, A H and Zwiers, F W},
doi = {10.1175/JCLI-D-17-0552.1},
journal = {Journal of Climate},
number = {19},
pages = {7771--7787},
title = {{Attribution of Arctic Sea Ice Decline from 1953 to 2012 to Influences from Natural, Greenhouse Gas, and Anthropogenic Aerosol Forcing}},
volume = {31},
year = {2018}
}
@article{doi:10.1002/2015GL064583,
abstract = {Abstract Previous Paleoclimate Model Intercomparison Project (PMIP) simulations of the Last Glacial Maximum (LGM) Atlantic Meridional Overturning Circulation (AMOC) showed dissimilar results on transports and structure. Here we analyze the most recent PMIP3 models, which show a consistent increase (on average by 41 ± 26{\%}) and deepening (663 ± 550 m) of the AMOC with respect to preindustrial simulations, in contrast to some reconstructions from proxy data. Simulations run with the University of Victoria (UVic) ocean circulation model suggest that this is caused by changes in the Northern Hemisphere wind stress, brought about by the presence of ice sheets over North America in the LGM. When forced with LGM wind stress anomalies from PMIP3 models, the UVic model responds with an increase of the northward salt transport in the North Atlantic, which strengthens North Atlantic Deep Water formation and the AMOC. These results improve our understanding of the LGM AMOC's driving forces and suggest that some ocean mechanisms may not be correctly represented in PMIP3 models or some proxy data may need reinterpretation.},
author = {Muglia, Juan and Schmittner, Andreas},
doi = {10.1002/2015GL064583},
journal = {Geophysical Research Letters},
keywords = {AMOC,PMIP3,circulation,glacial},
number = {22},
pages = {9862--9868},
title = {{Glacial Atlantic overturning increased by wind stress in climate models}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2015GL064583},
volume = {42},
year = {2015}
}
@article{gmd-2019-357,
author = {Mulcahy, Jane P and Johnson, Colin and Jones, Colin G. and Povey, Adam C and Scott, Catherine E and Sellar, Alistair and Turnock, Steven T and Woodhouse, Matthew T and Abraham, Nathan Luke and Andrews, Martin B and Bellouin, Nicolas and Browse, Jo and Carslaw, Ken S and Dalvi, Mohit and Folberth, Gerd A and Glover, Matthew and Grosvenor, Daniel P. and Hardacre, Catherine and Hill, Richard and Johnson, Ben and Jones, Andy and Kipling, Zak and Mann, Graham and Mollard, James and O'Connor, Fiona M and Palmi{\'{e}}ri, Julien and Reddington, Carly and Rumbold, Steven T and Richardson, Mark and Schutgens, Nick A J and Stier, Philip and Stringer, Marc and Tang, Yongming and Walton, Jeremy and Woodward, Stephanie and Yool, Andrew},
doi = {10.5194/gmd-13-6383-2020},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {dec},
number = {12},
pages = {6383--6423},
title = {{Description and evaluation of aerosol in UKESM1 and HadGEM3-GC3.1 CMIP6 historical simulations}},
url = {https://gmd.copernicus.org/articles/13/6383/2020/},
volume = {13},
year = {2020}
}
@article{doi:10.1002/2016GL071337,
abstract = {Abstract We analyze the Atlantic multidecadal oscillation (AMO) in the preindustrial (PI) and historical (HIST) simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) to assess the drivers of the observed AMO from 1865 to 2005. We draw 141 year samples from the 41 CMIP5 model's PI runs and compare the correlation and variance between the observed AMO and the simulated PI and HIST AMO. The correlation coefficients in 38 forced (HIST) models are above the 90{\%} confidence level and explain up to 56{\%} of the observed variance. The probability that any of the unforced (PI) models do as well is less than 3{\%} in 31 models. Multidecadal variability is larger in 39 CMIP5 HIST simulations and in all HIST members of the Community Earth System Model Large Ensemble than their corresponding PI. We conclude that there is an essential role for external forcing in driving the observed AMO.},
author = {Murphy, Lisa N and Bellomo, Katinka and Cane, Mark and Clement, Amy},
doi = {10.1002/2016GL071337},
journal = {Geophysical Research Letters},
keywords = {Atlantic multidecadal oscillation,CESM-LE,CMIP5},
number = {5},
pages = {2472--2480},
title = {{The role of historical forcings in simulating the observed Atlantic multidecadal oscillation}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2016GL071337},
volume = {44},
year = {2017}
}
@article{Murphy2013,
author = {Murphy, D M},
doi = {10.1038/ngeo1740},
journal = {Nature Geoscience},
month = {mar},
pages = {258},
publisher = {Nature Publishing Group},
title = {{Little net clear-sky radiative forcing from recent regional redistribution of aerosols}},
url = {http://dx.doi.org/10.1038/ngeo1740 http://10.0.4.14/ngeo1740 https://www.nature.com/articles/ngeo1740{\#}supplementary-information},
volume = {6},
year = {2013}
}
@article{Najafi2016,
abstract = {While it is generally accepted that the observed reduction of the Northern Hemisphere spring snow cover extent (SCE) is linked to warming of the climate system caused by human induced greenhouse gas emissions, it has been difficult to robustly quantify the anthropogenic contribution to the observed change. This study addresses the challenge by undertaking a formal detection and attribution analysis of SCE changes based on several observational datasets with different structural characteristics, in order to account for the substantial observational uncertainty. The datasets considered include a blended in situ-satellite dataset extending from 1923 to 2012 (Brown), the National Oceanic and Atmospheric Administration (NOAA) snow chart Climate Data Record for 1968--2012, the Global Land Data Assimilation System version 2.0 (GLDAS-2 Noah) reanalysis for 1951--2010, and the NOAA 20th-century reanalysis, version 2 (20CR2) covering 1948--2012. We analyse observed early spring (March-April) and late spring (May-June) NH SCE extent changes in these datasets using climate simulations of the responses to anthropogenic and natural forcings combined (ALL) and to natural forcings alone (NAT) from the Coupled Model Intercomparison Project Phase 5 (CMIP5). The ALL-forcing response is detected in all of the observed records, indicating that observed changes are inconsistent with internal variability. The analysis also shows that the ALL-forcing simulations substantially underestimate the observed changes as recorded in the Brown and NOAA datasets, but that they are more consistent with changes seen in the GLDAS and 20CR2 reanalyses. A two-signal analysis of the GLDAS data is able to detect the influence of the anthropogenic component of the observed SCE changes separately from the effect of natural forcing. Despite dataset and modelling uncertainty, these results, together with the understanding of the causes of observed warming over the past century, provide substantial evidence of a human contribution to the observed decline in Northern Hemisphere spring snow cover extent.},
author = {Najafi, Mohammad Reza and Zwiers, Francis W and Gillett, Nathan P},
doi = {10.1007/s10584-016-1632-2},
issn = {1573-1480},
journal = {Climatic Change},
month = {jun},
number = {3},
pages = {571--586},
title = {{Attribution of the spring snow cover extent decline in the Northern Hemisphere, Eurasia and North America to anthropogenic influence}},
url = {https://doi.org/10.1007/s10584-016-1632-2},
volume = {136},
year = {2016}
}
@article{najafi2017attribution,
author = {Najafi, Mohammad Reza and Zwiers, Francis W and Gillett, Nathan P},
doi = {10.1002/2017GL075016},
journal = {Geophysical Research Letters},
number = {21},
pages = {11--12},
publisher = {Wiley Online Library},
title = {{Attribution of observed streamflow changes in key British Columbia drainage basins}},
volume = {44},
year = {2017}
}
@article{Nakamura2015,
abstract = {Abstract This paper examines the possible linkage between the recent reduction in Arctic sea-ice extent and the wintertime Arctic Oscillation (AO)/North Atlantic Oscillation (NAO). Observational analyses using the ERA interim reanalysis and merged Hadley/Optimum Interpolation Sea Surface Temperature data reveal that a reduced (increased) sea-ice area in November leads to more negative (positive) phases of the AO and NAO in early and late winter, respectively. We simulate the atmospheric response to observed sea-ice anomalies using a high-top atmospheric general circulation model (AGCM for Earth Simulator, AFES version 4.1). The results from the simulation reveal that the recent Arctic sea-ice reduction results in cold winters in mid-latitude continental regions, which are linked to an anomalous circulation pattern similar to the negative phase of AO/NAO with an increased frequency of large negative AO events by a factor of over two. Associated with this negative AO/NAO phase, cold air advection from the Arctic to the mid-latitudes increases. We found that the stationary Rossby wave response to the sea-ice reduction in the Barents Sea region induces this anomalous circulation. We also found a positive feedback mechanism resulting from the anomalous meridional circulation that cools the mid-latitudes and warms the Arctic, which adds an extra heating to the Arctic air column equivalent to about 60{\%} of the direct surface heat release from the sea-ice reduction. The results from this high-top model experiment also suggested a critical role of the stratosphere in deepening the tropospheric annular mode and modulation of the NAO in mid to late winter through stratosphere-troposphere coupling.},
annote = {Arctic sea ice-atmos impact
Obs: Hurrell SST{\&}SIC, ERA-interim, 1979-2012, detrended
Model: AFES4.1 {\ldots} Prescribe sea ice thickness (SIT) while sea ice fraction is 0 or 1
- CNTL: 60-member, SST and SIT from 1979-1983 clim
- N.ICE: 60-member, SST from 1979-1983 cim, SIT from 2005-2009 clim
Both fixed radiative forcing agents

- Obs regression against sea ice area (SIA) loss in Nov: Negative NAM with clear NAO signal in SLP/z500 from fall, becomes stronger and peaks in DJF/JFM, and rapidly disappear in FMA
- Model N.ICE-CNTL: Similar nagative NAM/NAO response, peaks in DJF/JDM
- In model, upward propagation of stationary Rossby wave in response to sea ice loss -{\textgreater} Changes meridional overturning circulation -{\textgreater} signal propagates downward to the troposphere in mid-/late winter
- Modulations of PDF of NAM index without chaging the spatial z500 anomaly structure},
author = {Nakamura, Tetsu and Yamazaki, Koji and Iwamoto, Katsushi and Honda, Meiji and Miyoshi, Yasunobu and Ogawa, Yasunobu and Ukita, Jinro},
doi = {10.1002/2014JD022848},
issn = {2169-897X},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {Arctic Oscillation,Arctic sea-ice loss,long-term changes,severe winter},
month = {mar},
number = {8},
pages = {3209--3227},
publisher = {Wiley-Blackwell},
title = {{A negative phase shift of the winter AO/NAO due to the recent Arctic sea-ice reduction in late autumn}},
url = {https://doi.org/10.1002/2014JD022848},
volume = {120},
year = {2015}
}
@article{Neukom2018,
abstract = {Model simulations and proxy-based reconstructions are the main tools for quantifying pre-instrumental climate variations. For some metrics such as Northern Hemisphere mean temperatures, there is remarkable agreement between models and reconstructions. For other diagnostics, such as the regional response to volcanic eruptions, or hemispheric temperature differences, substantial disagreements between data and models have been reported. Here, we assess the potential sources of these discrepancies by comparing 1000-year hemispheric temperature reconstructions based on real-world paleoclimate proxies with climate-model-based pseudoproxies. These pseudoproxy experiments (PPE) indicate that noise inherent in proxy records and the unequal spatial distribution of proxy data are the key factors in explaining the data-model differences. For example, lower inter-hemispheric correlations in reconstructions can be fully accounted for by these factors in the PPE. Noise and data sampling also partly explain the reduced amplitude of the response to external forcing in reconstructions compared to models. For other metrics, such as inter-hemispheric differences, some, although reduced, discrepancy remains. Our results suggest that improving proxy data quality and spatial coverage is the key factor to increase the quality of future climate reconstructions, while the total number of proxy records and reconstruction methodology play a smaller role.},
author = {Neukom, Raphael and Schurer, Andrew P and Steiger, Nathan. J and Hegerl, Gabriele C},
doi = {10.1038/s41598-018-25862-2},
issn = {2045-2322},
journal = {Scientific Reports},
number = {1},
pages = {7572},
title = {{Possible causes of data model discrepancy in the temperature history of the last Millennium}},
url = {https://doi.org/10.1038/s41598-018-25862-2},
volume = {8},
year = {2018}
}
@article{Nevison2016,
author = {Nevison, C. D. and Manizza, M. and Keeling, R. F. and Stephens, B. B. and Bent, J. D. and Dunne, J. and Ilyina, T. and Long, M. and Resplandy, L. and Tjiputra, J. and Yukimoto, S.},
doi = {10.1002/2015GL067584},
issn = {00948276},
journal = {Geophysical Research Letters},
keywords = {APO,CMIP5 models,Southern Ocean carbon cycle,air‐sea fluxes,carbon cycle,ocean carbon sink},
month = {mar},
number = {5},
pages = {2077--2085},
publisher = {Wiley-Blackwell},
title = {{Evaluating CMIP5 ocean biogeochemistry and Southern Ocean carbon uptake using atmospheric potential oxygen: Present-day performance and future projection}},
url = {http://doi.wiley.com/10.1002/2015GL067584},
volume = {43},
year = {2016}
}
@article{Newman2016a,
abstract = {In review},
author = {Newman, Matthew and Alexander, Michael A. and Ault, Toby R. and Cobb, Kim M. and Deser, Clara and {Di Lorenzo}, Emanuele and Mantua, Nathan J. and Miller, Arthur J. and Minobe, Shoshiro and Nakamura, Hisashi and Schneider, Niklas and Vimont, Daniel J. and Phillips, Adam S. and Scott, James D. and Smith, Catherine A.},
doi = {10.1175/JCLI-D-15-0508.1},
isbn = {0916-8370},
issn = {08948755},
journal = {Journal of Climate},
number = {12},
pages = {4399--4427},
pmid = {4},
title = {{The Pacific decadal oscillation, revisited}},
volume = {29},
year = {2016}
}
@article{Newman2011b,
abstract = {Using a multivariate, “patterns-based”, red noise approach to 42 years of observed tropical SST, thermocline depth, and zonal wind stress seasonal anomalies, it is shown that natural random variations can account for the observed variability of Central Pacific (CP) and Eastern Pacific (EP) ENSO events. The recent multidecadal increase in the number of CP events relative to EP events, which has been hypothesized to be connected to anthropogenic change in the state of the ocean, is also found to be consistent with multivariate red noise and hence with stationary statistics. ENSO “flavors” are the consequence of differing combinations of two initially orthogonal spatial patterns that are precursors to CP or EP events of both signs. These precursors can be excited by random weather forcing and subsequently result in SST anomaly amplification primarily through surface or thermocline feedbacks, respectively.},
author = {Newman, Matthew and Shin, Sang-Ik and Alexander, Michael A},
doi = {10.1029/2011GL047658},
journal = {Geophysical Research Letters},
number = {14},
pages = {L14705},
title = {{Natural variation in ENSO flavors}},
volume = {38},
year = {2011}
}
@article{Nguyen2015,
abstract = {Changes of the Southern Hemisphere Hadley cell over the twentieth century are investigated using the Twentieth Century Reanalysis (20CR) and coupled model simulations from phase 5 of the Coupled Model Intercomparison Project (CMIP5). Trends computed on a 30-yr sliding window on the 20CR dataset reveal a statistically significant expansion of the Hadley cell from 1968 forced by an increasing surface global warming. This expansion is strongly associated with the intensification and poleward shift of the subtropical dry zone, which potentially explain the increasing trends of droughts in the subtropical regions such as southern Australia, South America, and Africa. Coupled models from the CMIP5 do not adequately simulate the observed amount of the Hadley expansion, only showing an average of one-fourth of the expansion as determined from the 20CR and only when simulations include greenhouse gas forcing as opposed to simulations including natural forcing only.},
annote = {Zonal mean Hadley circulation and subtropical high in SH
20CR, HadSLP2
CMIP5 historical, historicalGHG (half models include ozone), historicalNat
Hadley cell extent: Zero lat of meridional streamfunction 400-600hPa
Hadley cell intensity: Peak merdional streamfunction b/2 900 and 200 hPa
Subtropical high position: Latitude of max SLP
Subtropical high intensity:  Max SLP
30-year running least-square trend

- Statistically significant Hadley cell expansion since 1968, accompanied by intensification and poleward shift of subtropical high
- In models, GHG increase and ozone depletion contributes to the expansion but models still  underestimate the expansion},
author = {Nguyen, H. and Lucas, C. and Evans, A. and Timbal, B. and Hanson, L.},
doi = {10.1175/JCLI-D-15-0139.1},
isbn = {0894-8755},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Atmospheric circulation,Circulation/Dynamics,Coupled models,Models and modeling,Reanalysis data,Trends,Variability},
number = {20},
pages = {8067--8077},
title = {{Expansion of the Southern Hemisphere Hadley Cell in Response to Greenhouse Gas Forcing}},
volume = {28},
year = {2015}
}
@article{Ni2018b,
author = {Ni, Yan and Hsu, Pang-Chi},
doi = {10.1002/joc.5704},
issn = {08998418},
journal = {International Journal of Climatology},
month = {nov},
number = {13},
pages = {4875--4890},
title = {{Inter-annual variability of global monsoon precipitation in present-day and future warming scenarios based on 33 Coupled Model Intercomparison Project Phase 5 models}},
url = {http://doi.wiley.com/10.1002/joc.5704},
volume = {38},
year = {2018}
}
@article{Nidheesh2017c,
author = {Nidheesh, A. G. and Lengaigne, Matthieu and Vialard, J{\'{e}}r{\^{o}}me and Izumo, Takeshi and Unnikrishnan, A. S. and Cassou, Christophe},
doi = {10.1007/s00382-016-3514-8},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {nov},
number = {9-10},
pages = {3309--3326},
title = {{Influence of ENSO on the Pacific decadal oscillation in CMIP models}},
volume = {49},
year = {2017}
}
@article{Nieves532,
abstract = {Global warming apparently slowed, or even stopped, during the first decade of the 21st century. This pause is commonly called the {\{}$\backslash$textquotedblleft{\}}hiatus.{\{}$\backslash$textquotedblright{\}} We know, however, that Earth{\{}$\backslash$textquoteright{\}}s climate system is accumulating excess solar energy owing to the build-up of greenhouse gases in the atmosphere. Where, then, has this energy gone if not into the air? Nieves et al. find that over this period, the surface Pacific Ocean has cooled but the upper Indian and Southern Oceans have warmed. Thus, the decade-long hiatus that began in 2003 would appear to be the result of a redistribution of heat within the ocean, rather than a change in the whole-Earth warming rate.Science, this issue p. 532Recent modeling studies have proposed different scenarios to explain the slowdown in surface temperature warming in the most recent decade. Some of these studies seem to support the idea of internal variability and/or rearrangement of heat between the surface and the ocean interior. Others suggest that radiative forcing might also play a role. Our examination of observational data over the past two decades shows some significant differences when compared to model results from reanalyses and provides the most definitive explanation of how the heat was redistributed. We find that cooling in the top 100-meter layer of the Pacific Ocean was mainly compensated for by warming in the 100- to 300-meter layer of the Indian and Pacific Oceans in the past decade since 2003.},
author = {Nieves, Veronica and Willis, Josh K and Patzert, William C},
doi = {10.1126/science.aaa4521},
issn = {0036-8075},
journal = {Science},
number = {6247},
pages = {532--535},
publisher = {American Association for the Advancement of Science},
title = {{Recent hiatus caused by decadal shift in Indo-Pacific heating}},
url = {http://science.sciencemag.org/content/349/6247/532},
volume = {349},
year = {2015}
}
@article{Nijsse2020,
abstract = {Climate sensitivity to CO2remains the key uncertainty in projections of future climate change. Transient climate response (TCR) is the metric of temperature sensitivity that is most relevant to warming in the next few decades and contributes the biggest uncertainty to estimates of the carbon budgets consistent with the Paris targets. Equilibrium climate sensitivity (ECS) is vital for understanding longer-term climate change and stabilisation targets. In the IPCC 5th Assessment Report (AR5), the stated "likely" ranges (16 {\%}-84{\%} confidence) of TCR (1.0-2.5 K) and ECS (1.5-4.5 K) were broadly consistent with the ensemble of CMIP5 Earth system models (ESMs) available at the time. However, many of the latest CMIP6 ESMs have larger climate sensitivities, with 5 of 34 models having TCR values above 2.5K and an ensemble mean TCR of 2.0-0.4 K. Even starker, 12 of 34 models have an ECS value above 4.5 K. On the face of it, these latest ESM results suggest that the IPCC likely ranges may need revising upwards, which would cast further doubt on the feasibility of the Paris targets. Here we show that rather than increasing the uncertainty in climate sensitivity, the CMIP6 models help to constrain the likely range of TCR to 1.3-2.1 K, with a central estimate of 1.68 K. We reach this conclusion through an emergent constraint approach which relates the value of TCR linearly to the global warming from 1975 onwards. This is a period when the signal-to-noise ratio of the net radiative forcing increases strongly, so that uncertainties in aerosol forcing become progressively less problematic. We find a consistent emergent constraint on TCR when we apply the same method to CMIP5 models. Our constraints on TCR are in good agreement with other recent studies which analysed CMIP ensembles. The relationship between ECS and the post-1975 warming trend is less direct and also non-linear. However, we are able to derive a likely range of ECS of 1.9-3.4K from the CMIP6 models by assuming an underlying emergent relationship based on a two-box energy balance model. Despite some methodological differences; this is consistent with a previously published ECS constraint derived from warming trends in CMIP5 models to 2005. Our results seem to be part of a growing consensus amongst studies that have applied the emergent constraint approach to different model ensembles and to different aspects of the record of global warming},
author = {Nijsse, Femke J.M.M. and Cox, Peter M. and Williamson, Mark S.},
doi = {10.5194/esd-11-737-2020},
issn = {21904987},
journal = {Earth System Dynamics},
number = {3},
pages = {737--750},
title = {{Emergent constraints on transient climate response (TCR) and equilibrium climate sensitivity (ECS) from historical warming in CMIP5 and CMIP6 models}},
volume = {11},
year = {2020}
}
@article{Ning2016,
abstract = {The historical and future relationships between two major patterns of large-scale climate variability, the North Atlantic Oscillation (NAO) and the Pacific/North America pattern (PNA), and the regional winter temperature and precipitation over the eastern United States were systemically evaluated by using 17 general circulation models (GCMs) from the Coupled Model Intercomparison Project phase 5. Empirical orthogonal function analysis was used to define the NAO and PNA. The observed spatial patterns of NAO and PNA can be reproduced by all the GCMs with slight differences in locations of the centers of action and their average magnitudes. For the correlations with regional winter temperature and precipitation over the eastern US, GCMs perform best in capturing the relationships between the NAO and winter temperature, and between the PNA and winter temperature and precipitation. The differences between the observed and simulated relationships are mainly due to displacements of the simulated NAO and PNA centers of action and differences in their magnitudes. In simulations of the future, both NAO and PNA magnitudes increase, with uncertainties related to the model response and emission scenarios. When assessing the influences of future NAO/PNA changes on regional winter temperature, it is found that the main factors are related to changes in the magnitude of the NAO Azores center and total NAO magnitude, and the longitude of the PNA center over northwestern North America, total PNA magnitude, and the magnitude of the PNA center over the southeastern US.},
annote = {Model reproduction of NAO and PNA and their regional impacts on North America, and future modulations
- CMIP5 historical and RCP2.6, 4.5, 8.5
- NCEP/NCAR, with CRU TS3.21
- DJFM, 1950-1999 and 2050-2099

- NAO: EOF1 of SLP over the North Atlantic sector
{\ldots} Most of the models repoduces the SLP anomaly pattern, with understimated magnitude of the subtropical center
Most of the models can simulate winter temperature anomalies over the eastern US
- PNA: EOF1 of z500 over the Noth Pacific-North American sector
{\ldots} Models reproduces the z500 anomaly pattern well
Most of the models simulate the dipolar temperature anomalies b/w northwestern North America and the southerastern US
- Biases in impact patterns are consistent with biases in circulation pattern

- Future change in the patterns and impacts},
author = {Ning, Liang and Bradley, Raymond S},
doi = {10.1007/s00382-015-2643-9},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {3},
pages = {1257--1276},
title = {{NAO and PNA influences on winter temperature and precipitation over the eastern United States in CMIP5 GCMs}},
url = {https://doi.org/10.1007/s00382-015-2643-9},
volume = {46},
year = {2016}
}
@article{Nnamchi2015,
author = {Nnamchi, Hyacinth C. and Li, Jianping and Kucharski, Fred and Kang, In-Sik and Keenlyside, Noel S. and Chang, Ping and Farneti, Riccardo},
doi = {10.1038/ncomms9895},
issn = {2041-1723},
journal = {Nature Communications},
month = {dec},
number = {1},
pages = {8895},
title = {{Thermodynamic controls of the Atlantic Ni{\~{n}}o}},
url = {http://www.nature.com/articles/ncomms9895},
volume = {6},
year = {2015}
}
@article{Notz,
abstract = {We examine CMIP6 simulations of Arctic sea‐ice area and volume. We find that CMIP6 models produce a wide spread of mean Arctic sea‐ice area, capturing the observational estimate within the multimodel ensemble spread. The CMIP6 multimodel ensemble mean provides a more realistic estimate of the sensitivity of September Arctic sea‐ice area to a given amount of anthropogenic CO2 emissions and to a given amount of global warming, compared with earlier CMIP experiments. Still, most CMIP6 models fail to simulate at the same time a plausible evolution of sea‐ice area and of global mean surface temperature. In the vast majority of the available CMIP6 simulations, the Arctic Ocean becomes practically sea‐ice free (sea‐ice area {\textless}1 × 106 km2) in September for the first time before the Year 2050 in each of the four emission scenarios SSP1‐1.9, SSP1‐2.6, SSP2‐4.5, and SSP5‐8.5 examined here.},
author = {Notz, Dirk and D{\"{o}}rr, Jakob and Bailey, David A. and Blockley, Ed and Bushuk, Nitchell and Debernard, Jens Boldingh and Dekker, Evelien and DeRepentigny, Patricia and Docquier, David and Fuckar, Neven S. and Fyfe, John C. and Jahn, Alexandra and Holland, Marika and Hunke, Elizabeth and Iovino, Doroteaciro and Khosravi, Narges and Massonnet, Francois and Madec, Gurvan and O'Farrell, Siobhan and Petty, Alek and Rana, Arun and Roach, Lettie and Rosenblum, Erica and Rousset, Clement and Semmler, Tido and Stroeve, Julienne and Tremblay, Bruno and Toyoda, Takahiro and Tsujino, Hiroyuki and Vancoppenolle, Martin},
doi = {10.1029/2019GL086749},
journal = {Geophysical Research Letters},
number = {10},
pages = {e2019GL086749},
title = {{Arctic Sea Ice in CMIP6}},
url = {https://doi.org/10.1029/2019GL086749},
volume = {47},
year = {2020}
}
@article{doi:10.1029/2012GL051094,
abstract = {The very low summer extent of Arctic sea ice that has been observed in recent years is often casually interpreted as an early-warning sign of anthropogenic global warming. For examining the validity of this claim, previously IPCC model simulations have been used. Here, we focus on the available observational record to examine if this record allows us to identify either internal variability, self-acceleration, or a specific external forcing as the main driver for the observed sea-ice retreat. We find that the available observations are sufficient to virtually exclude internal variability and self-acceleration as an explanation for the observed long-term trend, clustering, and magnitude of recent sea-ice minima. Instead, the recent retreat is well described by the superposition of an externally forced linear trend and internal variability. For the externally forced trend, we find a physically plausible strong correlation only with increasing atmospheric CO2concentration. Our results hence show that the observed evolution of Arctic sea-ice extent is consistent with the claim that virtually certainly the impact of an anthropogenic climate change is observable in Arctic sea ice already today.},
author = {Notz, Dirk and Marotzke, Jochem},
doi = {10.1029/2012GL051094},
journal = {Geophysical Research Letters},
keywords = {anthropogenic climate change,attribution,measurements,sea ice},
number = {8},
pages = {L08502},
title = {{Observations reveal external driver for Arctic sea-ice retreat}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2012GL051094},
volume = {39},
year = {2012}
}
@article{Notz747,
abstract = {Arctic sea ice is disappearing rapidly, leading to predictions of an ice-free summer in the near future. Simulations of the timing of summer sea-ice loss differ substantially, making it difficult to evaluate the pace of the loss. Notz and Stroeve observed a linear relationship between the monthly-mean September sea-ice area and cumulative CO2 emissions. This allowed them to predict Arctic summer sea ice directly from the observational record. Interestingly, most models underestimate this loss.Science, this issue p. 747Arctic sea ice is retreating rapidly, raising prospects of a future ice-free Arctic Ocean during summer. Because climate-model simulations of the sea-ice loss differ substantially, we used a robust linear relationship between monthly-mean September sea-ice area and cumulative carbon dioxide (CO2) emissions to infer the future evolution of Arctic summer sea ice directly from the observational record. The observed linear relationship implies a sustained loss of 3 {\{}$\backslash$textpm{\}} 0.3 square meters of September sea-ice area per metric ton of CO2 emission. On the basis of this sensitivity, Arctic sea ice will be lost throughout September for an additional 1000 gigatons of CO2 emissions. Most models show a lower sensitivity, which is possibly linked to an underestimation of the modeled increase in incoming longwave radiation and of the modeled transient climate response.},
author = {Notz, Dirk and Stroeve, Julienne},
doi = {10.1126/science.aag2345},
issn = {0036-8075},
journal = {Science},
number = {6313},
pages = {747--750},
publisher = {American Association for the Advancement of Science},
title = {{Observed Arctic sea-ice loss directly follows anthropogenic CO2 emission}},
url = {http://science.sciencemag.org/content/354/6313/747},
volume = {354},
year = {2016}
}
@article{tc-8-229-2014,
author = {Notz, D},
doi = {10.5194/tc-8-229-2014},
journal = {The Cryosphere},
number = {1},
pages = {229--243},
title = {{Sea-ice extent and its trend provide limited metrics of model performance}},
url = {https://tc.copernicus.org/articles/8/229/2014/},
volume = {8},
year = {2014}
}
@article{Nowicki2016,
abstract = {Reducing the uncertainty in the past, present, and future contribution of ice sheets to sea-level change requires a coordinated effort between the climate and glaciology communities. The Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6) is the primary activity within the Coupled Model Intercomparison Project {\&}ndash; phase 6 (CMIP6) focusing on the Greenland and Antarctic ice sheets. In this paper, we describe the framework for ISMIP6 and its relationship with other activities within CMIP6. The ISMIP6 experimental design relies on CMIP6 climate models and includes, for the first time within CMIP, coupled ice-sheet{\&}ndash;climate models as well as standalone ice-sheet models. To facilitate analysis of the multi-model ensemble and to generate a set of standard climate inputs for standalone ice-sheet models, ISMIP6 defines a protocol for all variables related to ice sheets. ISMIP6 will provide a basis for investigating the feedbacks, impacts, and sea-level changes associated with dynamic ice sheets and for quantifying the uncertainty in ice-sheet-sourced global sea-level change.},
author = {Nowicki, Sophie M. J. and Payne, Anthony and Larour, Eric and Seroussi, Helene and Goelzer, Heiko and Lipscomb, William and Gregory, Jonathan and Abe-Ouchi, Ayako and Shepherd, Andrew},
doi = {10.5194/gmd-9-4521-2016},
isbn = {1991-9603},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {dec},
number = {12},
pages = {4521--4545},
title = {{Ice Sheet Model Intercomparison Project (ISMIP6) contribution to CMIP6}},
url = {https://www.geosci-model-dev.net/9/4521/2016/ http://www.geosci-model-dev.net/9/4521/2016/},
volume = {9},
year = {2016}
}
@article{Nowicki2018,
author = {Nowicki, Sophie M.J. and Seroussi, Helene},
doi = {10.5670/oceanog.2018.216},
issn = {10428275},
journal = {Oceanography},
month = {jun},
number = {2},
pages = {109--117},
title = {{Projections of Future Sea Level Contributions from the Greenland and Antarctic Ice Sheets: Challenges Beyond Dynamical Ice Sheet Modeling}},
url = {https://tos.org/oceanography/article/projections-of-future-sea-level-contributions-from-the-greenland-and-antarc},
volume = {31},
year = {2018}
}
@article{OReilly2016b,
author = {O'Reilly, Christopher H. and Huber, Markus and Woollings, Tim and Zanna, Laure},
doi = {10.1002/2016GL067925},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {mar},
number = {6},
pages = {2810--2818},
title = {{The signature of low‐frequency oceanic forcing in the Atlantic Multidecadal Oscillation}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2016GL067925},
volume = {43},
year = {2016}
}
@article{OReilly2019,
author = {O'Reilly, Christopher H. and Weisheimer, Antje and Woollings, Tim and Gray, Lesley J. and MacLeod, Dave},
doi = {10.1002/qj.3413},
issn = {00359009},
journal = {Quarterly Journal of the Royal Meteorological Society},
month = {jan},
number = {718},
pages = {131--146},
title = {{The importance of stratospheric initial conditions for winter North Atlantic Oscillation predictability and implications for the signal-to-noise paradox}},
url = {http://doi.wiley.com/10.1002/qj.3413},
volume = {145},
year = {2019}
}
@article{OReilly2019b,
abstract = {Atlantic multidecadal variability (AMV) of sea surface temperature exhibits an important influence on the climate of surrounding continents. It remains unclear, however, the extent to which AMV is due to internal climate variability (e.g., ocean circulation variability) or changes in external forcing (e.g., volcanic/anthropogenic aerosols or greenhouse gases). Here, the sources of AMV are examined over a 340-yr period using proxy indices, instrumental data, and output from the Last Millennium Ensemble (LME) simulation. The proxy AMV closely follows the accumulated atmospheric forcing from the instrumental North Atlantic Oscillation (NAO) reconstruction ( r = 0.65)—an “internal” source of AMV. This result provides strong observational evidence that much of the AMV is generated through the oceanic response to atmospheric circulation forcing, as previously demonstrated in targeted modeling studies. In the LME there is a substantial externally forced AMV component, which exhibits a modest but significant correlation with the proxy AMV (i.e., r = 0.37), implying that at least 13{\%} of the AMV is externally forced. In the LME simulations, however, the AMV response to accumulated NAO forcing is weaker than in the proxy/observational datasets. This weak response is possibly related to the decadal NAO variability, which is substantially weaker in the LME than in observations. The externally forced component in the proxy AMV is also related to the accumulated NAO forcing, unlike in the LME. This indicates that the external forcing is likely influencing the AMV through different mechanistic pathways: via changes in radiative forcing in the LME and via changes in atmospheric circulation in the observational/proxy record.},
author = {O'Reilly, Christopher H. and Zanna, Laure and Woollings, Tim},
doi = {10.1175/JCLI-D-19-0177.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {nov},
number = {22},
pages = {7727--7745},
title = {{Assessing External and Internal Sources of Atlantic Multidecadal Variability Using Models, Proxy Data, and Early Instrumental Indices}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-19-0177.1},
volume = {32},
year = {2019}
}
@article{OReilly2016c,
abstract = {Wintertime blocking is responsible for extended periods of anomalously cold and dry weather over Europe. In this study, the influence of the Gulf Stream sea surface temperature (SST) front on wintertime European blocking is investigated using a reanalysis dataset and a pair of atmospheric general circulation model (AGCM) simulations. The AGCM is forced with realistic and smoothed Gulf Stream SST, and blocking frequency over Europe is found to depend crucially on the Gulf Stream SST front. In the absence of the sharp SST gradient European blocking is significantly reduced and occurs further downstream. The Gulf Stream is found to significantly influence the surface temperature anomalies during blocking periods and the occurrence of associated cold spells. In particular the cold spell peak, located in central Europe, disappears in the absence of the Gulf Stream SST front. The nature of the Gulf Stream influence on European blocking development is then investigated using composite analysis. The presence of the Gulf Stream SST front is important in capturing the observed quasi-stationary development of European blocking. The development is characterised by increased lower-tropospheric meridional eddy heat transport in the Gulf Stream region and increased eddy kinetic energy at upper-levels, which acts to reinforce the quasi-stationary jet. When the Gulf Stream SST is smoothed the storm track activity is weaker, the development is less consistent and European blocking occurs less frequently.},
author = {O'Reilly, Christopher H and Minobe, Shoshiro and Kuwano-Yoshida, Akira},
doi = {10.1007/s00382-015-2919-0},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {5},
pages = {1545--1567},
title = {{The influence of the Gulf Stream on wintertime European blocking}},
url = {https://doi.org/10.1007/s00382-015-2919-0},
volume = {47},
year = {2016}
}
@article{Ogata2017,
author = {Ogata, Tomomichi and Johnson, Stephanie J. and Schiemann, Reinhard and Demory, Marie-Estelle and Mizuta, Ryo and Yoshida, Kohei and {Osamu Arakawa}},
doi = {10.1007/s00382-016-3517-5},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {nov},
number = {9-10},
pages = {3345--3361},
title = {{The resolution sensitivity of the Asian summer monsoon and its inter-model comparison between MRI-AGCM and MetUM}},
url = {http://link.springer.com/10.1007/s00382-016-3517-5},
volume = {49},
year = {2017}
}
@article{Ogawa2015,
author = {Ogawa, Fumiaki and Omrani, Nour-Eddine and Nishii, Kazuaki and Nakamura, Hisashi and Keenlyside, Noel},
doi = {10.1002/2015GL066538},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {nov},
number = {22},
pages = {10056--10063},
title = {{Ozone-induced climate change propped up by the Southern Hemisphere oceanic front}},
url = {http://doi.wiley.com/10.1002/2015GL066538},
volume = {42},
year = {2015}
}
@article{Ohba2009,
abstract = {Abstract Physical processes that are responsible for the asymmetric transition processes between El Ni{\~{n}}o and La Ni{\~{n}}a events are investigated by using observational data and physical models to examine the nonlinear atmospheric response to SST. The air?sea coupled system of ENSO is able to remain in a weak, cold event for up to 2 yr, while the system of a relatively warm event turns into a cold phase. Through analysis of the oceanic observational data, it is found that there is a strong difference in thermocline variations in relation to surface zonal wind anomalies in the equatorial Pacific (EP) during the mature-to-decaying phase of ENSO. The atmospheric response for the warm phase of ENSO causes a rapid reduction of the EP westerlies in boreal winter, which play a role in hastening the following ENSO transition through the generation of upwelling oceanic Kelvin waves. However, the anomalous EP easterlies in the cold phase persist to the subsequent spring, which tends to counteract the turnabout from the cold to warm phase of ENSO. A suite of idealized atmospheric general circulation model (AGCM) experiments are performed by imposing two different ENSO-related SST anomalies, which have equal amplitudes but opposite signs. The nonlinear climate response in the AGCM is found at the mature-to-decaying phase of ENSO that closely resembles the observations, including a zonal and meridional shift in the equatorial positions of the atmospheric wind. By using a simple ocean model, it is determined that the asymmetric responses of the equatorial zonal wind result in different recovery times of the thermocline in the eastern Pacific. Thus, the differences in transition processes between the warm and cold ENSO event are fundamentally due to the nonlinear atmospheric response to SST, which originates from the distribution of climatological SST and its seasonal changes. By including the asymmetric wind responses the intermediate air?sea coupled model herein demonstrates that the essential elements of the redevelopment of La Ni{\~{n}}a arise from the nonlinear atmospheric response to SST anomalies.},
annote = {doi: 10.1175/2008JCLI2334.1},
author = {Ohba, Masamichi and Ueda, Hiroaki},
doi = {10.1175/2008JCLI2334.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jan},
number = {1},
pages = {177--192},
publisher = {American Meteorological Society},
title = {{Role of Nonlinear Atmospheric Response to SST on the Asymmetric Transition Process of ENSO}},
url = {https://doi.org/10.1175/2008JCLI2334.1},
volume = {22},
year = {2009}
}
@article{Olonscheck2020a,
abstract = {Abstract Using seven single-model ensembles and the two multimodel ensembles CMIP5 and CMIP6, we show that observed and simulated trends in sea surface temperature (SST) patterns are globally consistent when accounting for internal variability. Some individual ensemble members simulate trends in large-scale SST patterns that closely resemble the observed ones. Observed regional trends that lie at the outer edge of the models' internal variability range allow two nonexclusive interpretations: (a) Observed trends are unusual realizations of the Earth's possible behavior and/or (b) the models are systematically biased but large internal variability leads to some good matches with the observations. The existing range of multidecadal SST trends is influenced more strongly by large internal variability than by differences in the model formulation or the observational data sets.},
annote = {https://doi.org/10.1029/2019GL086773},
author = {Olonscheck, Dirk and Rugenstein, Maria and Marotzke, Jochem},
doi = {https://doi.org/10.1029/2019GL086773},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {global climate models,internal variability,large ensembles,model evaluation,sea surface temperature patterns},
month = {may},
number = {10},
pages = {e2019GL086773},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Broad Consistency Between Observed and Simulated Trends in Sea Surface Temperature Patterns}},
url = {https://doi.org/10.1029/2019GL086773},
volume = {47},
year = {2020}
}
@article{Ortega2015a,
author = {Ortega, Pablo and Lehner, Flavio and Swingedouw, Didier and Masson-Delmotte, Valerie and Raible, Christoph C. and Casado, Mathieu and Yiou, Pascal},
doi = {10.1038/nature14518},
issn = {0028-0836},
journal = {Nature},
month = {jul},
number = {7558},
pages = {71--74},
title = {{A model-tested North Atlantic Oscillation reconstruction for the past millennium}},
url = {http://www.nature.com/articles/nature14518},
volume = {523},
year = {2015}
}
@article{Oschlies2017,
abstract = {Observational estimates and numerical models both indicate a significant overall decline in marine oxygen levels over the past few decades. Spatial patterns of oxygen change, however, differ considerably between observed and modelled estimates. Particularly in the tropical thermocline that hosts open-ocean oxygen minimum zones, observations indicate a general oxygen decline, whereas most of the state-of-the-art models simulate increasing oxygen levels. Possible reasons for the apparent model-data discrepancies are examined. In order to attribute observed historical variations in oxygen levels, we here study mechanisms of changes in oxygen supply and consumption with sensitivity model simulations. Specifically, the role of equatorial jets, of lateral and diapycnal mixing processes, of changes in the wind-driven circulation and atmospheric nutrient supply, and of some poorly constrained biogeochemical processes are investigated. Predominantly wind-driven changes in the low-latitude oceanic ventilation are identified as a possible factor contributing to observed oxygen changes in the low-latitude thermocline during the past decades, while the potential role of biogeochemical processes remains difficult to constrain. We discuss implications for the attribution of observed oxygen changes to anthropogenic impacts and research priorities that may help to improve our mechanistic understanding of oxygen changes and the quality of projections into a changing future.This article is part of the themed issue 'Ocean ventilation and deoxygenation in a warming world'.},
author = {Oschlies, Andreas and Duteil, Olaf and Getzlaff, Julia and Koeve, Wolfgang and Landolfi, Angela and Schmidtko, Sunke},
doi = {10.1098/rsta.2016.0325},
issn = {1364-503X},
journal = {Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences},
keywords = {climate change,deoxygenation,marine oxygen},
month = {sep},
number = {2102},
pages = {20160325},
pmid = {28784715},
title = {{Patterns of deoxygenation: sensitivity to natural and anthropogenic drivers}},
url = {http://www.ncbi.nlm.nih.gov/pubmed/28784715 http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=PMC5559420 http://rsta.royalsocietypublishing.org/lookup/doi/10.1098/rsta.2016.0325},
volume = {375},
year = {2017}
}
@article{Osprey2013,
abstract = { AbstractAn examination is made of stratospheric climate, circulation, and variability in configurations of the Hadley Centre Global Environmental Model version 2 (HadGEM2) differing only in stratospheric resolution and the placement of the model lid. This is made in the context of historical reconstructions of twentieth-century climate. A reduction in the westerly bias in the Northern Hemisphere polar night jet is found in the high-top model. The authors also find significant differences in the expression of tropical stratospheric variability, finding improvements in the high-top model for the presence of the quasi-biennial oscillation, for tropical upwelling consistent with interim European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-Interim) data, and for interannual changes in stratospheric water vapor concentration comparable to satellite observations. Further differences are seen at high latitudes during winter in the frequency of occurrence of sudden stratospheric warmings (SSWs). The occurrence rate of SSWs in the high-top simulations, (7.2 ± 0.5) decade−1, is statistically consistent with observations, (6.0 ± 1.0) decade−1, whereas they are one-third as frequent in the low-top simulations, (2.5 ± 0.5) decade−1. Furthermore, the structure of the timing of winter final warmings is only captured in the high-top model. A similar characterization for the time evolution of the width of the tropical upper troposphere is found between model configurations. It is concluded that an adequate representation of the stratosphere is required to capture the important modes of tropical and extratropical stratospheric variability in models. },
author = {Osprey, Scott M and Gray, Lesley J and Hardiman, Steven C and Butchart, Neal and Hinton, Tim J},
doi = {10.1175/JCLI-D-12-00147.1},
journal = {Journal of Climate},
number = {5},
pages = {1595--1606},
title = {{Stratospheric Variability in Twentieth-Century CMIP5 Simulations of the Met Office Climate Model: High Top versus Low Top}},
volume = {26},
year = {2013}
}
@article{Oster2015,
abstract = {The hydroclimate history of North America includes the formation and desiccation of large inland lakes and the growth and ablation of glaciers throughout the Quaternary period. At the Last Glacial Maximum, expanded pluvial lakes in the south and aridity in the northwest suggest that the winter westerly storm track was displaced southwards and migrated northwards as the Laurentide Ice Sheetwaned. However, lake highstands do not occur synchronously along zonal bands, in conflict with this hypothesis. Here we compile a network of precipitation proxy reconstructions from lakes, speleothems, groundwater deposits, packrat middens and glaciers from the western and southwestern US, which we compare with an ensemble of climate simulations to identify the controls of regional hydroclimatic change. The proxy records suggest a precipitation dipole during the Last Glacial Maximum, with wetter than modern conditions in the southwest and drier conditions near the ice sheet, and a northwest–southeast trending transition zone across the northern Great Basin. The models that simulate a weaker and south-shifted Aleutian low-pressure system, a strong North Pacific high-pressure system, and a high above the ice sheet best reproduce this regional variation. We therefore conclude that rather than a uniformly south-shifted storm track, a stronger jet that is squeezed and steered across the continent by high-pressure systems best explains the observed regional hydroclimate patterns of the Last Glacial Maximum.},
author = {Oster, Jessica L. and Ibarra, Daniel E. and Winnick, Matthew J. and Maher, Katharine},
doi = {10.1038/ngeo2365},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {mar},
number = {3},
pages = {201--205},
title = {{Steering of westerly storms over western North America at the Last Glacial Maximum}},
url = {http://www.nature.com/articles/ngeo2365},
volume = {8},
year = {2015}
}
@article{Ott2015,
author = {Ott, Irena and Romberg, Karin and Jacobeit, Jucundus},
doi = {10.1007/s00382-014-2394-z},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jun},
number = {11-12},
pages = {3043--3055},
title = {{Teleconnections of the tropical Atlantic and Pacific Oceans in a CMIP5 model ensemble}},
url = {http://link.springer.com/10.1007/s00382-014-2394-z},
volume = {44},
year = {2015}
}
@article{Ottera2010,
author = {Otter{\aa}, Odd Helge and Bentsen, Mats and Drange, Helge and Suo, Lingling},
doi = {10.1038/ngeo955},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {oct},
number = {10},
pages = {688--694},
title = {{External forcing as a metronome for Atlantic multidecadal variability}},
url = {http://www.nature.com/articles/ngeo955},
volume = {3},
year = {2010}
}
@article{Otto2015,
abstract = {{\textcopyright} 2015 Macmillan Publishers Limited. The 'pledge and review' approach to reducing greenhouse-gas emissions presents an opportunity to link mitigation goals explicitly to the evolving climate response. This seems desirable because the progression from the Intergovernmental Panel on Climate Change's fourth to fifth assessment reports has seen little reduction in uncertainty. A common reaction to persistent uncertainties is to advocate mitigation policies that are robust even under worst-case scenarios, thereby focusing attention on upper extremes of both the climate response and the costs of impacts and mitigation, all of which are highly contestable. Here we ask whether those contributing to the formation of climate policies can learn from 'adaptive management' techniques. Recognizing that long-lived greenhouse gas emissions have to be net zero by the time temperatures reach a target stabilization level, such as 2 °C above pre-industrial levels, and anchoring commitments to an agreed index of attributable anthropogenic warming would provide a transparent approach to meeting such a temperature goal without prior consensus on the climate response.},
author = {Otto, F.E.L. and Frame, D.J. and Otto, A. and Allen, M.R.},
doi = {10.1038/nclimate2716},
journal = {Nature Climate Change},
number = {10},
pages = {917--921},
title = {{Embracing uncertainty in climate change policy}},
volume = {5},
year = {2015}
}
@article{gmd-10-3979-2017,
author = {Otto-Bliesner, B L and Braconnot, P and Harrison, S P and Lunt, D J and Abe-Ouchi, A and Albani, S and Bartlein, P J and Capron, E and Carlson, A E and Dutton, A and Fischer, H and Goelzer, H and Govin, A and Haywood, A and Joos, F and LeGrande, A N and Lipscomb, W H and Lohmann, G and Mahowald, N and Nehrbass-Ahles, C and Pausata, F S R and Peterschmitt, J.-Y. and Phipps, S J and Renssen, H and Zhang, Q},
doi = {10.5194/gmd-10-3979-2017},
journal = {Geoscientific Model Development},
number = {11},
pages = {3979--4003},
title = {{The PMIP4 contribution to CMIP6 – Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations}},
url = {https://www.geosci-model-dev.net/10/3979/2017/},
volume = {10},
year = {2017}
}
@article{doi:10.1175/BAMS-D-14-00233.1,
abstract = { AbstractThe climate of the past millennium provides a baseline for understanding the background of natural climate variability upon which current anthropogenic changes are superimposed. As this period also contains high data density from proxy sources (e.g., ice cores, stalagmites, corals, tree rings, and sediments), it provides a unique opportunity for understanding both global and regional-scale climate responses to natural forcing. Toward that end, an ensemble of simulations with the Community Earth System Model (CESM) for the period 850–2005 (the CESM Last Millennium Ensemble, or CESM-LME) is now available to the community. This ensemble includes simulations forced with the transient evolution of solar intensity, volcanic emissions, greenhouse gases, aerosols, land-use conditions, and orbital parameters, both together and individually. The CESM-LME thus allows for evaluation of the relative contributions of external forcing and internal variability to changes evident in the paleoclimate data record, as well as providing a longer-term perspective for understanding events in the modern instrumental period. It also constitutes a dynamically consistent framework within which to diagnose mechanisms of regional variability. Results demonstrate an important influence of internal variability on regional responses of the climate system during the past millennium. All the forcings, particularly large volcanic eruptions, are found to be regionally influential during the preindustrial period, while anthropogenic greenhouse gas and aerosol changes dominate the forced variability of the mid- to late twentieth century. },
author = {Otto-Bliesner, Bette L and Brady, Esther C and Fasullo, John and Jahn, Alexandra and Landrum, Laura and Stevenson, Samantha and Rosenbloom, Nan and Mai, Andrew and Strand, Gary},
doi = {10.1175/BAMS-D-14-00233.1},
journal = {Bulletin of the American Meteorological Society},
number = {5},
pages = {735--754},
title = {{Climate Variability and Change since 850 CE: An Ensemble Approach with the Community Earth System Model}},
url = {https://doi.org/10.1175/BAMS-D-14-00233.1},
volume = {97},
year = {2016}
}
@article{Otto-Bliesner2014,
abstract = {During the last deglaciation, wetter conditions developed abruptly {\~{}}14,700 years ago in southeastern equatorial and northern Africa and continued into the Holocene. Explaining the abrupt onset and hemispheric coherence of this early African Humid Period is challenging due to opposing seasonal insolation patterns. In this work, we use a transient simulation with a climate model that provides a mechanistic understanding of deglacial tropical African precipitation changes. Our results show that meltwater-induced reduction in the Atlantic meridional overturning circulation (AMOC) during the early deglaciation suppressed precipitation in both regions. Once the AMOC reestablished, wetter conditions developed north of the equator in response to high summer insolation and increasing greenhouse gas (GHG) concentrations, whereas wetter conditions south of the equator were a response primarily to the GHG increase.},
author = {Otto-Bliesner, Bette L. and Russell, James M. and Clark, Peter U. and Liu, Zhengyu and Overpeck, Jonathan T. and Konecky, Bronwen and DeMenocal, Peter and Nicholson, Sharon E. and He, Feng and Lu, Zhengyao},
doi = {10.1126/science.1259531},
issn = {0036-8075},
journal = {Science},
month = {dec},
number = {6214},
pages = {1223--1227},
title = {{Coherent changes of southeastern equatorial and northern African rainfall during the last deglaciation}},
url = {https://www.sciencemag.org/lookup/doi/10.1126/science.1259531},
volume = {346},
year = {2014}
}
@article{Otto-Bliesner2021,
author = {Otto-Bliesner, Bette L. and Brady, Esther C. and Zhao, Anni and Brierley, Chris M. and Axford, Yarrow and Capron, Emilie and Govin, Aline and Hoffman, Jeremy S. and Isaacs, Elizabeth and Kageyama, Masa and Scussolini, Paolo and Tzedakis, Polychronis C. and Williams, Charles J. R. and Wolff, Eric and Abe-Ouchi, Ayako and Braconnot, Pascale and {Ramos Buarque}, Silvana and Cao, Jian and de Vernal, Anne and Guarino, Maria Vittoria and Guo, Chuncheng and LeGrande, Allegra N. and Lohmann, Gerrit and Meissner, Katrin J. and Menviel, Laurie and Morozova, Polina A. and Nisancioglu, Kerim H. and O'ishi, Ryouta and {Salas y M{\'{e}}lia}, David and Shi, Xiaoxu and Sicard, Marie and Sime, Louise and Stepanek, Christian and Tomas, Robert and Volodin, Evgeny and Yeung, Nicholas K. H. and Zhang, Qiong and Zhang, Zhongshi and Zheng, Weipeng},
doi = {10.5194/cp-17-63-2021},
issn = {1814-9332},
journal = {Climate of the Past},
month = {jan},
number = {1},
pages = {63--94},
title = {{Large-scale features of Last Interglacial climate: results from evaluating the lig127k simulations for the Coupled Model Intercomparison Project (CMIP6)–Paleoclimate Modeling Intercomparison Project (PMIP4)}},
url = {https://cp.copernicus.org/articles/17/63/2021/},
volume = {17},
year = {2021}
}
@article{otto2007last,
author = {Otto-Bliesner, B L and Hewitt, C D and Marchitto, T M and Brady, E and Abe-Ouchi, Ayako and Crucifix, Michel and Murakami, S and Weber, S L},
doi = {10.1029/2007GL029475},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {jun},
number = {12},
pages = {L12706},
publisher = {Wiley Online Library},
title = {{Last Glacial Maximum ocean thermohaline circulation: PMIP2 model intercomparisons and data constraints}},
url = {http://doi.wiley.com/10.1029/2007GL029475},
volume = {34},
year = {2007}
}
@article{doi:10.1029/2018GL078841,
abstract = {Abstract Anthropogenic-aerosol radiative forcing (AA) modulates multidecadal greenhouse radiative forcing. However, decadal climate responses to AA are poorly characterized given AA forcing uncertainty and internal climate variability. This motivates revisiting a recent claim that AA drove a negative trend in the Pacific Decadal Oscillation (PDO) and an associated cooling influence in the 10-15 years following the late-1990's El Ni{\~{n}}o. The average of a 50-member initial condition ensemble of the second generation Canadian Earth System Model CanESM2 that was forced only with AA does not exhibit the negative-PDO/slowdown response. However, spurious responses of this kind, that are artifacts of subsetting the larger ensemble in a manner consistent with published literature, can readily be found. This illustrates the caution needed in interpreting regional- and decadal-scale responses to AA, and suggests that improved characterization of model uncertainty in AA over the recent period is required.},
author = {Oudar, Thomas and Kushner, Paul J and Fyfe, John C and Sigmond, Michael},
doi = {10.1029/2018GL078841},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {sep},
number = {17},
pages = {9245--9252},
title = {{No Impact of Anthropogenic Aerosols on Early 21st Century Global Temperature Trends in a Large Initial-Condition Ensemble}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL078841 http://doi.wiley.com/10.1029/2018GL078841},
volume = {45},
year = {2018}
}
@article{Outten2015,
author = {Outten, Stephen and Thorne, Peter and Bethke, Ingo and Seland, {\O}yvind},
doi = {10.1002/2015JD023859},
issn = {2169-897X},
journal = {Journal of Geophysical Research: Atmospheres},
month = {sep},
number = {17},
pages = {8575--8596},
title = {{Investigating the recent apparent hiatus in surface temperature increases: 1. Construction of two 30-member Earth System Model ensembles}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2015JD023859},
volume = {120},
year = {2015}
}
@article{Owens2017,
abstract = {The Maunder minimum (MM) was a period of extremely low solar activity from approximately AD 1650 to 1715. In the solar physics literature, the MM is sometimes associated with a period of cooler global temperatures, referred to as the Little Ice Age (LIA), and thus taken as compelling evidence of a large, direct solar influence on climate. In this study, we bring together existing simulation and observational studies, particularly the most recent solar activity and paleoclimate reconstructions, to examine this relation. Using northern hemisphere surface air temperature reconstructions, the LIA can be most readily defined as an approximately 480 year period spanning AD 1440-1920, although not all of this period was notably cold. While the MM occurred within the much longer LIA period, the timing of the features are not suggestive of causation and should not, in isolation, be used as evidence of significant solar forcing of climate. Climate model simulations suggest multiple factors, particularly volcanic activity, were crucial for causing the cooler temperatures in the northern hemisphere during the LIA. A reduction in total solar irradiance likely contributed to the LIA at a level comparable to changing land use.},
author = {Owens, Mathew J. and Lockwood, Mike and Hawkins, Ed and Usoskin, Ilya and Jones, Gareth S. and Barnard, Luke and Schurer, Andrew and Fasullo, John},
doi = {10.1051/swsc/2017034},
issn = {2115-7251},
journal = {Journal of Space Weather and Space Climate},
month = {dec},
pages = {A33},
title = {{The Maunder minimum and the Little Ice Age: an update from recent reconstructions and climate simulations}},
url = {http://www.swsc-journal.org/10.1051/swsc/2017034},
volume = {7},
year = {2017}
}
@article{doi:10.1175/JCLI-D-16-0850.1,
abstract = { AbstractDetection and attribution methods in climatological research aim at assessing whether observed climate anomalies and trends are still consistent with the range of natural climate variations or rather an indication of anthropogenic climate change. In this study, the authors pursue a novel approach by using discriminant analysis to enhance the distinction between past and future climates from state-of-the-art climate model simulations. The method is based on multivariate fingerprints that are defined in the space of several prominent climate indices representing the thermal, dynamical, and hygric aspects of climate change. Attribution is carried out by means of a Bayesian classification approach.The leading discriminant function accounts for more than 99{\%} of total discriminability, with temperature variables, extratropical precipitation, and extratropical circulation modes mainly contributing to the discriminant power. The misclassification probability between probability density functions of past and future climates is substantially reduced by the discriminant analysis: from {\textgreater}50{\%} to {\textless}15{\%}. Since the mid-1980s, the observed anomalies of the considered climate indices are more or less consistently attributed to a climate under strong radiative forcing, projected for the first half of the twenty-first century. The authors also assess the sensitivity of their results to different emissions scenarios from the CMIP3 and CMIP5 multimodel ensembles, seasons, prior probabilities for the early twenty-first-century climate, estimates of the observational error, low-pass filters, variable compositions, group numbers, and reference data. },
author = {Paeth, Heiko and Pollinger, Felix and Ring, Christoph},
doi = {10.1175/JCLI-D-16-0850.1},
journal = {Journal of Climate},
number = {19},
pages = {7757--7776},
title = {{Detection and Attribution of Multivariate Climate Change Signals Using Discriminant Analysis and Bayesian Theorem}},
url = {https://doi.org/10.1175/JCLI-D-16-0850.1},
volume = {30},
year = {2017}
}
@article{PAGES2kConsortium2019a,
abstract = {Multi-decadal surface temperature changes may be forced by natural as well as anthropogenic factors, or arise unforced from the climate system. Distinguishing these factors is essential for estimating sensitivity to multiple climatic forcings and the amplitude of the unforced variability. Here we present 2,000-year-long global mean temperature reconstructions using seven different statistical methods that draw from a global collection of temperature-sensitive paleoclimate records. Our reconstructions display synchronous multi-decadal temperature fluctuations, which are coherent with one another and with fully forced CMIP5 millennial model simulations across the Common Era. The most significant attribution of pre-industrial (1300-1800 CE) variability at multi-decadal timescales is to volcanic aerosol forcing. Reconstructions and simulations qualitatively agree on the amplitude of the unforced global mean multi-decadal temperature variability, thereby increasing confidence in future projections of climate change on these timescales. The largest warming trends at timescales of 20 years and longer occur during the second half of the 20(th) century, highlighting the unusual character of the warming in recent decades.},
author = {{PAGES 2k Consortium}},
doi = {10.1038/s41561-019-0400-0},
edition = {2019/07/24},
issn = {1752-0894},
journal = {Nature geoscience},
language = {eng},
month = {jun},
number = {8},
pages = {643--649},
title = {{Consistent multi-decadal variability in global temperature reconstructions and simulations over the Common Era}},
url = {https://pubmed.ncbi.nlm.nih.gov/31372180 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6675609/},
volume = {12},
year = {2019}
}
@article{cp-11-1673-2015,
abstract = {Abstract. Estimated external radiative forcings, model results, and proxy-based climate reconstructions have been used over the past several decades to improve our understanding of the mechanisms underlying observed climate variability and change over the past millennium. Here, the recent set of temperature reconstructions at the continental-scale generated by the PAGES 2k project and a collection of state-of-the-art model simulations driven by realistic external forcings are jointly analysed. The first aim is to estimate the consistency between model results and reconstructions for each continental-scale region over the time and frequency domains. Secondly, the links between regions are investigated to determine whether reconstructed global-scale covariability patterns are similar to those identified in model simulations. The third aim is to assess the role of external forcings in the observed temperature variations. From a large set of analyses, we conclude that models are in relatively good agreement with temperature reconstructions for Northern Hemisphere regions, particularly in the Arctic. This is likely due to the relatively large amplitude of the externally forced response across northern and high-latitude regions, which results in a clearly detectable signature in both reconstructions and simulations. Conversely, models disagree strongly with the reconstructions in the Southern Hemisphere. Furthermore, the simulations are more regionally coherent than the reconstructions, perhaps due to an underestimation of the magnitude of internal variability in models or to an overestimation of the response to the external forcing in the Southern Hemisphere. Part of the disagreement might also reflect large uncertainties in the reconstructions, specifically in some Southern Hemisphere regions, which are based on fewer palaeoclimate records than in the Northern Hemisphere.},
author = {{PAGES 2k-PMIP3 group}},
doi = {10.5194/cp-11-1673-2015},
issn = {1814-9332},
journal = {Climate of the Past},
month = {dec},
number = {12},
pages = {1673--1699},
title = {{Continental-scale temperature variability in PMIP3 simulations and PAGES 2k regional temperature reconstructions over the past millennium}},
url = {https://www.clim-past.net/11/1673/2015/ https://cp.copernicus.org/articles/11/1673/2015/},
volume = {11},
year = {2015}
}
@article{Paik2017b,
abstract = { AbstractIn 2015, the sea ice extent (SIE) over the Sea of Okhotsk (Okhotsk SIE) hit a record low since 1979 during February–March, the period when the sea ice extent generally reaches its annual maximum. To quantify the role of anthropogenic influences on the changes observed in Okhotsk SIE, this study employed a fraction of attributable risk (FAR) analysis to compare the probability of occurrence of extreme Okhotsk SIE events and long-term SIE trends using phase 5 of the Coupled Model Intercomparison Project (CMIP5) multimodel simulations performed with and without anthropogenic forcing. It was found that because of anthropogenic influence, both the probability of extreme low Okhotsk SIEs that exceed the 2015 event and the observed long-term trends during 1979–2015 have increased by more than 4 times (FAR = 0.76 to 1). In addition, it is suggested that a strong negative phase of the North Pacific Oscillation (NPO) during midwinter (January–February) 2015 also contributed to the 2015 extreme SIE event. An analysis based on multiple linear regression was conducted to quantify relative contributions of the external forcing (anthropogenic plus natural) and the NPO (internal variability) to the observed SIE changes. About 56.0{\%} and 24.7{\%} of the 2015 SIE anomaly was estimated to be attributable to the external forcing and the strong negative NPO influence, respectively. The external forcing was also found to explain about 86.1{\%} of the observed long-term SIE trend. Further, projections from the CMIP5 models indicate that a sea ice–free condition may occur in the Sea of Okhotsk by the late twenty-first century in some models. },
author = {Paik, Seungmok and Min, Seung-Ki and Kim, Yeon-Hee and Kim, Baek-Min and Shiogama, Hideo and Heo, Joonghyeok},
doi = {10.1175/JCLI-D-16-0587.1},
journal = {Journal of Climate},
number = {12},
pages = {4693--4703},
title = {{Attributing Causes of 2015 Record Minimum Sea-Ice Extent in the Sea of Okhotsk}},
volume = {30},
year = {2017}
}
@article{Paik2017,
abstract = {This study analyzes climate responses to four volcanic eruptions that occurred since 1960s using observations (including reanalyses) and CMIP5 multi-model simulations. Changes in surface air temperature, specific humidity, and precipitation over the global land are examined during pre- to post-eruption years using a composite analysis. Observations exhibit consistent decreases in temperature, humidity, and precipitation following eruptions, which are reasonably captured by CMIP5 multi-models simulated including volcanic forcing. The observed and simulated decreases in temperature and humidity are stronger than the internal variability ranges (estimated from pre-industrial control simulations), indicating robust responses. On the other hand, the observed precipitation decrease is significant but the CMIP5 models considerably underestimate it, as reported by previous studies. In order to explore important physical processes determining climate responses to volcanic forcing, a surface energy budget is analyzed together with inter-model relationship between variables. A strong inter-model correlation (r = 0.89) appears between temperature and humidity, representing the Clausius–Clapeyron relation. Interestingly, precipitation is found to be closely related with latent heat flux (r = −0.50) and vertical motion ($\omega$) at 500 hPa level (r = −0.68), changes of which are also underestimated by models. Further, by comparing estimates of precipitation minus evaporation between land and ocean, which is significantly correlated with vertical motion (r = −0.73), it is found that monsoon circulation weakens after volcanic eruptions but CMIP5 models substantially underestimate it. Our results suggest that this dynamic response via monsoon circulation weakening can be a critical factor for models' underestimation of precipitation reduction to volcanic forcing.},
author = {Paik, Seungmok and Min, Seung-Ki},
doi = {10.1007/s00382-016-3125-4},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {3},
pages = {1017--1030},
title = {{Climate responses to volcanic eruptions assessed from observations and CMIP5 multi-models}},
url = {https://doi.org/10.1007/s00382-016-3125-4},
volume = {48},
year = {2017}
}
@article{Paik2020b,
abstract = {There remains large intersimulation spread in the hydrologic responses to tropical volcanic eruptions, and identifying the sources of diverse responses has important implications for assessing the side effects of solar geoengineering and improving decadal predictions. Here, we show that the intersimulation spread in the global monsoon drying response strongly relates to diverse El Ni{\~{n}}o responses to tropical eruptions. Most of the coupled climate models simulate El Ni{\~{n}}o–like equatorial eastern Pacific warming after volcanic eruptions but with different amplitudes, which drive a large spread of summer monsoon weakening and corresponding precipitation reduction. Two factors are further identified for the diverse El Ni{\~{n}}o responses. Different volcanic forcings induce systematic differences in the Maritime Continent drying and subsequent westerly winds over equatorial western Pacific, varying El Ni{\~{n}}o intensity. The internally generated warm water volume over the equatorial western Pacific in the pre-eruption month also contributes to the diverse El Ni{\~{n}}o development.},
author = {Paik, Seungmok and Min, Seung-Ki and Iles, Carley E and Fischer, Erich M and Schurer, Andrew P},
doi = {10.1126/sciadv.aba1212},
journal = {Science Advances},
month = {may},
number = {21},
pages = {eaba1212},
title = {{Volcanic-induced global monsoon drying modulated by diverse El Ni{\~{n}}o responses}},
url = {http://advances.sciencemag.org/content/6/21/eaba1212.abstract},
volume = {6},
year = {2020}
}
@article{Paik2020a,
abstract = {Abstract This study conducts a detection and attribution analysis of the observed changes in extreme precipitation during 1951?2015. Observed and CMIP6 multimodel simulated changes in annual maximum daily and consecutive 5-day precipitation are compared using an optimal fingerprinting technique for different spatial scales from global land, Northern Hemisphere extratropics, tropics, three continental regions (North America and western and eastern Eurasia), and global ?dry? and ?wet? land areas (as defined by their average extreme precipitation intensities). Results indicate that anthropogenic greenhouse gas influence is robustly detected in the observed intensification of extreme precipitation over the global land and most of the subregions considered, all with clear separation from natural and anthropogenic aerosol forcings. Also, the human-induced greenhouse gas increases are found to be a dominant contributor to the observed increase in extreme precipitation intensity, which largely follows the increased moisture availability under global warming.},
annote = {doi: 10.1029/2019GL086875},
author = {Paik, Seungmok and Min, Seung-Ki and Zhang, Xuebin and Donat, Markus G and King, Andrew D and Sun, Qiaohong},
doi = {10.1029/2019GL086875},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {jun},
number = {12},
pages = {e2019GL086875},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Determining the Anthropogenic Greenhouse Gas Contribution to the Observed Intensification of Extreme Precipitation}},
url = {https://doi.org/10.1029/2019GL086875},
volume = {47},
year = {2020}
}
@article{Paik2020c,
abstract = {This study conducts a detection and attribution analysis of the observed changes in boreal spring snow-cover extent (SCE) for an extended period of 1925-2019 for early spring (March and April) and 1970-2019 for late spring (May and June) using updated observations and multimodel simulations from phase 6 of the Coupled Model Intercomparison Project (CMIP6). The observed and simulated SCE changes over the Northern Hemisphere (NH), Eurasia, and North America are compared using an optimal fingerprinting technique. Detection results indicate that anthropogenic influences are robustly detected in the observed SCE decrease over NH and the continental regions, in separation from natural forcing influences. In contrast to previous studies, anthropogenic response in the early spring SCE shows a consistent magnitude with observations, due to an extension of the time period to 2019. It is demonstrated for the first time that the greenhouse gas (GHG) influence is robustly detected in separation from anthropogenic aerosol and natural forcing influences, and that most of the observed spring SCE decrease is attributable to GHG influences. The observed SCE decline is also found to be closely associated with the surface warming over the corresponding extratropical lands. Our first quantification of GHG contribution to the observed SCE changes has important implications for reliable future projections of the SCE changes and its hydrological and ecological impacts.},
author = {Paik, Seungmok and Min, Seung Ki},
doi = {10.1175/JCLI-D-20-0002.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Aerosols,Anthropogenic effects,Climate models,Greenhouse gases,Snow cover,Spring season},
month = {sep},
number = {21},
pages = {9261--9269},
title = {{Quantifying the anthropogenic greenhouse gas contribution to the observed spring snow-cover decline using the CMIP6 multimodel ensemble}},
url = {https://doi.org/10.1175/JCLI-D-20-0002.1},
volume = {33},
year = {2020}
}
@article{Pallotta,
abstract = {Studies seeking to identify a human-caused global warming signal generally rely on climate model estimates of the ‘‘noise'' of intrinsic natural variability. Assessing the reliability of these noise estimates is of critical importance. We evaluate here the statistical significance of differences between climate model and observational natural variability spectra for global-mean mid- to upper-tropospheric temperature (TMT). We use TMT information from satellites and large multimodel ensembles of forced and unforced simulations. Our main goal is to explore the sensitivity of model-versus-data spectral comparisons to a wide range of subjective decisions. These include the choice of satellite and climate model TMT datasets, the method for separating signal and noise, the frequency range considered, and the statistical model used to represent observed natural variability. Of particular interest is the amplitude of the interdecadal noise against which an anthropogenic tropospheric warming signal must be detected. We find that on time scales of 5–20 years, observed TMT variability is (on average) overestimated by the last two generations of climate models participating in the Coupled Model Intercomparison Project. This result is relatively insensitive to different plausible analyst choices, enhancing confidence in previous claims of detectable anthropogenic warming of the troposphere and indicating that these claims may be conservative. A further key finding is that two commonly used statistical models of short-term and long-term memory have deficiencies in their ability to capture the complex shape of observed TMT spectra.},
author = {Pallotta, Giuliana and Santer, Benjamin D.},
doi = {10.1175/JCLI-D-20-0023.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Climate variability,Spectral analysis/models/distribution,Statistics},
number = {23},
pages = {10383--10402},
title = {{Multi-frequency analysis of simulated versus observed variability in tropospheric temperature}},
volume = {33},
year = {2020}
}
@article{Palmer2014,
abstract = {We analyse a large number of multi-century pre-industrial control simulations from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) to investigate relationships between: net top-of-atmosphere radiation (TOA), globally averaged surface temperature (GST), and globally integrated ocean heat content (OHC) on decadal timescales. Consistent with previous studies, we find that large trends (∼0.3 K dec−1) in GST can arise from internal climate variability and that these trends are generally an unreliable indicator of TOA over the same period. In contrast, trends in total OHC explain 95{\%} or more of the variance in TOA for two-thirds of the models analysed; emphasizing the oceans' role as Earth's primary energy store. Correlation of trends in total system energy (TE ≡ time integrated TOA) against trends in OHC suggests that for most models the ocean becomes the dominant term in the planetary energy budget on a timescale of about 12 months. In the context of the recent pause in global surface temperature rise, we investigate the potential importance of internal climate variability in both TOA and ocean heat rearrangement. The model simulations suggest that both factors can account for O (0.1Wm−2) on decadal timescales and may play an important role in the recently observed trends in GST and 0–700 m (and 0–1800 m) ocean heat uptake. Keywords:},
author = {Palmer, M. D. and McNeall, D. J.},
doi = {10.1088/1748-9326/9/3/034016},
issn = {17489326},
journal = {Environmental Research Letters},
month = {mar},
number = {3},
pages = {34016},
publisher = {IOP Publishing},
title = {{Internal variability of Earth's energy budget simulated by CMIP5 climate models}},
volume = {9},
year = {2014}
}
@misc{Palmer2019,
abstract = {Given the slow unfolding of what may become catastrophic changes to Earth's climate, many are understandably distraught by failures of public policy to rise to the magnitude of the challenge. Few in the science community would think to question the scientific response to the unfolding changes. However, is the science community continuing to do its part to the best of its ability? In the domains where we can have the greatest influence, is the scientific community articulating a vision commensurate with the challenges posed by climate change? We think not.},
author = {Palmer, Tim and Stevens, Bjorn},
booktitle = {Proceedings of the National Academy of Sciences},
doi = {10.1073/pnas.1906691116},
issn = {10916490},
number = {49},
title = {{The scientific challenge of understanding and estimating climate change}},
volume = {116},
year = {2019}
}
@article{Papalexiou2020,
author = {Papalexiou, Simon Michael and Rajulapati, Chandra Rupa and Clark, Martyn P. and Lehner, Flavio},
doi = {10.1029/2020ef001667},
issn = {2328-4277},
journal = {Earth's Future},
number = {10},
pages = {e2020EF001667},
title = {{Robustness of CMIP6 Historical Global Mean Temperature Simulations: Trends, Long-Term Persistence, Autocorrelation, and Distributional Shape}},
volume = {8},
year = {2020}
}
@article{Park2016a,
abstract = {Monitoring and understanding climate-induced changes in the boreal and arctic vegetation is critical to aid in prognosticating their future. We used a 33 year (1982-2014) long record of satellite observations to robustly assess changes in metrics of growing season (onset: SOS, end: EOS and length: LOS) and seasonal total gross primary productivity. Particular attention was paid to evaluating the accuracy of these metrics by comparing them to multiple independent direct and indirect growing season and productivity measures. These comparisons reveal that the derived metrics capture the spatio-temporal variations and trends with acceptable significance level (generally p {\textless} 0.05). We find that LOS has lengthened by 2.60 d dec -1 (p {\textless} 0.05) due to an earlier onset of SOS (-1.61 d dec -1 , p {\textless} 0.05) and a delayed EOS (0.67 d dec -1 , p {\textless} 0.1) at the circumpolar scale over the past three decades. Relatively greater rates of changes in growing season were observed in Eurasia (EA) and in boreal regions than in North America (NA) and the arctic regions. However, this tendency of earlier SOS and delayed EOS was prominent only during the earlier part of the data record (1982-1999). During the later part (2000-2014), this tendency was reversed, i.e. delayed SOS and earlier EOS. As for seasonal total productivity, we find that 42.0{\%} of northern vegetation shows a statistically significant (p {\textless} 0.1) greening trend over the last three decades. This greening translates to a 20.9{\%} gain in productivity since 1982. In contrast, only 2.5{\%} of northern vegetation shows browning, or a 1.2{\%} loss of productivity. These trends in productivity were continuous through the period of record, unlike changes in growing season metrics. Similarly, we find relatively greater increasing rates of productivity in EA and in arctic regions than in NA and the boreal regions. These results highlight spatially and temporally varying vegetation dynamics and are reflective of biome-specific responses of northern vegetation during last three decades.},
author = {Park, Taejin and Ganguly, Sangram and T{\O}mmervik, Hans and Euskirchen, Eug{\'{e}}nie S. and H{\O}gda, Kjell Arild and Karlsen, Stein Rune and Brovkin, Victor and Nemani, Ramakrishna R. and Myneni, Ranga B.},
doi = {10.1088/1748-9326/11/8/084001},
issn = {17489326},
journal = {Environmental Research Letters},
keywords = {AVHRR,MODIS,boreal and arctic,climate change,gross primary productivity,photosynthetically active growing season,remote sensing},
number = {8},
pages = {084001},
title = {{Changes in growing season duration and productivity of northern vegetation inferred from long-term remote sensing data}},
volume = {11},
year = {2016}
}
@article{Park2018,
abstract = {Observed long-term variations in summer season timing and length in the Northern Hemisphere (NH) continents and their subregions were analyzed using temperature-based indices. The climatological mean showed coastal-inland contrast; summer starts and ends earlier inland than in coastal areas because of differences in heat capacity. Observations for the past 60 years (1953-2012) show lengthening of the summer season with earlier summer onset and delayed summer withdrawal across the NH. The summer onset advance contributed more to the observed increase in summer season length in many regions than the delay of summer withdrawal. To understand anthropogenic and natural contributions to the observed change, summer season trends from phase 5 of the Coupled Model Intercomparison Project (CMIP5) multimodel simulations forced with the observed external forcings [anthropogenic plus natural forcing (ALL), natural forcing only (NAT), and greenhouse gas forcing only (GHG)] were analyzed. ALL and GHG simulations were found to reproduce the overall observed global and regional lengthening trends, but NAT had negligible trends, which implies that increased greenhouse gases were the main cause of the observed changes. However, ALL runs tend to underestimate the observed trend of summer onset and overestimate that of withdrawal, the causes of which remain to be determined. Possible contributions of multidecadal variabilities, such as Pacific decadal oscillation and Atlantic multidecadal oscillation, to the observed regional trends in summer season length were also assessed. The results suggest that multidecadal variability can explain a moderate portion (about ±10{\%}) of the observed trends in summer season length, mainly over the high latitudes.},
author = {Park, Bo Joung and Kim, Yeon Hee and Min, Seung Ki and Lim, Eun Pa},
doi = {10.1175/JCLI-D-17-0643.1},
issn = {08948755},
journal = {Journal of Climate},
number = {17},
title = {{Anthropogenic and natural contributions to the lengthening of the summer season in the Northern Hemisphere}},
volume = {31},
year = {2018}
}
@article{Parsons2016,
abstract = { AbstractThis study is concerned with blocking events (BEs) in the Southern Hemisphere (SH), their past variability, and future projections. ERA-Interim (ERA-I) is used to compare the historical output from four general circulation models (GCMs) from phase 5 of the Coupled Model Intercomparison Project (CMIP5); the output of the representative concentration pathway 4.5 and 8.5 (RCP4.5 and RCP8.5) projections are also examined. ERA-I shows that the higher latitudes of the South Pacific Ocean (SPO) are the main blocking region, with blocking occurring predominantly in winter. The CMIP5 historical simulations also agree well with ERA-I for annual and seasonal BE locations and frequencies. A reduction in BEs is observed in the SPO in the 2071–2100 period in the RCP4.5 projections, and this is more pronounced for the RCP8.5 projections and occurs predominantly during the spring and summer seasons. Preliminary investigations imply that the southern annular mode (SAM) is negatively correlated with blocking activity in the SPO in all seasons in the reanalysis. This negative correlation is also observed in the GCM historical output. However, in the RCP projections this correlation is reduced in three of the four models during summer, suggesting that SAM may be less influential in summertime blocking in the future. },
author = {Parsons, Simon and Renwick, James A and McDonald, Adrian J},
doi = {10.1175/JCLI-D-15-0754.1},
journal = {Journal of Climate},
number = {21},
pages = {7599--7611},
title = {{An Assessment of Future Southern Hemisphere Blocking Using CMIP5 Projections from Four GCMs}},
volume = {29},
year = {2016}
}
@article{Parsons2017,
abstract = {AbstractAccurate assessments of future climate impacts require realistic simulation of interannual?century-scale temperature and precipitation variability. Here, well-constrained paleoclimate data and the latest generation of Earth system model data are used to evaluate the magnitude and spatial consistency of climate variance distributions across interannual to centennial frequencies. It is found that temperature variance generally increases with time scale in patterns that are spatially consistent among models, especially over the mid- and high-latitude oceans. However, precipitation is similar to white noise across much of the globe. When Earth system model variance is compared to variance generated by simple autocorrelation, it is found that tropical temperature variability in Earth system models is difficult to distinguish from variability generated by simple autocorrelation. By contrast, both forced and unforced Earth system models produce variability distinct from a simple autoregressive process over most high-latitude oceans. This new analysis of tropical paleoclimate records suggests that low-frequency variance dominates the temperature spectrum across the tropical Pacific and Indian Oceans, but in many Earth system models, interannual variance dominates the simulated central and eastern tropical Pacific temperature spectrum, regardless of forcing. Tropical Pacific model spectra are compared to spectra from the instrumental record, but the short instrumental record likely cannot provide accurate multidecadal?centennial-scale variance estimates. In the coming decades, both forced and natural patterns of decade?century-scale variability will determine climate-related risks. Underestimating low-frequency temperature and precipitation variability may significantly alter our understanding of the projections of these climate impacts.},
annote = {doi: 10.1175/JCLI-D-16-0863.1},
author = {Parsons, Luke A and Loope, Garrison R and Overpeck, Jonathan T and Ault, Toby R and Stouffer, Ronald and Cole, Julia E},
doi = {10.1175/JCLI-D-16-0863.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {aug},
number = {22},
pages = {8885--8912},
publisher = {American Meteorological Society},
title = {{Temperature and Precipitation Variance in CMIP5 Simulations and Paleoclimate Records of the Last Millennium}},
url = {https://doi.org/10.1175/JCLI-D-16-0863.1},
volume = {30},
year = {2017}
}
@article{Parsons2020,
abstract = {Attribution and prediction of global and regional warming requires a better understanding of the magnitude and spatial characteristics of internal global mean surface air temperature (GMST) variability. We examine interdecadal GMST variability in Coupled Modeling Intercomparison Projects, Phases 3, 5, and 6 (CMIP3, CMIP5, and CMIP6) preindustrial control (piControl), last millennium, and historical simulations and in observational data. We find that several CMIP6 simulations show more GMST interdecadal variability than the previous generations of model simulations. Nonetheless, we find that 100-year trends in CMIP6 piControl simulations never exceed the maximum observed warming trend. Furthermore, interdecadal GMST variability in the unforced piControl simulations is associated with regional variability in the high latitudes and the east Pacific, whereas interdecadal GMST variability in instrumental data and in historical simulations with external forcing is more globally coherent and is associated with variability in tropical deep convective regions.},
author = {Parsons, Luke A. and Brennan, M. Kathleen and Wills, Robert C.J. and Proistosescu, Cristian},
doi = {10.1029/2019GL086588},
issn = {19448007},
journal = {Geophysical Research Letters},
keywords = {CMIP6,climate change,climate dynamics,decadal climate variability,internal and forced variability,model-observation comparison},
number = {7},
pages = {e2019GL086588},
title = {{Magnitudes and Spatial Patterns of Interdecadal Temperature Variability in CMIP6}},
volume = {47},
year = {2020}
}
@article{Pasini2017,
author = {Pasini, Antonello and Triacca, Umberto and Attanasio, Alessandro},
doi = {10.1007/s00704-016-1818-6},
issn = {0177-798X},
journal = {Theoretical and Applied Climatology},
month = {aug},
number = {3-4},
pages = {873--880},
title = {{Evidence for the role of the Atlantic multidecadal oscillation and the ocean heat uptake in hiatus prediction}},
url = {http://link.springer.com/10.1007/s00704-016-1818-6},
volume = {129},
year = {2017}
}
@article{Passey2009,
abstract = {The East Asian monsoons have fluctuated in concert with high-latitude warmth during the past several hundred thousand years, with humid summer monsoon-dominant climates characterizing warm intervals, including interglacials and interstadials, and arid winter monsoon-dominant climates characterizing cool intervals, including glacials and stadials. Of the states comprising the mid-Pleistocene to recent climatic regime, interglacials are most similar in terms of high latitude ice volumes and temperatures to those extant during the late Miocene and early Pliocene. Thus, an important question is whether Mio-Pliocene climates in northern China were analogous to a hypothetical 'prolonged interglacial state,' with increased summer monsoon precipitation and expansion of forest and steppe environments at the expense of desert environments. We utilize new and previously published carbon isotopic data from fossil teeth and soil carbonates to place constraints on paleovegetation distributions and to help infer the behavior of the monsoon system between ∼ 7 and 4 Ma. We find that plants using the C4 photosynthetic pathway-which today are largely grasses found in regions with warm season precipitation-were present in northern China by late Miocene time, demonstrating that the C4 expansion in China was not significantly delayed compared to the global C4 event. During the late Miocene-early Pliocene interval, soil carbonate and tooth enamel $\delta$13C data indicate: 1) that nearly pure C3-plant ecosystems existed in the southern Chinese Loess Plateau (CLP), and therefore ecosystems there were dominated by woody dicot, herbaceous dicot, or cool-season grass vegetation (or a combination of these), and 2) that the CLP was characterized by a pattern of northward-increasing C4 vegetation and aridity. Utilizing a broadened conceptual model for interpreting $\delta$13C data, and citing independent faunal, floral, and lithostratgraphic data, we suggest that these patterns reflect northward expansion of forest and steppe ecosystems and relatively humid monsoon climates during the late Miocene and early Pliocene. An important implication of this interpretation is that the forcing mechanism illuminated by the temporal correlation during the Pleistocene between warm high latitudes and strong East Asian summer monsoons is a robust feature of the Eurasian tectonic-climatic system that predates the Plio-Pleistocene climatic reorganization. {\textcopyright} 2008 Elsevier B.V. All rights reserved.},
author = {Passey, Benjamin H. and Ayliffe, Linda K. and Kaakinen, Anu and Zhang, Zhaoqun and Eronen, Jussi T. and Zhu, Yanming and Zhou, Liping and Cerling, Thure E. and Fortelius, Mikael},
doi = {10.1016/j.epsl.2008.11.008},
isbn = {0012-821X},
issn = {0012821X},
journal = {Earth and Planetary Science Letters},
month = {jan},
number = {3-4},
pages = {443--452},
title = {{Strengthened East Asian summer monsoons during a period of high-latitude warmth? Isotopic evidence from Mio-Pliocene fossil mammals and soil carbonates from northern China}},
url = {https://linkinghub.elsevier.com/retrieve/pii/S0012821X08007164},
volume = {277},
year = {2009}
}
@article{doi:10.1029/2019GL083264,
abstract = {Abstract Many general circulation models fail to capture the observed frequency of atmospheric blocking events in the Northern Hemisphere; however, few studies have examined models in the Southern Hemisphere and those studies that have, have often been based on only a few models. To provide a comprehensive view of how the current generation of coupled general circulation models performs in the Southern Hemisphere and how blocking frequency changes under enhanced greenhouse gas forcing, we examine the output of 23 models from the Coupled Model Intercomparison Project Phase 5 (CMIP5). We find that models have differing biases during winter, when blocking occurrence is highest, though models underestimate blocking frequency south of Australia during summer. We show that models generally have a reduction in blocking frequency with future anthropogenic forcing, particularly in the Australia-New Zealand sector with the number of winter blocked days reduced by about one third by the end of the 21st century.},
author = {Patterson, Matthew and Bracegirdle, Thomas and Woollings, Tim},
doi = {10.1029/2019GL083264},
journal = {Geophysical Research Letters},
keywords = {Southern Hemisphere,atmospheric blocking,climate change},
number = {15},
pages = {9281--9290},
title = {{Southern Hemisphere Atmospheric Blocking in CMIP5 and Future Changes in the Australia-New Zealand Sector}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL083264},
volume = {46},
year = {2019}
}
@article{Pauling2017,
abstract = {Abstract Earth System Models do not reproduce the observed increase in Antarctic sea ice extent which may be due to the unrealistic representation of ice shelves. Here we investigate the response of sea ice to increasing freshwater input from ice shelves using the Community Earth System Model with the Community Atmosphere Model version 5 [CESM1(CAM5)]. We have conducted model experiments adding fresh water as if from ice shelf melt with a linear increase in the rate of input over the period 1980?2013. Including the effect of heat loss from the ocean to melt ice shelves resulted in significantly more positive trends in sea ice area. We found that an increase in the rate of change of freshwater input of ?45 Gt yr?2 was sufficient to offset the negative trend in sea ice area in CESM1(CAM5), although the freshwater input by the end of the experiment was larger than observed at that time.},
annote = {https://doi.org/10.1002/2017GL075017},
author = {Pauling, Andrew G and Smith, Inga J and Langhorne, Patricia J and Bitz, Cecilia M},
doi = {10.1002/2017GL075017},
issn = {00948276},
journal = {Geophysical Research Letters},
keywords = {Antarctica,climate models,freshwater input,latent heat,sea ice,sea ice area trends},
month = {oct},
number = {20},
pages = {10454--10461},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Time-Dependent Freshwater Input From Ice Shelves: Impacts on Antarctic Sea Ice and the Southern Ocean in an Earth System Model}},
url = {https://doi.org/10.1002/2017GL075017},
volume = {44},
year = {2017}
}
@article{Pauling2016b,
abstract = {ABSTRACTThe possibility that recent Antarctic sea ice expansion resulted from an increase in freshwater reaching the Southern Ocean is investigated here. The freshwater flux from ice sheet and ice shelf mass imbalance is largely missing in models that participated in phase 5 of the Coupled Model Intercomparison Project (CMIP5). However, on average, precipitation minus evaporation (P ? E) reaching the Southern Ocean has increased in CMIP5 models to a present value that is about greater than preindustrial times and 5?22 times larger than estimates of the mass imbalance of Antarctic ice sheets and shelves (119?544 ). Two sets of experiments were conducted from 1980 to 2013 in CESM1(CAM5), one of the CMIP5 models, artificially distributing freshwater either at the ocean surface to mimic iceberg melt or at the ice shelf fronts at depth. An anomalous reduction in vertical advection of heat into the surface mixed layer resulted in sea surface cooling at high southern latitudes and an associated increase in sea ice area. Enhancing the freshwater input by an amount within the range of estimates of the Antarctic mass imbalance did not have any significant effect on either sea ice area magnitude or trend. Freshwater enhancement of raised the total sea ice area by 1 ? 106 km2, yet this and even an enhancement of was insufficient to offset the sea ice decline due to anthropogenic forcing for any period of 20 years or longer. Further, the sea ice response was found to be insensitive to the depth of freshwater injection.},
author = {Pauling, Andrew G and Bitz, Cecilia M and Smith, Inga J and Langhorne, Patricia J},
doi = {10.1175/JCLI-D-15-0501.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jan},
number = {5},
pages = {1655--1672},
publisher = {American Meteorological Society},
title = {{The Response of the Southern Ocean and Antarctic Sea Ice to Freshwater from Ice Shelves in an Earth System Model}},
volume = {29},
year = {2016}
}
@article{Pausata2016a,
abstract = {The West African Monsoon (WAM) is crucial for the socio-economic stability of millions of people living in the Sahel. Severe droughts have ravaged the region in the last three decades of the 20th century, highlighting the need for a better understanding of the WAM dynamics. One of the most dramatic changes in the West African Monsoon (WAM) occurred between 15000-5000 yr BP, when increased summer rainfall led to the so-called "Green Sahara" and to a reduction in dust emissions from the region. However, model experiments are unable to fully reproduce the intensification and geographical expansion of the WAM during this period, even when vegetation over the Sahara is considered. Here, we use a fully coupled simulation for 6000 yr BP (Mid-Holocene) in which prescribed Saharan vegetation and dust concentrations are changed in turn. A closer agreement with proxy records is obtained only when both the Saharan vegetation changes and dust decrease are taken into account. The dust reduction strengthens the vegetation-albedo feedback, extending the monsoon's northern limit approximately 500 km further than the vegetation-change case only. We therefore conclude that accounting for changes in Saharan dust loadings is essential for improving model simulations of the WAM during the Mid-Holocene.},
author = {Pausata, Francesco S.R. and Messori, Gabriele and Zhang, Qiong},
doi = {10.1016/j.epsl.2015.11.049},
issn = {0012821X},
journal = {Earth and Planetary Science Letters},
keywords = {African Humid Period,Vegetation-dust feedbacks,West African Monsoon},
pages = {298--307},
publisher = {Elsevier},
title = {{Impacts of dust reduction on the northward expansion of the African monsoon during the Green Sahara period}},
volume = {434},
year = {2016}
}
@book{pearl2009causality,
address = {Cambridge, UK},
author = {Pearl, Judea},
doi = {10.1017/CBO9780511803161},
isbn = {9780511803161},
pages = {465},
publisher = {Cambridge University Press},
title = {{Causality: models, reasoning and inference}},
year = {2009}
}
@article{Pedersen2017,
author = {Pedersen, Rasmus A. and Langen, Peter L. and Vinther, Bo M.},
doi = {10.1007/s00382-016-3274-5},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {may},
number = {9-10},
pages = {3391--3407},
title = {{The last interglacial climate: comparing direct and indirect impacts of insolation changes}},
url = {http://link.springer.com/10.1007/s00382-016-3274-5},
volume = {48},
year = {2017}
}
@article{Peings2013,
abstract = {AbstractThe wintertime Northern Hemisphere (NH) atmospheric circulation response to current (2007?12) and projected (2080?99) Arctic sea ice decline is examined with the latest version of the Community Atmospheric Model (CAM5). The numerical experiments suggest that the current sea ice conditions force a remote atmospheric response in late winter that favors cold land surface temperatures over midlatitudes, as has been observed in recent years. Anomalous Rossby waves forced by the sea ice anomalies penetrate into the stratosphere in February and weaken the stratospheric polar vortex, resulting in negative anomalies of the northern annular mode (NAM) that propagate downward during the following weeks, especially over the North Pacific. The seasonality of the response is attributed to timing of the phasing between the forced and climatological waves. When sea ice concentration taken from projections of conditions at the end of the twenty-first century is prescribed to the model, negative anomalies of the NAM are visible in the troposphere, both in early and late winter. This response is mainly driven by the large warming of the lower troposphere over the Arctic, as little impact is found in the stratosphere in this experiment. As a result of the thermal expansion of the polar troposphere, the westerly flow is decelerated and a weak but statistically significant increase of the midlatitude meanders is identified. However, the thermodynamical response extends beyond the Arctic and offsets the dynamical effect, such that the stronger sea ice forcing has limited impact on the intensity of cold extremes over midlatitudes.},
annote = {Influence of present and future Arctic sea ice decline from CAM5 experiments
- CTL: 50 years, forced by climatological SST and SIC for 1979-2000
- 2010C: 50-member ensemble, Arctic SIC replaced by 2007-12 climatology (+ SST replaced where SIC significantly reduced)
- 2090C: 50-member ensemble, Arctic SIC replaced by 2080-99 CMIP5 CCSM4 RCP8.5
Radiative forcing is fixed at 2000 level

- In 2010C, stratospheric warming appears in the Arctic in February and propagates downward
- Projects onto negative NAM, but North Pacific signal is much stronger than Atlantic
- Constructive interference of forced and climatological planetary waves in February promotes SSW, but in earlier winter forced planetary waves are destructive
- In 2090C, the stratospheric response is much weaker, and negative NAM response appears within the troposphere

- Experiment is similar to Screen et al (2013 J Clim), who didn't find negative NAM response (but instead weak positive NAM in storatosphere) with CAM3 {\ldots} model dependence?},
author = {Peings, Yannick and Magnusdottir, Gudrun},
doi = {10.1175/JCLI-D-13-00272.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {sep},
number = {1},
pages = {244--264},
publisher = {American Meteorological Society},
title = {{Response of the Wintertime Northern Hemisphere Atmospheric Circulation to Current and Projected Arctic Sea Ice Decline: A Numerical Study with CAM5}},
url = {https://doi.org/10.1175/JCLI-D-13-00272.1},
volume = {27},
year = {2013}
}
@article{peings2016wintertime,
abstract = {through eddy–mean flow interactions. This modeling study supports that the positive phase of the AMV promotes the negative NAO in winter, while illustrating the impacts of the stratosphere and of the ocean–atmosphere feedbacks in the spatial pattern and timing of this response.},
author = {Peings, Yannick and Magnusdottir, Gudrun},
doi = {10.1007/s00382-015-2887-4},
issn = {14320894},
journal = {Climate Dynamics},
keywords = {Atlantic multidecadal variability,Cold extremes,Decadal forecasting,Jet stream,North Atlantic Oscillation,Ocean–atmosphere feedback,Rossby waves,Stratosphere–troposphere coupling,Teleconnection},
number = {3-4},
pages = {1029--1047},
publisher = {Springer},
title = {{Wintertime atmospheric response to Atlantic multidecadal variability: effect of stratospheric representation and ocean–atmosphere coupling}},
volume = {47},
year = {2016}
}
@article{Pendergrass2017,
abstract = {Precipitation is often quantified by the amount that falls over a given period of time, but not the rate at which most of it falls, or the rate associated with the most frequent events. Here, three metrics are introduced to distill salient characteristics of typical daily precipitation accumulation based on the full distribution of rainfall: rain amount peak (the rain rate at which the most rain falls); rain frequency peak (the most frequent non-zero rain rate); and rain amount width (a measure of the variability of typical precipitation accumulation). These metrics are applied to two observational datasets to describe the climatology of typical daily precipitation accumulation: GPCP One-Degree Daily (October 1996 – 2015) and TRMM 3B42 (January 1998 – October 2015). Results show that the rain frequency peak is similar to total rainfall in terms of geographical pattern and seasonal cycle, and varies inversely with rain amount width. In contrast, the rain amount peak varies distinctly, reaching maxi...},
author = {Pendergrass, Angeline G. and Deser, Clara},
doi = {10.1175/JCLI-D-16-0684.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Atmosphere,Climatology,Precipitation,Satellite observations},
month = {aug},
number = {15},
pages = {5985--6003},
title = {{Climatological characteristics of typical daily precipitation}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-16-0684.1},
volume = {30},
year = {2017}
}
@article{Peng2015a,
author = {Peng, Jing and Dan, Li},
doi = {10.1016/j.ecolmodel.2015.02.016},
journal = {Ecological modelling},
pages = {69--83},
publisher = {Elsevier},
title = {{Impacts of CO2 concentration and climate change on the terrestrial carbon flux using six global climate–carbon coupled models}},
volume = {304},
year = {2015}
}
@article{Perez2018,
abstract = {There has been about a forty per cent reduction in the transport of carbonate ions to the deep North Atlantic Ocean since preindustrial times, severely endangering cold-water corals.},
author = {Perez, Fiz F. and Fontela, Marcos and Garc{\'{i}}a-Ib{\'{a}}{\~{n}}ez, Maribel I. and Mercier, Herl{\'{e}} and Velo, Anton and Lherminier, Pascale and Zunino, Patricia and de la Paz, Mercedes and Alonso-P{\'{e}}rez, Fernando and Guallart, Elisa F. and Padin, Xose A.},
doi = {10.1038/nature25493},
issn = {0028-0836},
journal = {Nature},
keywords = {Marine chemistry,Physical oceanography},
month = {feb},
number = {7693},
pages = {515--518},
publisher = {Nature Publishing Group},
title = {{Meridional overturning circulation conveys fast acidification to the deep Atlantic Ocean}},
url = {http://www.nature.com/doifinder/10.1038/nature25493},
volume = {554},
year = {2018}
}
@article{Perez-Sanz2014c,
author = {Perez-Sanz, A and Li, G. and Gonzalez-Samperiz, P and Harrison, S. P.},
doi = {10.5194/cp-10-551-2014},
journal = {Climate of the Past},
pages = {551--568},
title = {{Evaluation of modern and mid-Holocene seasonal precipitation of the Mediterranean and northern Africa in the CMIP5 simulations}},
volume = {10},
year = {2014}
}
@article{perry2019projected,
author = {Perry, S J and McGregor, S and {Sen Gupta}, A. and England, M H and Maher, Nicola},
doi = {10.1007/s00382-019-05006-6},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jan},
number = {1-2},
pages = {395--412},
publisher = {Springer},
title = {{Projected late 21st century changes to the regional impacts of the El Ni{\~{n}}o-Southern Oscillation}},
url = {http://link.springer.com/10.1007/s00382-019-05006-6},
volume = {54},
year = {2020}
}
@article{Pfeffer2014,
abstract = {{\textless}p{\textgreater} The Randolph Glacier Inventory (RGI) is a globally complete collection of digital outlines of glaciers, excluding the ice sheets, developed to meet the needs of the Fifth Assessment of the Intergovernmental Panel on Climate Change for estimates of past and future mass balance. The RGI was created with limited resources in a short period. Priority was given to completeness of coverage, but a limited, uniform set of attributes is attached to each of the {\~{}}198 000 glaciers in its latest version, 3.2. Satellite imagery from 1999–2010 provided most of the outlines. Their total extent is estimated as 726 800 ± 34 000 km {\textless}sup{\textgreater}2{\textless}/sup{\textgreater} . The uncertainty, about ±5{\%}, is derived from careful single-glacier and basin-scale uncertainty estimates and comparisons with inventories that were not sources for the RGI. The main contributors to uncertainty are probably misinterpretation of seasonal snow cover and debris cover. These errors appear not to be normally distributed, and quantifying them reliably is an unsolved problem. Combined with digital elevation models, the RGI glacier outlines yield hypsometries that can be combined with atmospheric data or model outputs for analysis of the impacts of climatic change on glaciers. The RGI has already proved its value in the generation of significantly improved aggregate estimates of glacier mass changes and total volume, and thus actual and potential contributions to sea-level rise. {\textless}/p{\textgreater}},
author = {Pfeffer, W. Tad and Arendt, Anthony A. and Bliss, Andrew and Bolch, Tobias and Cogley, J. Graham and Gardner, Alex S. and Hagen, Jon-Ove and Hock, Regine and Kaser, Georg and Kienholz, Christian and Miles, Evan S. and Moholdt, Geir and M{\"{o}}lg, Nico and Paul, Frank and Radi{\'{c}}, Valentina and Rastner, Philipp and Raup, Bruce H. and Rich, Justin and Sharp, Martin J. and Consortium, The Randolph},
doi = {10.3189/2014JoG13J176},
issn = {0022-1430},
journal = {Journal of Glaciology},
keywords = {Antarctic glaciology,Arctic glaciology,glacier delineation,glacier mapping,remote sensing,tropical glaciology},
month = {jul},
number = {221},
pages = {537--552},
publisher = {Cambridge University Press},
title = {{The Randolph Glacier Inventory: a globally complete inventory of glaciers}},
url = {https://www.cambridge.org/core/product/identifier/S002214300020600X/type/journal{\_}article},
volume = {60},
year = {2014}
}
@article{Philip2018b,
abstract = {In northern and central Ethiopia, 2015 was a very dry year. Rainfall was only from one-half to three-quarters of the usual amount, with both the “belg” (February–May) and “kiremt” rains (June–September) affected. The timing of the rains that did fall was also erratic. Many crops failed, causing food shortages for many millions of people. The role of climate change in the probability of a drought like this is investigated, focusing on the large-scale precipitation deficit in February–September 2015 in northern and central Ethiopia. Using a gridded analysis that combines station data with satellite observations, it is estimated that the return period of this drought was more than 60 years (lower bound 95{\%} confidence interval), with a most likely value of several hundred years. No trend is detected in the observations, but the large natural variability and short time series means large trends could go undetected in the observations. Two out of three large climate model ensembles that simulated rainfall reasonably well show no trend while the third shows an increased probability of drought. Taking the model spread into account the drought still cannot be clearly attributed to anthropogenic climate change, with the 95{\%} confidence interval ranging from a probability decrease between preindustrial and today of a factor of 0.3 and an increase of a factor of 5 for a drought like this one or worse. A soil moisture dataset also shows a nonsignificant drying trend. According to ENSO correlations in the observations, the strong 2015 El Ni{\~{n}}o did increase the severity of the drought.},
author = {Philip, Sjoukje and Kew, Sarah F. and van Oldenborgh, Geert Jan and Otto, Friederike and O'Keefe, Sarah and Haustein, Karsten and King, Andrew and Zegeye, Abiy and Eshetu, Zewdu and Hailemariam, Kinfe and Singh, Roop and Jjemba, Eddie and Funk, Chris and Cullen, Heidi},
doi = {10.1175/JCLI-D-17-0274.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {mar},
number = {6},
pages = {2465--2486},
title = {{Attribution Analysis of the Ethiopian Drought of 2015}},
url = {https://journals.ametsoc.org/doi/10.1175/JCLI-D-17-0274.1},
volume = {31},
year = {2018}
}
@article{Phillips2014,
author = {Phillips, Adam S. and Deser, Clara and Fasullo, John},
doi = {10.1002/2014EO490002},
issn = {00963941},
journal = {Eos, Transactions American Geophysical Union},
keywords = {climate variability,decadal variability,model verification},
month = {dec},
number = {49},
pages = {453--455},
publisher = {Wiley-Blackwell},
title = {{Evaluating Modes of Variability in Climate Models}},
url = {http://doi.wiley.com/10.1002/2014EO490002},
volume = {95},
year = {2014}
}
@article{Piao2017a,
abstract = {Abstract No consensus has yet been reached on the major factors driving the observed increase in the seasonal amplitude of atmospheric CO2 in the northern latitudes. In this study, we used atmospheric CO2 records from 26 northern hemisphere stations with a temporal coverage longer than 15 years, and an atmospheric transport model prescribed with net biome productivity (NBP) from an ensemble of nine terrestrial ecosystem models, to attribute change in the seasonal amplitude of atmospheric CO2. We found significant (p {\textless} .05) increases in seasonal peak-to-trough CO2 amplitude (AMPP-T) at nine stations, and in trough-to-peak amplitude (AMPT-P) at eight stations over the last three decades. Most of the stations that recorded increasing amplitudes are in Arctic and boreal regions ({\textgreater}50°N), consistent with previous observations that the amplitude increased faster at Barrow (Arctic) than at Mauna Loa (subtropics). The multi-model ensemble mean (MMEM) shows that the response of ecosystem carbon cycling to rising CO2 concentration (eCO2) and climate change are dominant drivers of the increase in AMPP-T and AMPT-P in the high latitudes. At the Barrow station, the observed increase of AMPP-T and AMPT-P over the last 33 years is explained by eCO2 (39{\%} and 42{\%}) almost equally than by climate change (32{\%} and 35{\%}). The increased carbon losses during the months with a net carbon release in response to eCO2 are associated with higher ecosystem respiration due to the increase in carbon storage caused by eCO2 during carbon uptake period. Air-sea CO2 fluxes (10{\%} for AMPP-T and 11{\%} for AMPT-P) and the impacts of land-use change (marginally significant 3{\%} for AMPP-T and 4{\%} for AMPT-P) also contributed to the CO2 measured at Barrow, highlighting the role of these factors in regulating seasonal changes in the global carbon cycle.},
author = {Piao, Shilong and Liu, Zhuo and Wang, Yilong and Ciais, Philippe and Yao, Yitong and Peng, Shushi and Chevallier, Fr{\'{e}}d{\'{e}}ric and Friedlingstein, Pierre and Janssens, Ivan A and Pe{\~{n}}uelas, Josep and Sitch, Stephen and Wang, Tao},
doi = {doi:10.1111/gcb.13909},
issn = {1354-1013},
journal = {Global Change Biology},
number = {2},
pages = {608--616},
title = {{On the causes of trends in the seasonal amplitude of atmospheric CO2}},
volume = {24},
year = {2017}
}
@article{Pierce2012,
abstract = {The ocean's salinity field is driven primarily by evaporation, precipitation, and river discharge, all key elements of the Earth's hydrological cycle. Observations show the salinity field has been changing in recent decades. We perform a formal fingerprint-based detection and attribution analysis of these changes between 1955-2004, 60S and 60N, and in the top 700 m of the water column. We find that observed changes are inconsistent with the effects of natural climate variability, either internal to the climate system (such as El Nio and the Pacific Decadal Oscillation) or external (solar fluctuations and volcanic eruptions). However, the observed changes are consistent with the changes expected due to human forcing of the climate system. Joint changes in salinity and temperature yield a stronger signal of human effects on climate than either salinity or temperature alone. When examining individual depth levels, observed salinity changes are unlikely (p {\textless} 0.05) to have arisen from natural causes over the top 125 m of the water column, while temperature changes (and joint salinity/temperature changes) are distinct from natural variability over the top 250 m. {\textcopyright} 2012. American Geophysical Union. All Rights Reserved.},
author = {Pierce, David W. and Gleckler, Peter J. and Barnett, Tim P. and Santer, Benjamin D. and Durack, Paul J.},
doi = {10.1029/2012GL053389},
isbn = {0094-8276},
issn = {00948276},
journal = {Geophysical Research Letters},
keywords = {climate change,ocean salinity},
month = {nov},
number = {21},
pages = {L21704},
publisher = {Wiley-Blackwell},
title = {{The fingerprint of human-induced changes in the ocean's salinity and temperature fields}},
url = {http://doi.wiley.com/10.1029/2012GL053389},
volume = {39},
year = {2012}
}
@article{doi:10.1002/2016GL069551,
abstract = {Abstract State-of-the art climate models generally struggle to represent important features of the large-scale circulation. Common model deficiencies include an equatorward bias in the location of the midlatitude westerlies and an overly zonal orientation of the North Atlantic storm track. Orography is known to strongly affect the atmospheric circulation and is notoriously difficult to represent in coarse-resolution climate models. Yet how the representation of orography affects circulation biases in current climate models is not understood. Here we show that the effects of switching off the parameterization of drag from low-level orographic blocking in one climate model resemble the biases of the Coupled Model Intercomparison Project Phase 5 ensemble: An overly zonal wintertime North Atlantic storm track and less European blocking events, and an equatorward shift in the Southern Hemispheric jet and increase in the Southern Annular Mode time scale. This suggests that typical circulation biases in coarse-resolution climate models may be alleviated by improved parameterizations of low-level drag.},
author = {Pithan, Felix and Shepherd, Theodore G and Zappa, Giuseppe and Sandu, Irina},
doi = {10.1002/2016GL069551},
journal = {Geophysical Research Letters},
keywords = {extratropical circulation,model biases,orographic drag},
number = {13},
pages = {7231--7240},
title = {{Climate model biases in jet streams, blocking and storm tracks resulting from missing orographic drag}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2016GL069551},
volume = {43},
year = {2016}
}
@article{Planton2020a,
abstract = {El Ni{\~{n}}o–Southern Oscillation (ENSO) is the dominant mode of interannual climate variability on the planet, with far-reaching global impacts. It is therefore key to evaluate ENSO simulations in state-of-the-art numerical models used to study past, present, and future climate. Recently, the Pacific Region Panel of the International Climate and Ocean: Variability, Predictability and Change (CLIVAR) Project, as a part of the World Climate Research Programme (WCRP), led a community-wide effort to evaluate the simulation of ENSO variability, teleconnections, and processes in climate models. The new CLIVAR 2020 ENSO metrics package enables model diagnosis, comparison, and evaluation to 1) highlight aspects that need improvement; 2) monitor progress across model generations; 3) help in selecting models that are well suited for particular analyses; 4) reveal links between various model biases, illuminating the impacts of those biases on ENSO and its sensitivity to climate change; and to 5) advance ENSO literacy. By interfacing with existing model evaluation tools, the ENSO metrics package enables rapid analysis of multipetabyte databases of simulations, such as those generated by the Coupled Model Intercomparison Project phases 5 (CMIP5) and 6 (CMIP6). The CMIP6 models are found to significantly outperform those from CMIP5 for 8 out of 24 ENSO-relevant metrics, with most CMIP6 models showing improved tropical Pacific seasonality and ENSO teleconnections. Only one ENSO metric is significantly degraded in CMIP6, namely, the coupling between the ocean surface and subsurface temperature anomalies, while the majority of metrics remain unchanged.},
author = {Planton, Yann Y and Guilyardi, Eric and Wittenberg, Andrew T and Lee, Jiwoo and Gleckler, Peter J and Bayr, Tobias and McGregor, Shayne and McPhaden, Michael J and Power, Scott and Roehrig, Romain and Vialard, J{\'{e}}r{\^{o}}me and Voldoire, Aurore},
doi = {10.1175/BAMS-D-19-0337.1},
issn = {0003-0007},
journal = {Bulletin of the American Meteorological Society},
month = {feb},
number = {2},
pages = {E193--E217},
title = {{Evaluating Climate Models with the CLIVAR 2020 ENSO Metrics Package}},
url = {https://doi.org/10.1175/BAMS-D-19-0337.1},
volume = {102},
year = {2021}
}
@article{Po-Chedley2021,
abstract = {A long-standing discrepancy exists between general circulation models (GCMs) and satellite observations: The multimodel mean temperature of the midtroposphere (TMT) in the tropics warms at approximately twice the rate of observations. Using a large ensemble of simulations from a single climate model, we find that tropical TMT trends (1979–2018) vary widely and that a subset of realizations are within the range of satellite observations. Realizations with relatively small tropical TMT trends are accompanied by subdued sea-surface warming in the tropical central and eastern Pacific. Observed changes in sea-surface temperature have a similar pattern, implying that the observed tropical TMT trend has been reduced by multidecadal variability. We also assess the latest generation of GCMs from the Coupled Model Intercomparison Project Phase 6 (CMIP6). CMIP6 simulations with muted warming over the central and eastern Pacific also show reduced tropical tropospheric warming. We find that 13{\%} of the model realizations have tropical TMT trends within the observed trend range. These simulations are from models with both small and large climate sensitivity values, illustrating that the magnitude of tropical tropospheric warming is not solely a function of climate sensitivity. For global averages, one-quarter of model simulations exhibit TMT trends in accord with observations. Our results indicate that even on 40-y timescales, natural climate variability is important to consider when comparing observed and simulated tropospheric warming and is sufficiently large to explain TMT trend differences between models and satellite data.},
author = {Po-Chedley, Stephen and Santer, Benjamin D. and Fueglistaler, Stephan and Zelinka, Mark D. and Cameron-Smith, Philip J. and Painter, Jeffrey F. and Fu, Qiang},
doi = {10.1073/pnas.2020962118},
issn = {0027-8424},
journal = {Proceedings of the National Academy of Sciences},
month = {mar},
number = {13},
pages = {e2020962118},
title = {{Natural variability contributes to model–satellite differences in tropical tropospheric warming}},
url = {http://www.pnas.org/lookup/doi/10.1073/pnas.2020962118},
volume = {118},
year = {2021}
}
@article{Polade2013,
author = {Polade, Suraj D. and Gershunov, Alexander and Cayan, Daniel R. and Dettinger, Michael D. and Pierce, David W.},
doi = {10.1002/grl.50491},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {may},
number = {10},
pages = {2296--2301},
title = {{Natural climate variability and teleconnections to precipitation over the Pacific-North American region in CMIP3 and CMIP5 models}},
url = {http://doi.wiley.com/10.1002/grl.50491},
volume = {40},
year = {2013}
}
@article{Polson2014,
abstract = {The Northern Hemisphere monsoons are an integral component of Earth's hydrological cycle and affect the lives of billions of people. Observed precipitation in the monsoon regions underwent substantial changes during the second half of the twentieth century, with drying from the 1950s to mid-1980s and increasing precipitation in recent decades. Modeling studies suggest that anthropogenic aerosols have been a key factor driving changes in tropical and monsoon precipitation. Here we apply detection and attribution methods to determine whether observed changes are driven by human influences using fingerprints of individual forcings (i.e., greenhouse gas, anthropogenic aerosol, and natural) derived from climate models. The results show that the observed changes can only be explained when including the influence of anthropogenic aerosols, even after accounting for internal climate variability. Anthropogenic aerosol, not greenhouse gas or natural forcing, has been the dominant influence on Northern Hemisphere monsoon precipitation over the second half of the twentieth century.},
annote = {NH summer monsoon precipitation
1950-2005
4 observational datasets of land precip
CMIP5 historical, historicalGHG, historicalAA, historicalNat, historicalAnt
Monsoon-area MJJAS precip 
Detection {\&} Attribution

- NH summer monsoon precip decreased from 1950s to mid-80s, followed by strengthening
- Anthropogenic fingerprint is detectable
- Most important forcing from anthropogenic aerosols
- GHG acts to strengthen the NH summer monsoon, but aerosols affect oppositely and dominates over GHG influence
- Inclusion of indirect effects does not significantly improve D{\&}A},
author = {Polson, D and Bollasina, M and Hegerl, G C and Wilcox, L J},
doi = {10.1002/2014GL060811},
journal = {Geophysical Research Letters},
keywords = {10.1002/2014GL060811 and monsoon,anthropogenic aerosol,climate models,detection and attribution,precipitation},
pages = {6023--6029},
title = {{Decreased monsoon precipitation in the Northern Hemisphere due to anthropogenic aerosols}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2014GL060811},
volume = {41},
year = {2014}
}
@article{Polson2016,
author = {Polson, D and Hegerl, G C and Solomon, S},
doi = {10.1088/1748-9326/11/7/074024},
issn = {1748-9326},
journal = {Environmental Research Letters},
month = {jul},
number = {7},
pages = {074024},
title = {{Precipitation sensitivity to warming estimated from long island records}},
volume = {11},
year = {2016}
}
@article{Polson2017,
author = {Polson, D and Hegerl, G C},
doi = {10.1002/2016GL071194},
journal = {Geophysical Research Letters},
pages = {365--373},
title = {{Strengthening contrast between precipitation in tropical wet and dry regions}},
volume = {44},
year = {2017}
}
@article{Polvani2013,
abstract = {The recent observed positive trends in total Antarctic sea ice extent are at odds with the expectation of melting sea ice in a warming world. More problematic yet, climate models indicate that sea ice should decrease around Antarctica in response to both increasing greenhouse gases and stratospheric ozone depletion. The resolution of this puzzle, we suggest, may lie in the large natural variability of the coupled atmosphere‒ocean‒sea‒ice system. Contrasting forced and control integrations from four state‒of‒the‒art Coupled Model Intercomparison Project Phase 5 (CMIP5) models, we show that the observed Antarctic sea ice trend falls well within the distribution of trends arising naturally in the system, and that the forced response in the models is small compared to the natural variability. From this, we conclude that it may prove difficult to attribute the observed trends in total Antarctic sea ice to anthropogenic forcings, although some regional features might be easier to explain.},
author = {Polvani, Lorenzo M and Smith, Karen L},
doi = {10.1002/grl.50578},
isbn = {1944-8007},
issn = {00948276},
journal = {Geophysical Research Letters},
keywords = {Antarctic sea ice,global climate models,natural variability,sea ice trends},
month = {may},
number = {12},
pages = {3195--3199},
publisher = {Wiley-Blackwell},
title = {{Can natural variability explain observed Antarctic sea ice trends? New modeling evidence from CMIP5}},
volume = {40},
year = {2013}
}
@article{Polvani2020,
abstract = {The rapid warming of the Arctic, perhaps the most striking evidence of climate change, is believed to have arisen from increases in atmospheric concentrations of GHGs1 since the Industrial Revolution. While the dominant role of carbon dioxide is undisputed, another important set of anthropogenic GHGs was also being emitted over the second half of the twentieth century: ozone-depleting2 substances (ODS). These compounds, in addition to causing the ozone hole over Antarctica, have long been recognized3 as powerful GHGs. However, their contribution to Arctic warming has not been quantified. We do so here by analysing ensembles of climate model integrations specifically designed for this purpose, spanning the period 1955–2005 when atmospheric concentrations of ODS increased rapidly. We show that, when ODS are kept fixed, forced Arctic surface warming and forced sea-ice loss are only half as large as when ODS are allowed to increase. We also demonstrate that the large impact of ODS on the Arctic occurs primarily via direct radiative warming, not via ozone depletion. Our findings reveal a substantial contribution of ODS to recent Arctic warming, and highlight the importance of the Montreal Protocol as a major climate change-mitigation treaty.},
author = {Polvani, L M and Previdi, M and England, M R and Chiodo, G and Smith, K L},
doi = {10.1038/s41558-019-0677-4},
issn = {1758-6798},
journal = {Nature Climate Change},
number = {2},
pages = {130--133},
title = {{Substantial twentieth-century Arctic warming caused by ozone-depleting substances}},
url = {https://doi.org/10.1038/s41558-019-0677-4},
volume = {10},
year = {2020}
}
@article{doi:10.1111/gcb.13988,
abstract = {Abstract As the applications of Earth system models (ESMs) move from general climate projections toward questions of mitigation and adaptation, the inclusion of land management practices in these models becomes crucial. We carried out a survey among modeling groups to show an evolution from models able only to deal with land-cover change to more sophisticated approaches that allow also for the partial integration of land management changes. For the longer term a comprehensive land management representation can be anticipated for all major models. To guide the prioritization of implementation, we evaluate ten land management practices—forestry harvest, tree species selection, grazing and mowing harvest, crop harvest, crop species selection, irrigation, wetland drainage, fertilization, tillage, and fire—for (1) their importance on the Earth system, (2) the possibility of implementing them in state-of-the-art ESMs, and (3) availability of required input data. Matching these criteria, we identify “low-hanging fruits” for the inclusion in ESMs, such as basic implementations of crop and forestry harvest and fertilization. We also identify research requirements for specific communities to address the remaining land management practices. Data availability severely hampers modeling the most extensive land management practice, grazing and mowing harvest, and is a limiting factor for a comprehensive implementation of most other practices. Inadequate process understanding hampers even a basic assessment of crop species selection and tillage effects. The need for multiple advanced model structures will be the challenge for a comprehensive implementation of most practices but considerable synergy can be gained using the same structures for different practices. A continuous and closer collaboration of the modeling, Earth observation, and land system science communities is thus required to achieve the inclusion of land management in ESMs.},
author = {Pongratz, Julia and Dolman, Han and Don, Axel and Erb, Karl-Heinz and Fuchs, Richard and Herold, Martin and Jones, Chris and Kuemmerle, Tobias and Luyssaert, Sebastiaan and Meyfroidt, Patrick and Naudts, Kim},
doi = {10.1111/gcb.13988},
journal = {Global Change Biology},
keywords = {Earth observations,Earth system models,climate,croplands,forestry,grazing,land management,land use},
number = {4},
pages = {1470--1487},
title = {{Models meet data: Challenges and opportunities in implementing land management in Earth system models}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.13988},
volume = {24},
year = {2018}
}
@article{Poulsen2018,
author = {Poulsen, Mads B and Jochum, Markus and Nuterman, Roman},
doi = {10.1016/j.ocemod.2018.01.008},
issn = {14635003},
journal = {Ocean Modelling},
month = {apr},
pages = {1--15},
title = {{Parameterized and resolved Southern Ocean eddy compensation}},
url = {https://linkinghub.elsevier.com/retrieve/pii/S1463500318300258},
volume = {124},
year = {2018}
}
@article{Power2018a,
abstract = {Increases in greenhouse gas emissions are expected to cause changes in both climatic variability in the Pacific linked to the El Ni{\~{n}}o-Southern Oscillation (ENSO), and in long-term average climate. While mean-state and variability changes have been studied separately, much less is known about their combined impact or relative importance. Additionally, studies of projected changes in ENSO have tended to focus on changes in, or adjacent to, the Pacific. Here we examine projected changes in climatic conditions during El Ni{\~{n}}o years and in ENSO-driven precipitation variability in 36 CMIP5 models. The models are forced according to the RCP8.5 scenario in which there are large, unmitigated increases in greenhouse gas concentrations during the 21st century. We examine changes over much of the globe, including 25 IPCC widely spread SREX regions. We confirm that precipitation variability associated with ENSO is projected to increase in the tropical Pacific, consistent with earlier research. We also find that the enhanced tropical Pacific variability drives ENSO-related variability increases in 19 SREX regions during DJF, and in 18 during JJA. This externally-forced increase in ENSO-driven precipitation variability around the world is of order 15-20{\%}. An increase of this size, although substantial, is easily masked at the regional level by internally-generated multidecadal variability in individual runs. The projected changes in ENSO-driven precipitation variability are typically much smaller than projected changes in both mean-state and ENSO neutral conditions in nearly all regions.},
author = {Power, Scott B. and Delage, Fran{\c{c}}ois P.D.},
doi = {10.1175/JCLI-D-18-0138.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Atmosphere,Climate change,Climate variability,ENSO},
number = {15},
pages = {6189--6207},
title = {{El Ni{\~{n}}o-Southern oscillation and associated climatic conditions around the world during the latter half of the twenty-first century}},
volume = {31},
year = {2018}
}
@article{Power1999,
abstract = {The success of an ENSO-based statistical rainfall prediction scheme and the influence of ENSO on Australia are shown to vary in association with a coherent, inter-decadal oscillation in surface temperature over the Pacific Ocean. When this Inter-decadal Pacific Oscillation (IPO) raises temperatures in the tropical Paci"c Ocean, there is no robust relationship between year-to-year Australian climate variations and ENSO. When the IPO lowers temperature in the same region, on the other hand, year-to-year ENSO variability is closely associated with year-to-year variability in rainfall, surface temperature, river {\#}ow and the domestic wheat crop yield. The contrast in ENSO's in{\#}uence between the two phases of the IPO is quite remarkable. This highlights exciting new avenues for obtaining improved climate predictions.},
author = {Power, S.B. and Casey, T. and Folland, C. and Colman, A. and Mehta, V.},
doi = {10.1007/s003820050284},
isbn = {0930-7575},
issn = {09307575},
journal = {Climate Dynamics},
number = {5},
pages = {319--324},
pmid = {50090442},
title = {{Inter-decadal modulation of the impact of ENSO on Australia}},
volume = {15},
year = {1999}
}
@article{Power2017,
author = {Power, Scott B. and Delage, Fran{\c{c}}ois and Wang, Guomin and Smith, Ian and Kociuba, Greg},
doi = {10.1007/s00382-016-3326-x},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jul},
number = {1-2},
pages = {53--69},
title = {{Apparent limitations in the ability of CMIP5 climate models to simulate recent multi-decadal change in surface temperature: implications for global temperature projections}},
url = {http://link.springer.com/10.1007/s00382-016-3326-x},
volume = {49},
year = {2017}
}
@article{Praetorius2015,
abstract = {The processes responsible for driving the expansion of the ocean's oxygen minimum zones remain uncertain; here sediment core data from the Gulf of Alaska suggest that reduced oxygen solubility was a result of ocean warming initiating the expansion of the North Pacific oxygen minimum zone, leading to increased marine productivity and carbon export and, in turn, further reductions in dissolved oxygen levels. The processes responsible for driving the expansion of the ocean's oxygen minimum zones — also known as hypoxic or 'dead' zones — remain uncertain. This paper describes two warming events during the last deglacial transition that coincide with a shift to hypoxia, based on sediment core data from the Gulf of Alaska. The data suggest that reduced oxygen solubility was a result of ocean warming initiating the expansion of the North Pacific oxygen minimum zone, leading to increased marine productivity and carbon export and, in turn, further reductions in dissolved oxygen levels. Marine sediments from the North Pacific document two episodes of expansion and strengthening of the subsurface oxygen minimum zone (OMZ) accompanied by seafloor hypoxia during the last deglacial transition1,2,3,4. The mechanisms driving this hypoxia remain under debate1,2,3,4,5,6,7,8,9,10,11. We present a new high-resolution alkenone palaeotemperature reconstruction from the Gulf of Alaska that reveals two abrupt warming events of 4–5 degrees Celsius at the onset of the B{\o}lling and Holocene intervals that coincide with sudden shifts to hypoxia at intermediate depths. The presence of diatomaceous laminations and hypoxia-tolerant benthic foraminiferal species, peaks in redox-sensitive trace metals12,13, and enhanced 15N/14N ratio of organic matter13, collectively suggest association with high export production. A decrease in 18O/16O values of benthic foraminifera accompanying the most severe deoxygenation event indicates subsurface warming of up to about 2 degrees Celsius. We infer that abrupt warming triggered expansion of the North Pacific OMZ through reduced oxygen solubility and increased marine productivity via physiological effects; following initiation of hypoxia, remobilization of iron from hypoxic sediments could have provided a positive feedback on ocean deoxygenation through increased nutrient utilization and carbon export. Such a biogeochemical amplification process implies high sensitivity of OMZ expansion to warming.},
author = {Praetorius, S. K. and Mix, A. C. and Walczak, M. H. and Wolhowe, M. D. and Addison, J. A. and Prahl, F. G.},
doi = {10.1038/nature15753},
issn = {0028-0836},
journal = {Nature},
keywords = {Marine chemistry,Palaeoceanography},
month = {nov},
number = {7578},
pages = {362--366},
publisher = {Nature Publishing Group},
title = {{North Pacific deglacial hypoxic events linked to abrupt ocean warming}},
url = {http://www.nature.com/articles/nature15753},
volume = {527},
year = {2015}
}
@article{Prescott2019,
author = {Prescott, C.L. and Haywood, A.M. and Dolan, A.M. and Hunter, S.J. and Tindall, J.C.},
doi = {10.1016/j.gloplacha.2018.12.002},
issn = {09218181},
journal = {Global and Planetary Change},
month = {feb},
pages = {33--46},
title = {{Indian monsoon variability in response to orbital forcing during the late Pliocene}},
url = {https://linkinghub.elsevier.com/retrieve/pii/S0921818118302273},
volume = {173},
year = {2019}
}
@article{Previdi2016a,
abstract = {Global and regional climate models robustly simulate increases in Antarctic surface mass balance (SMB) during the twentieth and twenty-first centuries in response to anthropogenic global warming. Despite these robust model projections, however, observations indicate that there has been no significant change in Antarctic SMB in recent decades. We show that this apparent discrepancy between models and observations can be explained by the fact that the anthropogenic climate change signal during the second half of the twentieth century is small compared to the noise associated with natural climate variability. Using an ensemble of 35 global coupled climate models to separate signal and noise, we find that the forced SMB increase due to global warming in recent decades is unlikely to be detectable as a result of large natural SMB variability. However, our analysis reveals that the anthropogenic impact on Antarctic SMB is very likely to emerge from natural variability by the middle of the current century, thus mitigating future increases in global sea level.},
author = {Previdi, Michael and Polvani, Lorenzo M.},
doi = {10.1088/1748-9326/11/9/094001},
issn = {1748-9326},
journal = {Environmental Research Letters},
month = {sep},
number = {9},
pages = {094001},
title = {{Anthropogenic impact on Antarctic surface mass balance, currently masked by natural variability, to emerge by mid-century}},
url = {https://iopscience.iop.org/article/10.1088/1748-9326/11/9/094001},
volume = {11},
year = {2016}
}
@article{Priestley2020b,
abstract = {The representation of the winter and summer extratropical storm tracks in both hemispheres is evaluated in detail for the available models in phase 6 of the Coupled Model intercomparison Project (CMIP6). The state of the storm tracks from 1979 to 2014 is compared to that in ERA5 using a Lagrangian objective cyclone tracking algorithm. It is found that the main biases present in the previous generation of models (CMIP5) still persist, albeit to a lesser extent. The equatorward bias around the SH is much reduced and there appears to be some improvement in mean biases with the higher-resolution models, such as the zonal tilt of the North Atlantic storm track. Low-resolution models have a tendency to underestimate the frequency of high-intensity cyclones with all models simulating a peak intensity that is too low for cyclones in the SH. Explosively developing cyclones are underestimated across all ocean basins and in both hemispheres. In particular the models struggle to capture the rapid deepening required for these cyclones. For all measures, the CMIP6 models exhibit an overall improvement compared to the previous generation of CMIP5 models. In the NH most improvements can be attributed to increased horizontal resolution, whereas in the SH the impact of resolution is less apparent and any improvements are likely a result of improved model physics.},
author = {Priestley, Matthew D. K. and Ackerley, Duncan and Catto, Jennifer L. and Hodges, Kevin I. and McDonald, Ruth E. and Lee, Robert W.},
doi = {10.1175/JCLI-D-19-0928.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {aug},
number = {15},
pages = {6315--6343},
title = {{An Overview of the Extratropical Storm Tracks in CMIP6 Historical Simulations}},
url = {https://journals.ametsoc.org/doi/10.1175/JCLI-D-19-0928.1},
volume = {33},
year = {2020}
}
@article{Purich2016,
author = {Purich, Ariaan and Cai, Wenju and England, Matthew H and Cowan, Tim},
doi = {10.1038/ncomms10409},
journal = {Nature Communications},
month = {feb},
pages = {10409},
publisher = {The Author(s)},
title = {{Evidence for link between modelled trends in Antarctic sea ice and underestimated westerly wind changes}},
url = {http://dx.doi.org/10.1038/ncomms10409 http://10.0.4.14/ncomms10409 https://www.nature.com/articles/ncomms10409{\#}supplementary-information},
volume = {7},
year = {2016}
}
@article{Purich2019,
abstract = {Abstract Following a multidecade increase, Antarctic sea ice declined drastically during austral spring 2016. Suggested causes of the sea ice decline include lingering effects of the 2015/2016 extreme El Ni{\~{n}}o and a tropical Indian Ocean teleconnection to high-latitude atmospheric circulation. Here, we conduct pacemaker experiments using a full coupled climate model forced with observed tropical sea surface temperature to examine the impact of the Indian and Pacific Oceans on southern high latitudes during spring 2016. Our experiments suggest that a Rossby wave teleconnection from the tropical Indian Ocean contributed to the sea ice decline during spring 2016, with less influence from the Pacific Ocean. However, we find considerable spread in the magnitude of sea ice anomalies across ensemble members, suggesting that while an Indian Ocean teleconnection likely played a role, intrinsic atmospheric variability and high-latitude ocean conditions may also have been important in driving the observed 2016 spring sea ice decline.},
annote = {doi: 10.1029/2019GL082671},
author = {Purich, Ariaan and England, Matthew H},
doi = {10.1029/2019GL082671},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {Antarctica,Southern Ocean,climate variability,sea ice,tropical teleconnection},
month = {jun},
number = {12},
pages = {6848--6858},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Tropical Teleconnections to Antarctic Sea Ice During Austral Spring 2016 in Coupled Pacemaker Experiments}},
url = {https://doi.org/10.1029/2019GL082671},
volume = {46},
year = {2019}
}
@article{Purkey2010,
abstract = {Abyssal global and deep Southern Ocean temperature trends are quantified between the 1990s and 2000s to assess the role of recent warming of these regions in global heat and sea level budgets. The authors 1) compute warming rates with uncertainties along 28 full-depth, high-quality hydrographic sections that have been occupied two or more times between 1980 and 2010; 2) divide the global ocean into 32 basins, defined by the topography and climatological ocean bottom temperatures; and then 3) estimate temperature trends in the 24 sampled basins. The three southernmost basins show a strong statistically significant abyssal warming trend, with that warming signal weakening to the north in the central Pacific, western Atlantic, and eastern Indian Oceans. Eastern Atlantic and western Indian Ocean basins show statistically insignificant abyssal cooling trends. Excepting the Arctic Ocean and Nordic seas, the rate of abyssal (below 4000 m) global ocean heat content change in the 1990s and 2000s is equiva...},
author = {Purkey, Sarah G. and Johnson, Gregory C.},
doi = {10.1175/2010JCLI3682.1},
isbn = {0894-8755},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Fronts,Heat budgets,Sea level,Temperature,Trends},
month = {dec},
number = {23},
pages = {6336--6351},
title = {{Warming of global abyssal and deep Southern Ocean waters between the 1990s and 2000s: Contributions to global heat and sea level rise budgets}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/2010JCLI3682.1},
volume = {23},
year = {2010}
}
@article{Qasmi2017,
abstract = {A realistic simulation of the Atlantic Multidecadal Variability (AMV) and related teleconnections is essential to resolve and understand the potential predictability over Europe at decadal timescale. Based on a large ensemble of state-of-the-art climate models, we show that a considerable intermodel spread exists in the spatiotemporal properties of the simulated AMV and teleconnections with European summer temperature. The greater the persistence, variance, and basin-scale spatial coherence, the stronger the teleconnection. We demonstrate that only a few members of a few models produce a teleconnection that is consistent with observational estimates over the instrumental period. This highlights the possible extreme nature of the last century teleconnection and/or a detrimental underestimation of ocean-land teleconnectivity in many climate models. Yet we emphasize the considerable uncertainties due to methods used to disentangle internal and externally forced variations in observations, and to sampling, which must be correctly accounted when analyses are performed on short temporal records.},
author = {Qasmi, Sa{\"{i}}d and Cassou, Christophe and Bo{\'{e}}, Julien},
doi = {10.1002/2017GL074886},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {Atlantic Multidecadal Variability,CMIP5,model evaluation,teleconnection over Europe},
month = {nov},
number = {21},
pages = {11140--11149},
title = {{Teleconnection Between Atlantic Multidecadal Variability and European Temperature: Diversity and Evaluation of the Coupled Model Intercomparison Project Phase 5 Models}},
url = {https://onlinelibrary.wiley.com/doi/10.1002/2017GL074886},
volume = {44},
year = {2017}
}
@article{Qasmi2020b,
abstract = {The response of the European climate to the Atlantic multidecadal variability (AMV) remains difficult to isolate in observations because of the presence of strong internal variability and anthropogenically forced signals. Using model sensitivity experiments proposed within the CMIP6/Decadal Climate Prediction Project Component C (DCPP-C) framework, the wintertime AMV–Europe teleconnection is here investigated in large ensembles of pacemaker-type simulations conducted with the CNRM-CM5 global circulation model. To evaluate the sensitivity of the model response to the AMV amplitude, twin experiments with the AMV forcing pattern multiplied by 2 and 3 (2xAMV and 3xAMV, respectively) are performed in complement to the reference ensemble (1xAMV). Based on a flow analog method, we show that the AMV-forced atmospheric circulation tends to cool down the European continent, whereas the residual signal, mostly including thermodynamical processes, contributes to warming. In 1xAMV, both terms cancel each other, explaining the overall weak AMV-forced atmospheric signal. In 2xAMV and 3xAMV, the thermodynamical contribution overcomes the dynamical cooling and is responsible for milder and wetter conditions found at large scale over Europe. The thermodynamical term includes the advection of warmer and more humid oceanic air penetrating inland and the modification of surface radiative fluxes linked to both altered cloudiness and snow-cover reduction acting as a positive feedback with the AMV amplitude. The dynamical anomalous circulation combines 1) a remote response to enhanced diabatic heating acting as a Rossby wave source in the western tropical Atlantic and 2) a local response associated with warmer SST over the subpolar gyre favoring an anomalous high. The extratropical influence is reinforced by polar amplification due to sea ice melting in all the subarctic seas. The weight between the tropical–extratropical processes and associated feedbacks is speculated to partly explain the nonlinear sensibility of the response to the AMV forcing amplitude, challenging thus the use of the so-called pattern-scaling technique to evaluate teleconnectivity and related impacts associated with decadal variability.},
author = {Qasmi, Sa{\"{i}}d and Cassou, Christophe and Bo{\'{e}}, Julien},
doi = {10.1175/JCLI-D-19-0428.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {apr},
number = {7},
pages = {2681--2700},
title = {{Teleconnection Processes Linking the Intensity of the Atlantic Multidecadal Variability to the Climate Impacts over Europe in Boreal Winter}},
url = {https://journals.ametsoc.org/jcli/article/33/7/2681/346412/Teleconnection-Processes-Linking-the-Intensity-of},
volume = {33},
year = {2020}
}
@article{Qian2015b,
abstract = {AbstractThe annual cycle is the largest variability for many climate variables outside the tropics. Whether human activities have affected the annual cycle at the regional scale is unclear. In this study, long-term changes in the amplitude of surface air temperature annual cycle in the observations are compared with those simulated by the climate models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5). Different spatial domains ranging from hemispheric to subcontinental scales in mid- to high-latitude land areas for the period 1950?2005 are considered. Both the optimal fingerprinting and a nonoptimal detection and attribution technique are used. The results show that the space?time pattern of model-simulated responses to the combined effect of anthropogenic and natural forcings is consistent with the observed changes. In particular, models capture not only the decrease in the temperature seasonality in the northern high latitudes and East Asia, but also the increase in the Mediterranean region. A human influence on the weakening in the temperature seasonality in the Northern Hemisphere is detected, particularly in the high latitudes (50°?70°N) where the influence of the anthropogenic forcing can be separated from that of the natural forcing.},
author = {Qian, Cheng and Zhang, Xuebin},
doi = {10.1175/JCLI-D-14-00821.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {apr},
number = {15},
pages = {5908--5921},
publisher = {American Meteorological Society},
title = {{Human Influences on Changes in the Temperature Seasonality in Mid- to High-Latitude Land Areas}},
volume = {28},
year = {2015}
}
@article{Quan2018,
author = {Quan, Xiao-Wei and Hoerling, Martin P. and Perlwitz, Judith and Diaz, Henry F.},
doi = {10.1175/JCLI-D-18-0068.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {sep},
number = {18},
pages = {7225--7236},
title = {{On the Time of Emergence of Tropical Width Change}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-18-0068.1},
volume = {31},
year = {2018}
}
@article{Rios2015a,
abstract = {Global ocean acidification is caused primarily by the ocean's uptake of CO2 as a consequence of increasing atmospheric CO2 levels. We present observations of the oceanic decrease in pH at the basin scale (50 °S-36 °N) for the Atlantic Ocean over two decades (1993-2013). Changes in pH associated with the uptake of anthropogenic CO2 ($\Delta$pHCant) and with variations caused by biological activity and ocean circulation ($\Delta$pHNat) are evaluated for different water masses. Output from an Institut Pierre Simon Laplace climate model is used to place the results into a longer-term perspective and to elucidate the mechanisms responsible for pH change. The largest decreases in pH (∆pH) were observed in central, mode, and intermediate waters, with a maximum $\Delta$pH value in South Atlantic Central Waters of -0.042 ± 0.003. The $\Delta$pH trended toward zero in deep and bottom waters. Observations and model results show that pH changes generally are dominated by the anthropogenic component, which accounts for rates between -0.0015 and -0.0020/y in the central waters. The anthropogenic and natural components are of the same order of magnitude and reinforce one another in mode and intermediate waters over the time period. Large negative $\Delta$pHNat values observed in mode and intermediate waters are driven primarily by changes in CO2 content and are consistent with (i) a poleward shift of the formation region during the positive phase of the Southern Annular Mode in the South Atlantic and (ii) an increase in the rate of the water mass formation in the North Atlantic.},
author = {R{\'{i}}os, Aida F and Resplandy, Laure and Garc{\'{i}}a-Ib{\'{a}}{\~{n}}ez, Maribel I and Fajar, Noelia M and Velo, Anton and Padin, Xose A and Wanninkhof, Rik and Steinfeldt, Reiner and Ros{\'{o}}n, Gabriel and P{\'{e}}rez, Fiz F},
doi = {10.1073/pnas.1504613112},
issn = {1091-6490},
journal = {Proceedings of the National Academy of Sciences},
keywords = {anthropogenic carbon,climate model,ocean acidification,pH,water masses},
month = {aug},
number = {32},
pages = {9950--5},
pmid = {26216947},
publisher = {National Academy of Sciences},
title = {{Decadal acidification in the water masses of the Atlantic Ocean.}},
url = {http://www.ncbi.nlm.nih.gov/pubmed/26216947 http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=PMC4538673},
volume = {112},
year = {2015}
}
@article{Rackow2019,
abstract = {{\textless}p{\textgreater}Abstract. Models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) show substantial biases in the deep ocean that are larger than the level of natural variability and the response to enhanced greenhouse gas concentrations. Here, we analyze the influence of horizontal resolution in a hierarchy of five multi-resolution simulations with the AWI Climate Model (AWI-CM), the climate model used at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, which employs a sea ice–ocean model component formulated on unstructured meshes. The ocean grid sizes considered range from a nominal resolution of ∼1∘ (CMIP5 type) up to locally eddy resolving. We show that increasing ocean resolution locally to resolve ocean eddies leads to reductions in deep ocean biases, although these improvements are not strictly monotonic for the five different ocean grids. A detailed diagnosis of the simulations allows to identify the origins of the biases. We find that two key regions at the surface are responsible for the development of the deep bias in the Atlantic Ocean: the northeastern North Atlantic and the region adjacent to the Strait of Gibraltar. Furthermore, the Southern Ocean density structure is equally improved with locally explicitly resolved eddies compared to parameterized eddies. Part of the bias reduction can be traced back towards improved surface biases over outcropping regions, which are in contact with deeper ocean layers along isopycnal surfaces. Our prototype simulations provide guidance for the optimal choice of ocean grids for AWI-CM to be used in the final runs for phase 6 of CMIP (CMIP6) and for the related flagship simulations in the High Resolution Model Intercomparison Project (HighResMIP). Quite remarkably, retaining resolution only in areas of high eddy activity along with excellent scalability characteristics of the unstructured-mesh sea ice–ocean model enables us to perform the multi-centennial climate simulations needed in a CMIP context at (locally) eddy-resolving resolution with a throughput of 5–6 simulated years per day.{\textless}/p{\textgreater}},
author = {Rackow, Thomas and Sein, Dmitry V. and Semmler, Tido and Danilov, Sergey and Koldunov, Nikolay V. and Sidorenko, Dmitry and Wang, Qiang and Jung, Thomas},
doi = {10.5194/gmd-12-2635-2019},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {jul},
number = {7},
pages = {2635--2656},
title = {{Sensitivity of deep ocean biases to horizontal resolution in prototype CMIP6 simulations with AWI-CM1.0}},
url = {https://gmd.copernicus.org/articles/12/2635/2019/},
volume = {12},
year = {2019}
}
@article{10.1088/1748-9326/abd4fe,
abstract = {Using state-of-the-art models from the Coupled Model Intercomparison Project Phases 5 and 6 (CMIP5/6), future changes of sudden stratospheric warming (SSW) events under a moderate emission scenario (RCP45/SSP245) and a strong emissions scenario (RCP85/SSP585) are evaluated with respect to the historical simulations. Changes in four characteristics of SSWs are examined in 54 models: the SSW frequency, the seasonal distribution, stratosphere-troposphere coupling, and the persistency of the distorted or displaced polar vortex. The composite results show that none of these four aspects will change robustly. An insignificant (though positive) change in the SSW frequency from historical simulations to RCP45/SSP245 and then to RCP85/SSP585 is consistently projected by CMIP5 and CMIP6 multimodel ensembles (MMEs) in most wintertime months (December–March). This increase in the SSW frequency is most pronounced in mid- (late-) winter in CMIP6 (CMIP5). No shift in the seasonality of SSWs is simulated especially in the CMIP6 future scenarios. Both the reanalysis and CMIP5/6 historical simulations exhibit strong stratosphere-troposphere coupling during SSWs, and the coupling strength is nearly unchanged in the future scenario simulations. The near surface responds immediately after the onset of SSWs in both historical and future scenarios experiments, denoted by the deep downward propagation of zonal-mean easterly anomalies from the stratosphere to the troposphere. On average, the composite circumpolar easterly winds persist for 8 days in the reanalysis and CMIP5/6 historical experiments, which are projected to remain unchanged in both the moderate and strong emissions scenarios, implying the lifecycle of SSWs will not change.},
author = {Rao, Jian and Garfinkel, Chaim I},
doi = {10.1088/1748-9326/abd4fe},
issn = {1748-9326},
journal = {Environmental Research Letters},
month = {mar},
number = {3},
pages = {034024},
title = {{CMIP5/6 models project little change in the statistical characteristics of sudden stratospheric warmings in the 21st century}},
url = {https://iopscience.iop.org/article/10.1088/1748-9326/abd4fe},
volume = {16},
year = {2021}
}
@article{Rathore2020,
abstract = {Recent research shows that 90{\%} of the net global ocean heat gain during 2005–2015 was confined to the southern hemisphere with little corresponding heat gain in the northern hemisphere ocean. We propose that this heating pattern of the ocean is driven by anthropogenic climate change and an asymmetric climate variation between the two hemispheres. This asymmetric variation is found in the pre-industrial control simulations from 11 climate models. While both layers (0–700 m and 700–2000 m) experience steady anthropogenic warming, the 0–700 m layer experiences large internal variability, which primarily drives the observed hemispheric asymmetry of global ocean heat gain in 0–2000 m layer. We infer that the rate of global ocean warming is consistent with the climate simulations for this period. However, the observed hemispheric asymmetry in heat gain can be explained by the Earth's internal climate variability without invoking alternate hypotheses, such as asymmetric aerosol loading. Observations of global ocean heat content during 2005–2015 have shown a strong hemispheric asymmetry, and the southern hemisphere accounts 92{\%} of the total heat gain. Here, the authors show that the rate of observed global ocean warming is consistent with a forced symmetric climate change signal and an asymmetric climate variation for this period.},
author = {Rathore, Saurabh and Bindoff, Nathaniel L. and Phillips, Helen E. and Feng, Ming},
doi = {10.1038/s41467-020-15754-3},
issn = {2041-1723},
journal = {Nature Communications},
keywords = {Climate sciences,Ocean sciences},
month = {dec},
number = {1},
pages = {2008},
publisher = {Nature Publishing Group},
title = {{Recent hemispheric asymmetry in global ocean warming induced by climate change and internal variability}},
url = {http://www.nature.com/articles/s41467-020-15754-3},
volume = {11},
year = {2020}
}
@article{doi:10.1029/2002JD002670,
abstract = {We present the Met Office Hadley Centre's sea ice and sea surface temperature (SST) data set, HadISST1, and the nighttime marine air temperature (NMAT) data set, HadMAT1. HadISST1 replaces the global sea ice and sea surface temperature (GISST) data sets and is a unique combination of monthly globally complete fields of SST and sea ice concentration on a 1° latitude-longitude grid from 1871. The companion HadMAT1 runs monthly from 1856 on a 5° latitude-longitude grid and incorporates new corrections for the effect on NMAT of increasing deck (and hence measurement) heights. HadISST1 and HadMAT1 temperatures are reconstructed using a two-stage reduced-space optimal interpolation procedure, followed by superposition of quality-improved gridded observations onto the reconstructions to restore local detail. The sea ice fields are made more homogeneous by compensating satellite microwave-based sea ice concentrations for the impact of surface melt effects on retrievals in the Arctic and for algorithm deficiencies in the Antarctic and by making the historical in situ concentrations consistent with the satellite data. SSTs near sea ice are estimated using statistical relationships between SST and sea ice concentration. HadISST1 compares well with other published analyses, capturing trends in global, hemispheric, and regional SST well, containing SST fields with more uniform variance through time and better month-to-month persistence than those in GISST. HadMAT1 is more consistent with SST and with collocated land surface air temperatures than previous NMAT data sets.},
author = {Rayner, N A and Parker, D E and Horton, E B and Folland, C K and Alexander, L V and Rowell, D P and Kent, E C and Kaplan, A},
doi = {10.1029/2002JD002670},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {bias correction,climate change,climate data reconstruction,night marine air temperature,sea ice,sea surface temperature},
number = {D14},
title = {{Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2002JD002670},
volume = {108},
year = {2003}
}
@article{ISI:000426707100043,
abstract = {This work documents long-term changes in the Southern Hemisphere circulation in the austral spring-summer season in the Coupled Intercomparison Project Phase 5 models, showing that those changes are larger in magnitude and closer to ERA-Interim and other reanalyses if models include a dynamical representation of the stratosphere. Specifically, models with a high-top and included dynamical and-in some cases-chemical feedbacks within the stratosphere better simulate the lower stratospheric cooling observed over 1979-2001 and strongly driven by ozone depletion, when compared to the other models. This occurs because high-top models can fully capture the stratospheric large scale circulation response to the ozone-induced cooling. Interestingly, this difference is also found at the surface for the Southern Annular Mode (SAM) changes, even though all model categories tend to underestimate SAM trends over those decades. In this analysis, models including a proper dynamical stratosphere are more sensitive to lower stratospheric cooling in their tropospheric circulation response. After a brief discussion of two RCP scenarios, our study confirms that at least for large changes in the extratropical regions, stratospheric changes induced by external forcing have to be properly simulated, as they are important drivers of tropospheric climate variations.},
author = {Rea, Gloria and Riccio, Angelo and Fierli, Federico and Cairo, Francesco and Cagnazzo, Chiara},
doi = {10.1007/s00382-017-3746-2},
issn = {0930-7575},
journal = {Climate Dynamics},
number = {5-6},
pages = {2239--2255},
title = {{Stratosphere-resolving CMIP5 models simulate different changes in the Southern Hemisphere}},
type = {Article},
url = {http://link.springer.com/10.1007/s00382-017-3746-2},
volume = {50},
year = {2018}
}
@article{Reintges2017,
abstract = {Uncertainty in the strength of the Atlantic Meridional Overturning Circulation (AMOC) is analyzed in the Coupled Model Intercomparison Project Phase 3 (CMIP3) and Phase 5 (CMIP5) projections for the twenty-first century; and the different sources of uncertainty (scenario, internal and model) are quantified. Although the uncertainty in future projections of the AMOC index at 30°N is larger in CMIP5 than in CMIP3, the signal-to-noise ratio is comparable during the second half of the century and even larger in CMIP5 during the first half. This is due to a stronger AMOC reduction in CMIP5. At lead times longer than a few decades, model uncertainty dominates uncertainty in future projections of AMOC strength in both the CMIP3 and CMIP5 model ensembles. Internal variability significantly contributes only during the first few decades, while scenario uncertainty is relatively small at all lead times. Model uncertainty in future changes in AMOC strength arises mostly from uncertainty in density, as uncertainty arising from wind stress (Ekman transport) is negligible. Finally, the uncertainty in changes in the density originates mostly from the simulation of salinity, rather than temperature. High-latitude freshwater flux and the subpolar gyre projections were also analyzed, because these quantities are thought to play an important role for the future AMOC changes. The freshwater input in high latitudes is projected to increase and the subpolar gyre is projected to weaken. Both the freshening and the gyre weakening likely influence the AMOC by causing anomalous salinity advection into the regions of deep water formation. While the high model uncertainty in both parameters may explain the uncertainty in the AMOC projection, deeper insight into the mechanisms for AMOC is required to reach a more quantitative conclusion.},
author = {Reintges, Annika and Martin, Thomas and Latif, Mojib and Keenlyside, Noel S},
doi = {10.1007/s00382-016-3180-x},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {5},
pages = {1495--1511},
title = {{Uncertainty in twenty-first century projections of the Atlantic Meridional Overturning Circulation in CMIP3 and CMIP5 models}},
url = {https://doi.org/10.1007/s00382-016-3180-x},
volume = {49},
year = {2017}
}
@article{Reul2014,
abstract = {An analysis is presented for the spatial and intensity distributions of North Atlantic extreme atmospheric events crossing the buoyant Amazon-Orinoco freshwater plume. The sea surface cooling amplitude in the wake of an ensemble of storm tracks traveling in that region is estimated from satellite products for the period 1998-2012. For the most intense storms, cooling is systematically reduced by ∼50{\%} over the plume area compared to surroundings open-ocean waters. Historical salinity and temperature observations from in situ profiles indicate that salt-driven vertical stratification, enhanced oceanic heat content, and barrier-layer presence within the plume waters are likely key oceanic factors to explain these results. Satellite SMOS surface salinity data combined with in situ observations are further used to detail the oceanic response to category 4 hurricane Igor in 2010. Argo and satellite measurements confirm the haline stratification impact on the cooling inhibition as the hurricane crossed the river plume. Over this region, the SSS mapping capability is further tested and demonstrated to monitor the horizontal distribution of the vertical stratification parameter. SMOS SSS data can thus be used to consistently anticipate the cooling inhibition in the wake of TCs traveling over the Amazon-Orinoco plume region.},
author = {Reul, Nicolas and Quilfen, Yves and Chapron, Bertrand and Fournier, Severine and Kudryavtsev, Vladimir and Sabia, Roberto},
doi = {10.1002/2014JC010107},
issn = {21699291},
journal = {Journal of Geophysical Research: Oceans},
keywords = {Amazon-Orinocco river plume,SMOS SSS,barrier-layer,cooling inhibition,haline stratification,hurricanes},
month = {dec},
number = {12},
pages = {8271--8295},
title = {{Multisensor observations of the Amazon-Orinoco river plume interactions with hurricanes}},
url = {http://doi.wiley.com/10.1002/2014JC010107},
volume = {119},
year = {2014}
}
@misc{RGIConsortium2017,
abstract = {The Randolph Glacier Inventory (RGI 6.0) is a global inventory of glacier outlines. It is supplemental to the Global Land Ice Measurements from Space initiative (GLIMS). Production of the RGI was motivated by the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5). Future updates will be made to the RGI and the GLIMS Glacier Database in parallel during a transition period. As all these data are incorporated into the GLIMS Glacier Database and as download tools are developed to obtain GLIMS data in the RGI data format, the RGI will evolve into a downloadable subset of GLIMS, offering complete one-time coverage, version control, and a standard set of attributes. For more details, and for a complete list of contributors, please see the RGI 6.0 Technical Report (PDF format). For the glacier regions used see the GTN-G Glacier Regions.},
address = {CO, USA},
author = {{RGI Consortium}},
doi = {10.7265/n5-rgi-60},
publisher = {Technical Report. Global Land Ice Measurements from Space},
title = {{Randolph Glacier Inventory – A Dataset of Global Glacier Outlines: Version 6.0}},
url = {http://www.glims.org/RGI/randolph60.html},
urldate = {2019-12-21},
year = {2017}
}
@incollection{Rhein2013,
address = {Cambridge, United Kingdom and New York, NY, USA},
author = {Rhein, M. and Rintoul, S. R. and Aoki, S. and Campos, E. and Chambers, D. and Feely, R. A. and Gulev, S. and Johnson, G. C. and Josey, S. A. and Kostianoy, A. and Mauritzen, C. and Roemmich, D. and Talley, L. D. and Wang, F. and Contributing authors},
booktitle = {Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change},
doi = {10.1017/CBO9781107415324.010},
editor = {Stocker, T F and Qin, D and Plattner, G.-K. and Tignor, M and Allen, S K and Boschung, J and Nauels, A and Xia, Y and Bex, V and Midgley, P M},
isbn = {9781107661820},
pages = {255--316},
publisher = {Cambridge University Press},
title = {{Observations: Ocean}},
url = {https://www.ipcc.ch/report/ar5/wg1},
year = {2013}
}
@article{Ribes2013a,
abstract = {Attribution of global near-surface temperature changes is revisited using simulations from the coupled model intercomparison project 5 and methodological improvements from the regularised optimal fingerprinting approach. The analysis of global mean temperature shows that changes can be robustly detected and attributed to anthropogenic influence. However, the differences between results from individual models and observations are found to be larger than the simulated internal variability in several cases. Discrimination between greenhouse gases and other anthropogenic forcings, based on the global mean only, is more difficult due to collinearity of temporal response patterns. Using spatio-temporal data provides less robust conclusions with respect to detection and attribution, as the results tend to deteriorate as the spatial resolution increases. More importantly, some inconsistencies between individual models and observations are found in this case. Such behaviour is not observed in a perfect model framework, where pseudo-observations and the expected response patterns are provided by the same model. However, using response patterns from a model other than the one used for pseudo-observations may lead to the same behaviour as real observations. Our results suggest that additional sources of uncertainty, such as modeling uncertainty or observational uncertainty, should not be neglected in detection and attribution. {\textcopyright} 2013 Springer-Verlag Berlin Heidelberg.},
author = {Ribes, Aur{\'{e}}lien and Terray, Laurent},
doi = {10.1007/s00382-013-1736-6},
issn = {09307575},
journal = {Climate Dynamics},
keywords = {Attribution,Climate change,Detection,Global temperature,Optimal fingerprints},
number = {11-12},
pages = {2837--2853},
title = {{Application of regularised optimal fingerprinting to attribution. Part II: Application to global near-surface temperature}},
volume = {41},
year = {2013}
}
@article{Ribes2017,
abstract = {{\textcopyright} 2016, Springer-Verlag Berlin Heidelberg. We propose here a new statistical approach to climate change detection and attribution that is based on additive decomposition and simple hypothesis testing. Most current statistical methods for detection and attribution rely on linear regression models where the observations are regressed onto expected response patterns to different external forcings. These methods do not use physical information provided by climate models regarding the expected response magnitudes to constrain the estimated responses to the forcings. Climate modelling uncertainty is difficult to take into account with regression based methods and is almost never treated explicitly. As an alternative to this approach, our statistical model is only based on the additivity assumption; the proposed method does not regress observations onto expected response patterns. We introduce estimation and testing procedures based on likelihood maximization, and show that climate modelling uncertainty can easily be accounted for. Some discussion is provided on how to practically estimate the climate modelling uncertainty based on an ensemble of opportunity. Our approach is based on the “models are statistically indistinguishable from the truth” paradigm, where the difference between any given model and the truth has the same distribution as the difference between any pair of models, but other choices might also be considered. The properties of this approach are illustrated and discussed based on synthetic data. Lastly, the method is applied to the linear trend in global mean temperature over the period 1951–2010. Consistent with the last IPCC assessment report, we find that most of the observed warming over this period (+0.65 K) is attributable to anthropogenic forcings (+0.67 ± 0.12 K, 90 {\%} confidence range), with a very limited contribution from natural forcings (- 0.01 ± 0.02 K).},
author = {Ribes, A. and Zwiers, F.W. and Aza{\"{i}}s, J.-M. and Naveau, P.},
doi = {10.1007/s00382-016-3079-6},
journal = {Climate Dynamics},
number = {1-2},
pages = {367--386},
title = {{A new statistical approach to climate change detection and attribution}},
volume = {48},
year = {2017}
}
@article{Ribes2009,
abstract = {The ``optimal fingerprint'' method, usually used for detection and attribution studies, requires to know, or, in practice, to estimate the covariance matrix of the internal climate variability. In this work, a new adaptation of the ``optimal fingerprints'' method is presented. The main goal is to allow the use of a covariance matrix estimate based on an observation dataset in which the number of years used for covariance estimation is close to the number of observed time series. Our adaptation is based on the use of a regularized estimate of the covariance matrix, that is well-conditioned, and asymptotically more precise, in the sense of the mean square error. This method is shown to be more powerful than the basic ``guess pattern fingerprint'', and than the classical use of a pseudo-inverted truncation of the empirical covariance matrix. The construction of the detection test is achieved by using a bootstrap technique particularly well-suited to estimate the internal climate variability in real world observations. In order to validate the efficiency of the detection algorithm with climate data, the methodology presented here is first applied with pseudo-observations derived from transient regional climate change scenarios covering the 1960--2099 period. It is then used to perform a formal detection study of climate change over France, analyzing homogenized observed temperature series from 1900 to 2006. In this case, the estimation of the covariance matrix is only based on a part of the observation dataset. This new approach allows the confirmation and extension of previous results regarding the detection of an anthropogenic climate change signal over the country.},
author = {Ribes, Aur{\'{e}}lien and Aza{\"{i}}s, Jean-Marc and Planton, Serge},
doi = {10.1007/s00382-009-0561-4},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {5},
pages = {707--722},
title = {{Adaptation of the optimal fingerprint method for climate change detection using a well-conditioned covariance matrix estimate}},
url = {https://doi.org/10.1007/s00382-009-0561-4},
volume = {33},
year = {2009}
}
@article{Ribes2021,
abstract = {Many studies have sought to constrain climate projections based on recent observations. Until recently, these constraints had limited impact, and projected warming ranges were driven primarily by model outputs. Here, we use the newest climate model ensemble, improved observations, and a new statistical method to narrow uncertainty on estimates of past and future human-induced warming. Cross-validation suggests that our method produces robust results and is not overconfident. We derive consistent observationally constrained estimates of attributable warming to date and warming rate, the response to a range of future scenarios, and metrics of climate sensitivity. We find that historical observations narrow uncertainty on projected future warming by about 50{\%}. Our results suggest that using an unconstrained multimodel ensemble is no longer the best choice for global mean temperature projections and that the lower end of previous estimates of 21st century warming can now be excluded.},
author = {Ribes, Aur{\'{e}}lien and Qasmi, Sa{\"{i}}d and Gillett, Nathan P},
doi = {10.1126/sciadv.abc0671},
journal = {Science Advances},
month = {jan},
number = {4},
pages = {eabc0671},
title = {{Making climate projections conditional on historical observations}},
url = {http://advances.sciencemag.org/content/7/4/eabc0671.abstract},
volume = {7},
year = {2021}
}
@article{Richardson2018a,
abstract = {The response of the hydrological cycle to climate forcings can be understood within the atmospheric energy budget framework. In this study precipitation and energy budget responses to five forcing agents are analyzed using 10 climate models from the Precipitation Driver Response Model Intercomparison Project (PDRMIP). Precipitation changes are split into a forcing-dependent fast response and a temperature-driven hydrological sensitivity. Globally, when normalized by top-of-atmosphere (TOA) forcing, fast precipitation changes are most sensitive to strongly absorbing drivers (CO 2 , black carbon). However, over land fast precipitation changes are most sensitive to weakly absorbing drivers (sulfate, solar) and are linked to rapid circulation changes. Despite this, land-mean fast responses to CO 2 and black carbon exhibit more intermodel spread. Globally, the hydrological sensitivity is consistent across forcings, mainly associated with increased longwave cooling, which is highly correlated with intermodel spread. The land-mean hydrological sensitivity is weaker, consistent with limited moisture availability. The PDRMIP results are used to construct a simple model for land-mean and sea-mean precipitation change based on sea surface temperature change and TOA forcing. The model matches well with CMIP5 ensemble mean historical and future projections, and is used to understand the contributions of different drivers. During the twentieth century, temperature-driven intensification of land-mean precipitation has been masked by fast precipitation responses to anthropogenic sulfate and volcanic forcing, consistent with the small observed trend. However, as projected sulfate forcing decreases, and warming continues, land-mean precipitation is expected to increase more rapidly, and may become clearly observable by the mid-twenty-first century.},
author = {Richardson, T. B. and Forster, P. M. and Andrews, T and Boucher, O. and Faluvegi, G. and Fl{\"{a}}schner, D. and Hodnebrog, {\O}. and Kasoar, M and Kirkev{\aa}g, A. and Lamarque, J.-F. and Myhre, Gunnar and Olivi{\'{e}}, D. and Samset, B. H. and Shawki, D and Shindell, D. and Takemura, T and Voulgarakis, A},
doi = {10.1175/JCLI-D-17-0240.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {dec},
number = {23},
pages = {9641--9657},
title = {{Drivers of Precipitation Change: An Energetic Understanding}},
url = {https://journals.ametsoc.org/doi/10.1175/JCLI-D-17-0240.1},
volume = {31},
year = {2018}
}
@article{Richter2014c,
abstract = {Coupled general circulation model (GCM) simulations participating in the Coupled Model Intercom- parison Project Phase 5 (CMIP5) are analyzed with respect to their performance in the equatorial Atlantic. In terms of the mean state, 29 out of 33 models examined continue to suffer from serious biases including an annual mean zonal equatorial SST gradient whose sign is opposite to obser- vations. Westerly surface wind biases in boreal spring play an important role in the reversed SST gradient by deep- ening the thermocline in the eastern equatorial Atlantic and thus reducing upwelling efficiency and SST cooling in the following months. Both magnitude and seasonal evolution of the biases are very similar to what was found previously for CMIP3 models, indicating that improvements have only been modest. The weaker than observed equatorial eas- terlies are also simulated by atmospheric GCMs forced with observed SST. They are related to both continental convection and the latitudinal position of the intertropical convergence zone (ITCZ). Particularly the latter has a strong influence on equatorial zonal winds in both the seasonal cycle and interannual variability. The dependence of equatorial easterlies on ITCZ latitude shows a marked asymmetry. From the equator to 15?N, the equatorial eas- terlies intensify approximately linearly with ITCZ latitude. When the ITCZ is south of the equator, on the other hand, the equatorial easterlies are uniformly weak. Despite seri- ous mean state biases, several models are able to capture some aspects of the equatorial mode of interannual SST variability, including amplitude, pattern, phase locking to boreal summer, and duration of events. The latitudinal position of the boreal spring ITCZ, through its influence on equatorial surface winds, appears to play an important role in initiating warm events. Keywords},
author = {Richter, Ingo and Xie, Shang Ping and Behera, Swadhin K. and Doi, Takeshi and Masumoto, Yukio},
doi = {10.1007/s00382-012-1624-5},
isbn = {0038201216},
issn = {09307575},
journal = {Climate Dynamics},
number = {1-2},
pages = {171--188},
title = {{Equatorial Atlantic variability and its relation to mean state biases in CMIP5}},
volume = {42},
year = {2014}
}
@article{Richter2015a,
author = {Richter, Ingo},
doi = {10.1002/wcc.338},
issn = {17577780},
journal = {WIREs Climate Change},
month = {may},
number = {3},
pages = {345--358},
title = {{Climate model biases in the eastern tropical oceans: causes, impacts and ways forward}},
url = {http://doi.wiley.com/10.1002/wcc.338},
volume = {6},
year = {2015}
}
@article{Richter2020,
abstract = {General circulation models of the Coupled Model Intercomparison Project Phase 6 (CMIP6) are examined with respect to their ability to simulate the mean state and variability of the tropical Atlantic and its linkage to the tropical Pacific. While, on average, mean state biases have improved little, relative to the previous intercomparison (CMIP5), there are now a few models with very small biases. In particular the equatorial Atlantic warm SST and westerly wind biases are mostly eliminated in these models. Furthermore, interannual variability in the equatorial and subtropical Atlantic is quite realistic in a number of CMIP6 models, which suggests that they should be useful tools for understanding and predicting variability patterns. The evolution of equatorial Atlantic biases follows the same pattern as in previous model generations, with westerly wind biases during boreal spring preceding warm sea-surface temperature (SST) biases in the east during boreal summer. A substantial portion of the westerly wind bias exists already in atmosphere-only simulations forced with observed SST, suggesting an atmospheric origin. While variability is relatively realistic in many models, SSTs seem less responsive to wind forcing than observed, both on the equator and in the subtropics, possibly due to an excessively deep mixed layer originating in the oceanic component. Thus models with realistic SST amplitude tend to have excessive wind amplitude. The models with the smallest mean state biases all have relatively high resolution but there are also a few low-resolution models that perform similarly well, indicating that resolution is not the only way toward reducing tropical Atlantic biases. The results also show a relatively weak link between mean state biases and the quality of the simulated variability. The linkage to the tropical Pacific shows a wide range of behaviors across models, indicating the need for further model improvement.},
author = {Richter, Ingo and Tokinaga, Hiroki},
doi = {10.1007/s00382-020-05409-w},
issn = {14320894},
journal = {Climate Dynamics},
number = {9-10},
pages = {2579--2601},
title = {{An overview of the performance of CMIP6 models in the tropical Atlantic: mean state, variability, and remote impacts}},
volume = {55},
year = {2020}
}
@article{Richter2020a,
author = {Richter, Kristin and Meyssignac, Benoit and Slangen, Aim{\'{e}}e B A and Melet, Ang{\'{e}}lique and Church, John A and Fettweis, Xavier and Marzeion, Ben and Agosta, C{\'{e}}cile and Ligtenberg, Stefan R M and Spada, Giorgio and Palmer, Matthew D and Roberts, Christopher D and Champollion, Nicolas},
doi = {10.1088/1748-9326/ab986e},
issn = {1748-9326},
journal = {Environmental Research Letters},
month = {sep},
number = {9},
pages = {094079},
title = {{Detecting a forced signal in satellite-era sea-level change}},
url = {https://iopscience.iop.org/article/10.1088/1748-9326/ab986e},
volume = {15},
year = {2020}
}
@article{Ridley2014,
abstract = {Understanding the cooling effect of recent volcanoes is of particular interest in the context of the post-2000 slowing of the rate of global warming. Satellite observations of aerosol optical depth above 15km have demonstrated that small-magnitude volcanic eruptions substantially perturb incoming solar radiation. Here we use lidar, Aerosol Robotic Network, and balloon-borne observations to provide evidence that currently available satellite databases neglect substantial amounts of volcanic aerosol between the tropopause and 15km at middle to high latitudes and therefore underestimate total radiative forcing resulting from the recent eruptions. Incorporating these estimates into a simple climate model, we determine the global volcanic aerosol forcing since 2000 to be ?0.19±0.09Wm?2. This translates into an estimated global cooling of 0.05 to 0.12°C. We conclude that recent volcanic events are responsible for more post-2000 cooling than is implied by satellite databases that neglect volcanic aerosol effects below 15 km.},
author = {Ridley, D. A. and Solomon, S. and Barnes, J. E. and Burlakov, V. D. and Deshler, T. and Dolgii, S. I. and Herber, A. B. and Nagai, T. and {Neely III}, R. R. and Nevzorov, A. V. and Ritter, C. and Sakai, T. and Santer, B. D. and Sato, M. and Schmidt, A. and Uchino, O. and Vernier, J. P.},
doi = {10.1002/2014GL061541},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {10.1002/2014GL061541 and volcanic aerosol,AERONET retrieval,forcing uncertainty,lower stratospheric AOD,stratospheric aerosol,warming hiatus},
pages = {7763--7769},
title = {{Total volcanic stratospheric aerosol optical depths and implications for global climate change}},
url = {http://onlinelibrary.wiley.com/doi/10.1002/2014GL061541/full},
volume = {41},
year = {2014}
}
@article{Rieger2020,
abstract = {Large volcanic eruptions reaching the stratosphere have caused marked perturbations to the global climate including cooling at the Earth's surface, changes in large-scale circulation and precipitation patterns and marked temporary reductions in global ocean heat content. Many studies have investigated these effects using climate models; however, uncertainties remain in the modelled response to these eruptions. This is due in part to the diversity of forcing datasets that are used to prescribe the distribution of stratospheric aerosols resulting from these volcanic eruptions, as well as uncertainties in optical property derivations from these datasets. To improve this situation for the sixth phase of the Coupled Model Intercomparison Project (CMIP6), a two-step process was undertaken. First, a combined stratospheric aerosol dataset, the Global Space-based Stratospheric Aerosol Climatology (GloSSAC; 1979-2016), was constructed. Next, GloSSAC, along with information from ice cores and Sun photometers, was used to generate aerosol distributions, characteristics and optical properties to construct a more consistent stratospheric aerosol forcing dataset for models participating in CMIP6. This “version 3” of the stratospheric aerosol forcing has been endorsed for use in all contributing CMIP6 simulations. Recent updates to the underlying GloSSAC from version 1 to version 1.1 affected the 1991-1994 period and necessitated an update to the stratospheric aerosol forcing from version 3 to version 4. As version 3 remains the official CMIP6 input, quantification of the impact on radiative forcing and climate is both relevant and timely for interpreting results from experiments such as the CMIP6 historical simulations. This study uses two models, the Canadian Earth System Model version 5 (CanESM5) and the Energy Exascale Earth System Model (E3SM) Atmosphere Model version 1 (EAMv1), to estimate the difference in instantaneous radiative forcing in simulated post-Pinatubo climate response when using version 4 instead of version 3. Differences in temperature, precipitation and radiative forcings are generally found to be small compared to internal variability. An exception to this is differences in monthly temperature anomalies near 24 km altitude in the tropics, which can be as large as 3 ◦C following the eruption of Mt. Pinatubo.},
author = {Rieger, Landon A. and Cole, Jason N.S. and Fyfe, John C. and Po-Chedley, Stephen and Cameron-Smith, Philip J. and Durack, Paul J. and Gillett, Nathan P. and Tang, Qi},
doi = {10.5194/gmd-13-4831-2020},
issn = {19919603},
journal = {Geoscientific Model Development},
number = {10},
pages = {4831--4843},
title = {{Quantifying CanESM5 and EAMv1 sensitivities to Mt. Pinatubo volcanic forcing for the CMIP6 historical experiment}},
url = {https://doi.org/10.5194/gmd-2019-381},
volume = {13},
year = {2020}
}
@article{gmd-13-1179-2020,
author = {Righi, Mattia and Andela, Bouwe and Eyring, Veronika and Lauer, Axel and Predoi, Valeriu and Schlund, Manuel and Vegas-Regidor, Javier and Bock, Lisa and Br{\"{o}}tz, Bj{\"{o}}rn and de Mora, Lee and Diblen, Faruk and Dreyer, Laura and Drost, Niels and Earnshaw, Paul and Hassler, Birgit and Koldunov, Nikolay and Little, Bill and {Loosveldt Tomas}, Saskia and Zimmermann, Klaus},
doi = {10.5194/gmd-13-1179-2020},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {mar},
number = {3},
pages = {1179--1199},
title = {{Earth System Model Evaluation Tool (ESMValTool) v2.0 – technical overview}},
url = {https://gmd.copernicus.org/articles/13/1179/2020/},
volume = {13},
year = {2020}
}
@article{Rignot2019b,
author = {Rignot, Eric and Mouginot, Jeremie and Scheuchl, Bernd and van den Broeke, Michiel R. and van Wessem, Melchior J. and Morlighem, Mathieu},
doi = {10.1073/pnas.1812883116},
issn = {0027-8424},
journal = {Proceedings of the National Academy of Sciences},
number = {4},
pages = {1--9},
pmid = {30642972},
title = {{Four decades of Antarctic Ice Sheet mass balance from 1979-2017}},
volume = {116},
year = {2019}
}
@article{Risbey2014,
author = {Risbey, James S and Lewandowsky, Stephan and Langlais, Clothilde and Monselesan, Didier P and O'Kane, Terence J and Oreskes, Naomi},
doi = {10.1038/nclimate2310},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {sep},
number = {9},
pages = {835--840},
publisher = {Nature Publishing Group},
title = {{Well-estimated global surface warming in climate projections selected for ENSO phase}},
url = {http://www.nature.com/articles/nclimate2310},
volume = {4},
year = {2014}
}
@article{Risbey2018,
author = {Risbey, James S and Lewandowsky, Stephan and Cowtan, Kevin and Oreskes, Naomi and Rahmstorf, Stefan and Jokim{\"{a}}ki, Ari and Foster, Grant},
doi = {10.1088/1748-9326/aaf342},
issn = {1748-9326},
journal = {Environmental Research Letters},
month = {dec},
number = {12},
pages = {123008},
title = {{A fluctuation in surface temperature in historical context: reassessment and retrospective on the evidence}},
url = {http://stacks.iop.org/1748-9326/13/i=12/a=123008?key=crossref.b97c8e3943aff113d12d0a9b1c36655b},
volume = {13},
year = {2018}
}
@article{Riser2016a,
abstract = {Fifteen years of ocean observations with the global Argo array},
author = {Riser, Stephen C. and Freeland, Howard J. and Roemmich, Dean and Wijffels, Susan and Troisi, Ariel and Belb{\'{e}}och, Mathieu and Gilbert, Denis and Xu, Jianping and Pouliquen, Sylvie and Thresher, Ann and {Le Traon}, Pierre-Yves and Maze, Guillaume and Klein, Birgit and Ravichandran, M. and Grant, Fiona and Poulain, Pierre-Marie and Suga, Toshio and Lim, Byunghwan and Sterl, Andreas and Sutton, Philip and Mork, Kjell-Arne and V{\'{e}}lez-Belch{\'{i}}, Pedro Joaqu{\'{i}}n and Ansorge, Isabelle and King, Brian and Turton, Jon and Baringer, Molly and Jayne, Steven R.},
doi = {10.1038/nclimate2872},
issn = {1758-678X},
journal = {Nature Climate Change},
keywords = {Climate change,Ocean sciences},
month = {feb},
number = {2},
pages = {145--153},
publisher = {Nature Publishing Group},
title = {{Fifteen years of ocean observations with the global Argo array}},
url = {http://www.nature.com/articles/nclimate2872},
volume = {6},
year = {2016}
}
@article{Ritter2017,
author = {Ritter, R. and Landsch{\"{u}}tzer, P. and Gruber, N. and Fay, A. R. and Iida, Y. and Jones, S. and Nakaoka, S. and Park, G.-H. and Peylin, P. and R{\"{o}}denbeck, C. and Rodgers, K. B. and Shutler, J. D. and Zeng, J.},
doi = {10.1002/2017GL074837},
issn = {00948276},
journal = {Geophysical Research Letters},
keywords = {CO2,SOCOM,Southern Ocean,carbon sink,observations,trends},
month = {dec},
number = {24},
pages = {12,339--12,348},
publisher = {Wiley-Blackwell},
title = {{Observation-Based Trends of the Southern Ocean Carbon Sink}},
url = {http://doi.wiley.com/10.1002/2017GL074837},
volume = {44},
year = {2017}
}
@article{Ritz2013,
abstract = {The Atlantic meridional overturning circulation is a key component of the climate system. Data and climate model reconstructions reveal a decline in the strength of the overturning circulation during the Heinrich1 and Younger Dryas cold events of the last glacial period.},
author = {Ritz, Stefan P and Stocker, Thomas F and Grimalt, Joan O and Menviel, Laurie and Timmermann, Axel},
doi = {10.1038/ngeo1723},
issn = {1752-0908},
journal = {Nature Geoscience},
number = {3},
pages = {208--212},
title = {{Estimated strength of the Atlantic overturning circulation during the last deglaciation}},
url = {https://doi.org/10.1038/ngeo1723},
volume = {6},
year = {2013}
}
@article{Roach,
abstract = {Fully coupled climate models have long shown a wide range of Antarctic sea ice states and evolution over the satellite era. Here, we present a high‐level evaluation of Antarctic sea ice in 40 models from the most recent phase of the Coupled Model Intercomparison Project (CMIP6). Many models capture key characteristics of the mean seasonal cycle of sea ice area (SIA), but some simulate implausible historical mean states compared to satellite observations, leading to large intermodel spread. Summer SIA is consistently biased low across the ensemble. Compared to the previous model generation (CMIP5), the intermodel spread in winter and summer SIA has reduced, and the regional distribution of sea ice concentration has improved. Over 1979–2018, many models simulate strong negative trends in SIA concurrently with stronger‐than‐observed trends in global mean surface temperature (GMST). By the end of the 21st century, models project clear differences in sea ice between forcing scenarios.},
author = {Roach, Lettie A. and D{\"{o}}rr, Jakob and Holmes, Caroline R. and Massonnet, Francois and Blockley, Edward W. and Notz, Dirk and Rackow, Thomas and Raphael, Marilyn N. and O'Farrell, Siobhan and Bailey, David A. and Bitz, Cecilia M.},
doi = {10.1029/2019GL086729},
journal = {Geophysical Research Letters},
number = {9},
pages = {e2019GL086729},
title = {{Antarctic Sea Ice in CMIP6}},
url = {https://doi.org/10.1029/2019GL086729},
volume = {47},
year = {2020}
}
@article{tc-12-365-2018,
author = {Roach, L A and Dean, S M and Renwick, J A},
doi = {10.5194/tc-12-365-2018},
journal = {The Cryosphere},
number = {1},
pages = {365--383},
title = {{Consistent biases in Antarctic sea ice concentration simulated by climate models}},
url = {https://www.the-cryosphere.net/12/365/2018/},
volume = {12},
year = {2018}
}
@article{Roberts2014,
abstract = {The Atlantic meridional overturning circulation (AMOC) at 26.5°N weakened by ?0.53 sverdrup (Sv)/yr between April 2004 and October 2012. To assess whether this trend is consistent with the expected ?noise? in the climate system, we compare the observed trend with estimates of internal variability derived from 14 control simulations from the Climate Model Intercomparison Project 5 (CMIP5). Eight year trends of ?0.53 Sv/yr are relatively common in two models but are extremely unusual (or out of range) in the other 12. However, all 14 models underestimate AMOC variability on interannual time scales. To account for this bias, we estimate plausible upper limits of internal AMOC variability by combining the temporal correlation characteristics of the AMOC from CMIP5 models with an observational estimate of interannual variability. We conclude that the observed AMOC trend is not significantly different (p{\textgreater} 0.01) from plausible estimates of internal variability. Detecting the influence of external climate forcings on the AMOC will require more than one decade of continuous observations.},
annote = {doi: 10.1002/2014GL059473},
author = {Roberts, C D and Jackson, L and McNeall, D},
doi = {10.1002/2014GL059473},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {AMOC,detection,significance,trend,variability},
month = {mar},
number = {9},
pages = {3204--3210},
publisher = {Wiley-Blackwell},
title = {{Is the 2004–2012 reduction of the Atlantic meridional overturning circulation significant?}},
url = {https://doi.org/10.1002/2014GL059473},
volume = {41},
year = {2014}
}
@article{Roberts2015,
abstract = {Since the end of the twentieth century, global mean surface temperature has not risen as rapidly as predicted by global climate models 1–3 (GCMs).This discrepancy has become known as the global warming ‘hiatus' and a variety of mechanisms1,4–17 have been proposed to explain the observed slowdown in warming. Focusing on internally generated variability, we use pre-industrial control simulations from an observationally constrained ensemble of GCMs and a statistical approach to evaluate the expected frequency and characteristics of variability-driven hiatus periods and their likelihood of future continuation. Given an expected forced warming trend of ∼0.2Kper decade, our constrained ensemble of GCM simplies that the probability of a variability-driven 10-year hiatus is ∼10{\%}, but less than 1{\%} for a 20-year hiatus. Although the absolute probabilityofa20-year hiatus is small, the probability that an existing 15-year hiatus will continue another five years is much higher (up to 25{\%}). Therefore, given the recognized contribution of internal climate variability to the reduced rate of global warming during the past 15 years, we should not be surprised if the current hiatus continues until the end of the decade. Following the termination of a variability-driven hiatus, we also show that there is an increased likelihood of accelerated global warming associated with release of heat from the sub-surface ocean and a reversal of the phase of decadal variability in the Pacific Ocean.},
author = {Roberts, C. D. and Palmer, M. D. and McNeall, D. and Collins, M.},
doi = {10.1038/nclimate2531},
isbn = {1758-678X},
issn = {17586798},
journal = {Nature Climate Change},
number = {4},
pages = {337--342},
title = {{Quantifying the likelihood of a continued hiatus in global warming}},
volume = {5},
year = {2015}
}
@article{Roberts2019b,
abstract = {The Coupled Model Intercomparison Project phase 6 (CMIP6) HighResMIP is a new experimental design for global climate model simulations that aims to assess the impact of model horizontal resolution on climate simulation fidelity.We describe a hierarchy of global coupled model resolutions based on the Hadley Centre Global Environment Model 3-Global Coupled vn 3.1 (HadGEM3-GC3.1) model that ranges from an atmosphere-ocean resolution of 130 km-1° to 25 km-1=12°, all using the same forcings and initial conditions. In order to make such high-resolution simulations possible, the experiments have a short 30-year spinup, followed by at least century-long simulations with constant forcing to assess drift. We assess the change in model biases as a function of both atmosphere and ocean resolution, together with the effectiveness and robustness of this new experimental design.We find reductions in the biases in top-of-atmosphere radiation components and cloud forcing. There are significant reductions in some common surface climate model biases as resolution is increased, particularly in the Atlantic for sea surface temperature and precipitation, primarily driven by increased ocean resolution. There is also a reduction in drift from the initial conditions both at the surface and in the deeper ocean at higher resolution. Using an eddy-present and eddy-rich ocean resolution enhances the strength of the North Atlantic ocean circulation (boundary currents, overturning circulation and heat transport), while an eddy-present ocean resolution has a considerably reduced Antarctic Circumpolar Current strength. All models have a reasonable representation of El Ni{\~{n}}o-Southern Oscillation. In general, the biases present after 30 years of simulations do not change character markedly over longer timescales, justifying the experimental design.},
author = {Roberts, Malcolm J. and Baker, Alex and Blockley, Ed W. and Calvert, Daley and Coward, Andrew and Hewitt, Helene T. and Jackson, Laura C. and Kuhlbrodt, Till and Mathiot, Pierre and Roberts, Christopher D. and Schiemann, Reinhard and Seddon, Jon and Vanni{\`{e}}re, Beno{\^{i}}t and {Luigi Vidale}, Pier},
doi = {10.5194/gmd-12-4999-2019},
issn = {19919603},
journal = {Geoscientific Model Development},
number = {12},
pages = {4999--5028},
title = {{Description of the resolution hierarchy of the global coupled HadGEM3-GC3.1 model as used in CMIP6 HighResMIP experiments}},
url = {https://www.geosci-model-dev-discuss.net/gmd-2019-148/},
volume = {12},
year = {2019}
}
@article{Roberts2018,
abstract = {Abstract. This paper presents atmosphere-only and coupled climate model configurations of the European Centre for Medium-Range Weather Forecasts Integrated Forecasting System (ECMWF-IFS) for different combinations of ocean and atmosphere resolution. These configurations are used to perform multi-decadal ensemble experiments following the protocols of the High Resolution Model Intercomparison Project (HighResMIP) and phase 6 of the Coupled Model Intercomparison Project (CMIP6). These experiments are used to evaluate the sensitivity of major biases in the atmosphere, ocean, and cryosphere to changes in atmosphere and ocean resolution. All configurations successfully reproduce the observed long-term trends in global mean surface temperature. Furthermore, following an adjustment to account for drift in the subsurface ocean, coupled configurations of ECMWF-IFS realistically reproduce observation-based estimates of ocean heat content change since 1950. Climatological surface biases in ECMWF-IFS are relatively insensitive to an increase in atmospheric resolution from ∼ 50 to ∼ 25km. However, increasing the horizontal resolution of the atmosphere while maintaining the same vertical resolution enhances the magnitude of a cold bias in the lower stratosphere. In coupled configurations, there is a strong sensitivity to an increase in ocean model resolution from 1 to 0.25°. However, this sensitivity to ocean resolution takes many years to fully manifest and is less apparent in the first year of integration. This result has implications for the ECMWF coupled model development strategy that typically relies on the analysis of biases in short ( {\textless} 1 year) ensemble (re)forecast data sets. The impacts of increased ocean resolution are particularly evident in the North Atlantic and Arctic, where they are associated with an improved Atlantic meridional overturning circulation, increased meridional ocean heat transport, and more realistic sea-ice cover. In the tropical Pacific, increased ocean resolution is associated with improvements to the magnitude and asymmetry of El Ni{\~{n}}o–Southern Oscillation (ENSO) variability and better representation of non-linear sea surface temperature (SST)–radiation feedbacks during warm events. However, increased ocean model resolution also increases the magnitude of a warm bias in the Southern Ocean. Finally, there is tentative evidence that both ocean coupling and increased atmospheric resolution can improve teleconnections between tropical Pacific rainfall and geopotential height anomalies in the North Atlantic.},
author = {Roberts, Christopher D. and Senan, Retish and Molteni, Franco and Boussetta, Souhail and Mayer, Michael and Keeley, Sarah P. E.},
doi = {10.5194/gmd-11-3681-2018},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {sep},
number = {9},
pages = {3681--3712},
title = {{Climate model configurations of the ECMWF Integrated Forecasting System (ECMWF-IFS cycle 43r1) for HighResMIP}},
url = {https://www.geosci-model-dev.net/11/3681/2018/},
volume = {11},
year = {2018}
}
@article{Roberts2019,
abstract = {A multimodel, multiresolution set of simulations over the period 1950-2014 using a common forcing protocol from CMIP6 HighResMIP have been completed by six modeling groups. Analysis of tropical cyclone performance using two different tracking algorithms suggests that enhanced resolution toward 25 km typically leads to more frequent and stronger tropical cyclones, together with improvements in spatial distribution and storm structure. Both of these factors reduce typical GCM biases seen at lower resolution. Using single ensemble members of each model, there is little evidence of systematic improvement in interannual variability in either storm frequency or accumulated cyclone energy as compared with observations when resolution is increased. Changes in the relationships between large-scale drivers of climate variability and tropical cyclone variability in the Atlantic Ocean are also not robust to model resolution. However, using a larger ensemble of simulations (of up to 14 members) with one model at different resolutions does show evidence of increased skill at higher resolution. The ensemble mean correlation of Atlantic interannual tropical cyclone variability increases from ∼0.5 to ∼0.65 when resolution increases from 250 to 100 km. In the northwestern Pacific Ocean the skill keeps increasing with 50-km resolution to 0.7. These calculations also suggest that more than six members are required to adequately distinguish the impact of resolution within the forced signal from the weather noise.},
author = {Roberts, Malcolm John and Camp, Joanne and Seddon, Jon and Vidale, Pier Luigi and Hodges, Kevin and Vanniere, Benoit and Mecking, Jenny and Haarsma, Rein and Bellucci, Alessio and Scoccimarro, Enrico and Caron, Louis Philippe and Chauvin, Fabrice and Terray, Laurent and Valcke, Sophie and Moine, Marie Pierre and Putrasahan, Dian and Roberts, Christopher and Senan, Retish and Zarzycki, Colin and Ullrich, Paul},
doi = {10.1175/JCLI-D-19-0639.1},
issn = {08948755},
journal = {Journal of Climate},
number = {7},
pages = {2557--2583},
title = {{Impact of model resolution on tropical cyclone simulation using the HighResMIP-PRIMAVERA multimodel ensemble}},
volume = {33},
year = {2020}
}
@article{Robertsa,
abstract = {A multimodel, multiresolution ensemble using Coupled Model Intercomparison Project Phase 6 (CMIP6) High Resolution Model Intercomparison Project (HighResMIP) coupled experiments is used to assess the performance of key aspects of the North Atlantic circulation. The Atlantic Meridional Overturning Circulation (AMOC), and related heat transport, tends to become stronger as ocean model resolution is enhanced, better agreeing with observations at 26.5°N. However, for most models the circulation remains too shallow compared to observations and has a smaller temperature contrast between the northward and southward limbs of the AMOC. These biases cause the northward heat transport to be systematically too low for a given overturning strength. The higher-resolution models also tend to have too much deep mixing in the subpolar gyre. In the period 2015–2050 the overturning circulation tends to decline more rapidly in the higher-resolution models, which is related to both the mean state and to the subpolar gyre contribution to deep water formation. The main part of the decline comes from the Florida Current component of the circulation. Such large declines in AMOC are not seen in the models with resolutions more typically used for climate studies, suggesting an enhanced risk for Northern Hemisphere climate change. However, only a small number of different ocean models are included in the study.},
author = {Roberts, Malcolm J. and Jackson, Laura C. and Roberts, Christopher D. and Meccia, Virna and Docquier, David and Koenigk, Torben and Ortega, Pablo and Moreno-Chamarro, Eduardo and Bellucci, Alessio and Coward, Andrew and Drijfhout, Sybren and Exarchou, Eleftheria and Gutjahr, Oliver and Hewitt, Helene and Iovino, Doroteaciro and Lohmann, Katja and Putrasahan, Dian and Schiemann, Reinhard and Seddon, Jon and Terray, Laurent and Xu, Xiaobiao and Zhang, Qiuying and Chang, Ping and Yeager, Stephen G. and Castruccio, Frederic S. and Zhang, Shaoqing and Wu, Lixin},
doi = {10.1029/2019MS002014},
issn = {19422466},
journal = {Journal of Advances in Modeling Earth Systems},
keywords = {AMOC,Atlantic,future projection,model resolution,ocean circulation},
number = {8},
pages = {e2019MS002014},
title = {{Sensitivity of the Atlantic Meridional Overturning Circulation to Model Resolution in CMIP6 HighResMIP Simulations and Implications for Future Changes}},
volume = {12},
year = {2020}
}
@article{Roberts,
abstract = {Future changes in tropical cyclone properties are an important component of climate change impacts and risk for many tropical and midlatitude countries. In this study we assess the performance of a multimodel ensemble of climate models, at resolutions ranging from 250 to 25 km. We use a common experimental design including both atmosphere-only and coupled simulations run over the period 1950–2050, with two tracking algorithms applied uniformly across the models. There are overall improvements in tropical cyclone frequency, spatial distribution, and intensity in models at 25 km resolution, with several of them able to represent very intense storms. Projected tropical cyclone activity by 2050 generally declines in the South Indian Ocean, while changes in other ocean basins are more uncertain and sensitive to both tracking algorithm and imposed forcings. Coupled models with smaller biases suggest a slight increase in average TC 10 m wind speeds by 2050.},
author = {Roberts, Malcolm John and Camp, Joanne and Seddon, Jon and Vidale, Pier Luigi and Hodges, Kevin and Vanni{\`{e}}re, Beno{\^{i}}t and Mecking, Jenny and Haarsma, Rein and Bellucci, Alessio and Scoccimarro, Enrico and Caron, Louis Philippe and Chauvin, Fabrice and Terray, Laurent and Valcke, Sophie and Moine, Marie Pierre and Putrasahan, Dian and Roberts, Christopher D. and Senan, Retish and Zarzycki, Colin and Ullrich, Paul and Yamada, Yohei and Mizuta, Ryo and Kodama, Chihiro and Fu, Dan and Zhang, Qiuying and Danabasoglu, Gokhan and Rosenbloom, Nan and Wang, Hong and Wu, Lixin},
doi = {10.1029/2020GL088662},
issn = {19448007},
journal = {Geophysical Research Letters},
keywords = {CMIP6,future change,high resolution,model bias,tracking algorithms,tropical cyclones},
number = {14},
pages = {e2020GL088662},
title = {{Projected Future Changes in Tropical Cyclones Using the CMIP6 HighResMIP Multimodel Ensemble}},
volume = {47},
year = {2020}
}
@article{Robson2012,
abstract = {AbstractIn the mid-1990s, the subpolar gyre of the North Atlantic underwent a remarkable rapid warming, with sea surface temperatures increasing by around 1°C in just 2 yr. This rapid warming followed a prolonged positive phase of the North Atlantic Oscillation (NAO) but also coincided with an unusually negative NAO index in the winter of 1995/96. By comparing ocean analyses and carefully designed model experiments, it is shown that this rapid warming can be understood as a delayed response to the prolonged positive phase of the NAO and not simply an instantaneous response to the negative NAO index of 1995/96. Furthermore, it is inferred that the warming was partly caused by a surge and subsequent decline in the meridional overturning circulation and northward heat transport of the Atlantic Ocean. These results provide persuasive evidence of significant oceanic memory on multiannual time scales and are therefore encouraging for the prospects of developing skillful predictions.},
annote = {doi: 10.1175/JCLI-D-11-00443.1},
author = {Robson, Jon and Sutton, Rowan and Lohmann, Katja and Smith, Doug and Palmer, Matthew D},
doi = {10.1175/JCLI-D-11-00443.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jan},
number = {12},
pages = {4116--4134},
publisher = {American Meteorological Society},
title = {{Causes of the Rapid Warming of the North Atlantic Ocean in the Mid-1990s}},
url = {https://doi.org/10.1175/JCLI-D-11-00443.1},
volume = {25},
year = {2012}
}
@article{Robson2020,
author = {Robson, Jon and Aksenov, Yevgeny and Bracegirdle, Thomas J. and Dimdore‐Miles, Oscar and Griffiths, Paul T. and Grosvenor, Daniel P. and Hodson, Daniel L. R. and Keeble, James and MacIntosh, Claire and Megann, Alex and Osprey, Scott and Povey, Adam C. and Schr{\"{o}}der, David and Yang, Mingxi and Archibald, Alexander T. and Carslaw, Ken S. and Gray, Lesley and Jones, Colin and Kerridge, Brian and Knappett, Diane and Kuhlbrodt, Till and Russo, Maria and Sellar, Alistair and Siddans, Richard and Sinha, Bablu and Sutton, Rowan and Walton, Jeremy and Wilcox, Laura J.},
doi = {10.1029/2020MS002126},
issn = {1942-2466},
journal = {Journal of Advances in Modeling Earth Systems},
month = {sep},
number = {9},
pages = {e2020MS002126},
title = {{The Evaluation of the North Atlantic Climate System in UKESM1 Historical Simulations for CMIP6}},
url = {https://onlinelibrary.wiley.com/doi/10.1029/2020MS002126},
volume = {12},
year = {2020}
}
@article{Rodriguez-Fonseca2015,
author = {Rodr{\'{i}}guez-Fonseca, Belen and Mohino, Elsa and Mechoso, Carlos R. and Caminade, Cyril and Biasutti, Michela and Gaetani, Marco and Garcia-Serrano, J. and Vizy, Edward K. and Cook, Kerry and Xue, Yongkang and Polo, Irene and Losada, Teresa and Druyan, Leonard and Fontaine, Bernard and Bader, Juergen and Doblas-Reyes, Francisco J. and Goddard, Lisa and Janicot, Serge and Arribas, Alberto and Lau, William and Colman, Andrew and Vellinga, M. and Rowell, David P. and Kucharski, Fred and Voldoire, Aurore},
doi = {10.1175/JCLI-D-14-00130.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {may},
number = {10},
pages = {4034--4060},
title = {{Variability and Predictability of West African Droughts: A Review on the Role of Sea Surface Temperature Anomalies}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-14-00130.1},
volume = {28},
year = {2015}
}
@article{tc-2020-265,
abstract = {Abstract. Around the world, small ice caps and glaciers have been losing mass and retreating since the start of the industrial era. Estimates are that this has contributed approximately 30 {\%} of the observed sea-level rise over the same period. It is important to understand the relative importance of natural and anthropogenic components of this mass loss. One recent study concluded that the best estimate of the magnitude of the anthropogenic mass loss over the industrial era was only 25 {\%} of the total, implying a predominantly natural cause. Here we show that the anthropogenic fraction of the total mass loss of a given glacier depends only on the magnitudes and rates of the natural and anthropogenic components of climate change and on the glacier's response time. We consider climate change over the past millennium using synthetic scenarios, palaeoclimate reconstructions, numerical climate simulations, and instrumental observations. We use these climate histories to drive a glacier model that can represent a wide range of glacier response times, and we evaluate the magnitude of the anthropogenic mass loss relative to the observed mass loss. The slow cooling over the preceding millennium followed by the rapid anthropogenic warming of the industrial era means that, over the full range of response times for small ice caps and glaciers, the central estimate of the magnitude of the anthropogenic mass loss is essentially 100 {\%} of the observed mass loss. The anthropogenic magnitude may exceed 100 {\%} in the event that, without anthropogenic climate forcing, glaciers would otherwise have been gaining mass. Our results bring assessments of the attribution of glacier mass loss into alignment with assessments of others aspects of climate change, such as global-mean temperature. Furthermore, these results reinforce the scientific and public understanding of centennial-scale glacier retreat as an unambiguous consequence of human activity.},
author = {Roe, Gerard H and Christian, John Erich and Marzeion, Ben},
doi = {10.5194/tc-15-1889-2021},
issn = {1994-0424},
journal = {The Cryosphere},
month = {apr},
number = {4},
pages = {1889--1905},
title = {{On the attribution of industrial-era glacier mass loss to anthropogenic climate change}},
url = {https://tc.copernicus.org/articles/15/1889/2021/},
volume = {15},
year = {2021}
}
@article{Roe2017,
abstract = {The near-global retreat of glaciers over the last century provides some of the most iconic imagery for communicating the reality of anthropogenic climate change to the public. Surprisingly, however, there has not been a quantitative foundation for attributing the retreats to climate change, except in the global aggregate. This gap, between public perception and scientific basis, is due to uncertainties in numerical modelling and the short length of glacier mass-balance records. Here we present a method for assessing individual glacier change based on the signal-to-noise ratio, a robust metric that is insensitive to uncertainties in glacier dynamics. Using only meteorological and glacier observations, and the characteristic decadal response time of glaciers, we demonstrate that observed retreats of individual glaciers represent some of the highest signal-to-noise ratios of climate change yet documented. Therefore, in many places, the centennial-scale retreat of the local glaciers does indeed constitute categorical evidence of climate change.},
author = {Roe, Gerard H. and Baker, Marcia B. and Herla, Florian},
doi = {10.1038/ngeo2863},
issn = {17520908},
journal = {Nature Geoscience},
month = {dec},
number = {2},
pages = {95--99},
publisher = {Nature Publishing Group},
title = {{Centennial glacier retreat as categorical evidence of regional climate change}},
volume = {10},
year = {2017}
}
@article{Roemmich2015,
abstract = {Increasing heat content of the global ocean dominates the energy imbalance in the climate system. Here we show that ocean heat gain over the 0-2,000 m layer continued at a rate of 0.4-0.6 W m-2 during 2006-2013. The depth dependence and spatial structure of temperature changes are described on the basis of the Argo Program's accurate and spatially homogeneous data set, through comparison of three Argo-only analyses. Heat gain was divided equally between upper ocean, 0-500 m and 500-2,000 m components. Surface temperature and upper 100 m heat content tracked interannual El Ni{\~{n}}o/Southern Oscillation fluctuations, but were offset by opposing variability from 100-500 m. The net 0-500 m global average temperature warmed by 0.005 °C yr -. Between 500 and 2,000 m steadier warming averaged 0.002 °C yr - with a broad intermediate-depth maximum between 700 and 1,400 m. Most of the heat gain (67 to 98{\%}) occurred in the Southern Hemisphere extratropical ocean. Although this hemispheric asymmetry is consistent with inhomogeneity of radiative forcing and the greater area of the Southern Hemisphere ocean, ocean dynamics also influence regional patterns of heat gain.},
author = {Roemmich, Dean and Church, John and Gilson, John and Monselesan, Didier and Sutton, Philip and Wijffels, Susan},
doi = {10.1038/nclimate2513},
isbn = {1758-678X},
issn = {17586798},
journal = {Nature Climate Change},
keywords = {Physical oceanography,ocean,structure,update,vertical,warming},
month = {mar},
number = {3},
pages = {240--245},
publisher = {Nature Publishing Group},
title = {{Unabated planetary warming and its ocean structure since 2006}},
url = {citeulike-article-id:13507284 http://www.nature.com/articles/nclimate2513},
volume = {5},
year = {2015}
}
@article{doi:10.1175/JCLI-D-16-0455.1,
abstract = { AbstractObservations indicate that the Arctic sea ice cover is rapidly retreating while the Antarctic sea ice cover is steadily expanding. State-of-the-art climate models, by contrast, typically simulate a moderate decrease in both the Arctic and Antarctic sea ice covers. However, in each hemisphere there is a small subset of model simulations that have sea ice trends similar to the observations. Based on this, a number of recent studies have suggested that the models are consistent with the observations in each hemisphere when simulated internal climate variability is taken into account. Here sea ice changes during 1979–2013 are examined in simulations from the most recent Coupled Model Intercomparison Project (CMIP5) as well as the Community Earth System Model Large Ensemble (CESM-LE), drawing on previous work that found a close relationship in climate models between global-mean surface temperature and sea ice extent. All of the simulations with 1979–2013 Arctic sea ice retreat as fast as observations are found to have considerably more global warming than observations during this time period. Using two separate methods to estimate the sea ice retreat that would occur under the observed level of global warming in each simulation in both ensembles, it is found that simulated Arctic sea ice retreat as fast as observations would occur less than 1{\%} of the time. This implies that the models are not consistent with the observations. In the Antarctic, simulated sea ice expansion as fast as observations is found to typically correspond with too little global warming, although these results are more equivocal. As a result, the simulations do not capture the observed asymmetry between Arctic and Antarctic sea ice trends. This suggests that the models may be getting the right sea ice trends for the wrong reasons in both polar regions. },
author = {Rosenblum, Erica and Eisenman, Ian},
doi = {10.1175/JCLI-D-16-0455.1},
journal = {Journal of Climate},
number = {16},
pages = {6265--6278},
title = {{Sea Ice Trends in Climate Models Only Accurate in Runs with Biased Global Warming}},
url = {https://doi.org/10.1175/JCLI-D-16-0455.1},
volume = {30},
year = {2017}
}
@article{Rotstayn2013,
author = {Rotstayn, Leon D},
doi = {10.1088/1748-9326/8/4/044028},
issn = {1748-9326},
journal = {Environmental Research Letters},
month = {dec},
number = {4},
pages = {044028},
title = {{Projected effects of declining anthropogenic aerosols on the southern annular mode}},
url = {http://stacks.iop.org/1748-9326/8/i=4/a=044028?key=crossref.1ae55219c7e138a3d57a42073eeed77c},
volume = {8},
year = {2013}
}
@article{Rougier2016,
abstract = { AbstractIn fields such as climate science, it is common to compile an ensemble of different simulators for the same underlying process. It is a striking observation that the ensemble mean often outperforms at least half of the ensemble members in mean squared error (measured with respect to observations). In fact, as demonstrated in the most recent IPCC report, the ensemble mean often outperforms all or almost all of the ensemble members across a range of climate variables. This paper shows that these could be mathematical results based on convexity and averaging but with implications for the properties of the current generation of climate simulators. },
author = {Rougier, Jonathan},
doi = {10.1175/JCLI-D-16-0012.1},
journal = {Journal of Climate},
number = {24},
pages = {8865--8870},
title = {{Ensemble Averaging and Mean Squared Error}},
volume = {29},
year = {2016}
}
@article{Rowell2015,
abstract = {The “long rains” season of East Africa has recently experienced a series of devastating droughts, whereas the majority of climate models predict increasing rainfall for the coming decades. This has been termed the East African climate paradox and has implications for developing viable adaptation policies. A logical framework is adopted that leads to six key hypotheses that could explain this paradox. The first hypothesis that the recent observed trend is due to poor quality data is promptly rejected. An initial judgment on the second hypothesis that the projected trend is founded on poor modeling is beyond the scope of a single study. Analysis of a natural variability hypothesis suggests this is unlikely to have been the dominant driver of recent droughts, although it may have contributed. The next two hypotheses explore whether the balance between competing forcings could be changing. Regarding the possibility that the past trend could be due to changing anthropogenic aerosol emissions, the results of sensitivity experiments are highly model dependent, but some show a significant impact on the patterns of tropical SST trends, aspects of which likely caused the recent long rains droughts. Further experiments suggest land-use changes are unlikely to have caused the recent droughts. The last hypothesis that the response to CO2 emissions is nonlinear explains no more than 10{\%} of the contrast between recent and projected trends. In conclusion, it is recommended that research priorities now focus on providing a process-based expert judgment of the reliability of East Africa projections, improving the modeling of aerosol impacts on rainfall, and better understanding the relevant natural variability.},
author = {Rowell, David P. and Booth, Ben B. B. and Nicholson, Sharon E. and Good, Peter},
doi = {10.1175/JCLI-D-15-0140.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {dec},
number = {24},
pages = {9768--9788},
title = {{Reconciling Past and Future Rainfall Trends over East Africa}},
url = {https://doi.org/10.1175/JCLI-D-15-0140.1 http://journals.ametsoc.org/doi/10.1175/JCLI-D-15-0140.1},
volume = {28},
year = {2015}
}
@article{Ruggieri2020a,
abstract = {The influence of the Atlantic multidecadal variability (AMV) on the North Atlantic storm track and eddy-driven jet in the winter season is assessed via a coordinated analysis of idealized simulations with state-of-the-art coupled models. Data used are obtained from a multimodel ensemble of AMV± experiments conducted in the framework of the Decadal Climate Prediction Project component C. These experiments are performed by nudging the surface of the Atlantic Ocean to states defined by the superimposition of observed AMV± anomalies onto the model climatology. A robust extratropical response is found in the form of a wave train extending from the Pacific to the Nordic seas. In the warm phase of the AMV compared to the cold phase, the Atlantic storm track is typically contracted and less extended poleward and the low-level jet is shifted toward the equator in the eastern Atlantic. Despite some robust features, the picture of an uncertain and model-dependent response of the Atlantic jet emerges and we demonstrate a link between model bias and the character of the jet response.},
author = {Ruggieri, Paolo and Bellucci, Alessio and Nicol{\'{i}}, Dario and Athanasiadis, Panos J. and Gualdi, Silvio and Cassou, Christophe and Castruccio, Fred and Danabasoglu, Gokhan and Davini, Paolo and Dunstone, Nick and Eade, Rosemary and Gastineau, Guillaume and Harvey, Ben and Hermanson, Leon and Qasmi, Sa{\"{i}}d and Ruprich-Robert, Yohan and Sanchez-Gomez, Emilia and Smith, Doug and Wild, Simon and Zampieri, Matteo},
doi = {10.1175/JCLI-D-19-0981.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jan},
number = {1},
pages = {347--360},
title = {{Atlantic Multidecadal Variability and North Atlantic Jet: A Multimodel View from the Decadal Climate Prediction Project}},
url = {https://journals.ametsoc.org/view/journals/clim/34/1/JCLI-D-19-0981.1.xml},
volume = {34},
year = {2021}
}
@article{Rupp2013,
abstract = {Significant declines in spring Northern Hemisphere (NH) snow cover extent (SCE) have been observed over the last five decades. As one step toward understanding the causes of this decline, an optimal fingerprinting technique is used to look for consistency in the temporal pattern of spring NH SCE between observations and simulations from 15 global climate models (GCMs) that form part of phase 5 of the Coupled Model Intercomparison Project. The authors examined simulations from 15 GCMs that included both natural and anthropogenic forcing and simulations from 7 GCMs that included only natural forcing. The decline in observed NH SCE could be largely explained by the combined natural and anthropogenic forcing but not by natural forcing alone. However, the 15 GCMs, taken as a whole, underpredicted the combined forcing response by a factor of 2. How much of this underprediction was due to underrepresentation of the sensitivity to external forcing of the GCMs or to their underrepresentation of internal variability has yet to be determined.},
author = {Rupp, David E. and Mote, Philip W. and Bindoff, Nathaniel L. and Stott, Peter A. and Robinson, David A.},
doi = {10.1175/JCLI-D-12-00563.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {sep},
number = {18},
pages = {6904--6914},
title = {{Detection and Attribution of Observed Changes in Northern Hemisphere Spring Snow Cover}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-12-00563.1},
volume = {26},
year = {2013}
}
@article{Ruprich-Robert2017,
abstract = {AbstractThe climate impacts of the observed Atlantic Multidecadal Variability (AMV) are investigated using the GFDL-CM2.1 and the NCAR-CESM1 coupled climate models. The model North Atlantic sea surface temperatures are restored to fixed anomalies corresponding to an estimate of the internally driven component of the observed AMV. Both models show that during boreal summer the AMV alters the Walker Circulation and generates precipitation anomalies over the whole tropical belt. A warm phase of the AMV yields reduced precipitation over western US, drier conditions over the Mediterranean basin, and wetter conditions over Northern Europe. During boreal winter, the AMV modulates by a factor of {\{}{\~{}}{\}}2 the frequency of occurrence of El Ni{\{}{\~{n}}{\}}o/La Ni{\{}{\~{n}}{\}}a events. This response is associated with anomalies over the Pacific that project onto the Interdecadal Pacific Oscillation pattern, i.e., Pacific Decadal Oscillation-like anomalies in the Northern hemisphere and a symmetrical pattern in the Southern Hemisphere. This winter...},
author = {Ruprich-Robert, Yohan and Msadek, Rym and Castruccio, Frederic and Yeager, Stephen and Delworth, Tom and Danabasoglu, Gokhan},
doi = {10.1175/JCLI-D-16-0127.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {ENSO,Multidecadal variability,North Atlantic Oscillation,Pacific decadal oscillation,Pacific-North American pattern/oscillation},
number = {8},
pages = {2785--2810},
title = {{Assessing the climate impacts of the observed atlantic multidecadal variability using the GFDL CM2.1 and NCAR CESM1 global coupled models}},
volume = {30},
year = {2017}
}
@article{Ruprich-Robert2015,
author = {Ruprich-Robert, Yohan and Cassou, Christophe},
doi = {10.1007/s00382-014-2176-7},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jan},
number = {1-2},
pages = {229--253},
title = {{Combined influences of seasonal East Atlantic Pattern and North Atlantic Oscillation to excite Atlantic multidecadal variability in a climate model}},
url = {http://link.springer.com/10.1007/s00382-014-2176-7},
volume = {44},
year = {2015}
}
@article{Ruprich-Robert2018,
abstract = {The impacts of the Atlantic multidecadal variability (AMV) on summertime North American climate are investigated using three coupled global climate models (CGCMs) in which North Atlantic sea surface temperatures (SSTs) are restored to observed AMV anomalies. Large ensemble simulations are performed to estimate how AMV can modulate the occurrence of extreme weather such as heat waves. It is shown that, in response to an AMV warming, all models simulate a precipitation deficit and a warming over northern Mexico and the southern United States that lead to an increased number of heat wave days by about 30{\%} compared to an AMV cooling. The physical mechanisms associated with these impacts are discussed. The positive tropical Atlantic SST anomalies associated with the warm AMV drive a Matsuno–Gill-like atmospheric response that favors subsidence over northern Mexico and the southern United States. This leads to a warming of the whole tropospheric column, and to a decrease in relative humidity, cloud cover, and precipitation. Soil moisture response to AMV also plays a role in the modulation of heat wave occurrence. An AMV warming favors dry soil conditions over northern Mexico and the southern United States by driving a year-round precipitation deficit through atmospheric teleconnections coming both directly from the North Atlantic SST forcing and indirectly from the Pacific. The indirect AMV teleconnections highlight the importance of using CGCMs to fully assess the AMV impacts on North America. Given the potential predictability of the AMV, the teleconnections discussed here suggest a source of predictability for the North American climate variability and in particular for the occurrence of heat waves at multiyear time scales.},
author = {Ruprich-Robert, Yohan and Delworth, Thomas and Msadek, Rym and Castruccio, Frederic and Yeager, Stephen and Danabasoglu, Gokhan},
doi = {10.1175/JCLI-D-17-0270.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {may},
number = {9},
pages = {3679--3700},
title = {{Impacts of the Atlantic Multidecadal Variability on North American Summer Climate and Heat Waves}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-17-0270.1},
volume = {31},
year = {2018}
}
@article{doi:10.1002/2017JC013461,
abstract = {Abstract The Southern Ocean is central to the global climate and the global carbon cycle, and to the climate's response to increasing levels of atmospheric greenhouse gases, as it ventilates a large fraction of the global ocean volume. Global coupled climate models and earth system models, however, vary widely in their simulations of the Southern Ocean and its role in, and response to, the ongoing anthropogenic trend. Due to the region's complex water-mass structure and dynamics, Southern Ocean carbon and heat uptake depend on a combination of winds, eddies, mixing, buoyancy fluxes, and topography. Observationally based metrics are critical for discerning processes and mechanisms, and for validating and comparing climate and earth system models. New observations and understanding have allowed for progress in the creation of observationally based data/model metrics for the Southern Ocean. Metrics presented here provide a means to assess multiple simulations relative to the best available observations and observational products. Climate models that perform better according to these metrics also better simulate the uptake of heat and carbon by the Southern Ocean. This report is not strictly an intercomparison, but rather a distillation of key metrics that can reliably quantify the “accuracy” of a simulation against observed, or at least observable, quantities. One overall goal is to recommend standardization of observationally based benchmarks that the modeling community should aspire to meet in order to reduce uncertainties in climate projections, and especially uncertainties related to oceanic heat and carbon uptake.},
author = {Russell, Joellen L. and Kamenkovich, Igor and Bitz, Cecilia and Ferrari, Raffaele and Gille, Sarah T. and Goodman, Paul J. and Hallberg, Robert and Johnson, Kenneth and Khazmutdinova, Karina and Marinov, Irina and Mazloff, Matthew and Riser, Stephen and Sarmiento, Jorge L. and Speer, Kevin and Talley, Lynne D. and Wanninkhof, Rik},
doi = {10.1002/2017JC013461},
isbn = {21699275},
issn = {21699291},
journal = {Journal of Geophysical Research: Oceans},
keywords = {Carbon uptake,Heat uptake,Observationally based metrics,Southern Ocean,aogcm,ar6{\_}research,carbon uptake,cgcm,esm,heat uptake,metrics,observationally based metrics,ocean,southern},
month = {may},
number = {5},
pages = {3120--3143},
publisher = {Wiley-Blackwell},
title = {{Metrics for the Evaluation of the Southern Ocean in Coupled Climate Models and Earth System Models}},
url = {http://doi.wiley.com/10.1002/2017JC013461 citeulike-article-id:14614897 http://dx.doi.org/10.1002/2017jc013461},
volume = {123},
year = {2018}
}
@article{Rypdal2018,
abstract = {The main features of the instrumental globalmean surface temperature (GMST) are reasonably well described by a simple linear response model driven by anthropogenic, volcanic and solar forcing. This model acts as a linear long-memory filter of the forcing signal. The physical interpretation of this filtering is the delayed response due to the thermal inertia of the ocean. This description is considerably more accurate if El Ni{\~{n}}o Southern Oscillation (ENSO) and the AtlanticMultidecadal Oscillation (AMO) are regarded as additional forcings of the global temperature and hence subject to the same filtering as the other forcing components. By considering these as predictors in a linear regression scheme,more than 92{\%} of the variance in the instrumental GMST over the period 1870-2017 is explained by this model, in particular, all features of the 1998-2015 hiatus, including its death. While the more prominent pauses during 1870-1915 and 1940-1970 can be attributed to clustering in time of strong volcanic eruptions, the recent hiatus is an unremarkable phenomenon that is attributed to ENSO with a small contribution from solar activity.},
author = {Rypdal, Kristoffer},
doi = {10.3390/cli6030064},
issn = {22251154},
journal = {Climate},
number = {3},
pages = {64},
title = {{The life and death of the recent global surface warming hiatus parsimoniously explained}},
volume = {6},
year = {2018}
}
@article{Seferian2016,
abstract = {Abstract. We document the first version of the Centre National de Recherches M{\'{e}}t{\'{e}}orologiques Earth system model (CNRM-ESM1). This model is based on the physical core of the CNRM climate model version 5 (CNRM-CM5) model and employs the Interactions between Soil, Biosphere and Atmosphere (ISBA) and the Pelagic Interaction Scheme for Carbon and Ecosystem Studies (PISCES) as terrestrial and oceanic components of the global carbon cycle. We describe a preindustrial and 20th century climate simulation following the CMIP5 protocol. We detail how the various carbon reservoirs were initialized and analyze the behavior of the carbon cycle and its prominent physical drivers. Over the 1986–2005 period, CNRM-ESM1 reproduces satisfactorily several aspects of the modern carbon cycle. On land, the model captures the carbon cycling through vegetation and soil, resulting in a net terrestrial carbon sink of 2.2 Pg C year−1. In the ocean, the large-scale distribution of hydrodynamical and biogeochemical tracers agrees with a modern climatology from the World Ocean Atlas. The combination of biological and physical processes induces a net CO2 uptake of 1.7 Pg C year−1 that falls within the range of recent estimates. Our analysis shows that the atmospheric climate of CNRM-ESM1 compares well with that of CNRM-CM5. Biases in precipitation and shortwave radiation over the tropics generate errors in gross primary productivity and ecosystem respiration. Compared to CNRM-CM5, the revised ocean–sea ice coupling has modified the sea-ice cover and ocean ventilation, unrealistically strengthening the flow of North Atlantic deep water (26.1 ± 2 Sv). It results in an accumulation of anthropogenic carbon in the deep ocean.},
author = {S{\'{e}}f{\'{e}}rian, Roland and Delire, Christine and Decharme, Bertrand and Voldoire, Aurore and {Salas y Melia}, David and Chevallier, Matthieu and Saint-Martin, David and Aumont, Olivier and Calvet, Jean-Christophe and Carrer, Dominique and Douville, Herv{\'{e}} and Franchist{\'{e}}guy, Laurent and Joetzjer, Emilie and S{\'{e}}n{\'{e}}si, S{\'{e}}phane},
doi = {10.5194/gmd-9-1423-2016},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {apr},
number = {4},
pages = {1423--1453},
title = {{Development and evaluation of CNRM Earth system model – CNRM-ESM1}},
url = {https://gmd.copernicus.org/articles/9/1423/2016/},
volume = {9},
year = {2016}
}
@article{Seferian2019,
abstract = {This study introduces CNRM-ESM2-1, the Earth system (ES) model of second generation developed by CNRM-CERFACS for the sixth phase of the Coupled Model Intercomparison Project (CMIP6). CNRM-ESM2-1 offers a higher model complexity than the Atmosphere-Ocean General Circulation Model CNRM-CM6-1 by adding interactive ES components such as carbon cycle, aerosols, and atmospheric chemistry. As both models share the same code, physical parameterizations, and grid resolution, they offer a fully traceable framework to investigate how far the represented ES processes impact the model performance over present-day, response to external forcing and future climate projections. Using a large variety of CMIP6 experiments, we show that represented ES processes impact more prominently the model response to external forcing than the model performance over present-day. Both models display comparable performance at replicating modern observations although the mean climate of CNRM-ESM2-1 is slightly warmer than that of CNRM-CM6-1. This difference arises from land cover-aerosol interactions where the use of different soil vegetation distributions between both models impacts the rate of dust emissions. This interaction results in a smaller aerosol burden in CNRM-ESM2-1 than in CNRM-CM6-1, leading to a different surface radiative budget and climate. Greater differences are found when comparing the model response to external forcing and future climate projections. Represented ES processes damp future warming by up to 10{\%} in CNRM-ESM2-1 with respect to CNRM-CM6-1. The representation of land vegetation and the CO2-water-stomatal feedback between both models explain about 60{\%} of this difference. The remainder is driven by other ES feedbacks such as the natural aerosol feedback.},
annote = {doi: 10.1029/2019MS001791},
author = {S{\'{e}}f{\'{e}}rian, Roland and Nabat, Pierre and Michou, Martine and Saint‐Martin, David and Voldoire, Aurore and Colin, Jeanne and Decharme, Bertrand and Delire, Christine and Berthet, Sarah and Chevallier, Matthieu and S{\'{e}}n{\'{e}}si, Stephane and Franchisteguy, Laurent and Vial, Jessica and Mallet, Marc and Joetzjer, Emilie and Geoffroy, Olivier and Gu{\'{e}}r{\'{e}}my, Jean-Fran{\c{c}}ois and Moine, Marie-Pierre and Msadek, Rym and Ribes, Aur{\'{e}}lien and Rocher, Matthias and Roehrig, Romain and Salas‐y‐M{\'{e}}lia, David and Sanchez, Emilia and Terray, Laurent and Valcke, Sophie and Waldman, Robin and Aumont, Olivier and Bopp, Laurent and Deshayes, Julie and {\'{E}}th{\'{e}}, Christian and Madec, Gurvan},
doi = {10.1029/2019MS001791},
issn = {1942-2466},
journal = {Journal of Advances in Modeling Earth Systems},
keywords = {CMIP6,Earth system modeling,aerosols,biogeochemical cycles,climate modeling,future projections},
month = {dec},
number = {12},
pages = {4182--4227},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Evaluation of CNRM Earth System Model, CNRM‐ESM2‐1: Role of Earth System Processes in Present‐Day and Future Climate}},
url = {https://doi.org/10.1029/2019MS001791 https://onlinelibrary.wiley.com/doi/abs/10.1029/2019MS001791},
volume = {11},
year = {2019}
}
@article{Seferian,
abstract = {Purpose of Review: The changes or updates in ocean biogeochemistry component have been mapped between CMIP5 and CMIP6 model versions, and an assessment made of how far these have led to improvements in the simulated mean state of marine biogeochemical models within the current generation of Earth system models (ESMs). Recent Findings: The representation of marine biogeochemistry has progressed within the current generation of Earth system models. However, it remains difficult to identify which model updates are responsible for a given improvement. In addition, the full potential of marine biogeochemistry in terms of Earth system interactions and climate feedback remains poorly examined in the current generation of Earth system models. Summary: Increasing availability of ocean biogeochemical data, as well as an improved understanding of the underlying processes, allows advances in the marine biogeochemical components of the current generation of ESMs. The present study scrutinizes the extent to which marine biogeochemistry components of ESMs have progressed between the 5th and the 6th phases of the Coupled Model Intercomparison Project (CMIP).},
author = {S{\'{e}}f{\'{e}}rian, Roland and Berthet, Sarah and Yool, Andrew and Palmi{\'{e}}ri, Julien and Bopp, Laurent and Tagliabue, Alessandro and Kwiatkowski, Lester and Aumont, Olivier and Christian, James and Dunne, John and Gehlen, Marion and Ilyina, Tatiana and John, Jasmin G. and Li, Hongmei and Long, Matthew C. and Luo, Jessica Y. and Nakano, Hideyuki and Romanou, Anastasia and Schwinger, J{\"{o}}rg and Stock, Charles and Santana-Falc{\'{o}}n, Yeray and Takano, Yohei and Tjiputra, Jerry and Tsujino, Hiroyuki and Watanabe, Michio and Wu, Tongwen and Wu, Fanghua and Yamamoto, Akitomo},
doi = {10.1007/s40641-020-00160-0},
issn = {21986061},
journal = {Current Climate Change Reports},
keywords = {Biogeochemistry-Climate Feedbacks,CMIP5,CMIP6,Marine Biogeochemistry,Model Performance},
number = {3},
pages = {95--119},
title = {{Tracking Improvement in Simulated Marine Biogeochemistry Between CMIP5 and CMIP6}},
volume = {6},
year = {2020}
}
@article{Sevellec2018,
abstract = {In a changing climate, there is an ever-increasing societal demand for accurate and reliable interannual predictions. Accurate and reliable interannual predictions of global temperatures are key for determining the regional climate change impacts that scale with global temperature, such as precipitation extremes, severe droughts, or intense hurricane activity, for instance. However, the chaotic nature of the climate system limits prediction accuracy on such timescales. Here we develop a novel method to predict global-mean surface air temperature and sea surface temperature, based on transfer operators, which allows, by-design, probabilistic forecasts. The prediction accuracy is equivalent to operational forecasts and its reliability is high. The post-1998 global warming hiatus is well predicted. For 2018–2022, the probabilistic forecast indicates a warmer than normal period, with respect to the forced trend. This will temporarily reinforce the long-term global warming trend. The coming warm period is associated with an increased likelihood of intense to extreme temperatures. The important numerical efficiency of the method (a few hundredths of a second on a laptop) opens the possibility for real-time probabilistic predictions carried out on personal mobile devices.},
author = {S{\'{e}}vellec, Florian and Drijfhout, Sybren S},
doi = {10.1038/s41467-018-05442-8},
issn = {2041-1723},
journal = {Nature Communications},
number = {1},
pages = {3024},
title = {{A novel probabilistic forecast system predicting anomalously warm 2018–2022 reinforcing the long-term global warming trend}},
url = {https://doi.org/10.1038/s41467-018-05442-8},
volume = {9},
year = {2018}
}
@article{Saffioti2015,
author = {Saffioti, Claudio and Fischer, Erich M. and Knutti, Reto},
doi = {10.1002/2015GL063091},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {apr},
number = {7},
pages = {2385--2391},
title = {{Contributions of atmospheric circulation variability and data coverage bias to the warming hiatus}},
url = {http://doi.wiley.com/10.1002/2015GL063091},
volume = {42},
year = {2015}
}
@article{doi:10.1029/2019GL084763,
abstract = {Abstract The Southern Hemisphere zonal circulation manifests a downward influence of the stratosphere on the troposphere from late spring to early summer. However, the strength and timescale of the connection, given the stratospheric state, have not been explicitly quantified. Here, SH zonal wind reanalysis time series are analyzed with a methodology designed to detect the minimal set of statistical predictors of multiple interacting variables via conditional independence tests. Our results confirm from data that the variability of the stratospheric polar vortex is a predictor of the tropospheric eddy-driven jet between September and January. The vortex variability explains about 40{\%} of monthly mean jet variability at a lead time of 1 month and can entirely account for the observed jet persistence. Our statistical model can quantitatively connect the multidecadal trends observed in the vortex and jet during the satellite era. This shows how short-term variability can help understand statistical links in long-term changes.},
author = {Saggioro, Elena and Shepherd, Theodore G},
doi = {10.1029/2019GL084763},
journal = {Geophysical Research Letters},
keywords = {Southern Hemisphere zonal circulation,Stratosphere-Troposphere coupling,Time-series Causal Network,autocorrelation timescale,intra-seasonal transition,zonal circulation trends},
number = {22},
pages = {13479--13487},
title = {{Quantifying the Timescale and Strength of Southern Hemisphere Intraseasonal Stratosphere-troposphere Coupling}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL084763},
volume = {46},
year = {2019}
}
@article{Saji2006,
abstract = {Abstract The twentieth-century simulations using by 17 coupled ocean–atmosphere general circulation models (CGCMs) submitted to the Intergovernmental Panel on Climate Change's Fourth Assessment Report (IPCC AR4) are evaluated for their skill in reproducing the observed modes of Indian Ocean (IO) climate variability. Most models successfully capture the IO's delayed, basinwide warming response a few months after El Ni{\~{n}}o–Southern Oscillation (ENSO) peaks in the Pacific. ENSO's oceanic teleconnection into the IO, by coastal waves through the Indonesian archipelago, is poorly simulated in these models, with significant shifts in the turning latitude of radiating Rossby waves. In observations, ENSO forces, by the atmospheric bridge mechanism, strong ocean Rossby waves that induce anomalies of SST, atmospheric convection, and tropical cyclones in a thermocline dome over the southwestern tropical IO. While the southwestern IO thermocline dome is simulated in nearly all of the models, this ocean Rossby wave respo...},
author = {Saji, N. H. and Xie, S-P. and Yamagata, T. and Saji, N. H. and Xie, S-P. and Yamagata, T.},
doi = {10.1175/JCLI3847.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {sep},
number = {17},
pages = {4397--4417},
title = {{Tropical Indian Ocean Variability in the IPCC Twentieth-Century Climate Simulations}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/JCLI3847.1},
volume = {19},
year = {2006}
}
@article{Sallee2020,
abstract = {The surface mixed layer of the world ocean regulates global climate by controlling heat and carbon exchanges between the atmosphere and the oceanic interior. It also plays a pivotal function in shaping marine ecosystems, by hosting most of the ocean's primary production and providing the conduit for oxygenation of deep oceanic layers. Yet despite these important climatic and life-supporting roles, very little is known about whether and how the mixed layer is being affected by global climate change. Here, we address this gap by revisiting almost 50 years of oceanographic observations, from which we characterize the climatic evolution of mixed layer stability and depth. We show that the density contrast across the mixed-layer base has increased strongly over the past five decades, at a summertime rate of 7.4–13.9 {\%}.dec-1 that is more than 13 times greater than previous estimates, and possibly at an even greater rate in winter. Counter-intuitively, and in contrast to what is commonly assumed, this increased stability is associated with a worldwide deepening of the summer mixed layer, at a rate of 6.2–9.6 {\%}.dec-1 or several meters per decade. The concurrent stabilisation and deepening of the mixed layer are shown to have been most likely caused by a generalised intensification of wave-driven turbulence and wind-forced instabilities at upper-ocean fronts. Our results challenge current understanding of the ocean's response to climate change, call for reconsideration of past changes in marine primary production, and provide a critical benchmark for Earth System Model evaluation and advancement.},
author = {Sall{\'{e}}e, Jean-Baptiste and Pellichero, Violaine and Akhoudas, Camille and Pauthenet, Etienne and Vignes, Lucie and Schmidtko, Sunke and Garabato, Alberto Naveira and Sutherland, Peter and Kuusela, Mikael},
doi = {10.1038/s41586-021-03303-x},
issn = {0028-0836},
journal = {Nature},
month = {mar},
number = {7851},
pages = {592--598},
title = {{Summertime increases in upper-ocean stratification and mixed-layer depth}},
url = {https://www.nature.com/articles/s41586-021-03303-x},
volume = {591},
year = {2021}
}
@article{Sallee2013,
abstract = {The ability of the models contributing to the fifth Coupled Models Intercomparison Project (CMIP5) to represent the Southern Ocean hydrological properties and its overturning is investigated in a water mass framework. Models have a consistent warm and light bias spread over the entire water column. The greatest bias occurs in the ventilated layers, which are volumetrically dominated by mode and intermediate layers. The ventilated layers have been observed to have a strong fingerprint of climate change and to impact climate by sequestrating a significant amount of heat and carbon dioxide. The mode water layer is poorly represented in the models and both mode and intermediate water have a significant fresh bias. Under increased radiative forcing, models simulate a warming and lightening of the entire water column, which is again greatest in the ventilated layers, highlighting the importance of these layers for propagating the climate signal into the deep ocean. While the intensity of the water mass overturning is relatively consistent between models, when compared to observation-based reconstructions, they exhibit a slightly larger rate of overturning at shallow to intermediate depths, and a slower rate of overturning deeper in the water column. Under increased radiative forcing, atmospheric fluxes increase the rate of simulated upper cell overturning, but this increase is counterbalanced by diapycnal fluxes, including mixed-layer horizontal mixing, and mostly vanishes. {\textcopyright} 2013. American Geophysical Union. All Rights Reserved.},
author = {Sall{\'{e}}e, J.-B. and Shuckburgh, E. and Bruneau, N. and Meijers, A. J.S. and Bracegirdle, T. J. and Wang, Z. and Roy, T.},
doi = {10.1002/jgrc.20135},
isbn = {2169-9291},
issn = {21699291},
journal = {Journal of Geophysical Research: Oceans},
keywords = {CMIP5,Southern Ocean,overturning,water mass},
month = {apr},
number = {4},
pages = {1830--1844},
publisher = {Wiley-Blackwell},
title = {{Assessment of Southern Ocean water mass circulation and characteristics in CMIP5 models: Historical bias and forcing response}},
url = {http://doi.wiley.com/10.1002/jgrc.20135},
volume = {118},
year = {2013}
}
@article{Salzmann2016a,
author = {Salzmann, Marc},
doi = {10.1126/sciadv.1501572},
issn = {2375-2548},
journal = {Science Advances},
month = {jun},
number = {6},
pages = {e1501572},
title = {{Global warming without global mean precipitation increase?}},
url = {https://www.science.org/doi/10.1126/sciadv.1501572},
volume = {2},
year = {2016}
}
@article{Sandeep2014,
abstract = {There is still considerable uncertainty con-cerning twentieth century trends in the Pacific Walker Circulation (PWC). In this paper, observational datasets, coupled (CMIP5) and uncoupled (AGCM) model simula-tions, and additional numerical sensitivity experiments are analyzed to investigate twentieth century changes in the PWC and their physical mechanisms. The PWC weakens over the century in the CMIP5 simulations, but strengthens in the AGCM simulations and also in the observational twentieth century reanalysis (20CR) dataset. It is argued that the weakening in the CMIP5 simulations is not a consequence of a reduced global convective mass flux expected from simple considerations of the global hydro-logical response to global warming, but is rather due to a weakening of the zonal equatorial Pacific sea surface temperature (SST) gradient. Further clarification is provided by additional uncoupled atmospheric general circulation model simulations in which the ENSO-unre-lated and ENSO-related portions of the observed SST changes are prescribed as lower boundary conditions. Both sets of SST forcing fields have a global warming trend, and both sets of simulations produce a weakening of the global convective mass flux. However, consistent with the strong role of the zonal SST gradient, the PWC strengthens in the simulations with the ENSO-unrelated SST forcing, which has a strengthening zonal SST gradient, despite the weakening of the global convective mass flux. Overall, our results suggest that the PWC strengthened during twentieth century global warming, but also that this strengthening was partly masked by a weakening trend associated with ENSO-related PWC variability.},
annote = {Pacific Walker circulation
1901-2004 trend
$\Delta$SLP, $\Delta$SST
CMIP5 historical experiment, observational reconstruction (HadSLP2, HadISST), 20CR, AGCM experiments

- $\Delta$SLP has weakened but $\Delta$SST strengthened in reconstructions and 20CR
- Both weaken in CMIP5 historical experiment
- Both strengthen in AMIP forced by either of HadISST, ERSSTv3b, COBE-SST

- SST decomposed into ENSO-related and -unrelated components
-{\textgreater} AGCM experiment
- Weakening in ENSO-related, Strengthening in ENSO-unrelated SST

- Global convective mass flux is not a constraint to the Walker circulation
- In response to ENSO-unrelated SST, the circulation strengthens due to enhanced $\Delta$SST},
author = {Sandeep, S. and Stordal, Frode and Sardeshmukh, Prashant D. and Compo, Gilbert P.},
doi = {10.1007/s00382-014-2135-3},
isbn = {0930-7575},
issn = {14320894},
journal = {Climate Dynamics},
keywords = {ENSO,Hydrological cycle,Pacific Walker Circulation},
number = {1-2},
pages = {103--117},
title = {{Pacific Walker Circulation variability in coupled and uncoupled climate models}},
volume = {43},
year = {2014}
}
@article{santer2019quantifying,
author = {Santer, Benjamin D and Fyfe, John C and Solomon, Susan and Painter, Jeffrey F and Bonfils, C{\'{e}}line and Pallotta, Giuliana and Zelinka, Mark D},
doi = {10.1073/pnas.1904586116},
journal = {Proceedings of the National Academy of Sciences},
number = {40},
pages = {19821--19827},
publisher = {National Acad Sciences},
title = {{Quantifying stochastic uncertainty in detection time of human-caused climate signals}},
volume = {116},
year = {2019}
}
@article{Santer2007,
author = {Santer, B. D. and Mears, C. and Wentz, Frank J and Taylor, Karl E. and Gleckler, P. J. and Wigley, T. M. L. and Barnett, Tim P. and Boyle, J. S. and Bruggemann, W. and Gillett, Nathan P. and Klein, Stephen A. and Meehl, Gerald A and Nozawa, Toru and Pierce, David W. and Stott, Peter A. and Washington, W M and Wehner, Michael F},
doi = {10.1073/pnas.0702872104},
issn = {0027-8424},
journal = {Proceedings of the National Academy of Sciences},
month = {sep},
number = {39},
pages = {15248--15253},
title = {{Identification of human-induced changes in atmospheric moisture content}},
url = {https://doi.org/10.1073/pnas.0702872104 http://www.pnas.org/cgi/doi/10.1073/pnas.0702872104},
volume = {104},
year = {2007}
}
@article{Santer2013,
abstract = {Since the late 1970s, satellite-based instruments have monitored global changes in atmospheric temperature. These measurements reveal multidecadal tropospheric warming and stratospheric cooling, punctuated by short-term volcanic signals of reverse sign. Similar long- and short-term temperature signals occur in model simulations driven by human-caused changes in atmospheric composition and natural variations in volcanic aerosols. Most previous comparisons of modeled and observed atmospheric temperature changes have used results from individual models and individual observational records. In contrast, we rely on a large multimodel archive and multiple observational datasets. We show that a human-caused latitude/altitude pattern of atmospheric temperature change can be identified with high statistical confidence in satellite data. Results are robust to current uncertainties in models and observations. Virtually all previous research in this area has attempted to discriminate an anthropogenic signal from internal variability. Here, we present evidence that a human-caused signal can also be identified relative to the larger "total" natural variability arising from sources internal to the climate system, solar irradiance changes, and volcanic forcing. Consistent signal identification occurs because both internal and total natural variability (as simulated by state-of-the-art models) cannot produce sustained global-scale tropospheric warming and stratospheric cooling. Our results provide clear evidence for a discernible human influence on the thermal structure of the atmosphere.},
author = {Santer, B.D. and Painter, J.F. and Bonfils, C. and Mears, C.A. and Solomon, S. and Wigley, T.M.L. and Gleckler, P.J. and Schmidt, G.A. and Doutriaux, C. and Gillett, N.P. and Taylor, K.E. and Thorne, P.W. and Wentz, F.J.},
doi = {10.1073/pnas.1305332110},
journal = {Proceedings of the National Academy of Sciences},
number = {43},
pages = {17235--17240},
title = {{Human and natural influences on the changing thermal structure of the atmosphere}},
volume = {110},
year = {2013}
}
@article{Santer2014,
abstract = {Despite continued growth in atmospheric levels of greenhouse gases, global mean surface and tropospheric temperatures have shown slower warming since 1998 than previously. Possible explanations for the slow-down include internal climate variability, external cooling influences and observational errors. Several recent modelling studies have examined the contribution of early twenty-first-century volcanic eruptions to the muted surface warming. Here we present a detailed analysis of the impact of recent volcanic forcing on tropospheric temperature, based on observations as well as climate model simulations. We identify statistically significant correlations between observations of stratospheric aerosol optical depth and satellite-based estimates of both tropospheric temperature and short-wave fluxes at the top of the atmosphere. We show that climate model simulations without the effects of early twenty-first-century volcanic eruptions overestimate the tropospheric warming observed since 1998. In two simulations with more realistic volcanic influences following the 1991 Pinatubo eruption, differences between simulated and observed tropospheric temperature trends over the period 1998 to 2012 are up to 15{\%} smaller, with large uncertainties in the magnitude of the effect. To reduce these uncertainties, better observations of eruption-specific properties of volcanic aerosols are needed, as well as improved representation of these eruption-specific properties in climate model simulations. {\textcopyright} 2014 Macmillan Publishers Limited.},
author = {Santer, B.D. and Bonfils, C. and Painter, J.F. and Zelinka, M.D. and Mears, C. and Solomon, S. and Schmidt, G.A. and Fyfe, J.C. and Cole, J.N.S. and Nazarenko, L. and Taylor, K.E. and Wentz, F.J.},
doi = {10.1038/ngeo2098},
journal = {Nature Geoscience},
number = {3},
pages = {185--189},
title = {{Volcanic contribution to decadal changes in tropospheric temperature}},
volume = {7},
year = {2014}
}
@article{Santer2009,
abstract = {In a recent multimodel detection and attribution (D{\&}A) study using the pooled results from 22 different climate models, the simulated "fingerprint" pattern of anthropogenically caused changes in water vapor was identifiable with high statistical confidence in satellite data. Each model received equal weight in the D{\&}A analysis, despite large differences in the skill with which they simulate key aspects of observed climate. Here, we examine whether water vapor D{\&}A results are sensitive to model quality. The "top 10" and "bottom 10" models are selected with three different sets of skill measures and two different ranking approaches. The entire D{\&}A analysis is then repeated with each of these different sets of more or less skillful models. Our performance metrics include the ability to simulate the mean state, the annual cycle, and the variability associated with El Ni{\~{n}}o. We find that estimates of an anthropogenic water vapor fingerprint are insensitive to current model uncertainties, and are governed by basic physical processes that are well-represented in climate models. Because the fingerprint is both robust to current model uncertainties and dissimilar to the dominant noise patterns, our ability to identify an anthropogenic influence on observed multidecadal changes in water vapor is not affected by "screening" based on model quality.},
author = {Santer, B D and Taylor, K E and Gleckler, P J and Bonfils, C and Barnett, T P and Pierce, D W and Wigley, T M L and Mears, C and Wentz, F J and Bruggemann, W. and Gillett, N P and Klein, S A and Solomon, S and Stott, P A and Wehner, M F},
doi = {10.1073/pnas.0901736106},
issn = {0027-8424},
journal = {Proceedings of the National Academy of Sciences},
month = {sep},
number = {35},
pages = {14778--14783},
title = {{Incorporating model quality information in climate change detection and attribution studies}},
url = {http://www.pnas.org/cgi/doi/10.1073/pnas.0901736106},
volume = {106},
year = {2009}
}
@article{Santer2017b,
abstract = {AbstractUpdated and improved satellite retrievals of the temperature of the mid-to-upper troposphere (TMT) are used to address key questions about the size and significance of TMT trends, agreement with model-derived TMT values, and whether models and satellite data show similar vertical profiles of warming. A recent study claimed that TMT trends over 1979 and 2015 are 3 times larger in climate models than in satellite data but did not correct for the contribution TMT trends receive from stratospheric cooling. Here, it is shown that the average ratio of modeled and observed TMT trends is sensitive to both satellite data uncertainties and model–data differences in stratospheric cooling. When the impact of lower-stratospheric cooling on TMT is accounted for, and when the most recent versions of satellite datasets are used, the previously claimed ratio of three between simulated and observed near-global TMT trends is reduced to approximately 1.7. Next, the validity of the statement that satellite data show n...},
author = {Santer, Benjamin D. and Solomon, Susan and Pallotta, Giuliana and Mears, Carl and Po-Chedley, Stephen and Fu, Qiang and Wentz, Frank and Zou, Cheng Zhi and Painter, Jeffrey and Cvijanovic, Ivana and Bonfils, C{\'{e}}line},
doi = {10.1175/JCLI-D-16-0333.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Anthropogenic effects,Climate variability,Ensembles,Model evaluation/performance,Regression analysis,Troposphere},
number = {1},
pages = {373--392},
title = {{Comparing tropospheric warming in climate models and satellite data}},
volume = {30},
year = {2017}
}
@article{Santer2017a,
abstract = {In the early twenty-first century, satellite-derived tropospheric warming trends were generally smaller than trends estimated from a large multi-model ensemble. Because observations and coupled model simulations do not have the same phasing of natural internal variability, such decadal differences in simulated and observed warming rates invariably occur. Here we analyse global-mean tropospheric temperatures from satellites and climate model simulations to examine whether warming rate differences over the satellite era can be explained by internal climate variability alone. We find that in the last two decades of the twentieth century, differences between modelled and observed tropospheric temperature trends are broadly consistent with internal variability. Over most of the early twenty-first century, however, model tropospheric warming is substantially larger than observed; warming rate differences are generally outside the range of trends arising from internal variability. The probability that multi-decadal internal variability fully explains the asymmetry between the late twentieth and early twenty-first century results is low (between zero and about 9{\%}). It is also unlikely that this asymmetry is due to the combined effects of internal variability and a model error in climate sensitivity. We conclude that model overestimation of tropospheric warming in the early twenty-first century is partly due to systematic deficiencies in some of the post-2000 external forcings used in the model simulations.},
author = {Santer, Benjamin D. and Fyfe, John C. and Pallotta, Giuliana and Flato, Gregory M. and Meehl, Gerald A. and England, Matthew H. and Hawkins, Ed and Mann, Michael E. and Painter, Jeffrey F. and Bonfils, C{\'{e}}line and Cvijanovic, Ivana and Mears, Carl and Wentz, Frank J. and Po-Chedley, Stephen and Fu, Qiang and Zou, Cheng Zhi},
doi = {10.1038/ngeo2973},
isbn = {1752-0894},
issn = {17520908},
journal = {Nature Geoscience},
keywords = {Atmospheric dynamics,Climate change},
month = {jun},
number = {7},
pages = {478--485},
publisher = {Nature Publishing Group},
title = {{Causes of differences in model and satellite tropospheric warming rates}},
url = {http://www.nature.com/doifinder/10.1038/ngeo2973},
volume = {10},
year = {2017}
}
@article{Santer2018c,
abstract = {We provide scientific evidence that a human-caused signal in the seasonal cycle of tropospheric temperature has emerged from the background noise of natural variability. Satellite data and the anthropogenic “fingerprint” predicted by climate models show common large-scale changes in geographical patterns of seasonal cycle amplitude. These common features include increases in amplitude at mid-latitudes in both hemispheres, amplitude decreases at high latitudes in the Southern Hemisphere, and small changes in the tropics. Simple physical mechanisms explain these features. The model fingerprint of seasonal cycle changes is identifiable with high statistical confidence in five out of six satellite temperature datasets. Our results suggest that attribution studies with the changing seasonal cycle provide powerful evidence for a significant human effect on Earth's climate.},
author = {Santer, Benjamin D. and Po-Chedley, Stephen and Zelinka, Mark D. and Cvijanovic, Ivana and Bonfils, C{\'{e}}line and Durack, Paul J. and Fu, Qiang and Kiehl, Jeffrey and Mears, Carl and Painter, Jeffrey and Pallotta, Giuliana and Solomon, Susan and Wentz, Frank J. and Zou, Cheng Zhi},
doi = {10.1126/science.aas8806},
issn = {10959203},
journal = {Science},
number = {6399},
pages = {eaas8806},
pmid = {30026201},
title = {{Human influence on the seasonal cycle of tropospheric temperature}},
volume = {361},
year = {2018}
}
@article{Santolaria-Otin2020,
abstract = {Spatial and temporal patterns of snow cover extent (SCE) and snow water equivalent (SWE) over the terrestrial Arctic are analyzed based on multiple observational datasets and an ensemble of CMIP5 models during 1979–2005. For evaluation of historical simulations of the Coupled Model Intercomparison Project (CMIP5) ensemble, we used two reanalysis products, one satellite-observed product and an ensemble of different datasets. The CMIP5 models tend to significantly underestimate the observed SCE in spring but are in better agreement with observations in autumn; overall, the observed annual SCE cycle is well captured by the CMIP5 ensemble. In contrast, for SWE, the annual cycle is significantly biased, especially over North America, where some models retain snow even in summer, in disagreement with observations. The snow margin position (SMP) in the CMIP5 historical simulations is in better agreement with observations in spring than in autumn, when close agreement across the CMIP5 models is only found in central Siberia. Historical experiments from most CMIP5 models show negative pan-Arctic trends in SCE and SWE. These trends are, however, considerably weaker (and less statistically significant) than those reported from observations. Most CMIP5 models can more accurately capture the trend pattern of SCE than that of SWE, which shows quantitative and qualitative differences with the observed trends over Eurasia. Our results demonstrate the importance of using multiple data sources for the evaluation of snow characteristics in climate models. Further developments should focus on the improvement of both dataset quality and snow representation in climate models, especially ESM-SnowMIP.},
author = {Santolaria-Ot{\'{i}}n, Mar{\'{i}}a and Zolina, Olga},
doi = {10.1007/s00382-020-05434-9},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {11},
pages = {2993--3016},
title = {{Evaluation of snow cover and snow water equivalent in the continental Arctic in CMIP5 models}},
url = {https://doi.org/10.1007/s00382-020-05434-9},
volume = {55},
year = {2020}
}
@article{Sasgen2020,
abstract = {Between 2003-2016, the Greenland ice sheet (GrIS) was one of the largest contributors to sea level rise, as it lost about 255 Gt of ice per year. This mass loss slowed in 2017 and 2018 to about 100 Gt yr −1 . Here we examine further changes in rate of GrIS mass loss, by analyzing data from the GRACE-FO (Gravity Recovery and Climate Experiment – Follow On) satellite mission, launched in May 2018. Using simulations with regional climate models we show that the mass losses observed in 2017 and 2018 by the GRACE and GRACE-FO missions are lower than in any other two year period between 2003 and 2019, the combined period of the two missions. We find that this reduced ice loss results from two anomalous cold summers in western Greenland, compounded by snow-rich autumn and winter conditions in the east. For 2019, GRACE-FO reveals a return to high melt rates leading to a mass loss of 223 ± 12 Gt month −1 during the month of July alone, and a record annual mass loss of 532 ± 58 Gt yr −1 .},
author = {Sasgen, Ingo and Wouters, Bert and Gardner, Alex S. and King, Michalea D. and Tedesco, Marco and Landerer, Felix W. and Dahle, Christoph and Save, Himanshu and Fettweis, Xavier},
doi = {10.1038/s43247-020-0010-1},
issn = {2662-4435},
journal = {Communications Earth {\&} Environment},
month = {dec},
number = {1},
pages = {8},
title = {{Return to rapid ice loss in Greenland and record loss in 2019 detected by the GRACE-FO satellites}},
url = {https://www.nature.com/articles/s43247-020-0010-1},
volume = {1},
year = {2020}
}
@article{Saurral2019,
author = {Saurral, Ramiro I. and Kucharski, Fred and Raggio, Gabriela A.},
doi = {10.1007/s00382-019-04950-7},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {dec},
number = {11},
pages = {6645--6663},
title = {{Variations in ozone and greenhouse gases as drivers of Southern Hemisphere climate in a medium-complexity global climate model}},
url = {http://link.springer.com/10.1007/s00382-019-04950-7},
volume = {53},
year = {2019}
}
@article{Scaife2018c,
abstract = {We review the growing evidence for a widespread inconsistency between the low strength of predictable signals in climate models and the relatively high level of agreement they exhibit with observed variability of the atmospheric circulation. This discrepancy is particularly evident in the climate variability of the Atlantic sector, where ensemble predictions using climate models generally show higher correlation with observed variability than with their own simulations, and higher correlations with observations than would be expected from their small signal-to-noise ratios, hence a ‘signal-to-noise paradox'. This unusual behaviour has been documented in multiple climate prediction systems and in the response to a number of different sources of climate variability. However, we also note that the total variance in the models is often close in magnitude to the observed variance, and so it is not a simple matter of models containing too much variability. Instead, the proportion of Atlantic climate variance that is predictable in climate models appears to be too weak in amplitude by a factor of two, or perhaps more. In this review, we provide a range of examples from existing studies to build the case for a problem that is common across different climate models, common to several different sources of climate variability and common across a range of timescales. We also discuss the wider implications of this intriguing paradox.},
author = {Scaife, Adam A. and Smith, Doug},
doi = {10.1038/s41612-018-0038-4},
issn = {23973722},
journal = {npj Climate and Atmospheric Science},
month = {dec},
number = {1},
pages = {28},
title = {{A signal-to-noise paradox in climate science}},
volume = {1},
year = {2018}
}
@article{Scaife2013,
author = {Scaife, Adam A. and Ineson, Sarah and Knight, Jeff R. and Gray, Lesley and Kodera, Kunihiko and Smith, Doug M.},
doi = {10.1002/grl.50099},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {jan},
number = {2},
pages = {434--439},
title = {{A mechanism for lagged North Atlantic climate response to solar variability}},
url = {http://doi.wiley.com/10.1002/grl.50099},
volume = {40},
year = {2013}
}
@article{Scaife2016,
author = {Scaife, A. A. and Karpechko, A. Yu. and Baldwin, M. P. and Brookshaw, A. and Butler, A. H. and Eade, R. and Gordon, M. and MacLachlan, C. and Martin, N. and Dunstone, N. and Smith, D.},
doi = {10.1002/asl.598},
issn = {1530261X},
journal = {Atmospheric Science Letters},
month = {jan},
number = {1},
pages = {51--56},
title = {{Seasonal winter forecasts and the stratosphere}},
url = {http://doi.wiley.com/10.1002/asl.598},
volume = {17},
year = {2016}
}
@article{Scheff2017,
abstract = {Past cold climates are often thought to have been “drier” than today on land, which appears to conflict with recent studies projecting widespread terrestrial drying with near-future warming. However, other work has found that over large portions of the continents, the conclusion of future “drying” vs. “wet- ting” strongly depends on the physical property of interest. Here, we show that this also holds in simulations of the Last Glacial Maximum: the conti- nents have generally wetter topsoils and higher values of standard climate- wetness metrics than in the preindustrial, as well as generally lower precipi- tation and ubiquitously lower photosynthesis (likely driven by the low CO2), with streamflow responses falling in between. Using a large existing global pollen and plant-fossil compilation, we also confirm that LGM grasslands and open woodlands grew at many sites of present-day forest, seasonal forests at many sites of present-day rainforest, and so forth, while changes in the opposite sense were few and spatially con- fined. These vegetation changes resemble the model photosynthesis responses but not the hydroclimate responses, while published lake-level changes resem- ble the latter but not the former. Thus, confidence in both the model hydro- logic and photosynthesis projections is increased, and there is no significant conflict. Instead, paleo- and modern climate researchers must carefully de- fine “wetting” and “drying,” and in particular should not assume hydrologic drying on the basis of vegetation decline, or vegetation stress on the basis of declines in hydroclimatic indicators.},
author = {Scheff, Jacob and Seager, Richard and Liu, Haibo and Coats, Sloan},
doi = {10.1175/JCLI-D-16-0854.1},
issn = {08948755},
journal = {Journal of Climate},
number = {17},
pages = {6593--6609},
title = {{Are glacials dry? Consequences for paleoclimatology and for greenhouse warming}},
volume = {30},
year = {2017}
}
@article{doi:10.1002/2014JD022989,
abstract = {Abstract Characteristic timescales for the Northern Annular Mode (NAM) and Southern Annular Mode (SAM) variability are diagnosed in historical simulations submitted to the Coupled Model Intercomparison Project Phase 5 (CMIP5) and are compared to the European Centre for Medium-Range Weather Forecasts ERA-Interim data. These timescales are calculated from geopotential height anomaly spectra using a recently developed method, where spectra are divided into low-frequency (Lorentzian) and high-frequency (exponential) parts to account for stochastic and chaotic behaviors, respectively. As found for reanalysis data, model spectra at high frequencies are consistent with low-order chaotic behavior, in contrast to an AR1 process at low frequencies. This places the characterization of the annular mode timescales in a more dynamical rather than purely stochastic context. The characteristic high-frequency timescales for the NAM and SAM derived from the model spectra at high frequencies are ∼5 days, independent of season, which is consistent with the timescales of ERA-Interim. In the low-frequency domain, however, models are slightly biased toward too long timescales, but within the error bars, a finding which is consistent with previous studies of CMIP3 models. For the SAM, low-frequency timescales in November, December, January, and February are overestimated in the models compared to ERA-Interim. In some models, the overestimation in the SAM austral summer timescale is partly due to interannual variability, which can inflate these timescales by up to ∼40{\%} in the models but only accounts for about 5{\%} in the ERA-Interim reanalysis.},
author = {Schenzinger, V and Osprey, S M},
doi = {10.1002/2014JD022989},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {annular mode,power spectra,stochastic},
number = {21},
pages = {11203--11214},
title = {{Interpreting the nature of Northern and Southern Annular Mode variability in CMIP5 Models}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2014JD022989},
volume = {120},
year = {2015}
}
@article{schiemann2018mean,
author = {Schiemann, Reinhard and Vidale, Pier Luigi and Shaffrey, Len C and Johnson, Stephanie J and Roberts, Malcolm J and Demory, Marie-Estelle and Mizielinski, Matthew S and Strachan, Jane},
doi = {10.5194/hess-22-3933-2018},
journal = {Hydrology and Earth System Sciences},
number = {7},
pages = {3933--3950},
publisher = {Copernicus},
title = {{Mean and extreme precipitation over European river basins better simulated in a 25km AGCM}},
volume = {22},
year = {2018}
}
@article{doi:10.1175/JCLI-D-16-0100.1,
abstract = { AbstractThe aim of this study is to investigate if the representation of Northern Hemisphere blocking is sensitive to resolution in current-generation atmospheric global circulation models (AGCMs). An evaluation is conducted of how well atmospheric blocking is represented in four AGCMs whose horizontal resolution is increased from a grid spacing of more than 100 km to about 25 km. It is shown that Euro-Atlantic blocking is simulated overall more credibly at higher resolution (i.e., in better agreement with a 50-yr reference blocking climatology created from the reanalyses ERA-40 and ERA-Interim). The improvement seen with resolution depends on the season and to some extent on the model considered. Euro-Atlantic blocking is simulated more realistically at higher resolution in winter, spring, and autumn, and robustly so across the model ensemble. The improvement in spring is larger than that in winter and autumn. Summer blocking is found to be better simulated at higher resolution by one model only, with little change seen in the other three models. The representation of Pacific blocking is not found to systematically depend on resolution. Despite the improvements seen with resolution, the 25-km models still exhibit large biases in Euro-Atlantic blocking. For example, three of the four 25-km models underestimate winter northern European blocking frequency by about one-third. The resolution sensitivity and biases in the simulated blocking are shown to be in part associated with the mean-state biases in the models' midlatitude circulation. },
author = {Schiemann, Reinhard and Demory, Marie-Estelle and Shaffrey, Len C and Strachan, Jane and Vidale, Pier Luigi and Mizielinski, Matthew S and Roberts, Malcolm J and Matsueda, Mio and Wehner, Michael F and Jung, Thomas},
doi = {10.1175/JCLI-D-16-0100.1},
journal = {Journal of Climate},
number = {1},
pages = {337--358},
title = {{The Resolution Sensitivity of Northern Hemisphere Blocking in Four 25-km Atmospheric Global Circulation Models}},
url = {https://doi.org/10.1175/JCLI-D-16-0100.1},
volume = {30},
year = {2017}
}
@article{article,
author = {Schiemann, Reinhard and Athanasiadis, Panos and Barriopedro, David and Doblas-Reyes, Francisco and Lohmann, Katja and Roberts, Malcolm and Sein, Dmitry and Roberts, Christopher and Terray, Laurent and Vidale, P L},
doi = {10.5194/wcd-1-277-2020},
journal = {Weather and Climate Dynamics},
pages = {277--292},
title = {{Northern Hemisphere blocking simulation in current climate models: evaluating progress from the Climate Model Intercomparison Project Phase 5 to 6 and sensitivity to resolution}},
volume = {1},
year = {2020}
}
@article{schimanke2013variability,
author = {Schimanke, Semjon and Spangehl, T and Huebener, H and Cubasch, U},
doi = {10.1007/s00382-012-1530-x},
journal = {Climate Dynamics},
number = {7-8},
pages = {1733--1747},
publisher = {Springer},
title = {{Variability and trends of major stratospheric warmings in simulations under constant and increasing GHG concentrations}},
volume = {40},
year = {2013}
}
@article{Schlosser2018b,
author = {Schlosser, E and Haumann, F A and Raphael, M N},
doi = {10.5194/tc-12-1103-2018},
journal = {The Cryosphere},
number = {3},
pages = {1103--1119},
title = {{Atmospheric influences on the anomalous 2016 Antarctic sea ice decay}},
volume = {12},
year = {2018}
}
@article{Schlund2020,
author = {Schlund, Manuel and Lauer, Axel and Gentine, Pierre and Sherwood, Steven C. and Eyring, Veronika},
doi = {10.5194/esd-11-1233-2020},
issn = {2190-4987},
journal = {Earth System Dynamics},
month = {dec},
number = {4},
pages = {1233--1258},
title = {{Emergent constraints on equilibrium climate sensitivity in CMIP5: do they hold for CMIP6?}},
url = {https://esd.copernicus.org/articles/11/1233/2020/},
volume = {11},
year = {2020}
}
@article{gmd-4-33-2011,
author = {Schmidt, G A and Jungclaus, J H and Ammann, C M and Bard, E and Braconnot, P and Crowley, T J and Delaygue, G and Joos, F and Krivova, N A and Muscheler, R and Otto-Bliesner, B L and Pongratz, J and Shindell, D T and Solanki, S K and Steinhilber, F and Vieira, L E A},
doi = {10.5194/gmd-4-33-2011},
journal = {Geoscientific Model Development},
number = {1},
pages = {33--45},
title = {{Climate forcing reconstructions for use in PMIP simulations of the last millennium (v1.0)}},
url = {https://gmd.copernicus.org/articles/4/33/2011/},
volume = {4},
year = {2011}
}
@article{Schmidt2014,
author = {Schmidt, Gavin A and Shindell, Drew T and Tsigaridis, Kostas},
doi = {10.1038/ngeo2105},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {mar},
number = {3},
pages = {158--160},
publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.},
title = {{Reconciling warming trends}},
url = {http://dx.doi.org/10.1038/ngeo2105 http://10.0.4.14/ngeo2105 http://www.nature.com/articles/ngeo2105},
volume = {7},
year = {2014}
}
@article{Schmidtko2017,
abstract = {The oxygen content of the global ocean has decreased by more than two per cent over the past five decades, with large variations found in different ocean basins and at different ocean depths.},
author = {Schmidtko, Sunke and Stramma, Lothar and Visbeck, Martin},
doi = {10.1038/nature21399},
issn = {0028-0836},
journal = {Nature},
keywords = {Climate sciences,Marine chemistry,Physical oceanography},
month = {feb},
number = {7641},
pages = {335--339},
publisher = {Nature Publishing Group},
title = {{Decline in global oceanic oxygen content during the past five decades}},
url = {http://www.nature.com/articles/nature21399},
volume = {542},
year = {2017}
}
@article{Schmith2014,
author = {Schmith, Torben and Yang, Shuting and Gleeson, Emily and Semmler, Tido},
doi = {10.1175/JCLI-D-13-00651.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {aug},
number = {16},
pages = {6343--6357},
title = {{How Much Have Variations in the Meridional Overturning Circulation Contributed to Sea Surface Temperature Trends since 1850? A Study with the EC-Earth Global Climate Model}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-13-00651.1},
volume = {27},
year = {2014}
}
@article{Schneider2018,
abstract = {Recent work suggests that natural variability has played a significant role in the increase of Antarctic sea ice extent during 1979--2013. The ice extent has responded strongly to atmospheric circulation changes, including a deepened Amundsen Sea Low (ASL), which in part has been driven by tropical variability. Nonetheless, this increase has occurred in the context of externally forced climate change, and it has been difficult to reconcile observed and modeled Antarctic sea ice trends. To understand observed-model disparities, this work defines the internally driven and radiatively forced patterns of Antarctic sea ice change and exposes potential model biases using results from two sets of historical experiments of a coupled climate model compared with observations. One ensemble is constrained only by external factors such as greenhouse gases and stratospheric ozone, while the other explicitly accounts for the influence of tropical variability by specifying observed SST anomalies in the eastern tropical Pacific. The latter experiment reproduces the deepening of the ASL, which drives an increase in regional ice extent due to enhanced ice motion and sea surface cooling. However, the overall sea ice trend in every ensemble member of both experiments is characterized by ice loss and is dominated by the forced pattern, as given by the ensemble-mean of the first experiment. This pervasive ice loss is associated with a strong warming of the ocean mixed layer, suggesting that the ocean model does not locally store or export anomalous heat efficiently enough to maintain a surface environment conducive to sea ice expansion. The pervasive upper-ocean warming, not seen in observations, likely reflects ocean mean-state biases.},
author = {Schneider, David P and Deser, Clara},
doi = {10.1007/s00382-017-3893-5},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {11},
pages = {4599--4618},
title = {{Tropically driven and externally forced patterns of Antarctic sea ice change: reconciling observed and modeled trends}},
url = {https://doi.org/10.1007/s00382-017-3893-5},
volume = {50},
year = {2018}
}
@article{Schott2009a,
author = {Schott, Friedrich A. and Xie, Shang-Ping and McCreary, Julian P.},
doi = {10.1029/2007RG000245},
issn = {8755-1209},
journal = {Reviews of Geophysics},
keywords = {Indian Ocean circulation,Indian Ocean dipole,climate variability},
month = {jan},
number = {1},
pages = {RG1002},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Indian Ocean circulation and climate variability}},
url = {http://doi.wiley.com/10.1029/2007RG000245},
volume = {47},
year = {2009}
}
@article{Schroeder2019,
abstract = {To date, a large variety of water vapour data records from satellite and reanalysis are available. It is key to understand the quality and uncertainty of these data records in order to fully exploit these records and to avoid data being employed incorrectly or misinterpreted. Therefore, it is important to inform users on accuracy and limitations of these data records based on consistent inter-comparisons carried out in the framework of international assessments. Addressing this challenge is the major objective of the Global Water and Energy Exchanges (GEWEX) water vapor assessment (G-VAP) which was initiated by the GEWEX Data and Assessments Panel (GDAP). Here, an overview of G-VAP objectives and an introduction to the results from G-VAP's first phase are given. After this overview, a summary of available data records on water vapour and closely related variables and a short introduction to the utilized methods are presented. The results from inter-comparisons, homogeneity testing and inter-comparison of trend estimates, achieved within G-VAP's first phase are summarized. The conclusions on future research directions for the wider community and for G-VAP's next phase are outlined and recommendations have been formulated. For instance, a key recommendation is the need for recalibration and improved inter-calibration of radiance data records and subsequent reprocessing in order to increase stability and to provide uncertainty estimates. This need became evident from a general disagreement in trend estimates (e.g., trends in TCWV ranging from −1.51 ± 0.17 kg/m2/decade to 1.22 ± 0.16 kg/m2/decade) and the presence of break points on global and regional scale. It will be a future activity of G-VAP to reassess the stability of updated or new data records and to assess consistency, i.e., the closeness of data records given their uncertainty estimates.},
author = {Schr{\"{o}}der, Marc and Lockhoff, Maarit and Shi, Lei and August, Thomas and Bennartz, Ralf and Brogniez, Helene and Calbet, Xavier and Fell, Frank and Forsythe, John and Gambacorta, Antonia and Ho, Shu-peng and Kursinski, E. and Reale, Anthony and Trent, Tim and Yang, Qiong},
doi = {10.3390/rs11030251},
issn = {2072-4292},
journal = {Remote Sensing},
month = {jan},
number = {3},
pages = {251},
title = {{The GEWEX Water Vapor Assessment: Overview and Introduction to Results and Recommendations}},
url = {https://doi.org/10.3390/rs11030251 http://www.mdpi.com/2072-4292/11/3/251},
volume = {11},
year = {2019}
}
@article{Schurer2020,
author = {Schurer, Andrew P. and Ballinger, Andrew P and Friedman, Andrew R. and Hegerl, Gabriele C.},
doi = {10.1088/1748-9326/ab83ab},
issn = {1748-9326},
journal = {Environmental Research Letters},
month = {sep},
number = {10},
pages = {104026},
title = {{Human influence strengthens the contrast between tropical wet and dry regions}},
url = {https://iopscience.iop.org/article/10.1088/1748-9326/ab83ab},
volume = {15},
year = {2020}
}
@article{Schurer2015,
abstract = {The recent warming “hiatus” is subject to intense interest, with proposed causes including natural forcing and internal variability. Here we derive samples of all natural and internal variability from observations and a recent proxy reconstruction to investigate the likelihood that these two sources of variability could produce a hiatus or rapid warming in surface temperature. The likelihood is found to be consistent with that calculated previously for models and exhibits a similar spatial pattern, with an Interdecadal Pacific Oscillation-like structure, although with more signal in the Atlantic than in model patterns. The number and length of events increases if natural forcing is also considered, particularly in the models. From the reconstruction it can be seen that large eruptions, such as Mount Tambora in 1815, or clusters of eruptions, may result in a hiatus of over 20 years, a finding supported by model results.},
author = {Schurer, Andrew P. and Hegerl, Gabriele C. and Obrochta, Stephen P.},
doi = {10.1002/2015GL064458},
isbn = {0094-8276},
issn = {19448007},
journal = {Geophysical Research Letters},
keywords = {natural climate variability},
number = {14},
pages = {5974--5982},
title = {{Determining the likelihood of pauses and surges in global warming}},
volume = {42},
year = {2015}
}
@article{Schurer2018,
abstract = {The transient climate response (TCR) quantifies the warming expected during a transient doubling of greenhouse gas concentrations in the atmosphere. Many previous studies quantifying the observed historic response to greenhouse gases, and with it the TCR, use multimodel mean fingerprints and found reasonably constrained values, which contributed to the IPCC estimated ({\textgreater}66{\%}) range from 1° to 2.5°C. Here, it is shown that while the multimodel mean fingerprint is statistically more powerful than any individual model's fingerprint, it does lead to overconfident results when applied to synthetic data, if model uncertainty is neglected. Here, a Bayesian method is used that estimates TCR, accounting for climate model and observational uncertainty with indices of global temperature that aim at constraining the aerosol contribution to the historical record better. Model uncertainty in the aerosol response was found to be large. Nevertheless, an overall TCR estimate of 0.4°-3.1°C ({\textgreater}90{\%}) was calculated from the historical record, which reduces to 1.0°-2.6°C when using prior information that rules out negative TCR values and model misestimates of more than a factor of 3, and to 1.2°-2.4°C when using the multimodel mean fingerprints with a variance correction. Modeled temperature, like in the observations, is calculated as a blend of sea surface and air temperatures.},
author = {Schurer, Andrew P. and Hegerl, Gabi and Ribes, Aur{\'{e}}lien and Polson, Debbie and Morice, Colin and Tett, Simon},
doi = {10.1175/JCLI-D-17-0717.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Aerosols,Climate sensitivity,Greenhouse gases,Regression analysis,Statistical techniques},
month = {oct},
number = {20},
pages = {8645--8663},
title = {{Estimating the transient climate response from observed warming}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-17-0717.1},
volume = {31},
year = {2018}
}
@article{Schurer2014,
author = {Schurer, Andrew P. and Tett, Simon F. B. and Hegerl, Gabriele C.},
doi = {10.1038/ngeo2040},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {feb},
number = {2},
pages = {104--108},
title = {{Small influence of solar variability on climate over the past millennium}},
url = {http://www.nature.com/articles/ngeo2040},
volume = {7},
year = {2014}
}
@article{Schurer2013a,
abstract = {AbstractReconstructions of past climate show notable temperature variability over the past millennium, with relatively warm conditions during the Medieval Climate Anomaly (MCA) and a relatively cold Little Ice Age (LIA). Multimodel simulations of the past millennium are used together with a wide range of reconstructions of Northern Hemispheric mean annual temperature to separate climate variability from 850 to 1950 CE into components attributable to external forcing and internal climate variability. External forcing is found to contribute significantly to long-term temperature variations irrespective of the proxy reconstruction, particularly from 1400 onward. Over the MCA alone, however, the effect of forcing is only detectable in about half of the reconstructions considered, and the response to forcing in the models cannot explain the warm conditions around 1000 CE seen in some reconstructions. The residual from the detection analysis is used to estimate internal variability independent from climate modeling, and it is found that the recent observed 50- and 100-yr hemispheric temperature trends are substantially larger than any of the internally generated trends even using the large residuals over the MCA. Variations in solar output and explosive volcanism are found to be the main drivers of climate change from 1400 to 1900, but for the first time a significant contribution from greenhouse gas variations to the cold conditions during 1600?1800 is also detected. The proxy reconstructions tend to show a smaller forced response than is simulated by the models. This discrepancy is shown, at least partly, to be likely associated with the difference in the response to large volcanic eruptions between reconstructions and model simulations.},
annote = {doi: 10.1175/JCLI-D-12-00826.1},
author = {Schurer, Andrew P and Hegerl, Gabriele C and Mann, Michael E and Tett, Simon F B and Phipps, Steven J},
doi = {10.1175/JCLI-D-12-00826.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {mar},
number = {18},
pages = {6954--6973},
publisher = {American Meteorological Society},
title = {{Separating Forced from Chaotic Climate Variability over the Past Millennium}},
url = {https://doi.org/10.1175/JCLI-D-12-00826.1},
volume = {26},
year = {2013}
}
@article{scoccimarro2017tropical,
abstract = {Through tropical cyclone (TC) activity the ocean and the atmosphere exchange a large amount of energy. In this work possible improvements introduced by a higher coupling frequency are tested between the two components of a climate model in the representation of TC intensity and TC–ocean feedbacks. The analysis is based on the new Centro Euro-Mediterraneo per I Cambiamenti Climatici Climate Model (CMCC-CM2-VHR), capable of representing realistic TCs up to category-5 storms. A significant role of the negative sea surface temperature (SST) feedback, leading to a weakening of the cyclone intensity, is made apparent by the improved representation of high-frequency coupled processes. The first part of this study demonstrates that a more realistic representation of strong TC count is obtained by coupling atmosphere and ocean components at hourly instead of daily frequency. Coherently, the positive bias of the annually averaged power dissipation index associated with TCs is reduced by one order of magnitude when coupling at the hourly frequency, compared to both forced mode and daily coupling frequency results. The second part of this work shows a case study (a modeled category-5 typhoon) analysis to verify the impact of a more realistic representation of the high-frequency coupling in representing the TC effect on the ocean; the theoretical subsurface warming induced by TCs is well represented when coupling the two components at the higher frequency. This work demonstrates that an increased horizontal resolution of model components is not sufficient to ensure a realistic representation of intense and fast-moving systems, such as tropical and extratropical cyclones, but a concurrent increase in coupling frequency is required.},
author = {Scoccimarro, Enrico and Fogli, Pier Giuseppe and Reed, Kevin A and Gualdi, Silvio and Masina, Simona and Navarra, Antonio},
doi = {10.1175/JCLI-D-16-0292.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jan},
number = {1},
pages = {145--162},
title = {{Tropical Cyclone Interaction with the Ocean: The Role of High-Frequency (Subdaily) Coupled Processes}},
url = {https://journals.ametsoc.org/doi/10.1175/JCLI-D-16-0292.1},
volume = {30},
year = {2017}
}
@article{Screen2014,
abstract = {The ongoing loss of Arctic sea-ice cover has implications for the wider climate system. The detection and importance of the atmospheric impacts of sea-ice loss depends, in part, on the relative magnitudes of the sea-ice forced change compared to natural atmospheric internal variability (AIV). This study analyses large ensembles of two independent atmospheric general circulation models in order to separate the forced response to historical Arctic sea-ice loss (1979--2009) from AIV, and to quantify signal-to-noise ratios. We also present results from a simulation with the sea-ice forcing roughly doubled in magnitude. In proximity to regions of sea-ice loss, we identify statistically significant near-surface atmospheric warming and precipitation increases, in autumn and winter in both models. In winter, both models exhibit a significant lowering of sea level pressure and geopotential height over the Arctic. All of these responses are broadly similar, but strengthened and/or more geographically extensive, when the sea-ice forcing is doubled in magnitude. Signal-to-noise ratios differ considerably between variables and locations. The temperature and precipitation responses are significantly easier to detect (higher signal-to-noise ratio) than the sea level pressure or geopotential height responses. Equally, the local response (i.e., in the vicinity of sea-ice loss) is easier to detect than the mid-latitude or upper-level responses. Based on our estimates of signal-to-noise, we conjecture that the local near-surface temperature and precipitation responses to past Arctic sea-ice loss exceed AIV and are detectable in observed records, but that the potential atmospheric circulation, upper-level and remote responses may be partially or wholly masked by AIV.},
author = {Screen, James A and Deser, Clara and Simmonds, Ian and Tomas, Robert},
doi = {10.1007/s00382-013-1830-9},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {1},
pages = {333--344},
title = {{Atmospheric impacts of Arctic sea-ice loss, 1979–2009: separating forced change from atmospheric internal variability}},
url = {https://doi.org/10.1007/s00382-013-1830-9},
volume = {43},
year = {2014}
}
@article{Scussolinieaax7047,
abstract = {The last extended time period when climate may have been warmer than today was during the Last Interglacial (LIG; ca. 129 to 120 thousand years ago). However, a global view of LIG precipitation is lacking. Here, seven new LIG climate models are compared to the first global database of proxies for LIG precipitation. In this way, models are assessed in their ability to capture important hydroclimatic processes during a different climate. The models can reproduce the proxy-based positive precipitation anomalies from the preindustrial period over much of the boreal continents. Over the Southern Hemisphere, proxy-model agreement is partial. In models, LIG boreal monsoons have 42{\%} wider area than in the preindustrial and produce 55{\%} more precipitation and 50{\%} more extreme precipitation. Austral monsoons are weaker. The mechanisms behind these changes are consistent with stronger summer radiative forcing over boreal high latitudes and with the associated higher temperatures during the LIG.},
author = {Scussolini, Paolo and Bakker, Pepijn and Guo, Chuncheng and Stepanek, Christian and Zhang, Qiong and Braconnot, Pascale and Cao, Jian and Guarino, Maria-Vittoria and Coumou, Dim and Prange, Matthias and Ward, Philip J and Renssen, Hans and Kageyama, Masa and Otto-Bliesner, Bette and Aerts, Jeroen C J H},
doi = {10.1126/sciadv.aax7047},
journal = {Science Advances},
number = {11},
pages = {eaax7047},
publisher = {American Association for the Advancement of Science},
title = {{Agreement between reconstructed and modeled boreal precipitation of the Last Interglacial}},
url = {https://advances.sciencemag.org/content/5/11/eaax7047},
volume = {5},
year = {2019}
}
@article{Seager2019,
author = {Seager, Richard and Cane, Mark and Henderson, Naomi and Lee, Dong-Eun and Abernathey, Ryan and Zhang, Honghai},
doi = {10.1038/s41558-019-0505-x},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {jul},
number = {7},
pages = {517--522},
title = {{Strengthening tropical Pacific zonal sea surface temperature gradient consistent with rising greenhouse gases}},
url = {http://www.nature.com/articles/s41558-019-0505-x},
volume = {9},
year = {2019}
}
@article{gmd-13-6165-2020,
abstract = {Abstract. The second version of the coupled Norwegian Earth System Model (NorESM2) is presented and evaluated. NorESM2 is based on the second version of the Community Earth System Model (CESM2) and shares with CESM2 the computer code infrastructure and many Earth system model components. However, NorESM2 employs entirely different ocean and ocean biogeochemistry models. The atmosphere component of NorESM2 (CAM-Nor) includes a different module for aerosol physics and chemistry, including interactions with cloud and radiation; additionally, CAM-Nor includes improvements in the formulation of local dry and moist energy conservation, in local and global angular momentum conservation, and in the computations for deep convection and air–sea fluxes. The surface components of NorESM2 have minor changes in the albedo calculations and to land and sea-ice models. We present results from simulations with NorESM2 that were carried out for the sixth phase of the Coupled Model Intercomparison Project (CMIP6). Two versions of the model are used: one with lower (∼ 2∘) atmosphere–land resolution and one with medium (∼ 1∘) atmosphere–land resolution. The stability of the pre-industrial climate and the sensitivity of the model to abrupt and gradual quadrupling of CO2 are assessed, along with the ability of the model to simulate the historical climate under the CMIP6 forcings. Compared to observations and reanalyses, NorESM2 represents an improvement over previous versions of NorESM in most aspects. NorESM2 appears less sensitive to greenhouse gas forcing than its predecessors, with an estimated equilibrium climate sensitivity of 2.5 K in both resolutions on a 150-year time frame; however, this estimate increases with the time window and the climate sensitivity at equilibration is much higher. We also consider the model response to future scenarios as defined by selected Shared Socioeconomic Pathways (SSPs) from the Scenario Model Intercomparison Project defined under CMIP6. Under the four scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5), the warming in the period 2090–2099 compared to 1850–1879 reaches 1.3, 2.2, 3.0, and 3.9 K in NorESM2-LM, and 1.3, 2.1, 3.1, and 3.9 K in NorESM-MM, robustly similar in both resolutions. NorESM2-LM shows a rather satisfactory evolution of recent sea-ice area. In NorESM2-LM, an ice-free Arctic Ocean is only avoided in the SSP1-2.6 scenario.},
author = {Seland, {\O}yvind and Bentsen, Mats and Olivi{\'{e}}, Dirk and Toniazzo, Thomas and Gjermundsen, Ada and Graff, Lise Seland and Debernard, Jens Boldingh and Gupta, Alok Kumar and He, Yan-Chun and Kirkev{\aa}g, Alf and Schwinger, J{\"{o}}rg and Tjiputra, Jerry and Aas, Kjetil Schanke and Bethke, Ingo and Fan, Yuanchao and Griesfeller, Jan and Grini, Alf and Guo, Chuncheng and Ilicak, Mehmet and Karset, Inger Helene Hafsahl and Landgren, Oskar and Liakka, Johan and Moseid, Kine Onsum and Nummelin, Aleksi and Spensberger, Clemens and Tang, Hui and Zhang, Zhongshi and Heinze, Christoph and Iversen, Trond and Schulz, Michael},
doi = {10.5194/gmd-13-6165-2020},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {dec},
number = {12},
pages = {6165--6200},
title = {{Overview of the Norwegian Earth System Model (NorESM2) and key climate response of CMIP6 DECK, historical, and scenario simulations}},
url = {https://gmd.copernicus.org/articles/13/6165/2020/},
volume = {13},
year = {2020}
}
@article{sellar2019ukesm1,
author = {Sellar, Alistair A and Jones, Colin G and Mulcahy, Jane P. and Tang, Yongming and Yool, Andrew and Wiltshire, Andy and O'Connor, Fiona M. and Stringer, Marc and Hill, Richard and Palmieri, Julien and Woodward, Stephanie and Mora, Lee and Kuhlbrodt, Till and Rumbold, Steven T. and Kelley, Douglas I. and Ellis, Rich and Johnson, Colin E. and Walton, Jeremy and Abraham, Nathan Luke and Andrews, Martin B. and Andrews, Timothy and Archibald, Alex T. and Berthou, S{\'{e}}gol{\`{e}}ne and Burke, Eleanor and Blockley, Ed and Carslaw, Ken and Dalvi, Mohit and Edwards, John and Folberth, Gerd A. and Gedney, Nicola and Griffiths, Paul T. and Harper, Anna B. and Hendry, Maggie A. and Hewitt, Alan J. and Johnson, Ben and Jones, Andy and Jones, Chris D. and Keeble, James and Liddicoat, Spencer and Morgenstern, Olaf and Parker, Robert J. and Predoi, Valeriu and Robertson, Eddy and Siahaan, Antony and Smith, Robin S. and Swaminathan, Ranjini and Woodhouse, Matthew T. and Zeng, Guang and Zerroukat, Mohamed},
doi = {10.1029/2019MS001739},
issn = {1942-2466},
journal = {Journal of Advances in Modeling Earth Systems},
month = {dec},
number = {12},
pages = {4513--4558},
publisher = {Wiley Online Library},
title = {{UKESM1: Description and Evaluation of the U.K. Earth System Model}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019MS001739},
volume = {11},
year = {2019}
}
@article{Semmler2020,
author = {Semmler, Tido and Danilov, Sergey and Gierz, Paul and Goessling, Helge F. and Hegewald, Jan and Hinrichs, Claudia and Koldunov, Nikolay and Khosravi, Narges and Mu, Longjiang and Rackow, Thomas and Sein, Dmitry V. and Sidorenko, Dmitry and Wang, Qiang and Jung, Thomas},
doi = {10.1029/2019MS002009},
issn = {1942-2466},
journal = {Journal of Advances in Modeling Earth Systems},
keywords = {AWI climate model,Coupled Model Intercomparison Project,climate change,global climate model,unstructured mesh},
month = {sep},
number = {9},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Simulations for CMIP6 With the AWI Climate Model AWI-CM-1-1}},
url = {https://onlinelibrary.wiley.com/doi/10.1029/2019MS002009},
volume = {12},
year = {2020}
}
@article{Seneviratne2014,
author = {Seneviratne, Sonia I. and Donat, Markus G. and Mueller, Brigitte and Alexander, Lisa V.},
doi = {10.1038/nclimate2145},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {mar},
number = {3},
pages = {161--163},
title = {{No pause in the increase of hot temperature extremes}},
url = {http://www.nature.com/articles/nclimate2145},
volume = {4},
year = {2014}
}
@article{Seneviratne2016b,
abstract = {Global temperature targets, such as the widely accepted limit of an increase above pre-industrial temperatures of two degrees Celsius, may fail to communicate the urgency of reducing carbon dioxide (CO2) emissions. The translation of CO2 emissions into regional- and impact-related climate targets could be more powerful because such targets are more directly aligned with individual national interests. We illustrate this approach using regional changes in extreme temperatures and precipitation. These scale robustly with global temperature across scenarios, and thus with cumulative CO2 emissions. This is particularly relevant for changes in regional extreme temperatures on land, which are much greater than changes in the associated global mean.},
author = {Seneviratne, Sonia I. and Donat, Markus G. and Pitman, Andy J. and Knutti, Reto and Wilby, Robert L.},
doi = {10.1038/nature16542},
issn = {0028-0836},
journal = {Nature},
month = {jan},
number = {7587},
pages = {477--483},
title = {{Allowable CO2 emissions based on regional and impact-related climate targets}},
url = {http://www.nature.com/articles/nature16542},
volume = {529},
year = {2016}
}
@article{Seong2021,
abstract = {This study conducted a detection and attribution analysis of the observed global and regional changes in extreme temperatures during 1951-2015. HadEX3 observations were compared with multimodel simulations from the Coupled Model Intercomparison Project phase 6 (CMIP6) using an optimal fingerprinting technique. Annual maximum daily maximum and minimum temperatures (TXx and TNx; warm extremes) and annual minimum daily maximum and minimum temperatures (TXn and TNn; cold extremes) over land were analyzed considering global, continental, and subcontinental scales. Response patterns (fingerprints) of extreme temperatures to anthropogenic (ANT), greenhouse gases (GHG), aerosols (AA), and natural (NAT) forcings were obtained from CMIP6 forced simulations. The internal variability ranges were estimated from preindustrial control simulations. A two-signal detection analysis where the observations are regressed onto ANT and NAT fingerprints simultaneously reveals that ANT signals are robustly detected in separation from NAT over global and all continental domains (North and South America, Europe, Asia, and Oceania) for most of the extreme indices. ANT signals are also detected over many subcontinental regions, particularly for warm extremes (more than 60{\%} of 33 subregions). A three-signal detection analysis that considers GHG, AA, and NAT fingerprints simultaneously demonstrates that GHG signals are detected in isolation from other external forcings over global, continental, and several subcontinental domains especially for warm extremes, explaining most of the observed warming. Moreover, AA influences are detected for warm extremes over Europe and Asia, indicating significant offsetting cooling contributions. Overall, human influences are detected more frequently, compared to previous studies, particularly for cold extremes, due to the extended period and the improved spatial coverage of observations.},
author = {Seong, Min Gyu and Min, Seung Ki and Kim, Yeon Hee and Zhang, Xuebin and Sun, Ying},
doi = {10.1175/JCLI-D-19-1023.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Aerosols,Climate change,Climate models,Extreme events,Greenhouse gases,Surface temperature},
number = {3},
pages = {857--870},
title = {{Anthropogenic greenhouse gas and aerosol contributions to extreme temperature changes during 1951–2015}},
volume = {34},
year = {2021}
}
@article{Seth2019,
author = {Seth, Anji and Giannini, Alessandra and Rojas, Maisa and Rauscher, Sara A. and Bordoni, Simona and Singh, Deepti and Camargo, Suzana J.},
doi = {10.1007/s40641-019-00125-y},
issn = {2198-6061},
journal = {Current Climate Change Reports},
month = {jun},
number = {2},
pages = {63--79},
title = {{Monsoon Responses to Climate Changes – Connecting Past, Present and Future}},
url = {http://link.springer.com/10.1007/s40641-019-00125-y},
volume = {5},
year = {2019}
}
@article{doi:10.1002/2015JD024178,
abstract = {Abstract Sudden stratospheric warming (SSW) events can occur as either a split or a displacement of the stratospheric polar vortex. Recent observational studies have come to different conclusions about the relative impacts of these two types of SSW upon surface climate. A clearer understanding of their tropospheric impact would be beneficial for medium-range weather forecasts and could improve understanding of the physical mechanism for stratosphere-troposphere coupling. Here we perform the first multimodel comparison of stratospheric polar vortex splits and displacements, analyzing 13 stratosphere-resolving models from the fifth Coupled Model Intercomparison Project (CMIP5) ensemble. We find a wide range of biases among models in both the mean state of the vortex and the frequency of vortex splits and displacements, although these biases are closely related. Consistent with observational results, almost all models show vortex splits to occur barotropically throughout the depth of the stratosphere, while vortex displacements are more baroclinic. Vortex splits show a slightly stronger North Atlantic surface signal in the month following onset. However, the most significant difference in the surface response is that vortex displacements show stronger negative pressure anomalies over Siberia. This region is shown to be colocated with differences in tropopause height, suggestive of a localized response to lower stratospheric potential vorticity anomalies.},
author = {Seviour, William J M and Gray, Lesley J and Mitchell, Daniel M},
doi = {10.1002/2015JD024178},
issn = {2169897X},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {CMIP5,stratosphere,stratosphere-troposphere coupling,sudden stratospheric warming},
month = {feb},
number = {4},
pages = {1400--1413},
title = {{Stratospheric polar vortex splits and displacements in the high-top CMIP5 climate models}},
url = {http://doi.wiley.com/10.1002/2015JD024178 https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2015JD024178},
volume = {121},
year = {2016}
}
@article{tc-13-325-2019,
author = {Shannon, S and Smith, R and Wiltshire, A and Payne, T and Huss, M and Betts, R and Caesar, J and Koutroulis, A and Jones, D and Harrison, S},
doi = {10.5194/tc-13-325-2019},
journal = {The Cryosphere},
number = {1},
pages = {325--350},
title = {{Global glacier volume projections under high-end climate change scenarios}},
url = {https://www.the-cryosphere.net/13/325/2019/},
volume = {13},
year = {2019}
}
@article{doi:10.1175/JCLI-D-12-00592.1,
abstract = {AbstractThis is the first part of a three-part paper on North American climate in phase 5 of the Coupled Model Intercomparison Project (CMIP5) that evaluates the historical simulations of continental and regional climatology with a focus on a core set of 17 models. The authors evaluate the models for a set of basic surface climate and hydrological variables and their extremes for the continent. This is supplemented by evaluations for selected regional climate processes relevant to North American climate, including cool season western Atlantic cyclones, the North American monsoon, the U.S. Great Plains low-level jet, and Arctic sea ice. In general, the multimodel ensemble mean represents the observed spatial patterns of basic climate and hydrological variables but with large variability across models and regions in the magnitude and sign of errors. No single model stands out as being particularly better or worse across all analyses, although some models consistently outperform the others for certain variables across most regions and seasons and higher-resolution models tend to perform better for regional processes. The CMIP5 multimodel ensemble shows a slight improvement relative to CMIP3 models in representing basic climate variables, in terms of the mean and spread, although performance has decreased for some models. Improvements in CMIP5 model performance are noticeable for some regional climate processes analyzed, such as the timing of the North American monsoon. The results of this paper have implications for the robustness of future projections of climate and its associated impacts, which are examined in the third part of the paper.},
author = {Sheffield, Justin and Barrett, Andrew P and Colle, Brian and {Nelun Fernando}, D and Fu, Rong and Geil, Kerrie L and Hu, Qi and Kinter, Jim and Kumar, Sanjiv and Langenbrunner, Baird and Lombardo, Kelly and Long, Lindsey N and Maloney, Eric and Mariotti, Annarita and Meyerson, Joyce E and Mo, Kingtse C and {David Neelin}, J and Nigam, Sumant and Pan, Zaitao and Ren, Tong and Ruiz-Barradas, Alfredo and Serra, Yolande L and Seth, Anji and Thibeault, Jeanne M and Stroeve, Julienne C and Yang, Ze and Yin, Lei},
doi = {10.1175/JCLI-D-12-00592.1},
journal = {Journal of Climate},
number = {23},
pages = {9209--9245},
title = {{North American Climate in CMIP5 Experiments. Part I: Evaluation of Historical Simulations of Continental and Regional Climatology}},
url = {https://doi.org/10.1175/JCLI-D-12-00592.1},
volume = {26},
year = {2013}
}
@article{Shepherd2014,
abstract = {{\textcopyright} 2014 Macmillan Publishers Limited. All rights reserved 704. The evidence for anthropogenic climate change continues to strengthen, and concerns about severe weather events are increasing. As a result, scientific interest is rapidly shifting from detection and attribution of global climate change to prediction of its impacts at the regional scale. However, nearly everything we have any confidence in when it comes to climate change is related to global patterns of surface temperature, which are primarily controlled by thermodynamics. In contrast, we have much less confidence in atmospheric circulation aspects of climate change, which are primarily controlled by dynamics and exert a strong control on regional climate. Model projections of circulation-related fields, including precipitation, show a wide range of possible outcomes, even on centennial timescales. Sources of uncertainty include low-frequency chaotic variability and the sensitivity to model error of the circulation response to climate forcing. As the circulation response to external forcing appears to project strongly onto existing patterns of variability, knowledge of errors in the dynamics of variability may provide some constraints on model projections. Nevertheless, higher scientific confidence in circulation-related aspects of climate change will be difficult to obtain. For effective decision-making, it is necessary to move to a more explicitly probabilistic, risk-based approach.},
author = {Shepherd, T.G.},
doi = {10.1038/NGEO2253},
journal = {Nature Geoscience},
number = {10},
pages = {703--708},
title = {{Atmospheric circulation as a source of uncertainty in climate change projections}},
volume = {7},
year = {2014}
}
@article{Shepherd2018,
abstract = {The Antarctic Ice Sheet is an important indicator of climate change and driver of sea-level rise. Here we combine satellite observations of its changing volume, flow and gravitational attraction with modelling of its surface mass balance to show that it lost 2,720 ± 1,390 billion tonnes of ice between 1992 and 2017, which corresponds to an increase in mean sea level of 7.6 ± 3.9 millimetres (errors are one standard deviation). Over this period, ocean-driven melting has caused rates of ice loss from West Antarctica to increase from 53 ± 29 billion to 159 ± 26 billion tonnes per year; ice-shelf collapse has increased the rate of ice loss from the Antarctic Peninsula from 7 ± 13 billion to 33 ± 16 billion tonnes per year. We find large variations in and among model estimates of surface mass balance and glacial isostatic adjustment for East Antarctica, with its average rate of mass gain over the period 1992-2017 (5 ± 46 billion tonnes per year) being the least certain.},
author = {Shepherd, Andrew and Ivins, Erik and Rignot, Eric and Smith, Ben and {Van Den Broeke}, Michiel and Velicogna, Isabella and Whitehouse, Pippa and Briggs, Kate and Joughin, Ian and Krinner, Gerhard and Nowicki, Sophie and Payne, Tony and Scambos, Ted and Schlegel, Nicole and Geruo, A. and Agosta, C{\'{e}}cile and Ahlstr{\o}m, Andreas and Babonis, Greg and Barletta, Valentina and Blazquez, Alejandro and Bonin, Jennifer and Csatho, Beata and Cullather, Richard and Felikson, Denis and Fettweis, Xavier and Forsberg, Rene and Gallee, Hubert and Gardner, Alex and Gilbert, Lin and Groh, Andreas and Gunter, Brian and Hanna, Edward and Harig, Christopher and Helm, Veit and Horvath, Alexander and Horwath, Martin and Khan, Shfaqat and Kjeldsen, Kristian K. and Konrad, Hannes and Langen, Peter and Lecavalier, Benoit and Loomis, Bryant and Luthcke, Scott and McMillan, Malcolm and Melini, Daniele and Mernild, Sebastian and Mohajerani, Yara and Moore, Philip and Mouginot, Jeremie and Moyano, Gorka and Muir, Alan and Nagler, Thomas and Nield, Grace and Nilsson, Johan and Noel, Brice and Otosaka, Ines and Pattle, Mark E. and Peltier, W. Richard and Pie, Nadege and Rietbroek, Roelof and Rott, Helmut and Sandberg-S{\o}rensen, Louise and Sasgen, Ingo and Save, Himanshu and Scheuchl, Bernd and Schrama, Ernst and Schr{\"{o}}der, Ludwig and Seo, Ki Weon and Simonsen, Sebastian and Slater, Tom and Spada, Giorgio and Sutterley, Tyler and Talpe, Matthieu and Tarasov, Lev and {Van De Berg}, Willem Jan and {Van Der Wal}, Wouter and {Van Wessem}, Melchior and Vishwakarma, Bramha Dutt and Wiese, David and Wouters, Bert},
doi = {10.1038/s41586-018-0179-y},
isbn = {1364-503X},
issn = {14764687},
journal = {Nature},
keywords = {Climate,Cryospheric science,change impacts},
month = {jun},
number = {7709},
pages = {219--222},
pmid = {29899482},
publisher = {Nature Publishing Group},
title = {{Mass balance of the Antarctic Ice Sheet from 1992 to 2017}},
url = {http://www.nature.com/articles/s41586-018-0179-y},
volume = {558},
year = {2018}
}
@article{Shepherd2012,
abstract = {We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of Earth's polar ice sheets. We find that there is good agreement between different satellite methods—especially in Greenland and West Antarctica—and that combining satellite data sets leads to greater certainty. Between 1992 and 2011, the ice sheets of Greenland, East Antarctica, West Antarctica, and the Antarctic Peninsula changed in mass by –142 T 49, +14 T 43, –65 T 26, and –20 T 14 gigatonnes year−1, respectively. Since 1992, the polar ice sheets have contributed, on average, 0.59 T 0.20 millimeter year−1 to the rate of global sea-level rise.},
archivePrefix = {arXiv},
arxivId = {NIHMS150003},
author = {Shepherd, Andrew and Ivins, Erik R and Geruo, A. and Barletta, Valentina R and Bentley, Mike J and Bettadpur, Srinivas and Briggs, Kate H and Bromwich, David H and Forsberg, Ren{\'{e}} and Galin, Natalia and Horwath, Martin and Jacobs, Stan and Joughin, Ian and King, Matt A and Lenaerts, Jan T.M. and Li, Jilu and Ligtenberg, Stefan R.M. and Luckman, Adrian and Luthcke, Scott B and McMillan, Malcolm and Meister, Rakia and Milne, Glenn and Mouginot, Jeremie and Muir, Alan and Nicolas, Julien P and Paden, John and Payne, Antony J and Pritchard, Hamish and Rignot, Eric and Rott, Helmut and S{\o}rensen, Louise Sandberg and Scambos, Ted A and Scheuchl, Bernd and Schrama, Ernst J.O. and Smith, Ben and Sundal, Aud V and {Van Angelen}, Jan H. and {Van De Berg}, Willem J. and {Van Den Broeke}, Michiel R. and Vaughan, David G and Velicogna, Isabella and Wahr, John and Whitehouse, Pippa L and Wingham, Duncan J and Yi, Donghui and Young, Duncan and Zwally, H Jay},
doi = {10.1126/science.1228102},
eprint = {NIHMS150003},
isbn = {1095-9203 (Electronic)$\backslash$r0036-8075 (Linking)},
issn = {10959203},
journal = {Science},
month = {nov},
number = {6111},
pages = {1183--1189},
pmid = {23197528},
publisher = {American Association for the Advancement of Science},
title = {{A reconciled estimate of ice-sheet mass balance}},
url = {http://www.ncbi.nlm.nih.gov/pubmed/23197528},
volume = {338},
year = {2012}
}
@article{Shepherd2020,
abstract = {The Greenland Ice Sheet has been a major contributor to global sea-level rise in recent decades1,2, and it is expected to continue to be so3. Although increases in glacier flow4–6 and surface melting7–9 have been driven by oceanic10–12 and atmospheric13,14 warming, the magnitude and trajectory of the ice sheet's mass imbalance remain uncertain. Here we compare and combine 26 individual satellite measurements of changes in the ice sheet's volume, flow and gravitational potential to produce a reconciled estimate of its mass balance. The ice sheet was close to a state of balance in the 1990s, but annual losses have risen since then, peaking at 345 ± 66 billion tonnes per year in 2011. In all, Greenland lost 3,902 ± 342 billion tonnes of ice between 1992 and 2018, causing the mean sea level to rise by 10.8 ± 0.9 millimetres. Using three regional climate models, we show that the reduced surface mass balance has driven 1,964 ± 565 billion tonnes (50.3 per cent) of the ice loss owing to increased meltwater runoff. The remaining 1,938 ± 541 billion tonnes (49.7 per cent) of ice loss was due to increased glacier dynamical imbalance, which rose from 46 ± 37 billion tonnes per year in the 1990s to 87 ± 25 billion tonnes per year since then. The total rate of ice loss slowed to 222 ± 30 billion tonnes per year between 2013 and 2017, on average, as atmospheric circulation favoured cooler conditions15 and ocean temperatures fell at the terminus of Jakobshavn Isbr{\ae}16. Cumulative ice losses from Greenland as a whole have been close to the rates predicted by the Intergovernmental Panel on Climate Change for their high-end climate warming scenario17, which forecast an additional 70 to 130 millimetres of global sea-level rise by 2100 compared with their central estimate.},
author = {Shepherd, Andrew and Ivins, Erik and Rignot, Eric and Smith, Ben and van den Broeke, Michiel and Velicogna, Isabella and Whitehouse, Pippa and Briggs, Kate and Joughin, Ian and Krinner, Gerhard and Nowicki, Sophie and Payne, Tony and Scambos, Ted and Schlegel, Nicole and A, Geruo and Agosta, C{\'{e}}cile and Ahlstr{\o}m, Andreas and Babonis, Greg and Barletta, Valentina R. and Bj{\o}rk, Anders A. and Blazquez, Alejandro and Bonin, Jennifer and Colgan, William and Csatho, Beata and Cullather, Richard and Engdahl, Marcus E. and Felikson, Denis and Fettweis, Xavier and Forsberg, Rene and Hogg, Anna E. and Gallee, Hubert and Gardner, Alex and Gilbert, Lin and Gourmelen, Noel and Groh, Andreas and Gunter, Brian and Hanna, Edward and Harig, Christopher and Helm, Veit and Horvath, Alexander and Horwath, Martin and Khan, Shfaqat and Kjeldsen, Kristian K. and Konrad, Hannes and Langen, Peter L. and Lecavalier, Benoit and Loomis, Bryant and Luthcke, Scott and McMillan, Malcolm and Melini, Daniele and Mernild, Sebastian and Mohajerani, Yara and Moore, Philip and Mottram, Ruth and Mouginot, Jeremie and Moyano, Gorka and Muir, Alan and Nagler, Thomas and Nield, Grace and Nilsson, Johan and No{\"{e}}l, Brice and Otosaka, Ines and Pattle, Mark E. and Peltier, W. Richard and Pie, Nad{\`{e}}ge and Rietbroek, Roelof and Rott, Helmut and {Sandberg S{\o}rensen}, Louise and Sasgen, Ingo and Save, Himanshu and Scheuchl, Bernd and Schrama, Ernst and Schr{\"{o}}der, Ludwig and Seo, Ki Weon and Simonsen, Sebastian B. and Slater, Thomas and Spada, Giorgio and Sutterley, Tyler and Talpe, Matthieu and Tarasov, Lev and van de Berg, Willem Jan and van der Wal, Wouter and van Wessem, Melchior and Vishwakarma, Bramha Dutt and Wiese, David and Wilton, David and Wagner, Thomas and Wouters, Bert and Wuite, Jan},
doi = {10.1038/s41586-019-1855-2},
issn = {14764687},
journal = {Nature},
number = {7798},
pages = {233--239},
pmid = {31822019},
title = {{Mass balance of the Greenland Ice Sheet from 1992 to 2018}},
volume = {579},
year = {2020}
}
@article{Sherriff-Tadano2018,
abstract = {Coupled modeling studies have recently shown that the existence of the glacial ice sheets intensifies the Atlantic meridional overturning circulation (AMOC). However, most models show a strong AMOC in their simulations of the Last Glacial Maximum (LGM), which is biased compared to reconstructions that indicate both a weaker and stronger AMOC during the LGM. Therefore, a detailed investigation of the mechanism behind this intensification of the AMOC is important for a better understanding of the glacial climate and the LGM AMOC. Here, various numerical simulations are conducted to focus on the effect of wind changes due to glacial ice sheets on the AMOC and the crucial region where the wind modifies the AMOC. First, from atmospheric general circulation model experiments, the effect of glacial ice sheets on the surface wind is evaluated. Second, from ocean general circulation model experiments, the influence of the wind stress change on the AMOC is evaluated by applying wind stress anomalies regionally or at different magnitudes as a boundary condition. These experiments demonstrate that glacial ice sheets intensify the AMOC through an increase in the wind stress at the North Atlantic mid-latitudes, which is induced by the North American ice sheet. This intensification of the AMOC is caused by the increased oceanic horizontal and vertical transport of salt, while the change in sea ice transport has an opposite, though minor, effect. Experiments further show that the Eurasian ice sheet intensifies the AMOC by directly affecting the deep-water formation in the Norwegian Sea.},
author = {Sherriff-Tadano, Sam and Abe-Ouchi, Ayako and Yoshimori, Masakazu and Oka, Akira and Chan, Wing-Le},
doi = {10.1007/s00382-017-3780-0},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {7},
pages = {2881--2903},
title = {{Influence of glacial ice sheets on the Atlantic meridional overturning circulation through surface wind change}},
url = {https://doi.org/10.1007/s00382-017-3780-0},
volume = {50},
year = {2018}
}
@article{Sherwood2015,
abstract = {We present an updated version of the radiosonde dataset homogenized by Iterative Universal Kriging (IUKv2), now extended through February 2013, following the method used in the original version (Sherwood et al 2008 Robust tropospheric warming revealed by iteratively homogenized radiosonde data J. Clim. 21 5336-52). This method, in effect, performs a multiple linear regression of the data onto a structural model that includes both natural variability, trends, and time-changing instrument biases, thereby avoiding estimation biases inherent in traditional homogenization methods. One modification now enables homogenized winds to be provided for the first time. This, and several other small modifications made to the original method sometimes affect results at individual stations, but do not strongly affect broad-scale temperature trends. Temperature trends in the updated data show three noteworthy features. First, tropical warming is equally strong over both the 1959-2012 and 1979-2012 periods, increasing smoothly and almost moist-adiabatically from the surface (where it is roughly 0.14 K/decade) to 300 hPa (where it is about 0.25 K/decade over both periods), a pattern very close to that in climate model predictions. This contradicts suggestions that atmospheric warming has slowed in recent decades or that it has not kept up with that at the surface. Second, as shown in previous studies, tropospheric warming does not reach quite as high in the tropics and subtropics as predicted in typical models. Third, cooling has slackened in the stratosphere such that linear trends since 1979 are about half as strong as reported earlier for shorter periods. Wind trends over the period 1979-2012 confirm a strengthening, lifting and poleward shift of both subtropical westerly jets; the Northern one shows more displacement and the southern more intensification, but these details appear sensitive to the time period analysed. There is also a trend toward more easterly winds in the middle and upper troposphere of the deep tropics.},
author = {Sherwood, Steven C and Nishant, Nidhi},
doi = {10.1088/1748-9326/10/5/054007},
issn = {1748-9326},
journal = {Environmental Research Letters},
month = {may},
number = {5},
pages = {054007},
title = {{Atmospheric changes through 2012 as shown by iteratively homogenized radiosonde temperature and wind data (IUKv2)}},
url = {https://iopscience.iop.org/article/10.1088/1748-9326/10/5/054007},
volume = {10},
year = {2015}
}
@article{Shi2017,
abstract = {Many institutions worldwide have developed ocean reanalyses systems (ORAs) utilizing a variety of ocean models and assimilation techniques. However, the quality of salinity reanalyses arising from the various ORAs has not yet been comprehensively assessed. In this study, we assess the upper ocean salinity content (depth-averaged over 0–700 m) from 14 ORAs and 3 objective ocean analysis systems (OOAs) as part of the Ocean Reanalyses Intercomparison Project. Our results show that the best agreement between estimates of salinity from different ORAs is obtained in the tropical Pacific, likely due to relatively abundant atmospheric and oceanic observations in this region. The largest disagreement in salinity reanalyses is in the Southern Ocean along the Antarctic circumpolar current as a consequence of the sparseness of both atmospheric and oceanic observations in this region. The West Pacific warm pool is the largest region where the signal to noise ratio of reanalysed salinity anomalies is {\textgreater}1. Therefore, the current salinity reanalyses in the tropical Pacific Ocean may be more reliable than those in the Southern Ocean and regions along the western boundary currents. Moreover, we found that the assimilation of salinity in ocean regions with relatively strong ocean fronts is still a common problem as seen in most ORAs. The impact of the Argo data on the salinity reanalyses is visible, especially within the upper 500 m, where the interannual variability is large. The increasing trend in global-averaged salinity anomalies can only be found within the top 0–300 m layer, but with quite large diversity among different ORAs. Beneath the 300 m depth, the global-averaged salinity anomalies from most ORAs switch their trends from a slightly growing trend before 2002 to a decreasing trend after 2002. The rapid switch in the trend is most likely an artefact of the dramatic change in the observing system due to the implementation of Argo.},
author = {Shi, L. and Alves, O. and Wedd, R. and Balmaseda, M. A. and Chang, Y. and Chepurin, G. and Ferry, N. and Fujii, Y. and Gaillard, F. and Good, S. A. and Guinehut, S. and Haines, K. and Hernandez, F. and Lee, T. and Palmer, M. and Peterson, K. A. and Masuda, S. and Storto, A. and Toyoda, T. and Valdivieso, M. and Vernieres, G. and Wang, X. and Yin, Y.},
doi = {10.1007/s00382-015-2868-7},
issn = {14320894},
journal = {Climate Dynamics},
keywords = {Intercomparison,Ocean reanalyses,Salinity content},
number = {3},
pages = {1009--1029},
title = {{An assessment of upper ocean salinity content from the Ocean Reanalyses Inter-comparison Project (ORA-IP)}},
url = {https://doi.org/10.1007/s00382-015-2868-7},
volume = {49},
year = {2017}
}
@article{Shikha2018,
abstract = {Coupled ocean atmosphere general circulation models (CGCMs) are known to have deep ocean biases when simulated over long term climate timescales. Here, an analysis has been done for investigating the impacts of these deep ocean biases, especially those which occur in temperature and salinity, ensuing biases in ocean dynamics and large scale air-sea interactions in state of the art CGCMs. The outputs from historical runs of 20 Coupled Model Intercomparison Project Phase 5 (CMIP-5) models have been analyzed for Indian Ocean. All candidate models develop internal warm and saline biases approximately between a depth range of 100 and 800 m in long term simulations. These internal biases are found to have implications in large scale ocean dynamics via their linkage through baroclinicity of the ocean. The role of internal biases in the ensuing dynamics is correlated via relations between Brunt V{\"{a}}is{\"{a}}l{\"{a}} frequency (N2) and baroclinic wave speeds using both Sturm-Loiuville theorem and WKBJ approximation. The CMIP-5 models analyzed here have a higher baroclinic speed compared to that of observations. Annual propagating modes in the ocean reveal higher speeds in most of the models, and that the phase reversal is taking place at lead or lag by a month or more as compared to observations. The study suggests that faster wave propagation in climate models due to subsurface biases in temperature, salinity, N2 and baroclinicity have potential to impact simulated planetary scale events in terms of their life cycle, periodicity and seasonality as analyzed with Indian Ocean Dipole Zonal Mode. A corollary being a cautionary outlook on climate projections made by coupled models as long as the biases are persistent.},
author = {Shikha, Singh and Valsala, Vinu},
doi = {10.1016/J.DYNATMOCE.2018.10.001},
issn = {0377-0265},
journal = {Dynamics of Atmospheres and Oceans},
month = {dec},
pages = {55--74},
publisher = {Elsevier},
title = {{Subsurface ocean biases in climate models and its implications in the simulated interannual variability: A case study for Indian Ocean}},
url = {https://www.sciencedirect.com/science/article/pii/S0377026517301720},
volume = {84},
year = {2018}
}
@article{Si2017,
author = {Si, Dong and Hu, Aixue},
doi = {10.1175/JCLI-D-17-0065.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {oct},
number = {20},
pages = {8299--8316},
title = {{Internally Generated and Externally Forced Multidecadal Oceanic Modes and Their Influence on the Summer Rainfall over East Asia}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-17-0065.1},
volume = {30},
year = {2017}
}
@article{Sidorenko2019,
abstract = {A new global climate model setup using FESOM2.0 for the sea ice-ocean component and ECHAM6.3 for the atmosphere and land surface has been developed. Replacing FESOM1.4 by FESOM2.0 promises a higher efficiency of the new climate setup compared to its predecessor. The new setup allows for long-term climate integrations using a locally eddy-resolving ocean. Here it is evaluated in terms of (1) the mean state and long-term drift under preindustrial climate conditions, (2) the fidelity in simulating the historical warming, and (3) differences between coarse and eddy-resolving ocean configurations. The results show that the realism of the new climate setup is overall within the range of existing models. In terms of oceanic temperatures, the historical warming signal is of smaller amplitude than the model drift in case of a relatively short spin-up. However, it is argued that the strategy of “de-drifting” climate runs after the short spin-up, proposed by the HighResMIP protocol, allows one to isolate the warming signal. Moreover, the eddy-permitting/resolving ocean setup shows notable improvements regarding the simulation of oceanic surface temperatures, in particular in the Southern Ocean.},
author = {Sidorenko, D. and Goessling, H. F. and Koldunov, N. V. and Scholz, P. and Danilov, S. and Barbi, D. and Cabos, W. and Gurses, O. and Harig, S. and Hinrichs, C. and Juricke, S. and Lohmann, G. and Losch, M. and Mu, L. and Rackow, T. and Rakowsky, N. and Sein, D. and Semmler, T. and Shi, X. and Stepanek, C. and Streffing, J. and Wang, Q. and Wekerle, C. and Yang, H. and Jung, T.},
doi = {10.1029/2019MS001696},
issn = {19422466},
journal = {Journal of Advances in Modeling Earth Systems},
keywords = {FESOM,Finite Volume,climate model,ocean model,unstructured mesh},
number = {11},
pages = {3794--3815},
title = {{Evaluation of FESOM2.0 Coupled to ECHAM6.3: Preindustrial and HighResMIP Simulations}},
volume = {11},
year = {2019}
}
@article{Sigmond2008b,
abstract = {The atmospheric circulation response to CO2 doubling in various versions of an atmospheric general circulation model (AGCM) without a well-resolved stratosphere (“low-top” model), is compared to the response in a version of the same AGCM with a well-resolved stratosphere (“high-top” model). The doubled CO2 response of the “best-tuned” (i.e. operational) low-top model version is significantly different from that in the best-tuned high-top model version. Additional experiments show that this difference is not caused by the model lid height, but instead can be mainly attributed to differences in the settings of parameterized orographic gravity-wave drag which control the strength of the zonal wind in the mid- to high-latitude lower stratosphere and the mean sea-level pressure distribution. These findings suggest a link between the strength of the winds in the mid- to high-latitude lower stratosphere and tropospheric annular mode responses, and have implications for how to proceed with high-top low-top model intercomparisons.},
author = {Sigmond, Michael and Scinocca, John F and Kushner, Paul J},
doi = {10.1029/2008GL033573},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {jun},
number = {12},
pages = {L12706},
title = {{Impact of the stratosphere on tropospheric climate change}},
url = {http://doi.wiley.com/10.1029/2008GL033573},
volume = {35},
year = {2008}
}
@article{doi:10.1002/qj.2949,
abstract = {The ERA-Interim and JRA-55 reanalyses of synoptic data and several conventional analyses of monthly climatological data provide similar estimates of global-mean surface warming since 1979. They broadly agree on the character of interannual variability and the extremity of the 2015/2016 warm spell to which a strong El Ni{\~{n}}o and low Arctic sea-ice cover contribute. Nevertheless global and regional averages differ on various time-scales due to differences in data coverage and sea-surface temperature analyses; averages from those conventional datasets that infill where they lack direct observations agree better with the averages from the reanalyses. The latest warm event is less extreme when viewed in terms of atmospheric energy, which gives more weight to variability in the Tropics, where the thermal signal has greater vertical penetration and latent energy is a larger factor. Surface warming from 1998 to 2012 is larger than indicated by earlier versions of the conventional datasets used to characterize what the Fifth Assessment Report of the Intergovernmental Panel on Climate Change termed a hiatus in global warming. None of the datasets exhibit net warming over the Antarctic since 1979. Centennial trends from the conventional datasets, HadCRUT4 on the one hand and GISTEMP and NOAAGlobalTemp on the other, differ mainly because sea-surface temperatures differ. Infilling of values where direct observations are lacking is more questionable for the data-sparse earlier decades. Change since the eighteenth century is inevitably more uncertain than change over and after a modern baseline period. The latter is arguably best estimated separately for taking stock of actions to limit climate change, exploiting reanalyses and using satellite data to refine the conventional approach. Nevertheless, early in 2016 the global temperature appears to have first touched or briefly breached a level 1.5 °C above that early in the Industrial Revolution, having touched the 1.0 °C level in 1998 during a previous El Ni{\~{n}}o.},
author = {Simmons, A J and Berrisford, P and Dee, D P and Hersbach, H and Hirahara, S and Th{\'{e}}paut, J.-N.},
doi = {10.1002/qj.2949},
journal = {Quarterly Journal of the Royal Meteorological Society},
keywords = {Arctic warming,El Ni{\~{n}}o,atmospheric energy,reanalysis,temperature trends},
number = {702},
pages = {101--119},
title = {{A reassessment of temperature variations and trends from global reanalyses and monthly surface climatological datasets}},
url = {https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/qj.2949},
volume = {143},
year = {2017}
}
@article{Simmons2014,
abstract = {Abstract Low-frequency variability and trends in temperature from 1979 to 2012 are examined. Observational improvements are noted and near-surface behaviour of the ECMWF ERA-Interim reanalysis is reviewed. Attention is then focussed on how closely ERA-Interim fits the upper-air data it assimilates, the bias adjustments it infers for satellite data, and its agreement with the ERA-40, MERRA and JRA-55 reanalyses and with model simulations. Global-mean fits to independently homogenised radiosonde temperatures and variationally adjusted satellite brightness temperatures are mainly within 0.1 K in the troposphere, with some degradation over time from assimilating varying amounts of aircraft and rain-affected microwave-radiance data, and from a change in source of sea-surface-temperature analysis. Lower-tropospheric warming appears to be somewhat underestimated. Temperature variations in the tropical upper troposphere correlate well with those at the surface, but amplitude is more than doubled, in agreement with modelling. Specific humidity varies in concert; relative humidity is largely uniform, but dips during El Ni{\~{n}}o events. Agreement with the other reanalyses is particularly close in the lower stratosphere, where radiance data and the background model constrain cooling to be slightly slower than in the homogenised radiosonde data. Perturbations to global-mean temperatures from underestimating warming following the El Chich{\'{o}}n and Pinatubo volcanic eruptions and from assimilating recent GPSRO data are at most 0.2 K, less than 20{\%} of the net change since 1979 at 50 hPa. Middle-stratospheric variations are more uncertain. Recent cooling appears to be underestimated by assimilating increasing amounts of unadjusted radiosonde data, but results do not support a recent reprocessing of earlier sounding data that suggests stronger middle-stratospheric cooling than previously indicated. Strong analysed upper-stratospheric cooling agrees quite well with model simulations if occasional jumps due to unadjusted bias changes in high-sounding satellite data are discounted. Producing ERA-Interim in two separate streams caused only minor discontinuities where streams join at the start of 1989.},
annote = {https://doi.org/10.1002/qj.2317},
author = {Simmons, A J and Poli, P and Dee, D P and Berrisford, P and Hersbach, H and Kobayashi, S and Peubey, C},
doi = {https://doi.org/10.1002/qj.2317},
issn = {0035-9009},
journal = {Quarterly Journal of the Royal Meteorological Society},
keywords = {bias adjustment,observing-system improvement,reanalysis,temperature trends},
month = {jan},
number = {679},
pages = {329--353},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Estimating low-frequency variability and trends in atmospheric temperature using ERA-Interim}},
url = {https://doi.org/10.1002/qj.2317},
volume = {140},
year = {2014}
}
@article{Simpson2013,
author = {Simpson, Isla R. and Shepherd, Theodore G. and Hitchcock, Peter and Scinocca, John F.},
doi = {10.1175/JCLI-D-12-00495.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jul},
number = {14},
pages = {5220--5241},
title = {{Southern Annular Mode Dynamics in Observations and Models. Part II: Eddy Feedbacks}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00495.1},
volume = {26},
year = {2013}
}
@article{Simpson2018,
author = {Simpson, Isla R. and Deser, Clara and McKinnon, Karen A. and Barnes, Elizabeth A.},
doi = {10.1175/JCLI-D-18-0168.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {oct},
number = {20},
pages = {8313--8338},
title = {{Modeled and Observed Multidecadal Variability in the North Atlantic Jet Stream and Its Connection to Sea Surface Temperatures}},
volume = {31},
year = {2018}
}
@article{doi:10.1029/2019GL083758,
abstract = {Abstract A number of physically based hypotheses have been proposed to explain the surprising expansion of Antarctic sea ice area (SIA) over the satellite era (1979 to 2015). Here, we use a fully coupled state-of-the-art global climate model to show that internal variability alone can produce such multidecadal periods of Antarctic SIA expansion even as atmospheric CO2 increases at observed rates and the planet warms. When our model is started from a relatively warm Southern Ocean state, Antarctic SIA sometimes (in one of three ensemble members) expands over multidecadal time scales at a rate comparable to that over the satellite era. SIA expansion occurs concurrently with rising atmospheric CO2 and warming global surface temperatures, and SIA trends by region and sector resemble those over the satellite era. Our results suggest that internal variability over long time scales in the Southern Ocean region may suffice to explain Antarctic SIA expansion over the satellite era.},
author = {Singh, H A and Polvani, L M and Rasch, P J},
doi = {10.1029/2019GL083758},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {Antarctica,Atmosphere-Ocean-Ice Interactions,Internal Variability,Satellite Era,Sea Ice,Southern Ocean},
month = {dec},
number = {24},
pages = {14762--14771},
title = {{Antarctic Sea Ice Expansion, Driven by Internal Variability, in the Presence of Increasing Atmospheric CO2}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL083758 https://onlinelibrary.wiley.com/doi/10.1029/2019GL083758},
volume = {46},
year = {2019}
}
@article{Sinha2018,
author = {Sinha, B and Smeed, D A and McCarthy, G and Moat, B I and Josey, S A and Hirschi, J.J.-M. and Frajka-Williams, E and Blaker, A T and Rayner, D and Madec, G},
doi = {10.1016/j.pocean.2017.12.001},
issn = {0079-6611},
journal = {Progress in Oceanography},
keywords = {Atlantic Meridional Overturning Circulation,Ekman transport,Geostrophic transport,Level of no motion,Mooring array,Ocean general circulation model,RAPID/MOCHA},
pages = {101--123},
title = {{The accuracy of estimates of the overturning circulation from basin-wide mooring arrays}},
url = {http://www.sciencedirect.com/science/article/pii/S0079661116302439},
volume = {160},
year = {2018}
}
@article{Sippel2019b,
abstract = {{\textless}p{\textgreater}Internal atmospheric variability fundamentally limits predictability of climate and obscures evidence of anthropogenic climate change regionally and on time scales of up to a few decades. Dynamical adjustment techniques estimate and subsequently remove the influence of atmospheric circulation variability on temperature or precipitation. The residual component is expected to contain the thermodynamical signal of the externally forced response but with less circulation-induced noise. Existing techniques have led to important insights into recent trends in regional (hydro-) climate and their drivers, but the variance explained by circulation is often low. Here, we develop a novel dynamical adjustment technique by implementing principles from statistical learning. We demonstrate in an ensemble of Community Earth System Model (CESM) simulations that statistical learning methods, such as regularized linear models, establish a clearer relationship between circulation variability and atmospheric target variables, and need relatively short periods of record for training (around 30 years). The method accounts for, on average, 83{\%} and 78{\%} of European monthly winter temperature and precipitation variability at gridcell level, and around 80{\%} of global mean temperature and hemispheric precipitation variability. We show that the residuals retain forced thermodynamical contributions to temperature and precipitation variability. Accurate estimates of the total forced response can thus be recovered assuming that forced circulation changes are gradual over time. Overall, forced climate response estimates can be extracted at regional or global scales from approximately 3–5 times fewer ensemble members, or even a single realization, using statistical learning techniques. We anticipate the technique will contribute to reducing uncertainties around internal variability and facilitating climate change detection and attribution.{\textless}/p{\textgreater}},
author = {Sippel, Sebastian and Meinshausen, Nicolai and Merrifield, Anna and Lehner, Flavio and Pendergrass, Angeline G. and Fischer, Erich and Knutti, Reto},
doi = {10.1175/JCLI-D-18-0882.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {sep},
number = {17},
pages = {5677--5699},
title = {{Uncovering the Forced Climate Response from a Single Ensemble Member Using Statistical Learning}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-18-0882.1},
volume = {32},
year = {2019}
}
@article{Sippel2020,
abstract = {For generations, climate scientists have educated the public that ‘weather is not climate', and climate change has been framed as the change in the distribution of weather that slowly emerges from large variability over decades1–7. However, weather when considered globally is now in uncharted territory. Here we show that on the basis of a single day of globally observed temperature and moisture, we detect the fingerprint of externally driven climate change, and conclude that Earth as a whole is warming. Our detection approach invokes statistical learning and climate model simulations to encapsulate the relationship between spatial patterns of daily temperature and humidity, and key climate change metrics such as annual global mean temperature or Earth's energy imbalance. Observations are projected onto this relationship to detect climate change. The fingerprint of climate change is detected from any single day in the observed global record since early 2012, and since 1999 on the basis of a year of data. Detection is robust even when ignoring the long-term global warming trend. This complements traditional climate change detection, but also opens broader perspectives for the communication of regional weather events, modifying the climate change narrative: while changes in weather locally are emerging over decades, global climate change is now detected instantaneously.},
author = {Sippel, Sebastian and Meinshausen, Nicolai and Fischer, Erich M and Sz{\'{e}}kely, Enikő and Knutti, Reto},
doi = {10.1038/s41558-019-0666-7},
issn = {1758-6798},
journal = {Nature Climate Change},
number = {1},
pages = {35--41},
title = {{Climate change now detectable from any single day of weather at global scale}},
url = {https://doi.org/10.1038/s41558-019-0666-7},
volume = {10},
year = {2020}
}
@article{Sjolte2018a,
author = {Sjolte, Jesper and Sturm, Christophe and Adolphi, Florian and Vinther, Bo M. and Werner, Martin and Lohmann, Gerrit and Muscheler, Raimund},
doi = {10.5194/cp-14-1179-2018},
issn = {1814-9332},
journal = {Climate of the Past},
month = {aug},
number = {8},
pages = {1179--1194},
title = {{Solar and volcanic forcing of North Atlantic climate inferred from a process-based reconstruction}},
url = {https://cp.copernicus.org/articles/14/1179/2018/},
volume = {14},
year = {2018}
}
@article{Skliris2018,
author = {Skliris, N. and Zika, J. D. and Herold, L. and Josey, S. A. and Marsh, R.},
doi = {10.1007/s00382-017-4053-7},
issn = {0930-7575},
journal = {Climate Dynamics},
keywords = {Evaporation,Mediterranean Sea,Precipitation,Salinity,Water cycle,Water mass transformation},
month = {oct},
number = {7-8},
pages = {2857--2876},
publisher = {Springer Berlin Heidelberg},
title = {{Mediterranean sea water budget long-term trend inferred from salinity observations}},
url = {http://link.springer.com/10.1007/s00382-017-4053-7},
volume = {51},
year = {2018}
}
@article{Skliris2016,
abstract = {Global water cycle amplifying at less than the Clausius-Clapeyron rate},
author = {Skliris, Nikolaos and Zika, Jan D. and Nurser, George and Josey, Simon A. and Marsh, Robert},
doi = {10.1038/srep38752},
isbn = {2045-2322 (Electronic)$\backslash$r2045-2322 (Linking)},
issn = {20452322},
journal = {Scientific Reports},
keywords = {Physical oceanography,Projection and prediction},
month = {dec},
number = {1},
pages = {38752},
pmid = {27934946},
publisher = {Nature Publishing Group},
title = {{Global water cycle amplifying at less than the Clausius-Clapeyron rate}},
url = {http://www.nature.com/articles/srep38752},
volume = {6},
year = {2016}
}
@article{Skliris2014,
abstract = {Global hydrographic and air-sea freshwater flux datasets are used to investigate ocean salinity changes over 1950-2010 in relation to surface freshwater flux. On multi-decadal timescales, surface salinity increases (decreases) in evaporation (precipitation) dominated regions, the Atlantic-Pacific salinity contrast increases, and the upper thermocline salinity maximum increases while the salinity minimum of intermediate waters decreases. Potential trends in E-P are examined for 1950-2010 (using two reanalyses) and 1979-2010 (using four reanalyses and two blended products). Large differences in the 1950-2010 E-P trend patterns are evident in several regions, particularly the North Atlantic. For 1979-2010 some coherency in the spatial change patterns is evident but there is still a large spread in trend magnitude and sign between the six E-P products. However, a robust pattern of increased E-P in the southern hemisphere subtropical gyres is seen in all products. There is also some evidence in the tropical Pacific for a link between the spatial change patterns of salinity and E-P associated with ENSO. The water cycle amplification rate over specific regions is subsequently inferred from the observed 3-D salinity change field using a salt conservation equation in variable isopycnal volumes, implicitly accounting for the migration of isopycnal surfaces. Inferred global changes of E-P over 1950-2010 amount to an increase of 1 ± 0.6 {\%} in net evaporation across the subtropics and an increase of 4.2 ± 2 {\%} in net precipitation across subpolar latitudes. Amplification rates are approximately doubled over 1979-2010, consistent with accelerated broad-scale warming but also coincident with much improved salinity sampling over the latter period. {\textcopyright} 2014 Springer-Verlag Berlin Heidelberg.},
author = {Skliris, Nikolaos and Marsh, Robert and Josey, Simon A. and Good, Simon A. and Liu, Chunlei and Allan, Richard P.},
doi = {10.1007/s00382-014-2131-7},
issn = {14320894},
journal = {Climate Dynamics},
keywords = {Evaporation,Freshwater flux,Hydrological cycle,Precipitation,Salinity},
month = {aug},
number = {3-4},
pages = {709--736},
publisher = {Springer Berlin Heidelberg},
title = {{Salinity changes in the World Ocean since 1950 in relation to changing surface freshwater fluxes}},
volume = {43},
year = {2014}
}
@article{Slangen2016a,
abstract = {Sea-level change is an important consequence of anthropogenic climate change, as higher sea levels increase the frequency of sea-level extremes and the impact of coastal flooding and erosion on the coastal environment, infrastructure and coastal communities 1,2 . Although individual attribution studies have been done for ocean thermal expansion 3,4 and glacier mass loss 5 , two of the largest contributors to twentieth-century sea-level rise, this has not been done for the other contributors or total global mean sea-level change (GMSLC). Here, we evaluate the influence of greenhouse gases (GHGs), anthropogenic aerosols, natural radiative forcings and internal climate variability on sea-level contributions of ocean thermal expansion, glaciers, ice-sheet surface mass balance and total GMSLC. For each contribution, dedicated models are forced with results from the Coupled Model Intercomparison Project Phase 5 (CMIP5) climate model archive 6 . The sum of all included contributions explains 74  22{\%} (  2  ) of the observed GMSLC over the period 1900–2005. The natural radiative forcing makes essentially zero contribution over the twentieth century (2  15{\%} over the period 1900–2005), but combined with the response to past climatic variations explains 67  23{\%} of the observed rise before 1950 and only 9  18{\%} after 1970 (38  12{\%} over the period 1900–2005). In contrast, the anthropogenic forcing (primarily a balance between a positive sea-level contribution from GHGs and a partially osetting component from anthropogenic aerosols) explains only 15  55{\%} of the observations before 1950, but increases to become the dominant contribution to sea-level rise after 1970 (69  31{\%}), reaching 72  39{\%} in 2000 (37  38{\%} over the period 1900–2005).},
author = {Slangen, Aim{\'{e}}e B.A. and Church, John A. and Agosta, Cecile and Fettweis, Xavier and Marzeion, Ben and Richter, Kristin},
doi = {10.1038/nclimate2991},
isbn = {1758-678X},
issn = {17586798},
journal = {Nature Climate Change},
keywords = {Attribution,Physical oceanography},
month = {jul},
number = {7},
pages = {701--705},
publisher = {Nature Publishing Group},
title = {{Anthropogenic forcing dominates global mean sea-level rise since 1970}},
url = {http://www.nature.com/articles/nclimate2991},
volume = {6},
year = {2016}
}
@article{Slangen2015,
abstract = {Changes in Earth's climate are influenced by internal climate variability and external forcings, such as changes in solar radiation, volcanic eruptions, anthropogenic greenhouse gases (GHG), and aerosols. Although the response of surface temperature to external forcings has been studied extensively, this has not been done for sea level. Here, a range of climate model experiments for the twentieth century is used to study the response of global and regional sea level change to external climate forcings. Both the global mean thermosteric sea level and the regional dynamic sea level patterns show clear responses to anthropogenic forcings that are significantly different from internal climate variability and larger than the difference between models driven by the same external forcing. The regional sea level patterns are directly related to changes in surface winds in response to the external forcings. The spread between different realizations of the same model experiment is consistent with internal climate variability derived from preindustrial control simulations. The spread between the different models is larger than the internal variability, mainly in regions with large sea level responses. Although the sea level responses to GHG and anthropogenic aerosol forcing oppose each other in the global mean, there are differences on a regional scale, offering opportunities for distinguishing between these two forcings in observed sea level change.},
author = {Slangen, Aimee B. A. and Church, John A. and Zhang, Xuebin and Monselesan, Didier P.},
doi = {10.1175/JCLI-D-15-0376.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Atm/Ocean Structure/ Phenomena,Climate change,Climate models,Forcing,Models and modeling,Physical Meteorology and Climatology,Regional effects,Sea level},
month = {nov},
number = {21},
pages = {8521--8539},
title = {{The sea level response to external forcings in historical simulations of CMIP5 climate models}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-15-0376.1},
volume = {28},
year = {2015}
}
@article{Slangen2014,
abstract = {{\textcopyright} 2014. American Geophysical Union. Changes in sea level are driven by a range of natural and anthropogenic forcings. To better understand the response of global mean thermosteric sea level change to these forcings, we compare three observational data sets to experiments of 28 climate models with up to five different forcing scenarios for 1957-2005. We use the preindustrial control runs to determine the internal climate variability. Our analysis shows that anthropogenic greenhouse gas and aerosol forcing are required to explain the magnitude of the observed changes, while natural forcing drives most of the externally forced variability. The experiments that include anthropogenic and natural forcings capture the observed increased trend toward the end of the twentieth century best. The observed changes can be explained by scaling the natural-only experiment by 0.70 ± 0.30 and the anthropogenic-only experiment (including opposing forcing from greenhouse gases and aerosols) by 1.08 ± 0.13 (±2$\sigma$).},
author = {Slangen, Aim{\'{e}}e B.A. and Church, John A. and Zhang, Xuebin and Monselesan, Didier},
doi = {10.1002/2014GL061356},
issn = {19448007},
journal = {Geophysical Research Letters},
keywords = {CMIP5,detection {\&} attribution,sea‐level change},
month = {aug},
number = {16},
pages = {5951--5959},
publisher = {Wiley-Blackwell},
title = {{Detection and attribution of global mean thermosteric sea level change}},
url = {http://doi.wiley.com/10.1002/2014GL061356},
volume = {41},
year = {2014}
}
@article{Slangen2017a,
abstract = {AbstractSea level change is one of the major consequences of climate change and is projected to affect coastal communities around the world. Here, global mean sea level (GMSL) change estimated by 12 climate models from phase 5 of the World Climate Research Programme's Climate Model Intercomparison Project (CMIP5) is compared to observational estimates for the period 1900–2015. Observed and simulated individual contributions to GMSL change (thermal expansion, glacier mass change, ice sheet mass change, landwater storage change) are analyzed and compared to observed GMSL change over the period 1900–2007 using tide gauge reconstructions, and over the period 1993–2015 using satellite altimetry estimates. The model-simulated contributions explain 50{\%} ± 30{\%} (uncertainties 1.65$\sigma$ unless indicated otherwise) of the mean observed change from 1901–20 to 1988–2007. Based on attributable biases between observations and models, a number of corrections are proposed, which result in an improved explanation of 75{\%} ± 38{\%} o...},
author = {Slangen, Aim{\'{e}}e B. A. and Meyssignac, Benoit and Agosta, Cecile and Champollion, Nicolas and Church, John A. and Fettweis, Xavier and Ligtenberg, Stefan R. M. and Marzeion, Ben and Melet, Angelique and Palmer, Matthew D. and Richter, Kristin and Roberts, Christopher D. and Spada, Giorgio},
doi = {10.1175/JCLI-D-17-0110.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {nov},
number = {21},
pages = {8539--8563},
title = {{Evaluating Model Simulations of Twentieth-Century Sea Level Rise. Part I: Global Mean Sea Level Change}},
volume = {30},
year = {2017}
}
@article{Slater2020a,
author = {Slater, Thomas and Hogg, Anna E. and Mottram, Ruth},
doi = {10.1038/s41558-020-0893-y},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {oct},
number = {10},
pages = {879--881},
title = {{Ice-sheet losses track high-end sea-level rise projections}},
url = {https://www.nature.com/articles/s41558-020-0893-y},
volume = {10},
year = {2020}
}
@article{doi:10.1002/2014MS000363,
abstract = {Abstract High-resolution global climate modeling holds the promise of capturing planetary-scale climate modes and small-scale (regional and sometimes extreme) features simultaneously, including their mutual interaction. This paper discusses a new state-of-the-art high-resolution Community Earth System Model (CESM) simulation that was performed with these goals in mind. The atmospheric component was at 0.25° grid spacing, and ocean component at 0.1°. One hundred years of “present-day” simulation were completed. Major results were that annual mean sea surface temperature (SST) in the equatorial Pacific and El-Ni{\~{n}}o Southern Oscillation variability were well simulated compared to standard resolution models. Tropical and southern Atlantic SST also had much reduced bias compared to previous versions of the model. In addition, the high resolution of the model enabled small-scale features of the climate system to be represented, such as air-sea interaction over ocean frontal zones, mesoscale systems generated by the Rockies, and Tropical Cyclones. Associated single component runs and standard resolution coupled runs are used to help attribute the strengths and weaknesses of the fully coupled run. The high-resolution run employed 23,404 cores, costing 250 thousand processor-hours per simulated year and made about two simulated years per day on the NCAR-Wyoming supercomputer “Yellowstone.”},
author = {Small, R Justin and Bacmeister, Julio and Bailey, David and Baker, Allison and Bishop, Stuart and Bryan, Frank and Caron, Julie and Dennis, John and Gent, Peter and Hsu, Hsiao-ming and Jochum, Markus and Lawrence, David and Mu{\~{n}}oz, Ernesto and DiNezio, Pedro and Scheitlin, Tim and Tomas, Robert and Tribbia, Joseph and Tseng, Yu-heng and Vertenstein, Mariana},
doi = {10.1002/2014MS000363},
journal = {Journal of Advances in Modeling Earth Systems},
keywords = {CESM,climate modeling,high resolution},
number = {4},
pages = {1065--1094},
title = {{A new synoptic scale resolving global climate simulation using the Community Earth System Model}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2014MS000363},
volume = {6},
year = {2014}
}
@article{Small2015,
author = {Small, R. Justin and Curchitser, Enrique and Hedstrom, Katherine and Kauffman, Brian and Large, William G.},
doi = {10.1175/JCLI-D-15-0192.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {dec},
number = {23},
pages = {9409--9432},
title = {{The Benguela Upwelling System: Quantifying the Sensitivity to Resolution and Coastal Wind Representation in a Global Climate Model}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-15-0192.1},
volume = {28},
year = {2015}
}
@article{os-10-29-2014,
author = {Smeed, D A and McCarthy, G D and Cunningham, S A and Frajka-Williams, E and Rayner, D and Johns, W E and Meinen, C S and Baringer, M O and Moat, B I and Duchez, A and Bryden, H L},
doi = {10.5194/os-10-29-2014},
journal = {Ocean Science},
number = {1},
pages = {29--38},
title = {{Observed decline of the Atlantic meridional overturning circulation 2004–2012}},
url = {https://www.ocean-sci.net/10/29/2014/},
volume = {10},
year = {2014}
}
@article{Smeed2018a,
abstract = {Abstract The Atlantic Meridional Overturning Circulation (AMOC) is responsible for a variable and climatically important northward transport of heat. Using data from an array of instruments that span the Atlantic at 26°N, we show that the AMOC has been in a state of reduced overturning since 2008 as compared to 2004?2008. This change of AMOC state is concurrent with other changes in the North Atlantic such as a northward shift and broadening of the Gulf Stream and altered patterns of heat content and sea surface temperature. These changes resemble the response to a declining AMOC predicted by coupled climate models. Concurrent changes in air-sea fluxes close to the western boundary reveal that the changes in ocean heat transport and sea surface temperature have altered the pattern of ocean-atmosphere heat exchange over the North Atlantic. These results provide strong observational evidence that the AMOC is a major factor in decadal-scale variability of North Atlantic climate.},
annote = {doi: 10.1002/2017GL076350},
author = {Smeed, D A and Josey, S A and Beaulieu, C and Johns, W E and Moat, B I and Frajka-Williams, E and Rayner, D and Meinen, C S and Baringer, M O and Bryden, H L and McCarthy, G D},
doi = {10.1002/2017GL076350},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {AMOC,Atlantic,circulation,overturning},
month = {jan},
number = {3},
pages = {1527--1533},
publisher = {Wiley-Blackwell},
title = {{The North Atlantic Ocean Is in a State of Reduced Overturning}},
url = {https://doi.org/10.1002/2017GL076350},
volume = {45},
year = {2018}
}
@article{Smith2016a,
abstract = {The rate of global mean surface temperature (GMST) warming has slowed this century despite the increasing concentrations of greenhouse gases. Climate model experiments1, 2, 3, 4 show that this slowdown was largely driven by a negative phase of the Pacific Decadal Oscillation (PDO), with a smaller external contribution from solar variability, and volcanic and anthropogenic aerosols5, 6. The prevailing view is that this negative PDO occurred through internal variability7, 8, 9, 10, 11. However, here we show that coupled models from the Fifth Coupled Model Intercomparison Project robustly simulate a negative PDO in response to anthropogenic aerosols implying a potentially important role for external human influences. The recovery from the eruption of Mount Pinatubo in 1991 also contributed to the slowdown in GMST trends. Our results suggest that a slowdown in GMST trends could have been predicted in advance, and that future reduction of anthropogenic aerosol emissions, particularly from China, would promote a positive PDO and increased GMST trends over the coming years. Furthermore, the overestimation of the magnitude of recent warming by models is substantially reduced by using detection and attribution analysis to rescale their response to external factors, especially cooling following volcanic eruptions. Improved understanding of external influences on climate is therefore crucial to constrain near-term climate predictions.},
author = {Smith, Doug M. and Booth, Ben B.B. and Dunstone, Nick J. and Eade, Rosie and Hermanson, Leon and Jones, Gareth S. and Scaife, Adam A. and Sheen, Katy L. and Thompson, Vikki},
doi = {10.1038/nclimate3058},
isbn = {1758-678X},
issn = {17586798},
journal = {Nature Climate Change},
number = {10},
pages = {936--940},
title = {{Role of volcanic and anthropogenic aerosols in the recent global surface warming slowdown}},
volume = {6},
year = {2016}
}
@article{Smith2020b,
abstract = {Abstract. The effective radiative forcing, which includes the instantaneous forcing plus adjustments from the atmosphere and surface, has emerged as the key metric of evaluating human and natural influence on the climate. We evaluate effective radiative forcing and adjustments in 17 contemporary climate models that are participating in the Coupled Model Intercomparison Project (CMIP6) and have contributed to the Radiative Forcing Model Intercomparison Project (RFMIP). Present-day (2014) global-mean anthropogenic forcing relative to pre-industrial (1850) levels from climate models stands at 2.00 (±0.23) W m−2, comprised of 1.81 (±0.09) W m−2 from CO2, 1.08 (± 0.21) W m−2 from other well-mixed greenhouse gases, −1.01 (± 0.23) W m−2 from aerosols and −0.09 (±0.13) W m−2 from land use change. Quoted uncertainties are 1 standard deviation across model best estimates, and 90 {\%} confidence in the reported forcings, due to internal variability, is typically within 0.1 W m−2. The majority of the remaining 0.21 W m−2 is likely to be from ozone. In most cases, the largest contributors to the spread in effective radiative forcing (ERF) is from the instantaneous radiative forcing (IRF) and from cloud responses, particularly aerosol–cloud interactions to aerosol forcing. As determined in previous studies, cancellation of tropospheric and surface adjustments means that the stratospherically adjusted radiative forcing is approximately equal to ERF for greenhouse gas forcing but not for aerosols, and consequentially, not for the anthropogenic total. The spread of aerosol forcing ranges from −0.63 to −1.37 W m−2, exhibiting a less negative mean and narrower range compared to 10 CMIP5 models. The spread in 4×CO2 forcing has also narrowed in CMIP6 compared to 13 CMIP5 models. Aerosol forcing is uncorrelated with climate sensitivity. Therefore, there is no evidence to suggest that the increasing spread in climate sensitivity in CMIP6 models, particularly related to high-sensitivity models, is a consequence of a stronger negative present-day aerosol forcing and little evidence that modelling groups are systematically tuning climate sensitivity or aerosol forcing to recreate observed historical warming.},
author = {Smith, Christopher J. and Kramer, Ryan J. and Myhre, Gunnar and Alterskj{\ae}r, Kari and Collins, William and Sima, Adriana and Boucher, Olivier and Dufresne, Jean-Louis and Nabat, Pierre and Michou, Martine and Yukimoto, Seiji and Cole, Jason and Paynter, David and Shiogama, Hideo and O'Connor, Fiona M. and Robertson, Eddy and Wiltshire, Andy and Andrews, Timothy and Hannay, C{\'{e}}cile and Miller, Ron and Nazarenko, Larissa and Kirkev{\aa}g, Alf and Olivi{\'{e}}, Dirk and Fiedler, Stephanie and Lewinschal, Anna and Mackallah, Chloe and Dix, Martin and Pincus, Robert and Forster, Piers M.},
doi = {10.5194/acp-20-9591-2020},
issn = {1680-7324},
journal = {Atmospheric Chemistry and Physics},
month = {aug},
number = {16},
pages = {9591--9618},
title = {{Effective radiative forcing and adjustments in CMIP6 models}},
url = {https://acp.copernicus.org/articles/20/9591/2020/},
volume = {20},
year = {2020}
}
@article{Snow2017,
abstract = {West Antarctic Ice Sheet loss is a significant contributor to sea level rise. While the ice loss is thought to be triggered by fluctuations in oceanic heat at the ice shelf bases, ice sheet response to ocean variability remains poorly understood. Using a synchronously coupled ice-ocean model permitting grounding line migration, this study evaluates the response of an ice sheet to periodic variations in ocean forcing. Resulting oscillations in grounded ice volume amplitude is shown to grow as a nonlinear function of ocean forcing period. This implies that slower oscillations in climatic forcing are disproportionately important to ice sheets. The ice shelf residence time offers a critical time scale, above which the ice response amplitude is a linear function of ocean forcing period and below which it is quadratic. These results highlight the sensitivity of West Antarctic ice streams to perturbations in heat fluxes occurring at decadal time scales.},
author = {Snow, K. and Goldberg, D. N. and Holland, P. R. and Jordan, J. R. and Arthern, R. J. and Jenkins, A.},
doi = {10.1002/2017GL075745},
issn = {00948276},
journal = {Geophysical Research Letters},
keywords = {climate variability,ice sheet response,ice-ocean model,synchronous coupling},
month = {dec},
number = {23},
pages = {11878--11885},
title = {{The Response of Ice Sheets to Climate Variability}},
url = {http://doi.wiley.com/10.1002/2017GL075745},
volume = {44},
year = {2017}
}
@article{Solman2016,
abstract = {In this study, a set of five reanalysis datasets [ERA-Interim, NCEP–DOE AMIP-II reanalysis (R2), MERRA, the Twentieth Century Reanalysis (20CR), and the CFS Reanalysis (CFSR)] is used to provide a robust estimation of precipitation change in the middle-to-high latitudes of the Southern Hemisphere during the last three decades. Based on several metrics accounting for the eddy activity and moisture availability, an attempt is also made to identify the dynamical mechanisms triggering these changes during extended summer and winter seasons. To that aim, a weighted reanalysis ensemble is built using the inverse of the variance as weighting factors for each variable. Results showed that the weighted reanalysis ensemble reproduced the observed precipitation changes at high and middle latitudes during the two seasons, as depicted by the GPCP dataset. For the extended summer season, precipitation changes were dynamically consistent with changes in the eddy activity, attributed mostly to ozone depletion. For the extended winter season, the eddy activity and moisture availability both contributed to the precipitation changes, with the increased concentration of greenhouse gases being the main driver of the climate change signal.},
author = {Solman, Silvina A. and Orlanski, Isidoro},
doi = {10.1175/JCLI-D-15-0588.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {mar},
number = {5},
pages = {1673--1687},
title = {{Climate Change over the Extratropical Southern Hemisphere: The Tale from an Ensemble of Reanalysis Datasets}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-15-0588.1},
volume = {29},
year = {2016}
}
@article{doi:10.1175/JCLI-D-16-0034.1,
abstract = { AbstractIt has been suggested that changes in the atmospheric circulation caused by anthropogenic forcings are highly uncertain, owing to the large natural variability intrinsic to the system. Here, to assess the statistical significance of such changes for the midlatitude, large-scale atmospheric circulation of the Southern Hemisphere, a new 40-member ensemble of integrations, from 1920 to 2080, of the Community Earth System Model, version 5, is analyzed together with a companion 1800-yr-long preindustrial control integration of the same fully coupled model. For simplicity, only the latitudinal position and the strength of the zonal-mean eddy-driven jet are considered. Given the large year-to-year variability of these jet properties, this paper focuses on their decadal averages, which reflect the more slowly varying climate state. The analysis herein reveals that the forced response in such decadal averages easily emerges from the natural variability, with only a few model integrations typically needed to establish statistical significance. In particular, a forced summertime poleward shift of the jet in the latter part of the twentieth century and a strengthening of the jet during the twenty-first century in all seasons of the year are found. Contrasting these with changes in the southern annular mode, this confirms earlier studies demonstrating that such a mode is unable to distinguish different structural changes in the midlatitude jet. },
author = {Solomon, Abraham and Polvani, L M},
doi = {10.1175/JCLI-D-16-0034.1},
journal = {Journal of Climate},
number = {9},
pages = {3463--3470},
title = {{Highly Significant Responses to Anthropogenic Forcings of the Midlatitude Jet in the Southern Hemisphere}},
url = {https://doi.org/10.1175/JCLI-D-16-0034.1},
volume = {29},
year = {2016}
}
@article{ISI:000431799700001,
abstract = {The Southern Hemisphere (SH) zonal-mean circulation change in response to Antarctic ozone depletion is re-visited by examining a set of the latest model simulations archived for the Chemistry-Climate Model Initiative (CCMI) project. All models reasonably well reproduce Antarctic ozone depletion in the late 20th century. The related SH-summer circulation changes, such as a poleward intensification of westerly jet and a poleward expansion of the Hadley cell, are also well captured. All experiments exhibit quantitatively the same multi-model mean trend, irrespective of whether the ocean is coupled or prescribed. Results are also quantitatively similar to those derived from the Coupled Model Intercomparison Project phase 5 (CMIP5) high-top model simulations in which the stratospheric ozone is mostly prescribed with monthly- and zonally-averaged values. These results suggest that the ozone-hole-induced SH-summer circulation changes are robust across the models irrespective of the specific chemistry-atmosphere-ocean coupling.},
address = {TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND},
author = {Son, Seok-Woo and Han, Bo-Reum and Garfinkel, Chaim I and Kim, Seo-Yeon and Park, Rokjin and Abraham, N Luke and Akiyoshi, Hideharu and Archibald, Alexander T and Butchart, N and Chipperfield, Martyn P and Dameris, Martin and Deushi, Makoto and Dhomse, Sandip S and Hardiman, Steven C and J{\"{o}}ckel, Patrick and Kinnison, Douglas and Michou, Martine and Morgenstern, Olaf and O'Connor, Fiona M and Oman, Luke D and Plummer, David A and Pozzer, Andrea and Revell, Laura E and Rozanov, Eugene and Stenke, Andrea and Stone, Kane and Tilmes, Simone and Yamashita, Yousuke and Zeng, Guang},
doi = {10.1088/1748-9326/aabf21},
issn = {1748-9326},
journal = {Environmental Research Letters},
keywords = {Southern Hemisphere jet trends,c,ozone depletion},
month = {may},
number = {5},
pages = {054024},
publisher = {IOP PUBLISHING LTD},
title = {{Tropospheric jet response to Antarctic ozone depletion: An update with Chemistry-Climate Model Initiative (CCMI) models}},
type = {Article},
url = {https://iopscience.iop.org/article/10.1088/1748-9326/aabf21},
volume = {13},
year = {2018}
}
@article{Song2016,
abstract = {Arctic sea ice extent has been declining in recent decades. There is ongoing debate on the contribution of natural internal variability to recent and future Arctic sea ice changes. In this study, we contrast the trends in the forced and unforced simulations of carefully selected global climate models with the extended observed Arctic sea ice records. The results suggest that the natural variability explains no more than 42.3{\%} of the observed September sea ice extent trend during 35 a (1979–2013) satellite observations, which is comparable to the results of the observed sea ice record extended back to 1953 (61 a, less than 48.5{\%} natural variability). This reinforces the evidence that anthropogenic forcing plays a substantial role in the observed decline of September Arctic sea ice in recent decades. The magnitude of both positive and negative trends induced by the natural variability in the unforced simulations is slightly enlarged in the context of increasing greenhouse gases in the 21st century. However, the ratio between the realizations of positive and negative trends change has remained steady, which enforces the standpoint that external forcing will remain the principal determiner of the decreasing Arctic sea ice extent trend in the future.},
author = {Song, Mirong and Wei, Lixin and Wang, Zhenzhan},
doi = {10.1007/s13131-016-0854-5},
issn = {1869-1099},
journal = {Acta Oceanologica Sinica},
number = {5},
pages = {49--53},
title = {{Quantifying the contribution of natural variability to September Arctic sea ice decline}},
url = {https://doi.org/10.1007/s13131-016-0854-5},
volume = {35},
year = {2016}
}
@article{Sousa2018,
abstract = {Blocking occurrence and its impacts on European temperature have been studied in the last decade. However, most previous studies on blocking impacts have focused on winter only, disregarding its fingerprint in summer and differences with other synoptic patterns that also trigger temperature extremes. In this work, we provide a clear distinction between high-latitude blocking and sub-tropical ridges occurring in three sectors of the Euro-Atlantic region, describing their climatology and consequent impacts on European temperature during both winter and summer. Winter blocks (ridges) are generally associated to colder (warmer) than average conditions over large regions of Europe, in some areas with anomalies larger than 5 °C, particularly for the patterns occurring in the Atlantic and Central European sectors. During summer, there is a more regional response characterized by above average temperature for both blocking and ridge patterns, especially those occurring in continental areas, although negative temperature anomalies persist in southernmost areas during blocking. An objective analysis of the different forcing mechanisms associated to each considered weather regime has been performed, quantifying the importance of the following processes in causing the temperature anomalies: horizontal advection, vertical advection and diabatic heating. While during winter advection processes tend to be more relevant to explain temperature responses, in summer radiative heating under enhanced insolation plays a crucial role for both blocking and ridges. Finally, the changes in the distributions of seasonal temperature and in the frequencies of extreme temperature indices were also examined for specific areas of Europe. Winter blocking and ridge patterns are key drivers in the occurrence of regional cold and warm extreme temperatures, respectively. In summer, they are associated with substantial changes in the frequency of extremely warm days, but with different signatures in southern Europe. We conclude that there has been some misusage of the traditional blocking definition in the attribution of extreme events.},
author = {Sousa, Pedro M and Trigo, Ricardo M and Barriopedro, David and Soares, Pedro M M and Santos, Jo{\~{a}}o A},
doi = {10.1007/s00382-017-3620-2},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {1},
pages = {457--477},
title = {{European temperature responses to blocking and ridge regional patterns}},
url = {https://doi.org/10.1007/s00382-017-3620-2},
volume = {50},
year = {2018}
}
@article{doi:10.1175/JCLI-D-13-00599.1,
abstract = { AbstractA robust response of South Asian summer monsoon precipitation to increasing greenhouse gas concentration during the twenty-first century is identified in 23 models from phase 5 of the Coupled Model Intercomparison Project. The pattern of this response is dominated by two dipole structures, one oriented east–west across the Maritime Continent and another oriented north–south across the equatorial Indian Ocean, and is characterized by enhanced rainfall in South Asia and diminished rainfall over the Maritime Continent. The response is robust in the sense that the same pattern has a trend that is within one standard deviation of the trend of other models. Another robust feature is that the variability of precipitation about this trend decreases in all models, and hence becomes more detectable with time. The response is negligible compared to internal variability during the twentieth century but emerges clearly by the middle of the twenty-first century. Although the pattern as a whole is robust, the response over small land areas such as India has more uncertainty, with some models disagreeing even with the sign of the response. },
author = {Srivastava, Abhishekh K and DelSole, Timothy},
doi = {10.1175/JCLI-D-13-00599.1},
journal = {Journal of Climate},
number = {20},
pages = {7849--7860},
title = {{Robust Forced Response in South Asian Summer Monsoon in a Future Climate}},
url = {https://doi.org/10.1175/JCLI-D-13-00599.1},
volume = {27},
year = {2014}
}
@article{Staten2018,
author = {Staten, Paul W. and Lu, Jian and Grise, Kevin M. and Davis, Sean M. and Birner, Thomas},
doi = {10.1038/s41558-018-0246-2},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {sep},
number = {9},
pages = {768--775},
title = {{Re-examining tropical expansion}},
url = {http://www.nature.com/articles/s41558-018-0246-2},
volume = {8},
year = {2018}
}
@article{Staten2020,
abstract = {Over the past 15 years, numerous studies have suggested that the sinking branches of Earth's Hadley circulation and the associated subtropical dry zones have shifted poleward over the late twentieth century and early twenty-first century. Early estimates of this tropical widening from satellite observations and reanalyses varied from 0.25° to 3° latitude per decade, while estimates from global climate models show widening at the lower end of the observed range. In 2016, two working groups, the U.S. Climate Variability and Predictability (CLIVAR) working group on the Changing Width of the Tropical Belt and the International Space Science Institute (ISSI) Tropical Width Diagnostics Intercomparison Project, were formed to synthesize current understanding of the magnitude, causes, and impacts of the recent tropical widening evident in observations. These working groups concluded that the large rates of observed tropical widening noted by earlier studies resulted from their use of metrics that poorly capture changes in the Hadley circulation, or from the use of reanalyses that contained spurious trends. Accounting for these issues reduces the range of observed expansion rates to 0.25°–0.5° latitude decade‒1—within the range from model simulations. Models indicate that most of the recent Northern Hemisphere tropical widening is consistent with natural variability, whereas increasing greenhouse gases and decreasing stratospheric ozone likely played an important role in Southern Hemisphere widening. Whatever the cause or rate of expansion, understanding the regional impacts of tropical widening requires additional work, as different forcings can produce different regional patterns of widening.},
author = {Staten, Paul W. and Grise, Kevin M. and Davis, Sean M. and Karnauskas, Kristopher B. and Waugh, Darryn W. and Maycock, Amanda C. and Fu, Qiang and Cook, Kerry and Adam, Ori and Simpson, Isla R. and Allen, Robert J and Rosenlof, Karen and Chen, Gang and Ummenhofer, Caroline C. and Quan, Xiao-Wei and Kossin, James P. and Davis, Nicholas A. and Son, Seok-Woo},
doi = {10.1175/BAMS-D-19-0047.1},
issn = {0003-0007},
journal = {Bulletin of the American Meteorological Society},
month = {jun},
number = {6},
pages = {E897--E904},
title = {{Tropical Widening: From Global Variations to Regional Impacts}},
url = {https://journals.ametsoc.org/bams/article/101/6/E897/345575/Tropical-Widening-From-Global-Variations-to},
volume = {101},
year = {2020}
}
@article{Steinig2018,
author = {Steinig, S. and Harla{\ss}, J. and Park, W. and Latif, M.},
doi = {10.1038/s41598-018-20904-1},
issn = {2045-2322},
journal = {Scientific Reports},
month = {dec},
number = {1},
pages = {2569},
title = {{Sahel rainfall strength and onset improvements due to more realistic Atlantic cold tongue development in a climate model}},
url = {http://www.nature.com/articles/s41598-018-20904-1},
volume = {8},
year = {2018}
}
@article{Steinman988,
abstract = {Which recent climate changes have been forced by greenhouse gas emissions, and which have been natural fluctuations of the climate system? Steinman et al. combined observational data and a large collection of climate models to assess the Northern Hemisphere climate over the past 150 years (see the Perspective by Booth). At various points in time, the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation have played particularly large roles in producing temperature trends. Their effects have combined to cause the apparent pause in warming at the beginning of the 21st century, known as the warming {\{}$\backslash$textquotedblleft{\}}hiatus.{\{}$\backslash$textquotedblright{\}} This pause is projected to end in the near future as temperatures resume their upward climb.Science, this issue p. 988; see also p. 952 The recent slowdown in global warming has brought into question the reliability of climate model projections of future temperature change and has led to a vigorous debate over whether this slowdown is the result of naturally occurring, internal variability or forcing external to Earth{\{}$\backslash$textquoteright{\}}s climate system. To address these issues, we applied a semi-empirical approach that combines climate observations and model simulations to estimate Atlantic- and Pacific-based internal multidecadal variability (termed {\{}$\backslash$textquotedblleft{\}}AMO{\{}$\backslash$textquotedblright{\}} and {\{}$\backslash$textquotedblleft{\}}PMO,{\{}$\backslash$textquotedblright{\}} respectively). Using this method, the AMO and PMO are found to explain a large proportion of internal variability in Northern Hemisphere mean temperatures. Competition between a modest positive peak in the AMO and a substantially negative-trending PMO are seen to produce a slowdown or {\{}$\backslash$textquotedblleft{\}}false pause{\{}$\backslash$textquotedblright{\}} in warming of the past decade.},
author = {Steinman, Byron A and Mann, Michael E and Miller, Sonya K},
doi = {10.1126/science.1257856},
issn = {0036-8075},
journal = {Science},
number = {6225},
pages = {988--991},
publisher = {American Association for the Advancement of Science},
title = {{Atlantic and Pacific multidecadal oscillations and Northern Hemisphere temperatures}},
url = {http://science.sciencemag.org/content/347/6225/988},
volume = {347},
year = {2015}
}
@article{Stendardo2012,
author = {Stendardo, I. and Gruber, N.},
doi = {10.1029/2012JC007909},
issn = {01480227},
journal = {Journal of Geophysical Research: Oceans},
keywords = {North Atlantic,climate change,deoxygenation,heat content,oxygen changes,water masses},
month = {nov},
number = {C11},
pages = {C11004},
publisher = {Wiley-Blackwell},
title = {{Oxygen trends over five decades in the North Atlantic}},
url = {http://doi.wiley.com/10.1029/2012JC007909},
volume = {117},
year = {2012}
}
@article{Steptoe2016,
author = {Steptoe, H. and Wilcox, L. J. and Highwood, E. J.},
doi = {10.1002/2015JD024218},
issn = {2169897X},
journal = {Journal of Geophysical Research: Atmospheres},
month = {sep},
number = {17},
pages = {10029--10042},
title = {{Is there a robust effect of anthropogenic aerosols on the Southern Annular Mode?}},
url = {http://doi.wiley.com/10.1002/2015JD024218},
volume = {121},
year = {2016}
}
@article{Stern2014,
abstract = {We test for causality between radiative forcing and temperature using multivariate time series models and Granger causality tests that are robust to the non-stationary (trending) nature of global climate data. We find that both natural and anthropogenic forcings cause temperature change and also that temperature causes greenhouse gas concentration changes. Although the effects of greenhouse gases and volcanic forcing are robust across model specifications, we cannot detect any effect of black carbon on temperature, the effect of changes in solar irradiance is weak, and the effect of anthropogenic sulfate aerosols may be only around half that usually attributed to them. {\textcopyright} 2013 Springer Science+Business Media Dordrecht.},
author = {Stern, David I. and Kaufmann, Robert K.},
doi = {10.1007/s10584-013-1007-x},
issn = {0165-0009},
journal = {Climatic Change},
month = {jan},
number = {1-2},
pages = {257--269},
title = {{Anthropogenic and natural causes of climate change}},
url = {http://link.springer.com/10.1007/s10584-013-1007-x},
volume = {122},
year = {2014}
}
@article{Stevenson2012,
abstract = {Changes to the El Ni{\~{n}}o/Southern Oscillation (ENSO) and its atmospheric teleconnections under climate change are investigated using simulations conducted for the Coupled Model Intercomparison Project (CMIP5). The overall response to CO2increases is determined using 27 models, and the ENSO amplitude change based on the multi-model mean is indistinguishable from zero. However, changes between ensembles run with a given model are sometimes significant: for four of the eleven models having ensemble sizes larger than three, the 21st century change to ENSO amplitude is statistically significant. In these four models, changes to SST and wind stress do not differ substantially from those in the models with no ENSO response, indicating that mean changes are not predictive of the ENSO sensitivity to climate change. Also, ocean vertical stratification is less (more) sensitive to CO2in models where ENSO strengthens (weakens), likely due to a regulation of the subsurface temperature structure by ENSO-related poleward heat transport. Atmospheric teleconnections also show differences between models where ENSO amplitude does and does not respond to climate change; in the former case El Ni{\~{n}}o/La Ni{\~{n}}a-related sea level pressure anomalies strengthen with CO2, and in the latter they weaken and shift polewards and eastwards. These results illustrate the need for large ensembles to isolate significant ENSO climate change responses, and for future work on diagnosing the dynamical causes of inter-model teleconnection differences.},
author = {Stevenson, S. L.},
doi = {10.1029/2012GL052759},
isbn = {00948276 (ISSN)},
issn = {00948276},
journal = {Geophysical Research Letters},
number = {17},
pages = {1--5},
title = {{Significant changes to ENSO strength and impacts in the twenty-first century: Results from CMIP5}},
volume = {39},
year = {2012}
}
@article{Stevenson2017,
abstract = {The El Ni{\~{n}}o/Southern Oscillation (ENSO) exhibits considerable differences between the evolution of individual El Ni{\~{n}}o and La Ni{\~{n}}a events (‘ENSO diversity'), with significant implications for impacts studies. However, the degree to which external forcing may affect ENSO diversity is not well understood, due to both internal variability and potentially compensatory contributions from multiple forcings. The Community Earth System Model Last Millennium Ensemble (CESM LME) provides an ideal testbed for studying the sensitivity of twentieth century ENSO to forced climate changes, as it contains many realizations of the 850–2005 period with differing combinations of forcings. Metrics of ENSO amplitude and diversity are compared across LME simulations, and although forced changes to ENSO amplitude are generally small, forced changes to diversity are often detectable. Anthropogenic changes to greenhouse gas and ozone/aerosol emissions modify the persistence of Eastern and Central Pacific El Ni{\~{n}}o events, through shifts in the upwelling and zonal advective feedbacks; these influences generally cancel one another over the twentieth century. Other forcings can also be quite important: land use changes amplify Eastern Pacific El Ni{\~{n}}o events via modulating zonal advective heating, and orbital forcing tends to preferentially terminate twentieth century Central Pacific El Ni{\~{n}}o events due to enhanced eastern Pacific cooling during boreal winter and spring. Our results indicate that multiple anthropogenic and natural forcings can have substantial impacts on ENSO diversity, and suggest that correctly representing the net ENSO diversity response to climate change will depend on the precise balance between all these influences.},
author = {Stevenson, Samantha L. and Capotondi, Antonietta and Fasullo, John and Otto-Bliesner, Bette},
doi = {10.1007/s00382-017-3573-5},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jun},
number = {12},
pages = {7359--7374},
title = {{Forced changes to twentieth century ENSO diversity in a last Millennium context}},
url = {http://link.springer.com/10.1007/s00382-017-3573-5},
volume = {52},
year = {2019}
}
@article{Stolpe2020,
abstract = {Global mean temperature change simulated by climate models deviates from the observed temperature increase during decadal-scale periods in the past. In particular, warming during the ‘global warming hiatus' in the early twenty-first century appears overestimated in CMIP5 and CMIP6 multi-model means. We examine the role of equatorial Pacific variability in these divergences since 1950 by comparing 18 studies that quantify the Pacific contribution to the ‘hiatus' and earlier periods and by investigating the reasons for differing results. During the ‘global warming hiatus' from 1992 to 2012, the estimated contributions differ by a factor of five, with multiple linear regression approaches generally indicating a smaller contribution of Pacific variability to global temperature than climate model experiments where the simulated tropical Pacific sea surface temperature (SST) or wind stress anomalies are nudged towards observations. These so-called pacemaker experiments suggest that the ‘hiatus' is fully explained and possibly over-explained by Pacific variability. Most of the spread across the studies can be attributed to two factors: neglecting the forced signal in tropical Pacific SST, which is often the case in multiple regression studies but not in pacemaker experiments, underestimates the Pacific contribution to global temperature change by a factor of two during the ‘hiatus'; the sensitivity with which the global temperature responds to Pacific variability varies by a factor of two between models on a decadal time scale, questioning the robustness of single model pacemaker experiments. Once we have accounted for these factors, the CMIP5 mean warming adjusted for Pacific variability reproduces the observed annual global mean temperature closely, with a correlation coefficient of 0.985 from 1950 to 2018. The CMIP6 ensemble performs less favourably but improves if the models with the highest transient climate response are omitted from the ensemble mean.},
author = {Stolpe, Martin B. and Cowtan, Kevin and Medhaug, Iselin and Knutti, Reto},
doi = {10.1007/s00382-020-05493-y},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jan},
number = {1-2},
pages = {613--634},
title = {{Pacific variability reconciles observed and modelled global mean temperature increase since 1950}},
url = {http://link.springer.com/10.1007/s00382-020-05493-y},
volume = {56},
year = {2021}
}
@article{Stone2016,
abstract = {{\textcopyright} 2015, The Author(s). Despite being a well-established research field, the detection and attribution of observed climate change to anthropogenic forcing is not yet provided as a climate service. One reason for this is the lack of a methodology for performing tailored detection and attribution assessments on a rapid time scale. Here we develop such an approach, based on the translation of quantitative analysis into the “confidence” language employed in recent Assessment Reports of the Intergovernmental Panel on Climate Change. While its systematic nature necessarily ignores some nuances examined in detailed expert assessments, the approach nevertheless goes beyond most detection and attribution studies in considering contributors to building confidence such as errors in observational data products arising from sparse monitoring networks. When compared against recent expert assessments, the results of this approach closely match those of the existing assessments. Where there are small discrepancies, these variously reflect ambiguities in the details of what is being assessed, reveal nuances or limitations of the expert assessments, or indicate limitations of the accuracy of the sort of systematic approach employed here. Deployment of the method on 116 regional assessments of recent temperature and precipitation changes indicates that existing rules of thumb concerning the detectability of climate change ignore the full range of sources of uncertainty, most particularly the importance of adequate observational monitoring.},
author = {Stone, D.A. and Hansen, G.},
doi = {10.1007/s00382-015-2909-2},
journal = {Climate Dynamics},
number = {5-6},
pages = {1399--1415},
title = {{Rapid systematic assessment of the detection and attribution of regional anthropogenic climate change}},
volume = {47},
year = {2016}
}
@article{cp-12-1919-2016,
author = {Stone, E J and Capron, E and Lunt, D J and Payne, A J and Singarayer, J S and Valdes, P J and Wolff, E W},
doi = {10.5194/cp-12-1919-2016},
journal = {Climate of the Past},
number = {9},
pages = {1919--1932},
title = {{Impact of meltwater on high-latitude early Last Interglacial climate}},
url = {https://www.clim-past.net/12/1919/2016/},
volume = {12},
year = {2016}
}
@article{Stott2008,
abstract = {An analysis of observed and modeled oceanic salinity changes shows that significant changes of salinity, which are predicted in the World's oceans as a result of human influence, are beginning to emerge. A significant increase in salinity has been observed in recent decades in the 20N50N latitude band of the Atlantic ocean, although changes at sub-polar latitudes of the Atlantic, and in other ocean basins, are not found to be significant compared to modeled internal variability. An optimal detection analysis of spatial patterns of salinity trends detects a human influence on the observed salinity increases in the Atlantic ocean. These results indicate the growing potential for using observations to constrain important properties of the climate system's response to anthropogenic forcing.},
author = {Stott, Peter A. and Sutton, Rowan T. and Smith, Doug M.},
doi = {10.1029/2008GL035874},
isbn = {0094-8276},
issn = {00948276},
journal = {Geophysical Research Letters},
keywords = {climate change,climate variability,ocean salinity},
month = {nov},
number = {21},
pages = {L21702},
publisher = {Wiley-Blackwell},
title = {{Detection and attribution of Atlantic salinity changes}},
url = {http://doi.wiley.com/10.1029/2008GL035874},
volume = {35},
year = {2008}
}
@article{stouffer2017cmip5,
author = {Stouffer, Ronald J and Eyring, Veronika and Meehl, Gerald A and Bony, Sandrine and Senior, Cath and Stevens, Bj{\"{o}}rn and Taylor, K E},
doi = {10.1175/BAMS-D-15-00013.1},
journal = {Bulletin of the American Meteorological Society},
number = {1},
pages = {95--105},
title = {{CMIP5 scientific gaps and recommendations for CMIP6}},
volume = {98},
year = {2017}
}
@article{Stramma2012,
abstract = {{\textless}p{\textgreater}{\textless}p{\textgreater}{\textless}strong{\textgreater}Abstract.{\textless}/strong{\textgreater} Observations and model runs indicate trends in dissolved oxygen (DO) associated with current and ongoing global warming. However, a large-scale observation-to-model comparison has been missing and is presented here. This study presents a first global compilation of DO measurements covering the last 50 yr. It shows declining upper-ocean DO levels in many regions, especially the tropical oceans, whereas areas with increasing trends are found in the subtropics and in some subpolar regions. For the Atlantic Ocean south of 20° N, the DO history could even be extended back to about 70 yr, showing decreasing DO in the subtropical South Atlantic. The global mean DO trend between 50° S and 50° N at 300 dbar for the period 1960 to 2010 is {\&}ndash;0.066 $\mu$mol kg{\textless}sup{\textgreater}−1{\textless}/sup{\textgreater} yr{\textless}sup{\textgreater}−1{\textless}/sup{\textgreater}. Results of a numerical biogeochemical Earth system model reveal that the magnitude of the observed change is consistent with CO{\textless}sub{\textgreater}2{\textless}/sub{\textgreater}-induced climate change. However, the pattern correlation between simulated and observed patterns of past DO change is negative, indicating that the model does not correctly reproduce the processes responsible for observed regional oxygen changes in the past 50 yr. A negative pattern correlation is also obtained for model configurations with particularly low and particularly high diapycnal mixing, for a configuration that assumes a CO{\textless}sub{\textgreater}2{\textless}/sub{\textgreater}-induced enhancement of the C : N ratios of exported organic matter and irrespective of whether climatological or realistic winds from reanalysis products are used to force the model. Depending on the model configuration the 300 dbar DO trend between 50° S and 50° N is −0.027 to {\&}ndash;0.047 $\mu$mol kg{\textless}sup{\textgreater}−1{\textless}/sup{\textgreater} yr{\textless}sup{\textgreater}−1{\textless}/sup{\textgreater} for climatological wind forcing, with a much larger range of {\&}ndash;0.083 to +0.027 $\mu$mol kg{\textless}sup{\textgreater}−1{\textless}/sup{\textgreater} yr{\textless}sup{\textgreater}−1{\textless}/sup{\textgreater} for different initializations of sensitivity runs with reanalysis wind forcing. Although numerical models reproduce the overall sign and, to some extent, magnitude of observed ocean deoxygenation, this degree of realism does not necessarily apply to simulated regional patterns and the representation of processes involved in their generation. Further analysis of the processes that can explain the discrepancies between observed and modeled DO trends is required to better understand the climate sensitivity of oceanic oxygen fields and predict potential DO changes in the future.{\textless}/p{\textgreater}{\textless}/p{\textgreater}},
author = {Stramma, L. and Oschlies, A. and Schmidtko, S.},
doi = {10.5194/bg-9-4045-2012},
issn = {1726-4189},
journal = {Biogeosciences},
month = {oct},
number = {10},
pages = {4045--4057},
title = {{Mismatch between observed and modeled trends in dissolved upper-ocean oxygen over the last 50 yr}},
url = {https://www.biogeosciences.net/9/4045/2012/},
volume = {9},
year = {2012}
}
@article{doi:10.1029/2012GL052676,
abstract = {The rapid retreat and thinning of the Arctic sea ice cover over the past several decades is one of the most striking manifestations of global climate change. Previous research revealed that the observed downward trend in September ice extent exceeded simulated trends from most models participating in the World Climate Research Programme Coupled Model Intercomparison Project Phase 3 (CMIP3). We show here that as a group, simulated trends from the models contributing to CMIP5 are more consistent with observations over the satellite era (1979–2011). Trends from most ensemble members and models nevertheless remain smaller than the observed value. Pointing to strong impacts of internal climate variability, 16{\%} of the ensemble member trends over the satellite era are statistically indistinguishable from zero. Results from the CMIP5 models do not appear to have appreciably reduced uncertainty as to when a seasonally ice-free Arctic Ocean will be realized.},
author = {Stroeve, Julienne C and Kattsov, Vladimir and Barrett, Andrew and Serreze, Mark and Pavlova, Tatiana and Holland, Marika and Meier, Walter N},
doi = {10.1029/2012GL052676},
journal = {Geophysical Research Letters},
keywords = {Arctic,CMIP5,sea ice},
number = {16},
pages = {L16502},
title = {{Trends in Arctic sea ice extent from CMIP5, CMIP3 and observations}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2012GL052676},
volume = {39},
year = {2012}
}
@article{Strommen2019a,
author = {Strommen, Kristian and Palmer, Tim N.},
doi = {10.1002/qj.3414},
issn = {00359009},
journal = {Quarterly Journal of the Royal Meteorological Society},
month = {jan},
number = {718},
pages = {147--163},
title = {{Signal and noise in regime systems: A hypothesis on the predictability of the North Atlantic Oscillation}},
url = {http://doi.wiley.com/10.1002/qj.3414},
volume = {145},
year = {2019}
}
@article{Stuecker2017b,
abstract = {Abstract The 2016 austral spring was characterized by the lowest Southern Hemisphere (SH) sea ice extent seen in the satellite record (1979 to present) and coincided with anomalously warm surface waters surrounding most of Antarctica. We show that two distinct processes contributed to this event: First, the extreme El Ni{\~{n}}o event peaking in December–February 2015/2016 contributed to pronounced extratropical SH sea surface temperature and sea ice extent anomalies in the eastern Ross, Amundsen, and Bellingshausen Seas that persisted in part until the following 2016 austral spring. Second, internal unforced atmospheric variability of the Southern Annular Mode promoted the exceptional low sea ice extent in November–December 2016. These results suggest that a combination of tropically forced and internal SH atmospheric variability contributed to the unprecedented sea ice decline during the 2016 austral spring, on top of a background of slow changes expected from greenhouse gas and ozone forcing.},
author = {Stuecker, Malte F and Bitz, Cecilia M and Armour, Kyle C},
doi = {10.1002/2017GL074691},
journal = {Geophysical Research Letters},
number = {17},
pages = {9008--9019},
title = {{Conditions leading to the unprecedented low Antarctic sea ice extent during the 2016 austral spring season}},
volume = {44},
year = {2017}
}
@article{Su2017a,
abstract = {Ocean heat content (OHC) evolutions calculated from the data sets (WOA, MyOcean, ORAS4, and SODA) were examined at different depth ranges in this study. According to the OHC changes, the subsurface and deeper ocean (SDO, 300–2000 m) heat content rapidly increased over the world's ocean basins during 1998–2013, indicating significant warming in the SDO during the recent global surface warming hiatus. Almost all the ocean basins warmed up, but with various contributions to the global SDO warming tied to the recent hiatus. The role of the Indian Ocean is particularly important as it has accounted for about 30{\%} of global SDO heat uptake during the hiatus. The combined use of multiple data sets can reveal inconsistencies in SDO warming analysis results, and improve our understanding of the role of the SDO in the recent hiatus. The heat uptake in global SDO during the hiatus was about 2.37, 5.44, 3.75, and 2.44 × 10 22 joules with trends of 0.40, 0.70, 0.77, and 0.48 W m −2 according to WOA, MyOcean, ORAS4, and SODA respectively, presenting obviously inconsistent SDO warming signals. MyOcean shows OHC overestimates in different ocean basins, while ORAS4 presents more reliable SDO OHC analysis. In general, the global SDO has sequestered a significant amount of heat—about 3.50 × 10 22 joules with trends of 0.59 W m −2 on average among the four data sets—during the recent hiatus, demonstrating widespread and significant warming signals in the global SDO. There remain substantial uncertainties and discrepancies, however (especially in the PO and SO), in the available SDO warming information due to insufficient subsurface observation coverage and variations in the data set generation techniques used among different researchers.},
author = {Su, Hua and Wu, Xiangbai and Lu, Wenfang and Zhang, Weiwei and Yan, Xiao Hai},
doi = {10.1002/2016JC012481},
issn = {21699291},
journal = {Journal of Geophysical Research: Oceans},
keywords = {inconsistency,multisource data sets,recent global warming hiatus,subsurface and deeper ocean,warming signals},
month = {oct},
number = {10},
pages = {8182--8195},
title = {{Inconsistent Subsurface and Deeper Ocean Warming Signals During Recent Global Warming and Hiatus}},
url = {http://doi.wiley.com/10.1002/2016JC012481},
volume = {122},
year = {2017}
}
@article{Su2017,
author = {Su, Jingzhi and Zhang, Renhe and Wang, Huijun},
doi = {10.1038/srep43735},
journal = {Scientific Reports},
month = {mar},
pages = {43735},
publisher = {The Author(s)},
title = {{Consecutive record-breaking high temperatures marked the handover from hiatus to accelerated warming}},
url = {http://dx.doi.org/10.1038/srep43735 http://10.0.4.14/srep43735 https://www.nature.com/articles/srep43735{\#}supplementary-information},
volume = {7},
year = {2017}
}
@article{Suarez-Gutierrez2017,
abstract = {{\textcopyright}2017. American Geophysical Union. All Rights Reserved. We explore the extent to which internal variability can reconcile discrepancies between observed and simulated warming in the upper tropical troposphere. We compare all extant radiosonde-based estimates for the period 1958–2014 to simulations from the Coupled Model Intercomparison Project phase 5 multimodel ensemble and the 100 realization Max Planck Institute large ensemble. We consider annual mean temperatures and all available 30-and 15-year trends. Most observed trends fall within the ensemble spread for most of the record, and trends calculated over 15-year periods show better agreement than 15-year trends, with generally larger discrepancies for the older observational products. The simulated amplification of surface warming aloft in the troposphere is consistent with observations, and the linear correlation between surface and simultaneous tropospheric warming trends decreases with trend length. We conclude that trend differences between observations and simulations of tropical tropospheric temperatures are dominated by observational uncertainty and chaotic internal variability rather than by systematic errors in model performance.},
author = {Su{\'{a}}rez-Guti{\'{e}}rrez, L. and Li, C. and Thorne, P.W. and Marotzke, J.},
doi = {10.1002/2017GL073798},
journal = {Geophysical Research Letters},
number = {11},
pages = {5709--5719},
title = {{Internal variability in simulated and observed tropical tropospheric temperature trends}},
volume = {44},
year = {2017}
}
@article{Sun2016,
author = {Sun, Yong and Zhou, Tianjun and Ramstein, Gilles and Contoux, Camille and Zhang, Zhongshi},
doi = {10.1007/s00382-015-2656-4},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {mar},
number = {5-6},
pages = {1437--1457},
title = {{Drivers and mechanisms for enhanced summer monsoon precipitation over East Asia during the mid-Pliocene in the IPSL-CM5A}},
url = {http://link.springer.com/10.1007/s00382-015-2656-4},
volume = {46},
year = {2016}
}
@article{Sun2019,
author = {Sun, Cheng and Li, Jianping and Kucharski, Fred and Xue, Jiaqing and Li, Xiang},
doi = {10.1007/s00382-018-4201-8},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {feb},
number = {3-4},
pages = {1395--1411},
title = {{Contrasting spatial structures of Atlantic Multidecadal Oscillation between observations and slab ocean model simulations}},
url = {http://link.springer.com/10.1007/s00382-018-4201-8},
volume = {52},
year = {2019}
}
@article{Sun2018b,
author = {Sun, Yong and Ramstein, Gilles and Li, Laurent Z. X. and Contoux, Camille and Tan, Ning and Zhou, Tianjun},
doi = {10.1029/2018GL080061},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {nov},
number = {22},
pages = {12523--12533},
title = {{Quantifying East Asian Summer Monsoon Dynamics in the ECP4.5 Scenario With Reference to the Mid‐Piacenzian Warm Period}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GL080061},
volume = {45},
year = {2018}
}
@article{Swart2019a,
author = {Swart, Neil C. and Cole, Jason N. S. and Kharin, Viatcheslav V. and Lazare, Mike and Scinocca, John F. and Gillett, Nathan P. and Anstey, James and Arora, Vivek and Christian, James R. and Hanna, Sarah and Jiao, Yanjun and Lee, Warren G. and Majaess, Fouad and Saenko, Oleg A. and Seiler, Christian and Seinen, Clint and Shao, Andrew and Sigmond, Michael and Solheim, Larry and von Salzen, Knut and Yang, Duo and Winter, Barbara},
doi = {10.5194/gmd-12-4823-2019},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {nov},
number = {11},
pages = {4823--4873},
title = {{The Canadian Earth System Model version 5 (CanESM5.0.3)}},
url = {https://gmd.copernicus.org/articles/12/4823/2019/},
volume = {12},
year = {2019}
}
@article{Swart2018,
abstract = {The Southern Ocean has, on average, warmed and freshened over the past several decades. As a primary global sink for anthropogenic heat and carbon, to understand changes in the Southern Ocean is directly relevant to predicting the future evolution of the global climate system. However, the drivers of these changes are poorly understood, owing to sparse observational sampling, large amplitude internal variability, modelling uncertainties and the competing influence of multiple forcing agents. Here we construct an observational synthesis to quantify the temperature and salinity changes over the Southern Ocean and combine this with an ensemble of co-sampled climate model simulations. Using a detection and attribution analysis, we show that the observed changes are inconsistent with the internal variability or the response to natural forcing alone. Rather, the observed changes are primarily attributable to human-induced greenhouse gas increases, with a secondary role for stratospheric ozone depletion. Physically, the simulated changes are primarily driven by surface fluxes of heat and freshwater. The consistency between the observed changes and our simulations provides increased confidence in the ability of climate models to simulate large-scale thermohaline change in the Southern Ocean.},
author = {Swart, Neil C. and Gille, Sarah T. and Fyfe, John C. and Gillett, Nathan P.},
doi = {10.1038/s41561-018-0226-1},
issn = {1752-0894},
journal = {Nature Geoscience},
keywords = {Attribution,Climate change,Climate sciences,Ocean sciences},
month = {nov},
number = {11},
pages = {836--841},
publisher = {Nature Publishing Group},
title = {{Recent Southern Ocean warming and freshening driven by greenhouse gas emissions and ozone depletion}},
url = {http://www.nature.com/articles/s41561-018-0226-1},
volume = {11},
year = {2018}
}
@article{Swart2015b,
author = {Swart, Neil C and Fyfe, John C and Hawkins, Ed and Kay, Jennifer E and Jahn, Alexandra},
doi = {10.1038/nclimate2483},
journal = {Nature Climate Change},
month = {jan},
pages = {86},
publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.},
title = {{Influence of internal variability on Arctic sea-ice trends}},
url = {http://dx.doi.org/10.1038/nclimate2483 http://10.0.4.14/nclimate2483 https://www.nature.com/articles/nclimate2483{\#}supplementary-information},
volume = {5},
year = {2015}
}
@article{Swingedouw2017,
author = {Swingedouw, Didier and Mignot, Juliette and Ortega, Pablo and Khodri, Myriam and Menegoz, Martin and Cassou, Christophe and Hanquiez, Vincent},
doi = {10.1016/j.gloplacha.2017.01.006},
issn = {0921-8181},
journal = {Global and Planetary Change},
pages = {24--45},
title = {{Impact of explosive volcanic eruptions on the main climate variability modes}},
url = {http://www.sciencedirect.com/science/article/pii/S0921818116300352},
volume = {150},
year = {2017}
}
@article{Taguchi2017,
abstract = {Abstract Climatological frequency of major stratospheric sudden warmings (MSSWs) during northern winter has been repeatedly investigated using model simulations, but its model-to-model differences are relatively unexplained. Using an archive of the Coupled Model Intercomparison Project Phase 5 (CMIP5) historical simulations with 30 models, this study investigates the MSSW frequency of the simulations by building a framework in which the frequency is decomposed into a few factors. Results first demonstrate that the multimodel differences in the MSSW frequency are closely related to the mean and variability of the zonal mean zonal wind in the extratropical stratosphere in each simulation. An important point is that for each simulation, the zonal wind variability is further represented by a combination, or product, of average strength of extreme transient planetary wave forcings from the troposphere and average deceleration response of the polar vortex to an extreme wave forcing of fixed strength. This product can be interpreted and used as a proxy of large-scale dynamical variability of the polar vortex arising from the planetary wave-mean flow interaction. It turns out that a large portion of the CMIP5 model simulations underestimate one or both of the factors, leading to underestimations in dynamical variability. This contributes to the general underestimation of MSSW frequency in the simulations. This study proposes that this framework can be used in general to better understand MSSW frequency in different models and climate conditions (e.g., future climate change).},
author = {Taguchi, M},
doi = {10.1002/2016JD025826},
journal = {Journal of Geophysical Research: Atmospheres},
number = {10},
pages = {5144--5156},
title = {{A study of different frequencies of major stratospheric sudden warmings in CMIP5 historical simulations}},
volume = {122},
year = {2017}
}
@article{Takahashi2016,
abstract = {The Pacific trade winds, coupled with the zonal sea surface temperature gradient in the equatorial Pacific Ocean, control regional sea levels1 , and therefore their trend is a great concern in the Pacific Rim. Over the past two decades, easterly winds have been accelerated in association with eastern tropical Pacific cooling2 . They may represent natural interdecadal variability in the Pacific3 and possibly explain the recent global warming hiatus4–7 . However, the intensification of the winds has been the strongest ever observed in the past century2,5,8 , the reason for which is still unclear. Herewe show, using multiple climate simulations for 1921–2014 by a global climate model, that approximately one-third of the trade-wind intensification for 1991–2010 can be attributed to changes in sulfate aerosols. The multidecadal sea surface temperature anomaly induced mostly by volcanic aerosols dominates in the western North Pacific, and its sign changed rapidly from negative to positive in the 1990s, coherently with Atlantic multidecadal variability9–11 .Thewestern NorthPacificwarming resulted in intensification of trade winds to the west of the dateline. These trends have not contributed much to the global warming hiatus, but have greatly impacted rainfall over the western Pacific islands.},
author = {Takahashi, Chiharu and Watanabe, Masahiro},
doi = {10.1038/nclimate2996},
isbn = {1758-678X},
issn = {17586798},
journal = {Nature Climate Change},
number = {8},
pages = {768--772},
title = {{Pacific trade winds accelerated by aerosol forcing over the past two decades}},
volume = {6},
year = {2016}
}
@article{Takahashi2016a,
author = {Takahashi, Hanii and Su, Hui and Jiang, Jonathan H.},
doi = {10.1007/s00382-015-2732-9},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {may},
number = {9-10},
pages = {2787--2803},
title = {{Error analysis of upper tropospheric water vapor in CMIP5 models using “A-Train” satellite observations and reanalysis data}},
url = {http://link.springer.com/10.1007/s00382-015-2732-9},
volume = {46},
year = {2016}
}
@article{Tandon2015,
abstract = {AbstractNumerous studies have suggested that variations in the strength of the Atlantic meridional overturning circulation (AMOC) may drive predictable variations in North Atlantic sea surface temperature (NASST). However, two recent studies have presented results suggesting that coupled models disagree on both the sign and the phasing of the correlation between AMOC and NASST indices. These studies analyzed linearly detrended output from twentieth-century historical simulations in phases 3 and 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5). The present study argues that the apparent disagreement among models arises from a comingling of two processes: 1) a bottom-up effect in which unforced AMOC changes lead to NASST changes of the same sign and 2) a top-down effect in which forced NASST changes lead to AMOC changes of the opposite sign. Linear detrending is not appropriate for separating these two effects because the time scales of forced and unforced variations are not well separated. After forced variations are properly removed, the models come into much closer agreement with each other. This argument is supported by analysis of CMIP5 historical simulations, as well as preindustrial control simulations and a 29-member ensemble of the Community Earth System Model, version 1, covering the period 1920?2005. Additional analysis is presented suggesting that, even after the data are linearly detrended, a significant portion of observed NASST persistence may be externally forced.},
annote = {doi: 10.1175/JCLI-D-14-00664.1},
author = {Tandon, Neil F and Kushner, Paul J},
doi = {10.1175/JCLI-D-14-00664.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {may},
number = {16},
pages = {6309--6323},
publisher = {American Meteorological Society},
title = {{Does External Forcing Interfere with the AMOC's Influence on North Atlantic Sea Surface Temperature?}},
url = {https://doi.org/10.1175/JCLI-D-14-00664.1},
volume = {28},
year = {2015}
}
@article{Tao2016,
abstract = {Poleward expansion of the Hadley circulation has been an important topic in climate change studies in the past few years, and one of the critically important issues is how it is related to anthropogenic forcings. Using simulations from the coupled model intercomparison projection phase 5 (CMIP5), we study influences of anthropogenic forcings on the width and strength of the Hadley circulation. It is found that significant poleward expansion of the Hadley circulation can be reproduced in CMIP5 historical all-forcing simulations although the magnitude of trends is much weaker than observations. Simulations with individual forcings demonstrate that among three major types of anthropogenic forcings, increasing greenhouse gases (GHGs) and stratospheric ozone depletion all cause poleward expansion of the Hadley circulation, whereas anthropogenic aerosols do not have significant influences on the Hadley circulation. Increasing GHGs cause significant poleward expansion in both hemispheres, with the largest widening of the northern cell in boreal autumn. Stratospheric ozone depletion forces significant poleward expansion of the Hadley circulation for the southern cell in austral spring and summer and for the northern cell in boreal spring. In CMIP5 projection simulations for the twenty-first century, the magnitude of poleward expansion of the Hadley circulation increases with GHG forcing. On the other hand, ozone recovery competes with increasing GHGs in determining the width of the Hadley circulation, especially in austral summer. In both historical and projection simulations, the strength of the Hadley circulation shows significant weakening in winter in both hemispheres.},
annote = {Zonal mean Hadley cell
Meridional mass streamfunction
Annual mean, seasonality
CMIP5 historical, single forcing
1970-2005 (1970-2000 for ozone-only)

- Poleward expansion and weakening in both NH and SH with seasonal peaks in expansion strength, but much weaker than in reanalysis
- Both GHG increase and ozone depletion contribute to widening in both NH and SH
- GHG increase weakens Hadley circulation while ozone depletion strengthens
- Anthropogenic aerosols doesn't have significant influence on width and intensity of Hadley cell},
author = {Tao, Lijun and Hu, Yongyun and Liu, Jiping},
doi = {10.1007/s00382-015-2772-1},
issn = {14320894},
journal = {Climate Dynamics},
keywords = {Anthropogenic aerosols,Hadley circulation,Increasing greenhouse gases,Ozone depletion and recovery,Subtropical dry zone},
number = {9-10},
pages = {3337--3350},
publisher = {Springer Berlin Heidelberg},
title = {{Anthropogenic forcing on the Hadley circulation in CMIP5 simulations}},
volume = {46},
year = {2016}
}
@article{Tao2016a,
abstract = {Based on 15 Coupled Model Intercomparison Project (CMIP) phase 3 (CMIP3) and 32 CMIP phase 5 (CMIP5) models, a detailed diagnosis was carried out to understand what compose the biases in simulation of the Indian Ocean basin mode (IOBM) and its capacitor effect. Cloud-radiation-SST (CRS) feedback and wind-evaporation-SST (WES) feedback are the two major atmospheric processes for SST changes. Most CMIP models simulate a stronger CRS feedback and a weaker WES feedback. During boreal fall of the El Ni{\~{n}}o/Southern Oscillation developing year and the following spring, there are weak biases of suppressed rainfall anomalies over the Maritime Continent and anomalous anticyclone over South Indian Ocean. Most CMIP models simulate reasonable short wave radiation (SWR) and weaker latent heat flux (LHF) anomalies. This leads to a weak bias of atmospheric processes. During winter, however, the rainfall anomalies are stronger due to west bias, and the anomalous anticyclone is comparable to observations. As such, most models simulate stronger SWR and reasonable LHF anomalies, leading to a strong bias of atmospheric processes. The thermocline feedback is stronger in most models. Though there is a deep bias of climatology thermocline, most models capture reasonable sea surface height-induced SST anomalies. Therefore, the effect of oceanic processes offset the weak bias of atmospheric processes in spring, and the tropical Indian Ocean warming persists into summer. However, anomalous northwest Pacific (NWP) anticyclone is weaker due to weak and west bias of the capacitor effect. The unrealistic western Pacific SST anomalies in models favor the westward extension of Rossby wave from the Pacific, weakening the effect of Kelvin wave from the Indian Ocean. Moreover, the western Pacific warming forces the NWP anticyclone move farther north than observations, suggesting a major forcing from the Pacific. Compared to CMIP3, CMIP5 models simulate the feedbacks more realistically and display less diversity. Thus, the overall performance of CMIP5 models is better than that of CMIP3 models.},
annote = {Model reproduction of IOBM in CMIP3 and CMIP5 models
- CMIP3 20C3M, CMIP5 historical vs HadISST, NCEP/NCAR, SODA, PREC
- 1970-2000
- 3-month running mean, linearly detrended

- Both CMIP3 and CMIP5 MME means overall capture the transition from the IOD to IOBM
- Biases in SSTa magnitude, SSH, surface wind and heat flux anomalies
- In MME mean, no significant improvement from CMIP3 and CMIP5. But CMIP5 is less diverse than CMIP3, indicating better performance},
author = {Tao, Weichen and Huang, Gang and Hu, Kaiming and Gong, Hainan and Wen, Guanhuan and Liu, Lin},
doi = {10.1007/s00382-015-2579-0},
issn = {14320894},
journal = {Climate Dynamics},
keywords = {Atmospheric and oceanic processes,CMIP models,IOBM,Model biases,The capacitor effect},
number = {1-2},
pages = {205--226},
publisher = {Springer Berlin Heidelberg},
title = {{A study of biases in simulation of the Indian Ocean basin mode and its capacitor effect in CMIP3/CMIP5 models}},
url = {http://dx.doi.org/10.1007/s00382-015-2579-0},
volume = {46},
year = {2016}
}
@article{doi:10.1002/joc.3987,
abstract = {ABSTRACT On the basis of Coupled Model Intercomparison Project phase 5 (CMIP5) models, this study have examined the ability of models to capture the El Ni{\~{n}}o/Southern Oscillation (ENSO)–Indian Ocean Basin Mode (IOBM) relationship, and investigated the characteristics of interdecadal change of ENSO–IOBM relationship as well as the response of the ENSO–IOBM relationship to the global warming. Among 23 CMIP5 models, the capability of models in representing the IOBM depends largely on the simulation of ENSO. Moreover, half of the models can reproduce the unstable ENSO–IOBM relationship. Considering the simulations of ENSO, ENSO–IOBM relationship and interdecadal change, 6 of 23 CMIP5 models are chosen for further investigation. The interdecadal change of ENSO–IOBM relationship is relative to the three ENSO-related processes. During the high correlation (HC) period, the tropospheric temperature (TT) mechanism, oceanic Rossby waves and antisymmetric wind pattern are strong, prolonging the persistence of IOBM. In comparison, during the low correlation (LC) period, the three processes are weak. The results show that the shallow thermocline in the southwestern Indian Ocean (SWIO), increased interannual variability and prolonged periodicity of ENSO are all responsible for the interdecadal change. Furthermore, the possible changes of ENSO–IOBM relationship in the future are investigated. The ENSO-related tropical Indian Ocean (TIO) warming is strengthened under global warming. Despite the deepened thermocline over SWIO and unchanged ENSO activity, the ENSO-related TIO warming is strengthened by the enhanced TT mechanism, which is caused by the increased saturated specific humidity. The results reveal that there is more downward net heat flux (NHF) over the TIO, which is conducive to the TIO warming, and the latent heat flux (LHF) change makes a great contribution to the NHF change. The weakened upward or strengthened downward LHF is possibly due to the decreased anomalous sea–air temperature difference by strengthened TT mechanism.},
annote = {Model reproduction of IOBM in CMIP5 models and future change
- CMIP5 historical vs HadISST {\ldots} 1870-2005
- CMIP5 RCP4.5
- Removing 9-yr running mean

- Reproduction of D(0)JF(1) ENSO-MAM(1) IOBM relationship depends on ENSO pattern and magnitude
- More than half of the models (14 out of 23 models) capture interdecadal modulation of the ENSO-IOBM relationship reasonably well, while in 9 models the correlation is too stable (but not in the observed timing)
- Three processes that are suggested to transfer ENSO influence on IOBM are well captured by selected models (6 out of 23)
- Interdecadal changes in SWIO thermocline and ENSO intensity and persistence are all responsible for the changes in correlation
- Further analysis of future modulations},
author = {Tao, Weichen and Huang, Gang and Hu, Kaiming and Qu, Xia and Wen, Guanhuan and Gong, Hainan},
doi = {10.1002/joc.3987},
journal = {International Journal of Climatology},
keywords = {CMIP5,ENSO–IOBM relationship,Future change,Global warming,TT mechanism,sea–air temperature difference},
number = {3},
pages = {391--407},
title = {{Interdecadal modulation of ENSO teleconnections to the Indian Ocean Basin Mode and their relationship under global warming in CMIP5 models}},
url = {https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/joc.3987},
volume = {35},
year = {2015}
}
@article{Taschetto2014,
abstract = {The representation of the El Ni{\~{}} no–Southern Oscillation (ENSO) under historical forcing and future pro- jections is analyzed in 34 models from the Coupled Model Intercomparison Project phase 5 (CMIP5). Most models realistically simulate the observed intensity and location of maximum sea surface temperature (SST) anomalies during ENSO events. However, there exist systematic biases in the westward extent of ENSO- related SST anomalies, driven by unrealistic westward displacement and enhancement of the equatorial wind stress in the western Pacific. Almost all CMIP5 models capture the observed asymmetry in magnitude be- tween the warm and cold events (i.e., El Ni{\~{}} nos are stronger than La Ni{\~{}} nas) and between the two types of El Ni{\~{}} nos: that is, cold tongue (CT) El Ni{\~{}} nos are stronger than warm pool (WP) El Ni{\~{}} nos. However, most models fail to reproduce the asymmetry between the two types of La Ni{\~{}} nas, withCTstronger thanWPevents, which is opposite to observations. Most models capture the observed peak in ENSO amplitude around December; however, the seasonal evolution of ENSO has a large range of behavior across the models. The CMIP5 models generally reproduce the duration of CT El Ni{\~{}} nos but have biases in the evolution of the other types of events. The evolution of WP El Ni{\~{}} nos suggests that the decay of this event occurs through heat content discharge in the models rather than the advection of SST via anomalous zonal currents, as seems to occur in observations. No consistent changes are seen across the models in the location and magnitude of maximum SST anomalies, frequency, or temporal evolution of these events in a warmer world. 1.},
author = {Taschetto, Andr{\'{e}}a S. and Gupta, Alexander Sen and Jourdain, Nicolas C. and Santoso, Agus and Ummenhofer, Caroline C. and England, Matthew H.},
doi = {10.1175/JCLI-D-13-00437.1},
isbn = {0894-8755$\backslash$r1520-0442},
issn = {08948755},
journal = {Journal of Climate},
number = {8},
pages = {2861--2885},
title = {{Cold tongue and warm pool ENSO Events in CMIP5: Mean state and future projections}},
volume = {27},
year = {2014}
}
@incollection{Taschetto2020,
address = {Washington DC, USA},
author = {Taschetto, Andr{\'{e}}a S. and Ummenhofer, Caroline C. and Stuecker, Malte F. and Dommenget, Dietmar and Ashok, Karumuri and Rodrigues, R. R. and Yeh, Sang-Wook},
booktitle = {El Ni{\~{n}}o Southern Oscillation in a Changing Climate},
chapter = {14},
doi = {10.1002/9781119548164.ch14},
editor = {McPhaden, Michael J. and Santoso, Agus and Cai, Wenju},
isbn = {978-1-119-54812-6},
pages = {309--335},
publisher = {American Geophysical Union (AGU)},
title = {{ENSO atmospheric teleconnections}},
year = {2020}
}
@misc{Taylor2012,
abstract = {The fifth phase of the Coupled Model Intercomparison Project (CMIP5) will produce a state-of-the- art multimodel dataset designed to advance our knowledge of climate variability and climate change. Researchers worldwide are analyzing the model output and will produce results likely to underlie the forthcoming Fifth Assessment Report by the Intergovernmental Panel on Climate Change. Unprecedented in scale and attracting interest from all major climate modeling groups, CMIP5 includes “long term” simulations of twentieth-century climate and projections for the twenty-first century and beyond. Conventional atmosphere–ocean global climate models and Earth system models of intermediate complexity are for the first time being joined by more recently developed Earth system models under an experiment design that allows both types of models to be compared to observations on an equal footing. Besides the longterm experiments, CMIP5 calls for an entirely new suite of “near term” simulations focusing on recent decades...},
archivePrefix = {arXiv},
arxivId = {arXiv:1011.1669v3},
author = {Taylor, Karl E. and Stouffer, Ronald J. and Meehl, Gerald A.},
booktitle = {Bulletin of the American Meteorological Society},
doi = {10.1175/BAMS-D-11-00094.1},
eprint = {arXiv:1011.1669v3},
isbn = {0003-0007},
issn = {00030007},
month = {apr},
number = {4},
pages = {485--498},
pmid = {17798761},
publisher = {American Meteorological Society},
title = {{An overview of CMIP5 and the experiment design}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-11-00094.1},
volume = {93},
year = {2012}
}
@article{Tedesco2020,
author = {Tedesco, Marco and Fettweis, Xavier},
doi = {10.5194/tc-14-1209-2020},
issn = {1994-0424},
journal = {The Cryosphere},
month = {apr},
number = {4},
pages = {1209--1223},
title = {{Unprecedented atmospheric conditions (1948–2019) drive the 2019 exceptional melting season over the Greenland ice sheet}},
url = {https://tc.copernicus.org/articles/14/1209/2020/},
volume = {14},
year = {2020}
}
@article{Terray2012d,
author = {Terray, Laurent},
doi = {10.1029/2012GL053046},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {oct},
number = {19},
pages = {L19712},
title = {{Evidence for multiple drivers of North Atlantic multi-decadal climate variability}},
url = {http://doi.wiley.com/10.1029/2012GL053046},
volume = {39},
year = {2012}
}
@article{Terray2012,
abstract = {Changes in the global water cycle are expected as a result of anthropogenic climate change, but large uncertainties exist in how these changes will be manifest regionally. This is especially the case over the tropical oceans, where observed estimates of precipitation and evaporation disagree considerably. An alternative approach is to examine changes in near-surface salinity. Datasets of observed tropical Pacific and Atlantic near-surface salinity combined with climate model simulations are used to assess the possible causes and significance of salinity changes over the late twentieth century. Two different detection methodologies are then applied to evaluate the extent to which observed large-scale changes in near-surface salinity can be attributed to anthropogenic climate change. Basin-averaged observed changes are shown to enhance salinity geographical contrasts between the two basins: the Pacific is getting fresher and the Atlantic saltier. While the observed Pacific and interbasin-averaged salinity changes exceed the range of internal variability provided from control climate simulations, Atlantic changes are within the model estimates. Spatial patterns of salinity change, including a fresher western Pacific warm pool and a saltier subtropical North Atlantic, are not consistent with internal climate variability. They are similar to anthropogenic response patterns obtained from transient twentieth- and twenty-first-century integrations, therefore suggesting a discernible human influence on the late twentieth-century evolution of the tropical marine water cycle. Changes in the tropical and midlatitudes Atlantic salinity levels are not found to be significant compared to internal variability. Implications of the results for understanding of the recent and future marine tropical water cycle changes are discussed. {\textcopyright} 2012 American Meteorological Society.},
author = {Terray, Laurent and Corre, Lola and Cravatte, Sophie and Delcroix, Thierry and Reverdin, Gilles and Ribes, Aur{\'{e}}lien},
doi = {10.1175/JCLI-D-10-05025.1},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Climate change,Coupled models,Hydrologic cycle,Pattern detection,Salinity},
month = {feb},
number = {3},
pages = {958--977},
title = {{Near-surface salinity as nature's rain gauge to detect human influence on the Tropical water cycle}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-10-05025.1},
volume = {25},
year = {2012}
}
@article{doi:10.1029/2018GL078493,
abstract = {Key Points Structurally varying snowpack, vegetation, and albedo parameterizations drive most of the intermodel spread in snow albedo feedback Many models now exhibit a more realistic feedback than in the past, but issues with two models limit the reduction in ensemble spread Preliminary signs from ongoing model development are positive and suggest a likely reduction in spread among upcoming models},
author = {Thackeray, Chad W and Qu, Xin and Hall, Alex},
doi = {10.1029/2018GL078493},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {albedo feedback,climate models,structural biases},
month = {jun},
number = {12},
pages = {6223--6231},
title = {{Why Do Models Produce Spread in Snow Albedo Feedback?}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL078493 https://onlinelibrary.wiley.com/doi/10.1029/2018GL078493},
volume = {45},
year = {2018}
}
@article{Thackeray2015b,
abstract = {Effectively modeling the influence of terrestrial snow on climate in general circulation models is limited by imperfect knowledge and parameterization of arctic and subarctic climate processes and a lack of reliable observations for model evaluation and improvement. This study uses a number of satellite-derived data sets to evaluate how well the current generation of climate models from the Fifth Coupled Model Intercomparison Project (CMIP5) simulate the seasonal cycle of climatological snow cover fraction (SCF) and surface albedo over the Northern Hemisphere snow season (September-June). Using a variety of metrics, the CMIP5 models are found to simulate SCF evolution better than that of albedo. The seasonal cycle of SCF is well reproduced despite substantial biases in simulated surface albedo of snow-covered land ((sfc{\_}snow)), which affect both the magnitude and timing of the seasonal peak in (sfc{\_}snow) during the fall snow accumulation period, and the springtime snow ablation period. Insolation weighting demonstrates that the biases in (sfc{\_}snow) during spring are of greater importance for the surface energy budget. Albedo biases are largest across the boreal forest, where the simulated seasonal cycle of albedo is biased high in 15/16 CMIP5 models. This bias is explained primarily by unrealistic treatment of vegetation masking and subsequent overestimation (more than 50{\%} in some cases) of peak (sfc{\_}snow) rather than by biases in SCF. While seemingly straightforward corrections to peak (sfc{\_}snow) could yield significant improvements to simulated snow albedo feedback, changes in (sfc{\_}snow) could potentially introduce biases in other important model variables such as surface temperature.},
address = {2000 FLORIDA AVE NW},
author = {Thackeray, Chad W and Fletcher, Christopher G and Derksen, Chris},
doi = {10.1002/2015JD023325},
issn = {2169-897X},
journal = {Journal of Geophysical Research: Atmospheres},
month = {jun},
number = {12},
pages = {5831--5849},
publisher = {AMER GEOPHYSICAL UNION},
title = {{Quantifying the skill of CMIP5 models in simulating seasonal albedo and snow cover evolution}},
volume = {120},
year = {2015}
}
@article{Thackeray2018a,
abstract = {A highly uncertain aspect of anthropogenic climate change is the rate at which the global hydrologic cycle intensifies. The future change in global-mean precipitation per degree warming, or hydrologic sensitivity, exhibits a threefold spread (1–3{\%}/K) in current global climate models. In this study, we find that the intermodel spread in this value is associated with a significant portion of variability in future projections of extreme precipitation in the tropics, extending also into subtropical atmospheric river corridors. Additionally, there is a very tight intermodel relationship between changes in extreme and nonextreme precipitation, whereby models compensate for increasing extreme precipitation events by decreasing weak-moderate events. Another factor linked to changes in precipitation extremes is model resolution, with higher resolution models showing a larger increase in heavy extremes. These results highlight ways various aspects of hydrologic cycle intensification are linked in models and shed new light on the task of constraining precipitation extremes.},
author = {Thackeray, Chad W and DeAngelis, Anthony M and Hall, Alex and Swain, Daniel L. and Qu, Xin},
doi = {10.1029/2018GL079698},
issn = {19448007},
journal = {Geophysical Research Letters},
keywords = {climate change,extreme precipitation,global climate models,global hydrologic sensitivity,model uncertainty},
number = {20},
pages = {11343--11351},
title = {{On the Connection Between Global Hydrologic Sensitivity and Regional Wet Extremes}},
volume = {45},
year = {2018}
}
@article{Thackeray2016,
abstract = { AbstractProjections of twenty-first-century Northern Hemisphere (NH) spring snow cover extent (SCE) from two climate model ensembles are analyzed to characterize their uncertainty. Phase 5 of the Coupled Model Intercomparison Project (CMIP5) multimodel ensemble exhibits variability resulting from both model differences and internal climate variability, whereas spread generated from a Canadian Earth System Model–Large Ensemble (CanESM-LE) experiment is solely a result of internal variability. The analysis shows that simulated 1981–2010 spring SCE trends are slightly weaker than observed (using an ensemble of snow products). Spring SCE is projected to decrease by −3.7{\%} ± 1.1{\%} decade−1 within the CMIP5 ensemble over the twenty-first century. SCE loss is projected to accelerate for all spring months over the twenty-first century, with the exception of June (because most snow in this month has melted by the latter half of the twenty-first century). For 30-yr spring SCE trends over the twenty-first century, internal variability estimated from CanESM-LE is substantial, but smaller than intermodel spread from CMIP5. Additionally, internal variability in NH extratropical land warming trends can affect SCE trends in the near future (R2 = 0.45), while variability in winter precipitation can also have a significant (but lesser) impact on SCE trends. On the other hand, a majority of the intermodel spread is driven by differences in simulated warming (dominant in March–May) and snow cover available for melt (dominant in June). The strong temperature–SCE linkage suggests that model uncertainty in projections of SCE could be potentially reduced through improved simulation of spring season warming over land. },
author = {Thackeray, Chad W and Fletcher, Christopher G and Mudryk, Lawrence R and Derksen, Chris},
doi = {10.1175/JCLI-D-16-0341.1},
journal = {Journal of Climate},
number = {23},
pages = {8647--8663},
title = {{Quantifying the Uncertainty in Historical and Future Simulations of Northern Hemisphere Spring Snow Cover}},
volume = {29},
year = {2016}
}
@article{Thieblemont2015,
author = {Thi{\'{e}}blemont, R{\'{e}}mi and Matthes, Katja and Omrani, Nour-Eddine and Kodera, Kunihiko and Hansen, Felicitas},
doi = {10.1038/ncomms9268},
issn = {2041-1723},
journal = {Nature Communications},
month = {nov},
number = {1},
pages = {8268},
title = {{Solar forcing synchronizes decadal North Atlantic climate variability}},
url = {http://www.nature.com/articles/ncomms9268},
volume = {6},
year = {2015}
}
@article{Thielke2019,
author = {Thielke, Anja and M{\"{o}}lg, Thomas},
doi = {10.1002/joc.6085},
issn = {0899-8418},
journal = {International Journal of Climatology},
month = {sep},
number = {11},
pages = {4467--4478},
title = {{Observed and simulated Indian Ocean Dipole activity since the mid‐19th century and its relation to East African short rains}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/joc.6085},
volume = {39},
year = {2019}
}
@article{doi:10.1002/2015GL064833,
abstract = {Abstract We use surface air temperature to evaluate the decadal forecast skill of the fully coupled Max Planck Institut Earth System Model (MPI-ESM) initialized using only surface wind stress applied to the ocean component of the model (Modini: Model initialization by partially coupled spin-up). Our analysis shows that the greenhouse gas forcing alone results in a significant forecast skill on the 2–5 and 6–9 year range even for uninitialized hindcasts. For the first forecast year, the forecast skill of Modini is generally comparable with previous initialization procedures applied to MPI-ESM. But only Modini is able to generate a significant skill (correlation) in the tropical Pacific for a 2–5 year (and to a lesser extent for a 6–9 year) hindcast. Modini is also better able to capture the observed hiatus in global warming in hindcast mode than the other methods. Finally, we present forecasts for 2015 and the average of years 2016–2019 and 2020–2024, predicting an end to the hiatus.},
author = {Thoma, Malte and Greatbatch, Richard J and Kadow, Christopher and Gerdes, Ruediger},
doi = {10.1002/2015GL064833},
journal = {Geophysical Research Letters},
keywords = {CMIP5,decadal prediction,hiatus,skill scores},
number = {15},
pages = {6454--6461},
title = {{Decadal hindcasts initialized using observed surface wind stress: Evaluation and prediction out to 2024}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2015GL064833},
volume = {42},
year = {2015}
}
@article{Thomas2015a,
author = {Thomas, Jordan L. and Waugh, Darryn W. and Gnanadesikan, Anand},
doi = {10.1002/2015GL064521},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {jul},
number = {13},
pages = {5508--5515},
title = {{Southern Hemisphere extratropical circulation: Recent trends and natural variability}},
url = {http://doi.wiley.com/10.1002/2015GL064521},
volume = {42},
year = {2015}
}
@article{Thomas2015b,
abstract = {Abstract The representation of the nitrogen (N) cycle in Earth system models (ESMs) is strongly motivated by the constraint N poses on the sequestration of anthropogenic carbon (C). Models typically implement a stoichiometric relationship between C and N in which external supply and assimilation by organisms are adjusted to maintain their internal stoichiometry. N limitation of primary productivity thus occurs if the N supply from uptake and fixation cannot keep up with the construction of tissues allowed by C assimilation. This basic approach, however, presents considerable challenges in how to faithfully represent N limitation. Here, we review how N limitation is currently implemented and evaluated in ESMs and highlight challenges and opportunities in their future development. At or near steady state, N limitation is governed by the magnitude of losses from the plant-unavailable pool vs. N fixation and there are considerable differences in how models treat both processes. In nonsteady-state systems, the accumulation of N in pools with slow turnover rates reduces N available for plant uptake and can be challenging to represent when initializing ESM simulations. Transactional N limitation occurs when N is incorporated into various vegetation and soil pools and becomes available to plants only after it is mineralized, the dynamics of which depends on how ESMs represent decomposition processes in soils. Other challenges for ESMs emerge when considering seasonal to interannual climatic oscillations as they create asynchronies between C and N demand, leading to transient alternations between N surplus and deficit. Proper evaluation of N dynamics in ESMs requires conceptual understanding of the main levers that trigger N limitation, and we highlight key measurements and observations that can help constrain these levers. Two of the biggest challenges are the mechanistic representation of plant controls on N availability and turnover, including N fixation and organic matter decomposition processes.},
annote = {doi: 10.1111/gcb.12813},
author = {Thomas, R Quinn and Brookshire, E N Jack and Gerber, Stefan},
doi = {10.1111/gcb.12813},
issn = {1354-1013},
journal = {Global Change Biology},
keywords = {biogeochemical modeling,carbon cycle,carbon–climate feedbacks,climate change,global biogeochemical models,land-surface models,model evaluation,terrestrial ecosystems modeling},
month = {may},
number = {5},
pages = {1777--1793},
publisher = {John Wiley {\&} Sons, Ltd (10.1111)},
title = {{Nitrogen limitation on land: how can it occur in Earth system models?}},
url = {https://doi.org/10.1111/gcb.12813},
volume = {21},
year = {2015}
}
@article{Thompson2014b,
author = {Thompson, Diane M and Cole, Julia E and Shen, Glen T and Tudhope, Alexander W and Meehl, Gerald A},
doi = {10.1038/ngeo2321},
journal = {Nature Geoscience},
month = {dec},
pages = {117},
publisher = {Nature Publishing Group},
title = {{Early twentieth-century warming linked to tropical Pacific wind strength}},
url = {http://dx.doi.org/10.1038/ngeo2321 http://10.0.4.14/ngeo2321 https://www.nature.com/articles/ngeo2321{\#}supplementary-information},
volume = {8},
year = {2014}
}
@article{doi:10.1002/2014JD022805,
abstract = {Abstract To assess published hypotheses surrounding the recent slowdown in surface warming (hiatus), we compare five available global observational surface temperature estimates to two 30-member ensembles from the Norwegian Earth System Model (NorESM). Model ensembles are initialized in 1980 from the transient historical runs and driven with forcings used in the CMIP5 experiments and updated forcings based upon current observational understanding, described in Part 1. The ensembles' surface temperature trends are statistically indistinguishable over 1998–2012 despite differences in the prescribed forcings. There is thus no evidence that forcing errors play a significant role in explaining the hiatus according to NorESM. The observations fall either toward the lower portion of the ensembles or, for some observational estimates and regions, outside. The exception is the Arctic where the observations fall toward the upper ensemble bounds. Observational data set choices can make a large difference to findings of consistency or otherwise. Those NorESM ensemble members that exhibit Nino3.4 Sea Surface Temperature (SST) trends similar to observed also exhibit comparable tropical and to some extent global mean trends, supporting a role for El Nino Southern Oscillation in explaining the hiatus. Several ensemble members capture the marked seasonality observed in Northern Hemisphere midlatitude trends, with cooling in the wintertime and warming in the remaining seasons. Overall, we find that we cannot falsify NorESM as being capable of explaining the observed hiatus behavior. Importantly, this is not equivalent to concluding NorESM could simultaneously capture all important facets of the hiatus. Similar experiments with further, distinct, Earth System Models are required to verify our findings.},
author = {Thorne, Peter and Outten, Stephen and Bethke, Ingo and Seland, {\O}yvind},
doi = {10.1002/2014JD022805},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {GCM,ensemble,forcings,hiatus,temperature},
number = {17},
pages = {8597--8620},
title = {{Investigating the recent apparent hiatus in surface temperature increases: 2. Comparison of model ensembles to observational estimates}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2014JD022805},
volume = {120},
year = {2015}
}
@article{Tian2015,
author = {Tian, Baijun},
doi = {10.1002/2015GL064119},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {may},
number = {10},
pages = {4133--4141},
title = {{Spread of model climate sensitivity linked to double‐Intertropical Convergence Zone bias}},
url = {https://doi.org/10.1002/2015GL064119 https://onlinelibrary.wiley.com/doi/abs/10.1002/2015GL064119},
volume = {42},
year = {2015}
}
@article{Tian2013,
abstract = {This paper documents the climatological mean features of the Atmospheric Infrared Sounder (AIRS) monthly mean tropospheric air temperature (ta, K) and specific humidity (hus, kg/kg) products as part of the Obs4MIPs project and compares them to those from NASA's Modern Era Retrospective analysis for Research and Applications (MERRA) for validation and 16 models from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) for CMIP5 model evaluation. MERRA is warmer than AIRS in the free troposphere but colder in the boundary layer with differences typically less than 1 K. MERRA is also drier ({\~{}}10{\%}) than AIRS in the tropical boundary layer but wetter ({\~{}}30{\%}) in the tropical free troposphere and the extratropical troposphere. In particular, the large MERRA-AIRS specific humidity differences are mainly located in the deep convective cloudy regions indicating that the low sampling of AIRS in the cloudy regions may be the main reason for these differences. In comparison to AIRS and MERRA, the sixteen CMIP5 models can generally reproduce the climatological features of tropospheric air temperature and specific humidity well, but several noticeable biases exist. The models have a tropospheric cold bias (around 2 K), especially in the extratropical upper troposphere, and a double-ITCZ problem in the troposphere from 1000 hPa to 300 hPa, especially in the tropical Pacific. The upper-tropospheric cold bias exists in the most (13 of 16) models, and the double-ITCZ bias is found in all 16 CMIP5 models. Both biases are independent of the reference dataset used (AIRS or MERRA). Key Points The AIRS/CMIP5 data are described and validated. CMIP5 models are evaluated using AIRS data. Double-ITCZ syndrome {\&} upper-tropospheric cold bias exist in most CMIP5 models. {\textcopyright} 2012 American Geophysical Union. All Rights Reserved.},
author = {Tian, Baijun and Fetzer, Eric J. and Kahn, Brian H. and Teixeira, Joao and Manning, Evan and Hearty, Thomas},
doi = {10.1029/2012JD018607},
issn = {21698996},
journal = {Journal of Geophysical Research: Atmospheres},
keywords = {AIRS,CMIP5},
number = {1},
pages = {114--134},
title = {{Evaluating CMIP5 models using AIRS tropospheric air temperature and specific humidity climatology}},
volume = {118},
year = {2013}
}
@article{Tian2020,
author = {Tian, Baijun and Dong, Xinyu},
doi = {10.1029/2020GL087232},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {apr},
number = {8},
pages = {e2020GL087232},
title = {{The Double‐ITCZ Bias in CMIP3, CMIP5, and CMIP6 Models Based on Annual Mean Precipitation}},
url = {https://onlinelibrary.wiley.com/doi/10.1029/2020GL087232},
volume = {47},
year = {2020}
}
@article{Tierney2017,
abstract = {During the “Green Sahara” period (11,000 to 5000 years before the present), the Sahara desert received high amounts of rainfall, supporting diverse vegetation, permanent lakes, and human populations. Our knowledge of rainfall rates and the spatiotemporal extent of wet conditions has suffered from a lack of continuous sedimentary records. We present a quantitative reconstruction of western Saharan precipitation derived from leaf wax isotopes in marine sediments. Our data indicate that the Green Sahara extended to 31°N and likely ended abruptly. We find evidence for a prolonged “pause” in Green Sahara conditions 8000 years ago, coincident with a temporary abandonment of occupational sites by Neolithic humans. The rainfall rates inferred from our data are best explained by strong vegetation and dust feedbacks; without these mechanisms, climate models systematically fail to reproduce the Green Sahara. This study suggests that accurate simulations of future climate change in the Sahara and Sahel will require improvements in our ability to simulate vegetation and dust feedbacks.},
author = {Tierney, Jessica E. and Pausata, Francesco S. R. and DeMenocal, Peter B.},
doi = {10.1126/sciadv.1601503},
issn = {2375-2548},
journal = {Science Advances},
month = {jan},
number = {1},
pages = {e1601503},
title = {{Rainfall regimes of the Green Sahara}},
url = {https://advances.sciencemag.org/lookup/doi/10.1126/sciadv.1601503},
volume = {3},
year = {2017}
}
@article{Tierney2020,
abstract = {The Last Glacial Maximum (LGM), one of the best studied palaeoclimatic intervals, offers an excellent opportunity to investigate how the climate system responds to changes in greenhouse gases and the cryosphere. Previous work has sought to constrain the magnitude and pattern of glacial cooling from palaeothermometers1,2, but the uneven distribution of the proxies, as well as their uncertainties, has challenged the construction of a full-field view of the LGM climate state. Here we combine a large collection of geochemical proxies for sea surface temperature with an isotope-enabled climate model ensemble to produce a field reconstruction of LGM temperatures using data assimilation. The reconstruction is validated with withheld proxies as well as independent ice core and speleothem $\delta$18O measurements. Our assimilated product provides a constraint on global mean LGM cooling of −6.1 degrees Celsius (95 per cent confidence interval: −6.5 to −5.7 degrees Celsius). Given assumptions concerning the radiative forcing of greenhouse gases, ice sheets and mineral dust aerosols, this cooling translates to an equilibrium climate sensitivity of 3.4 degrees Celsius (2.4–4.5 degrees Celsius), a value that is higher than previous LGM-based estimates but consistent with the traditional consensus range of 2–4.5 degrees Celsius3,4.},
author = {Tierney, Jessica E. and Zhu, Jiang and King, Jonathan and Malevich, Steven B. and Hakim, Gregory J. and Poulsen, Christopher J.},
doi = {10.1038/s41586-020-2617-x},
issn = {14764687},
journal = {Nature},
number = {7822},
pages = {569--573},
pmid = {32848226},
title = {{Glacial cooling and climate sensitivity revisited}},
volume = {584},
year = {2020}
}
@article{Tierneyeaay3701,
abstract = {A major cause of uncertainties in climate projections is our imprecise knowledge of how much warming should occur as a result of a given increase in the amount of carbon dioxide in the atmosphere. Paleoclimate records have the potential to help us sharpen that understanding because they record such a wide variety of environmental conditions. Tierney et al. review the recent advances in data collection, statistics, and modeling that might help us better understand how rising levels of atmospheric carbon dioxide will affect future climate.Science, this issue p. eaay3701BACKGROUNDAnthropogenic emissions are rapidly altering Earth{\{}$\backslash$textquoteright{\}}s climate, pushing it toward a warmer state for which there is no historical precedent. Although no perfect analog exists for such a disruption, Earth{\{}$\backslash$textquoteright{\}}s history includes past climate states{\{}$\backslash$textemdash{\}}{\{}$\backslash$textquotedblleft{\}}paleoclimates{\{}$\backslash$textquotedblright{\}}{\{}$\backslash$textemdash{\}}that hold lessons for the future of our warming world. These periods in Earth{\{}$\backslash$textquoteright{\}}s past span a tremendous range of temperatures, precipitation patterns, cryospheric extent, and biospheric adaptations and are increasingly relevant for improving our understanding of how key elements of the climate system are affected by greenhouse gas levels. The rise of new geochemical and statistical methods, as well as improvements in paleoclimate modeling, allow for formal evaluation of climate models based on paleoclimate data. In particular, given that some of the newest generation of climate models have a high sensitivity to a doubling of atmospheric CO2, there is a renewed role for paleoclimates in constraining equilibrium climate sensitivity (ECS) and its dependence on climate background state.ADVANCESIn the past decade, an increasing number of studies have used paleoclimate temperature and CO2 estimates to infer ECS in the deep past, in both warm and cold climate states. Recent studies support the paradigm that ECS is strongly state-dependent, rising with increased CO2 concentrations. Simulations of past warm climates such as the Eocene further highlight the role that cloud feedbacks play in contributing to high ECS under increased CO2 levels. Paleoclimates have provided critical constraints on the assessment of future ice sheet stability and concomitant sea level rise, including the viability of threshold processes like marine ice cliff instability. Beyond global-scale changes, analyses of past changes in the water cycle have advanced our understanding of dynamical drivers of hydroclimate, which is highly relevant for regional climate projections and societal impacts. New and expanding techniques, such as analyses of single shells of foraminifera, are yielding subseasonal climate information that can be used to study how intra- and interannual modes of variability are affected by external climate forcing. Studies of extraordinary, transient departures in paleoclimate from the background state such as the Paleocene-Eocene Thermal Maximum provide critical context for the current anthropogenic aberration, its impact on the Earth system, and the time scale of recovery.A number of advances have eroded the {\{}$\backslash$textquotedblleft{\}}language barrier{\{}$\backslash$textquotedblright{\}} between climate model and proxy data, facilitating more direct use of paleoclimate information to constrain model performance. It is increasingly common to incorporate geochemical tracers, such as water isotopes, directly into model simulations, and this practice has vastly improved model-proxy comparisons. The development of new statistical approaches rooted in Bayesian inference has led to a more thorough quantification of paleoclimate data uncertainties. In addition, techniques like data assimilation allow for a formal combination of proxy and model data into hybrid products. Such syntheses provide a full-field view of past climates and can put constraints on climate variables that we have no direct proxies for, such as cloud cover or wind speed.OUTLOOKA common concern with using paleoclimate information as model targets is that non-CO2 forcings, such as aerosols and trace greenhouse gases, are not well known, especially in the distant past. Although evidence thus far suggests that such forcings are secondary to CO2, future improvements in both geochemical proxies and modeling are on track to tackle this issue. New and rapidly evolving geochemical techniques have the potential to provide improved constraints on the terrestrial biosphere, aerosols, and trace gases; likewise, biogeochemical cycles can now be incorporated into paleoclimate model simulations. Beyond constraining forcings, it is critical that proxy information is transformed into quantitative estimates that account for uncertainties in the proxy system. Statistical tools have already been developed to achieve this, which should make it easier to create robust targets for model evaluation. With this increase in quantification of paleoclimate information, we suggest that modeling centers include simulation of past climates in their evaluation and statement of their model performance. This practice is likely to narrow uncertainties surrounding climate sensitivity, ice sheets, and the water cycle and thus improve future climate projections.Past climates provide context for future climate scenarios.Both past (top) and future (bottom) climates are colored by their estimated change in global mean annual surface temperature relative to preindustrial conditions, ranging from blue (colder) to red (warmer). {\{}$\backslash$textquotedblleft{\}}Sustainability,{\{}$\backslash$textquotedblright{\}} {\{}$\backslash$textquotedblleft{\}}Middle road,{\{}$\backslash$textquotedblright{\}} and {\{}$\backslash$textquotedblleft{\}}High emissions{\{}$\backslash$textquotedblright{\}} represent the estimated global temperature anomalies at year 2300 from the Shared Socioeconomic Pathways (SSPs) SSP1-2.6, SSP2-4.5, and SSP5-8.5, respectively. In both the past and future cases, warmer climates are associated with increases in CO2 (indicated by the arrow). Ma, millions of years ago.As the world warms, there is a profound need to improve projections of climate change. Although the latest Earth system models offer an unprecedented number of features, fundamental uncertainties continue to cloud our view of the future. Past climates provide the only opportunity to observe how the Earth system responds to high carbon dioxide, underlining a fundamental role for paleoclimatology in constraining future climate change. Here, we review the relevancy of paleoclimate information for climate prediction and discuss the prospects for emerging methodologies to further insights gained from past climates. Advances in proxy methods and interpretations pave the way for the use of past climates for model evaluation{\{}$\backslash$textemdash{\}}a practice that we argue should be widely adopted.},
author = {Tierney, Jessica E and Poulsen, Christopher J and Monta{\~{n}}ez, Isabel P and Bhattacharya, Tripti and Feng, Ran and Ford, Heather L and H{\"{o}}nisch, B{\"{a}}rbel and Inglis, Gordon N and Petersen, Sierra V and Sagoo, Navjit and Tabor, Clay R and Thirumalai, Kaustubh and Zhu, Jiang and Burls, Natalie J and Foster, Gavin L and Godd{\'{e}}ris, Yves and Huber, Brian T and Ivany, Linda C and {Kirtland Turner}, Sandra and Lunt, Daniel J and McElwain, Jennifer C and Mills, Benjamin J W and Otto-Bliesner, Bette L and Ridgwell, Andy and Zhang, Yi Ge},
doi = {10.1126/science.aay3701},
issn = {0036-8075},
journal = {Science},
number = {6517},
pages = {eaay3701},
publisher = {American Association for the Advancement of Science},
title = {{Past climates inform our future}},
url = {https://science.sciencemag.org/content/370/6517/eaay3701},
volume = {370},
year = {2020}
}
@article{Tierney2015b,
abstract = {The recent decline in Horn of Africa rainfall during the March–May " long rains " season has fomented drought and famine, threatening food security in an already vulnerable region. Some attribute this decline to anthropogenic forcing, whereas others maintain that it is a feature of internal climate variability. We show that the rate of drying in the Horn of Africa during the 20th century is unusual in the context of the last 2000 years, is synchronous with recent global and regional warming, and therefore may have an anthropogenic component. In contrast to 20th century drying, climate models predict that the Horn of Africa will become wetter as global temperatures rise. The projected increase in rainfall mainly occurs during the September–November " short rains " season, in response to large-scale weakening of the Walker circulation. Most of the models overestimate short rains precipitation while underestimating long rains precipitation, causing the Walker circulation response to unrealistically dominate the annual mean. Our results highlight the need for accurate simulation of the seasonal cycle and an improved understanding of the dynamics of the long rains season to predict future rainfall in the Horn of Africa.},
author = {Tierney, Jessica E. and Ummenhofer, Caroline C. and DeMenocal, Peter B.},
doi = {10.1126/sciadv.1500682},
isbn = {2375-2548},
issn = {23752548},
journal = {Science Advances},
month = {oct},
number = {9},
pages = {e1500682},
pmid = {26601306},
publisher = {American Association for the Advancement of Science ({\{}AAAS{\}})},
title = {{Past and future rainfall in the Horn of Africa}},
volume = {1},
year = {2015}
}
@article{Tierney2019,
author = {Tierney, Jessica E. and Haywood, Alan M. and Feng, Ran and Bhattacharya, Tripti and Otto-Bliesner, Bette L.},
doi = {10.1029/2019gl083802},
issn = {0094-8276},
journal = {Geophysical Research Letters},
number = {15},
pages = {9136--9144},
title = {{Pliocene warmth consistent with greenhouse gas forcing}},
volume = {46},
year = {2019}
}
@article{Tokarska2019,
abstract = {More than 90{\%} of the Earth's energy imbalance is stored by the ocean. While previous studies have shown that changes in the ocean warming are detectable and distinct from internal variability of the climate system, an estimate of separate contributions by natural and individual anthropogenic forcings (such as greenhouse gases and aerosols) remains outstanding. Here we investigate anthropogenic and greenhouse-gas contributions to past ocean warming, and estimate their contributions to future sea level rise by the year 2100. By applying detection and attribution framework (regularized optimal fingerprinting), we show that ocean warming in the historical period is detectable and attributable to contributions from the aggregate anthropogenic forcing as well as greenhouse gas forcing alone. We also discuss the role of natural forcing on the ocean volume-averaged temperature and examine the impact of volcanic activity from the three main volcanoes occurring in the historical period 1955-2012. Our results suggest that estimated anthropogenic and greenhouse-gas contributions to ocean warming are consistent with observations, and observationally-constrained future thermosteric sea level rise projections support the central and lower part of the multi-model mean projection range distribution.},
author = {Tokarska, Katarzyna B. and Hegerl, Gabriele C. and Schurer, Andrew P. and Ribes, Aur{\'{e}}lien and Fasullo, John T.},
doi = {10.1088/1748-9326/ab23c1},
issn = {1748-9326},
journal = {Environmental Research Letters},
keywords = {Earthsystem modelling,Ocean warming,climate change,detection and attribution,thermosteric sea level},
month = {jul},
number = {7},
pages = {074020},
title = {{Quantifying human contributions to past and future ocean warming and thermosteric sea level rise}},
url = {https://iopscience.iop.org/article/10.1088/1748-9326/ab23c1},
volume = {14},
year = {2019}
}
@article{Tokarska2020,
abstract = {Future global warming estimates have been similar across past assessments, but several climate models of the latest Sixth Coupled Model Intercomparison Project (CMIP6) simulate much stronger warming, apparently inconsistent with past assessments. Here, we show that projected future warming is correlated with the simulated warming trend during recent decades across CMIP5 and CMIP6 models, enabling us to constrain future warming based on consistency with the observed warming. These findings carry important policy-relevant implications: The observationally constrained CMIP6 median warming in high emissions and ambitious mitigation scenarios is over 16 and 14{\%} lower by 2050 compared to the raw CMIP6 median, respectively, and over 14 and 8{\%} lower by 2090, relative to 1995-2014. Observationally constrained CMIP6 warming is consistent with previous assessments based on CMIP5 models, and in an ambitious mitigation scenario, the likely range is consistent with reaching the Paris Agreement target.},
author = {Tokarska, Katarzyna B. and Stolpe, Martin B. and Sippel, Sebastian and Fischer, Erich M. and Smith, Christopher J. and Lehner, Flavio and Knutti, Reto},
doi = {10.1126/sciadv.aaz9549},
issn = {23752548},
journal = {Science Advances},
number = {12},
pages = {eaaz9549},
title = {{Past warming trend constrains future warming in CMIP6 models}},
volume = {6},
year = {2020}
}
@article{Tokinaga2012,
author = {Tokinaga, Hiroki and Xie, Shang-Ping and Deser, Clara and Kosaka, Yu and Okumura, Yuko M},
doi = {10.1038/nature11576},
journal = {Nature},
month = {nov},
pages = {439},
publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.},
title = {{Slowdown of the Walker circulation driven by tropical Indo-Pacific warming}},
url = {http://dx.doi.org/10.1038/nature11576 http://10.0.4.14/nature11576 https://www.nature.com/articles/nature11576{\#}supplementary-information},
volume = {491},
year = {2012}
}
@article{Toohey2017,
abstract = {The injection of sulfur into the stratosphere by explosive volcanic eruptions is the cause of significant climate variability. Based on sulfate records from a suite of ice cores from Greenland and Antarctica, the eVolv2k database includes estimates of the magnitudes and approximate source latitudes of major volcanic stratospheric sulfur injection (VSSI) events from 500 BCE to 1900 CE, constituting an update of prior reconstructions and an extension of the record by 1000 years. The database incorporates improvements to the ice core records (in terms of synchronisation and dating) and refinements to the methods used to estimate VSSI from ice core records, and it includes first estimates of the random uncertainties in VSSI values. VSSI estimates for many of the largest eruptions, including Samalas (1257), Tambora (1815), and Laki (1783), are within 10 {\{}{\%}{\}} of prior estimates. A number of strong events are included in eVolv2k which are largely underestimated or not included in earlier VSSI reconstructions, including events in 540, 574, 682, and 1108 CE. The long-term annual mean VSSI from major volcanic eruptions is estimated to be ∼ 0.5 Tg [S] yr−1, ∼ 50 {\{}{\%}{\}} greater than a prior reconstruction due to the identification of more events and an increase in the magnitude of many intermediate events. A long-term latitudinally and monthly resolved stratospheric aerosol optical depth (SAOD) time series is reconstructed from the eVolv2k VSSI estimates, and the resulting global mean SAOD is found to be similar (within 33 {\{}{\%}{\}}) to a prior reconstruction for most of the largest eruptions. The long-term (500 BCE–1900 CE) average global mean SAOD estimated from the eVolv2k VSSI estimates including a constant background injection of stratospheric sulfur is ∼ 0.014, 30 {\{}{\%}{\}} greater than a prior reconstruction. These new long-term reconstructions of past VSSI and SAOD variability give context to recent volcanic forcing, suggesting that the 20th century was a period of somewhat weaker than average volcanic forcing, with current best estimates of 20th century mean VSSI and SAOD values being 25 and 14 {\{}{\%}{\}} less, respectively, than the mean of the 500 BCE to 1900 CE period. The reconstructed VSSI and SAOD data are available at https://doi.org/10.1594/WDCC/eVolv2k{\{}{\_}{\}}v2.},
author = {Toohey, Matthew and Sigl, Michael},
doi = {10.5194/essd-9-809-2017},
issn = {1866-3516},
journal = {Earth System Science Data},
month = {nov},
number = {2},
pages = {809--831},
title = {{Volcanic stratospheric sulfur injections and aerosol optical depth from 500 BCE to 1900 CE}},
volume = {9},
year = {2017}
}
@article{Trenberth2014c,
author = {Trenberth, Kevin E. and Fasullo, John T. and Branstator, Grant and Phillips, Adam S.},
doi = {10.1038/nclimate2341},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {oct},
number = {10},
pages = {911--916},
title = {{Seasonal aspects of the recent pause in surface warming}},
url = {http://www.nature.com/articles/nclimate2341},
volume = {4},
year = {2014}
}
@article{Trenberth2000,
author = {Trenberth, Kevin E. and Stepaniak, David P. and Caron, Julie M.},
doi = {10.1175/1520-0442(2000)013<3969:TGMAST>2.0.CO;2},
issn = {0894-8755},
journal = {Journal of Climate},
month = {nov},
number = {22},
pages = {3969--3993},
title = {{The Global Monsoon as Seen through the Divergent Atmospheric Circulation}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/1520-0442{\%}282000{\%}29013{\%}3C3969{\%}3ATGMAST{\%}3E2.0.CO{\%}3B2},
volume = {13},
year = {2000}
}
@article{Trenberth2017,
abstract = {Intermittency is a core characteristic of precipitation, not well described by data and very poorly modeled. Detailed analyses are made of near-global gridded (about 1°) hourly or 3-hourly precipitation rates from two updated observational datasets [3-hourly TRMM 3B42, version 7, and hourly CMORPH, version 1.0, bias corrected (CRT)] and from special runs of CESM from January 1998 to December 2013 to obtain hourly values. The analyses explore the intermittency of precipitation: the frequency, intensity, duration, and amounts. A comparison is made for all products using several metrics with a focus on the duration of events, and a new metric is proposed based on the ratio of the frequency of precipitation at certain rates (0.2–2 mm h−1) for hourly versus 3-hourly versus daily data. For all seasons and rain rates, TRMM values are similar in pattern to CMORPH, but durations are about 80{\%}–85{\%}. It is mainly over land in the monsoons that CMORPH exceeds TRMM rain durations. Observed duration of precipitation events in CMORPH over oceans are 12–15 h in the tropics and subtropics, much less than the {\~{}}20 h for CESM. Hence, the observational results differ somewhat but both are considerably different from the model, which has too much precipitation overall, and it precipitates far too often at low rates and not enough for intense rates, with the divide about 1–2 mm h−1. There is a need to properly represent precipitation phenomena and processes either explicitly or implicitly (parameterized).},
author = {Trenberth, Kevin E. and Zhang, Yongxin and Gehne, Maria},
doi = {10.1175/JHM-D-16-0263.1},
issn = {1525-755X},
journal = {Journal of Hydrometeorology},
month = {may},
number = {5},
pages = {1393--1412},
title = {{Intermittency in Precipitation: Duration, Frequency, Intensity, and Amounts Using Hourly Data}},
url = {http://journals.ametsoc.org/doi/10.1175/JHM-D-16-0263.1},
volume = {18},
year = {2017}
}
@article{Triacca2014,
abstract = {{\textcopyright} 2014 American Meteorological Society. It is well known that natural external forcings and decadal-to-millennial variability drove changes in the climate system throughout the Holocene. Regarding recent times, attribution studies have shown that greenhouse gases (GHGs) determined the trend of temperature (T) in the last half century, while circulation patterns contributed to modify its interannual, decadal, or multidecadal behavior over this period. Here temperature predictions based on vector autoregressive models (VARs) have been used to study the influence of GHGs and El Ni{\~{n}}o-Southern Oscillation (ENSO) on recent temperature behavior. It is found that in the last decades of steep temperature increase, ENSO shows just a very short-range influence on T, while GHGs are dominant for each forecast horizon. Conversely and quite surprisingly, in the previous quasi-stationary period the influences of GHGs and ENSO are comparable, even at longer range. Therefore, if the recent hiatus in global temperatures should persist into the near future, an enhancement of the role of ENSO can be expected. Finally, the predictive ability of GHGs is more evident in the Southern Hemisphere, where the temperature series is smoother.},
author = {Triacca, U. and Pasini, A. and Attanasio, A. and Giovannelli, A. and Lippi, M.},
doi = {10.1175/JCLI-D-13-00784.1},
journal = {Journal of Climate},
number = {20},
pages = {7903--7910},
title = {{Clarifying the roles of greenhouse gases and ENSO in recent global warming through their prediction performance}},
volume = {27},
year = {2014}
}
@article{Trouet2012,
author = {Trouet, V. and Scourse, J.D. and Raible, C.C.},
doi = {10.1016/j.gloplacha.2011.10.003},
issn = {09218181},
journal = {Global and Planetary Change},
month = {mar},
pages = {48--55},
title = {{North Atlantic storminess and Atlantic Meridional Overturning Circulation during the last Millennium: Reconciling contradictory proxy records of NAO variability}},
url = {https://linkinghub.elsevier.com/retrieve/pii/S092181811100155X},
volume = {84-85},
year = {2012}
}
@article{Trusel2018,
abstract = {The Greenland ice sheet (GrIS) is a growing contributor to global sea-level rise1, with recent ice mass loss dominated by surface meltwater runoff2,3. Satellite observations reveal positive trends in GrIS surface melt extent4, but melt variability, intensity and runoff remain uncertain before the satellite era. Here we present the first continuous, multi-century and observationally constrained record of GrIS surface melt intensity and runoff, revealing that the magnitude of recent GrIS melting is exceptional over at least the last 350 years. We develop this record through stratigraphic analysis of central west Greenland ice cores, and demonstrate that measurements of refrozen melt layers in percolation zone ice cores can be used to quantifiably, and reproducibly, reconstruct past melt rates. We show significant (P {\textless} 0.01) and spatially extensive correlations between these ice-core-derived melt records and modelled melt rates5,6 and satellite-derived melt duration4 across Greenland more broadly, enabling the reconstruction of past ice-sheet-scale surface melt intensity and runoff. We find that the initiation of increases in GrIS melting closely follow the onset of industrial-era Arctic warming in the mid-1800s, but that the magnitude of GrIS melting has only recently emerged beyond the range of natural variability. Owing to a nonlinear response of surface melting to increasing summer air temperatures, continued atmospheric warming will lead to rapid increases in GrIS runoff and sea-level contributions.},
author = {Trusel, Luke D. and Das, Sarah B. and Osman, Matthew B. and Evans, Matthew J. and Smith, Ben E. and Fettweis, Xavier and McConnell, Joseph R. and No{\"{e}}l, Brice P.Y. and van den Broeke, Michiel R.},
doi = {10.1038/s41586-018-0752-4},
issn = {14764687},
journal = {Nature},
number = {7734},
pages = {104--108},
pmid = {30518887},
title = {{Nonlinear rise in Greenland runoff in response to post-industrial Arctic warming}},
volume = {564},
year = {2018}
}
@article{Tuel2019,
abstract = {Global climate models generally overestimate recent tropospheric warming trends. While a number of explanations have been suggested, their relative impacts have not been quantified. In particular, interannual and long-term variability of tropospheric temperatures (TTT) is known to be strongly constrained by near-surface conditions in ocean regions of deep convection. Here, we analyze the role played by tropical sea surface temperature (SST) variability in recent decades in setting TTT. We find that Coupled Model Intercomparison Project Phase 5 models and observations agree on the interannual relationship between SSTs in regions of deep, tropical convection and TTT. Over the 1979–2018 period, most of the difference between model and satellite-based TTT trends can be explained by respective differences in SST warming trends in regions of deep convection. While large multidecadal patterns of SST variability certainly play a role, notably in the Pacific Ocean, other mechanisms may also contribute to the overestimation of recent SST warming in climate models.},
author = {Tuel, A.},
doi = {10.1029/2019GL083994},
issn = {19448007},
journal = {Geophysical Research Letters},
pages = {9023-- 9030},
title = {{Explaining differences between recent model and satellite tropospheric warming rates with tropical SSTs}},
volume = {46},
year = {2019}
}
@article{Turner2013,
abstract = {This paper examines the annual cycle and trends in Antarctic sea ice extent (SIE) for 18 models used in phase 5 of the Coupled Model Intercomparison Project (CMIP5) that were run with historical forcing for the 1850s to 2005. Many of the models have an annual SIE cycle that differs markedly from that observed over the last 30 years. The majority of models have too small of an SIE at the minimum in February, while several of the models have less than two-thirds of the observed SIE at the September maximum. In contrast to the satellite data, which exhibit a slight increase in SIE, the mean SIE of the models over 1979–2005 shows a decrease in each month, with the greatest multimodel mean percentage monthly decline of 13.6{\%} decade−1 in February and the greatest absolute loss of ice of −0.40 × 106 km2 decade−1 in September. The models have very large differences in SIE over 1860–2005. Most of the control runs have statistically significant trends in SIE over their full time span, and all of the models have a negative trend in SIE since the mid-nineteenth century. The negative SIE trends in most of the model runs over 1979–2005 are a continuation of an earlier decline, suggesting that the processes responsible for the observed increase over the last 30 years are not being simulated correctly.},
author = {Turner, John and Bracegirdle, Thomas J. and Phillips, Tony and Marshall, Gareth J. and {Scott Hosking}, J.},
doi = {10.1175/JCLI-D-12-00068.1},
isbn = {0894-8755},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Antarctica,Climate change,Numerical analysis/modeling,Sea ice},
month = {mar},
number = {5},
pages = {1473--1484},
title = {{An Initial Assessment of Antarctic Sea Ice Extent in the CMIP5 Models}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00068.1},
volume = {26},
year = {2013}
}
@article{doi:10.1002/2017GL073656,
abstract = {Abstract During austral spring 2016 Antarctic sea ice extent (SIE) decreased at a record rate of 75 × 103 km2 d−1, which was 46{\%} faster than the mean rate and 18{\%} faster than in any previous spring season during the satellite era. The decrease of sea ice area was also exceptional and 28{\%} greater than the mean. Anomalous negative retreat occurred in all sectors of the Antarctic but was greatest in the Weddell and Ross Seas. Record negative SIE anomalies for the day of year were recorded from 3 November 2016 to 9 April 2017. Rapid ice retreat in the Weddell Sea took place in strong northerly flow after an early maximum ice extent in late August. Rapid ice retreat occurred in November in the Ross Sea when surface pressure was at a record high level, with the Southern Annular Mode at its most negative for that month since 1968.},
author = {Turner, John and Phillips, Tony and Marshall, Gareth J and Hosking, J Scott and Pope, James O and Bracegirdle, Thomas J and Deb, Pranab},
doi = {10.1002/2017GL073656},
journal = {Geophysical Research Letters},
keywords = {Southern Ocean,sea ice,variability},
number = {13},
pages = {6868--6875},
title = {{Unprecedented springtime retreat of Antarctic sea ice in 2016}},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2017GL073656},
volume = {44},
year = {2017}
}
@article{Turner2016,
abstract = {We investigate the relationship between atmospheric circulation variability and the recent trends in Antarctic sea ice extent (SIE) using Coupled Model Intercomparison Project Phase 5 (CMIP5) atmospheric data, ECMWF Interim reanalysis fields and passive microwave satellite data processed with the Bootstrap version 2 algorithm. Over 1979--2013 the annual mean total Antarctic SIE increased at a rate of 195 {\{}$\backslash$texttimes{\}} 103 km2 dec−1 (1.6 {\%} dec−1), p {\textless} 0.01. The largest regional positive trend of annual mean SIE of 119 {\{}$\backslash$texttimes{\}} 103 km2 dec−1 (4.0 {\%} dec−1) has been in the Ross Sea sector. Off West Antarctica there is a high correlation between trends in SIE and trends in the near-surface winds. The Ross Sea SIE seasonal trends are positive throughout the year, but largest in spring. The stronger meridional flow over the Ross Sea has been driven by a deepening of the Amundsen Sea Low (ASL). Pre-industrial control and historical simulations from CMIP5 indicate that the observed deepening of the ASL and stronger southerly flow over the Ross Sea are within the bounds of modeled intrinsic variability. The spring trend would need to continue for another 11 years for it to fall outside the 2 standard deviation range seen in 90 {\%} of the simulations.},
author = {Turner, John and Hosking, J Scott and Marshall, Gareth J and Phillips, Tony and Bracegirdle, Thomas J},
doi = {10.1007/s00382-015-2708-9},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {7},
pages = {2391--2402},
title = {{Antarctic sea ice increase consistent with intrinsic variability of the Amundsen Sea Low}},
url = {https://doi.org/10.1007/s00382-015-2708-9},
volume = {46},
year = {2016}
}
@article{Undorf2018e,
author = {Undorf, S. and Polson, D. and Bollasina, M. A. and Ming, Y. and Schurer, A. and Hegerl, G. C.},
doi = {10.1029/2017JD027711},
issn = {2169897X},
journal = {Journal of Geophysical Research: Atmospheres},
month = {may},
number = {10},
pages = {4871--4889},
title = {{Detectable Impact of Local and Remote Anthropogenic Aerosols on the 20th Century Changes of West African and South Asian Monsoon Precipitation}},
volume = {123},
year = {2018}
}
@article{Undorf2018a,
abstract = {Abstract The extent and mechanisms of the Atlantic response to the historical (1850?1975) increase of sulphate aerosol emissions from North America and Europe as simulated in eight-member ensemble experiments with the coupled Community Earth System Model (CESM1)-Community Atmosphere Model version 5.3 are contrasted. The results show that aerosols from either source cause a long-term cooling of North Atlantic sea surface temperatures, with the patterns a combination of atmospheric aerosol effects and an aerosol-induced strengthening of the Atlantic Meridional Overturning Circulation. The response to North American emissions is larger since prevailing winds cause wider aerosol spread over the Atlantic, collocated with climatological cloud cover. The Intertropical Convergence Zone shifts southward affecting tropical precipitation globally. The simulated (multi)decadal components of sea surface temperature and Atlantic Meridional Overturning Circulation variability are furthermore primarily externally forced. The analysis provides novel insights into the mechanisms of aerosol impact on the Atlantic. It suggests that projected further emission reductions will lead to opposite changes.},
annote = {doi: 10.1029/2018GL079970},
author = {Undorf, S and Bollasina, M A and Booth, B B B and Hegerl, G C},
doi = {10.1029/2018GL079970},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {AMOC forcing,Atlantic multidecadal variability,CESM1 model,North Atlantic climate,anthropogenic aerosols,atmosphere-ocean interactions},
month = {nov},
number = {21},
pages = {11,911--930,940},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Contrasting the Effects of the 1850–1975 Increase in Sulphate Aerosols from North America and Europe on the Atlantic in the CESM}},
url = {https://doi.org/10.1029/2018GL079970},
volume = {45},
year = {2018}
}
@incollection{unfccc2015report,
author = {UNFCCC},
booktitle = {Report of the Conference of the Parties on its twenty-first session, held in Paris from 30 November to 13 December 2015. Addendum: Part two: Action taken by the Conference of the Parties at its twenty-first session},
doi = {https://unfccc.int/documents/9097},
pages = {1--36},
publisher = {United Nations Framework Convention on Climate Change (UNFCCC)},
series = {FCCC/CP/2015/10/Add.1},
title = {{Decision 1/CP.21: Adoption of the Paris Agreement}},
url = {https://unfccc.int/documents/9097},
year = {2016}
}
@article{Uotila2014,
abstract = {For the first time, we compute the sea-ice concentration budget of a fully coupled climate model, the Australian ACCESS model, in order to assess its realism in simulating the autumn–winter evolution of Antarctic sea ice. The sea-ice concentration budget consists of the local change, advection and divergence, and the residual component which represents the net effect of thermodynamics and ridging. Although the model simulates the evolution of sea-ice area reasonably well, its sea-ice concentration budget significantly deviates from the observed one. The modelled sea-ice budget components deviate from observed close to the Antarctic coast, where the modelled ice motion is more convergent, and near the ice edge, where the modelled ice is advected faster than observed due to inconsistencies between ice velocities. In the central ice pack the agreement between the model and observations is better. Based on this, we propose that efforts to simulate the observed Antarctic sea-ice trends should focus on improving the realism of modelled ice drift.},
author = {Uotila, P and Holland, P R and Vihma, T and Marsland, S J and Kimura, N},
doi = {10.1016/j.ocemod.2014.04.004},
issn = {1463-5003},
journal = {Ocean Modelling},
keywords = {Advection,Divergence,Thermodynamics},
pages = {33--42},
title = {{Is realistic Antarctic sea-ice extent in climate models the result of excessive ice drift?}},
url = {http://www.sciencedirect.com/science/article/pii/S1463500314000523},
volume = {79},
year = {2014}
}
@article{VandenHurk2016,
abstract = {Abstract. The Land Surface, Snow and Soil Moisture Model Intercomparison Project (LS3MIP) is designed to provide a comprehensive assessment of land surface, snow and soil moisture feedbacks on climate variability and climate change, and to diagnose systematic biases in the land modules of current Earth system models (ESMs). The solid and liquid water stored at the land surface has a large influence on the regional climate, its variability and predictability, including effects on the energy, water and carbon cycles. Notably, snow and soil moisture affect surface radiation and flux partitioning properties, moisture storage and land surface memory. They both strongly affect atmospheric conditions, in particular surface air temperature and precipitation, but also large-scale circulation patterns. However, models show divergent responses and representations of these feedbacks as well as systematic biases in the underlying processes. LS3MIP will provide the means to quantify the associated uncertainties and better constrain climate change projections, which is of particular interest for highly vulnerable regions (densely populated areas, agricultural regions, the Arctic, semi-arid and other sensitive terrestrial ecosystems). The experiments are subdivided in two components, the first addressing systematic land biases in offline mode (“LMIP”, building upon the 3rd phase of Global Soil Wetness Project; GSWP3) and the second addressing land feedbacks attributed to soil moisture and snow in an integrated framework (“LFMIP”, building upon the GLACE-CMIP blueprint).},
author = {van den Hurk, Bart and Kim, Hyungjun and Krinner, Gerhard and Seneviratne, Sonia I. and Derksen, Chris and Oki, Taikan and Douville, Herv{\'{e}} and Colin, Jeanne and Ducharne, Agn{\`{e}}s and Cheruy, Frederique and Viovy, Nicholas and Puma, Michael J. and Wada, Yoshihide and Li, Weiping and Jia, Binghao and Alessandri, Andrea and Lawrence, Dave M. and Weedon, Graham P. and Ellis, Richard and Hagemann, Stefan and Mao, Jiafu and Flanner, Mark G. and Zampieri, Matteo and Materia, Stefano and Law, Rachel M. and Sheffield, Justin},
doi = {10.5194/gmd-9-2809-2016},
issn = {1991-9603},
journal = {Geoscientific Model Development},
month = {aug},
number = {8},
pages = {2809--2832},
title = {{LS3MIP (v1.0) contribution to CMIP6: the Land Surface, Snow and Soil moisture Model Intercomparison Project – aims, setup and expected outcome}},
url = {https://www.geosci-model-dev.net/9/2809/2016/},
volume = {9},
year = {2016}
}
@article{van2015resolution,
abstract = {In this study, the authors investigate the effect of GCM spatial resolution on modeled precipitation over Europe. The objectives of the analysis are to determine whether climate models have sufficient spatial resolution to have an accurate representation of the storm tracks that affect precipitation. They investigate if there is a significant statistical difference in modeled precipitation between a medium-resolution ({\~{}}112-km horizontal resolution) and a high-resolution ({\~{}}25-km horizontal resolution) version of a state-of-the-art AGCM (EC-EARTH), if either model resolution gives a better representation of precipitation in the current climate, and what processes are responsible for the differences in modeled precipitation. The authors find that the high-resolution model gives a more accurate representation of northern and central European winter precipitation. The medium-resolution model has a larger positive bias in precipitation in most of the northern half of Europe. Storm tracks are better simulated in the high-resolution model, providing for a more accurate horizontal moisture transport and moisture convergence. Using a decomposition of the precipitation difference between the medium- and high-resolution model in a part related and a part unrelated to a difference in the distribution of vertical atmospheric velocity, the authors find that the smaller precipitation bias in central and northern Europe is largely unrelated to a difference in vertical velocity distribution. The smaller precipitation amount in these areas is in agreement with less moisture transport over this area in the high-resolution model. In areas with orography the change in vertical velocity distribution is found to be more important.},
author = {van Haren, Ronald and Haarsma, Reindert J and {Van Oldenborgh}, Geert Jan and Hazeleger, Wilco},
doi = {10.1175/JCLI-D-14-00279.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jul},
number = {13},
pages = {5134--5149},
title = {{Resolution Dependence of European Precipitation in a State-of-the-Art Atmospheric General Circulation Model}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-14-00279.1},
volume = {28},
year = {2015}
}
@article{VanKampenhout2020a,
abstract = {The response of the Greenland Ice Sheet (GrIS) to a warmer climate is uncertain on long time scales. Climate models, such as those participating in the Coupled Model Intercomparison Project phase 6 (CMIP6), are used to assess this uncertainty. The Community Earth System Model version 2.1 (CESM2) is a CMIP6 model capable of running climate simulations with either one-way coupling (fixed ice sheet geometry) or two-way coupling (dynamic geometry) to the GrIS. The model features prognostic snow albedo, online downscaling using elevation classes, and a firn pack to refreeze percolating melt water. Here we evaluate the representation of the GrIS surface energy balance and surface mass balance in CESM2 at 1° resolution with fixed GrIS geometry. CESM2 agrees closely with ERA-Interim reanalysis data for key controls on GrIS SMB: surface pressure, sea ice extent, 500 hPa geopotential height, wind speed, and 700 hPa air temperature. Cloudsat-CALIPSO data show that supercooled liquid-containing clouds are adequately represented, whereas comparisons to Moderate Resolution Imaging Spectroradiometer and CM SAF Cloud, Albedo, and Surface Radiation data set from Advanced Very High Resolution Radiometer data second edition data suggest that CESM2 underestimates surface albedo. The seasonal cycle and spatial patterns of surface energy balance and surface mass balance components in CESM2 agree well with regional climate model RACMO2.3p2, with GrIS-integrated melt, refreezing, and runoff bracketed by RACMO2 counterparts at 11 and 1 km. Time series of melt, runoff, and SMB show a break point around 1990, similar to RACMO2. These results suggest that GrIS SMB is realistic in CESM2, which adds confidence to coupled ice sheet-climate experiments that aim to assess the GrIS contribution to future sea level rise.},
author = {van Kampenhout, Leonardus and Lenaerts, Jan T. M. and Lipscomb, William H. and Lhermitte, Stef and No{\"{e}}l, Brice and Vizca{\'{i}}no, Miren and Sacks, William J. and van den Broeke, Michiel R.},
doi = {10.1029/2019JF005318},
issn = {2169-9003},
journal = {Journal of Geophysical Research: Earth Surface},
keywords = {CESM2,ESM,GCM,Greenland,ice sheets,surface mass balance},
month = {feb},
number = {2},
pages = {e2019JF005318},
title = {{Present‐Day Greenland Ice Sheet Climate and Surface Mass Balance in CESM2}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JF005318},
volume = {125},
year = {2020}
}
@article{Vannière2019,
abstract = {This study undertakes a multi-model comparison with the aim to describe and quantify systematic changes of the global energy and water budgets when the horizontal resolution of atmospheric models is increased and to identify common factors of these changes among models. To do so, we analyse an ensemble of twelve atmosphere-only and six coupled GCMs, with different model formulations and with resolutions spanning those of state-of-the-art coupled GCMs, i.e. from resolutions coarser than 100 km to resolutions finer than 25 km. The main changes in the global energy budget with resolution are a systematic increase in outgoing longwave radiation and decrease in outgoing shortwave radiation due to changes in cloud properties, and a systematic increase in surface latent heat flux; when resolution is increased from 100 to 25 km, the magnitude of the change of those fluxes can be as large as 5 W m−2. Moreover, all but one atmosphere-only model simulate a decrease of the poleward energy transport at higher resolution, mainly explained by a reduction of the equator-to-pole tropospheric temperature gradient. Regarding hydrological processes, our results are the following: (1) there is an increase of global precipitation with increasing resolution in all models (up to 40{\{}$\backslash$thinspace{\}}{\{}$\backslash$texttimes{\}}{\{}$\backslash$thinspace{\}}103 km3 year−1) but the partitioning between land and ocean varies among models; (2) the fraction of total precipitation that falls on land is on average 10{\%} larger at higher resolution in grid point models, but it is smaller at higher resolution in spectral models; (3) grid points models simulate an increase of the fraction of land precipitation due to moisture convergence twice as large as in spectral models; (4) grid point models, which have a better resolved orography, show an increase of orographic precipitation of up to 13{\{}$\backslash$thinspace{\}}{\{}$\backslash$texttimes{\}}{\{}$\backslash$thinspace{\}}103 km3 year−1 which explains most of the change in land precipitation; (5) at the regional scale, precipitation pattern and amplitude are improved with increased resolution due to a better simulated seasonal mean circulation. We discuss our results against several observational estimates of the Earth's energy budget and hydrological cycle and show that they support recent high estimates of global precipitation.},
author = {Vanni{\`{e}}re, Beno{\^{i}}t and Demory, Marie-Estelle and Vidale, Pier Luigi and Schiemann, Reinhard and Roberts, Malcolm J and Roberts, Christopher D and Matsueda, Mio and Terray, Laurent and Koenigk, Torben and Senan, Retish},
doi = {10.1007/s00382-018-4547-y},
issn = {1432-0894},
journal = {Climate Dynamics},
month = {jun},
number = {11},
pages = {6817--6846},
title = {{Multi-model evaluation of the sensitivity of the global energy budget and hydrological cycle to resolution}},
url = {https://doi.org/10.1007/s00382-018-4547-y},
volume = {52},
year = {2019}
}
@article{Vecchi2007,
abstract = {Abstract This study examines the response of the tropical atmospheric and oceanic circulation to increasing greenhouse gases using a coordinated set of twenty-first-century climate model experiments performed for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). The strength of the atmospheric overturning circulation decreases as the climate warms in all IPCC AR4 models, in a manner consistent with the thermodynamic scaling arguments of Held and Soden. The weakening occurs preferentially in the zonally asymmetric (i.e., Walker) rather than zonal-mean (i.e., Hadley) component of the tropical circulation and is shown to induce substantial changes to the thermal structure and circulation of the tropical oceans. Evidence suggests that the overall circulation weakens by decreasing the frequency of strong updrafts and increasing the frequency of weak updrafts, although the robustness of this behavior across all models cannot be confirmed because of the lack of data. As the climate warms, changes in both the atmospheric and ocean circulation over the tropical Pacific Ocean resemble ?El Ni{\~{n}}o?like? conditions; however, the mechanisms are shown to be distinct from those of El Ni{\~{n}}o and are reproduced in both mixed layer and full ocean dynamics coupled climate models. The character of the Indian Ocean response to global warming resembles that of Indian Ocean dipole mode events. The consensus of model results presented here is also consistent with recently detected changes in sea level pressure since the mid?nineteenth century.},
annote = {doi: 10.1175/JCLI4258.1},
author = {Vecchi, Gabriel A and Soden, Brian J},
doi = {10.1175/JCLI4258.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {sep},
number = {17},
pages = {4316--4340},
publisher = {American Meteorological Society},
title = {{Global Warming and the Weakening of the Tropical Circulation}},
url = {https://doi.org/10.1175/JCLI4258.1},
volume = {20},
year = {2007}
}
@article{Vecchi2006a,
abstract = {Since the mid-nineteenth century the Earth's surface has warmed, and models indicate that human activities have caused part of the warming by altering the radiative balance of the atmosphere. Simple theories suggest that global warming will reduce the strength of the mean tropical atmospheric circulation. An important aspect of this tropical circulation is a large-scale zonal (east-west) overturning of air across the equatorial Pacific Ocean--driven by convection to the west and subsidence to the east--known as the Walker circulation. Here we explore changes in tropical Pacific circulation since the mid-nineteenth century using observations and a suite of global climate model experiments. Observed Indo-Pacific sea level pressure reveals a weakening of the Walker circulation. The size of this trend is consistent with theoretical predictions, is accurately reproduced by climate model simulations and, within the climate models, is largely due to anthropogenic forcing. The climate model indicates that the weakened surface winds have altered the thermal structure and circulation of the tropical Pacific Ocean. These results support model projections of further weakening of tropical atmospheric circulation during the twenty-first century.},
author = {Vecchi, Gabriel A. and Soden, Brian J. and Wittenberg, Andrew T. and Held, Isaac M. and Leetmaa, Ants and Harrison, Matthew J.},
doi = {10.1038/nature04744},
isbn = {0028-0836},
issn = {14764687},
journal = {Nature},
number = {1},
pages = {73--76},
pmid = {16672967},
title = {{Weakening of tropical Pacific atmospheric circulation due to anthropogenic forcing}},
volume = {441},
year = {2006}
}
@article{Vera2014a,
author = {Vera, Carolina S and D{\'{i}}az, Leandro},
doi = {10.1002/joc.4153},
issn = {08998418},
journal = {International Journal of Climatology},
month = {aug},
number = {10},
pages = {3172--3177},
title = {{Anthropogenic influence on summer precipitation trends over South America in CMIP5 models}},
url = {https://onlinelibrary.wiley.com/doi/10.1002/joc.4153},
volume = {35},
year = {2015}
}
@article{Verma2019,
abstract = {The large-scale and long-term climate impacts of anthropogenic sulfate aerosols consist of Northern Hemisphere cooling and a southward shift of the tropical rain belt. On interannual time scales, however, the response to aerosols is localized with a sizable imprint on local ocean–atmosphere interaction. A large concentration of anthropogenic sulfates over Asia may impact ENSO by modifying processes and interactions that generate this coupled ocean–atmosphere variability. Here, we use climate model experiments with different degrees of ocean–atmosphere coupling to study the tropical Pacific response to an abrupt increase in anthropogenic sulfates. These include an atmospheric general circulation model (GCM) coupled to either a full-ocean GCM or a slab-ocean model, or simply forced by climatology of sea surface temperature. Comparing the responses helps differentiate between the fast atmospheric and slow ocean-mediated responses, and highlights the role of ocean–atmosphere coupling in the latter. We demonstrate the link between the Walker circulation and the equatorial Pacific upper-ocean dynamics in response to increased sulfate aerosols. The local surface cooling due to sulfate aerosols emitted over the Asian continent drives atmospheric subsidence over the equatorial west Pacific. The associated anomalous circulation imparts westerly momentum to the underlying Pacific Ocean, leading to an El Ni{\~{n}}o–like upper-ocean response and a transient warming of the east equatorial Pacific Ocean. The oceanic adjustment eventually contributes to its decay, giving rise to a damped oscillation of the tropical Pacific Ocean in response to abrupt anthropogenic sulfate aerosol forcing.},
author = {Verma, Tarun and Saravanan, R. and Chang, P. and Mahajan, S.},
doi = {10.1175/JCLI-D-19-0050.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {dec},
number = {23},
pages = {8205--8221},
title = {{Tropical Pacific Ocean Dynamical Response to Short-Term Sulfate Aerosol Forcing}},
url = {https://journals.ametsoc.org/jcli/article/32/23/8205/344302/Tropical-Pacific-Ocean-Dynamical-Response-to},
volume = {32},
year = {2019}
}
@article{Vidale2021,
abstract = {The role of model resolution in simulating geophysical vortices with the characteristics of realistic tropical cyclones (TCs) is well established. The push for increasing resolution continues, with general circulation models (GCMs) starting to use sub-10-km grid spacing. In the same context it has been suggested that the use of stochastic physics (SP) may act as a surrogate for high resolution, providing some of the benefits at a fraction of the cost. Either technique can reduce model uncertainty, and enhance reliability, by providing a more dynamic environment for initial synoptic disturbances to be spawned and to grow into TCs. We present results from a systematic comparison of the role of model resolution and SP in the simulation of TCs, using EC-Earth simulations from project Climate-SPHINX, in large ensemble mode, spanning five different resolutions. All tropical cyclonic systems, including TCs, were tracked explicitly. As in previous studies, the number of simulated TCs increases with the use of higher resolution, but SP further enhances TC frequencies by {\~{}}30{\%}, in a strikingly similar way. The use of SP is beneficial for removing systematic climate biases, albeit not consistently so for interannual variability; conversely, the use of SP improves the simulation of the seasonal cycle of TC frequency. An investigation of the mechanisms behind this response indicates that SP generates both higher TC (and TC seed) genesis rates, and more suitable environmental conditions, enabling a more efficient transition of TC seeds into TCs. These results were confirmed by the use of equivalent simulations with the HadGEM3-GC31 GCM.},
address = {Boston MA, USA},
author = {Vidale, Pier Luigi and Hodges, Kevin and Vanni{\`{e}}re, Benoit and Davini, Paolo and Roberts, Malcolm J. and Strommen, Kristian and Weisheimer, Antje and Plesca, Elina and Corti, Susanna},
doi = {10.1175/JCLI-D-20-0507.1},
issn = {0894-8755},
journal = {Journal of Climate},
language = {English},
month = {jun},
number = {11},
pages = {4315--4341},
publisher = {American Meteorological Society},
title = {{Impact of Stochastic Physics and Model Resolution on the Simulation of Tropical Cyclones in Climate GCMs}},
url = {https://journals.ametsoc.org/view/journals/clim/34/11/JCLI-D-20-0507.1.xml},
volume = {34},
year = {2021}
}
@article{Vijayeta2017,
abstract = {The CMIP model simulations show wide spread uncertainties in ENSO statistics and dynamics. In this study, we use the concept of the linear recharge oscillator (ReOsc) model to diagnose the ENSO-dynamics in CMIP3 and CMIP5 model simulations. The ReOsc model parameters allow us to quantify SST and thermocline damping, SST coupling to thermocline and vice-versa, sensitivity to wind stress and heat flux forcings and separate atmospheric from oceanic processes. Our results show that the ENSO-dynamics and their diversity within the CMIP ensemble can be well represented with the linear recharge oscillator model diagnostics. We also illustrate that the ENSO dynamics show larger biases relative to observations and spread within the models than simple large-scale statistics such as SST standard deviation would suggest. The CMIP models underestimate the atmospheric positive and negative feedbacks, they have compensating atmospheric and oceanic errors, the thermocline damping is too strong and stochastic noise forcings in models is too weak. The CMIP5 models show only marginal improvements relative to CMIP3. The results suggest that models can still be significantly improved and our analysis gives directions to what needs to be improved.},
author = {Vijayeta, Asha and Dommenget, Dietmar},
doi = {10.1007/s00382-017-3981-6},
isbn = {0038201739},
issn = {0930-7575},
journal = {Climate Dynamics},
keywords = {CGCM,CMIP simulations,Climate feedbacks,Coupled general circulation models,ENSO,ENSO dyanmics,El Nino dynamics,El Nino southern oscillation,Model evaluation,Ocean and atmospheric dynamics,Recharge oscillator model},
month = {sep},
number = {5-6},
pages = {1753--1771},
title = {{An evaluation of ENSO dynamics in CMIP simulations in the framework of the recharge oscillator model}},
url = {http://link.springer.com/10.1007/s00382-017-3981-6},
volume = {51},
year = {2018}
}
@article{ISI:000388676000007,
abstract = {Climate models robustly project that global warming will lead to a poleward shift of the annual-mean zonal-mean extratropical jet streams. The magnitude of such shifts remains uncertain, however, and recent work has indicated a potentially important role of cloud radiative interactions. The model spread found in realistic simulations with interactive sea surface temperatures (SSTs) is captured in aquaplanet simulations with prescribed SSTs, because of which the latter setup is adapted here to study the impact of regional atmospheric cloud radiative changes on the jet position. Simulations with two CMIP5 models and prescribed regional cloud changes show that the rise of tropical high-level clouds and the upward and poleward movement of midlatitude high-level clouds lead to poleward jet shifts. High-latitude low-level cloud changes shift the jet poleward in one model but not in the other. The impact of clouds on the jet operates via the atmospheric radiative forcing that is created by the cloud changes and is qualitatively reproduced in a dry model, although the latter is too sensitive because of its simplified treatment of diabatic processes. The 10-model CMIP5 aquaplanet ensemble of global warming exhibits correlations between jet shifts, regional temperature changes, and regional cloud changes that are consistent with the prescribed cloud simulations. This provides evidence that the atmospheric radiative forcing from tropical and midlatitude high-level cloud changes contributes to model uncertainty in future jet shifts, in addition to the surface radiative forcing from extratropical cloud changes highlighted by previous studies.},
annote = {Cloud-radiative feedback contributes to uncertainty in position and trends of jets.},
author = {Voigt, Aiko and Shaw, Tiffany A},
doi = {10.1175/JCLI-D-16-0140.1},
issn = {0894-8755},
journal = {Journal of Climate},
number = {23},
pages = {8399--8421},
title = {{Impact of Regional Atmospheric Cloud Radiative Changes on Shifts of the Extratropical Jet Stream in Response to Global Warming}},
type = {Article},
volume = {29},
year = {2016}
}
@article{Voldoire2019a,
abstract = {This paper describes the main characteristics of CNRM-CM6-1, the fully coupled atmosphere-ocean general circulation model of sixth generation jointly developed by Centre National de Recherches M{\'{e}}t{\'{e}}orologiques (CNRM) and Cerfacs for the sixth phase of the Coupled Model Intercomparison Project 6 (CMIP6). The paper provides a description of each component of CNRM-CM6-1, including the coupling method and the new online output software. We emphasize where model's components have been updated with respect to the former model version, CNRM-CM5.1. In particular, we highlight major improvements in the representation of atmospheric and land processes. A particular attention has also been devoted to mass and energy conservation in the simulated climate system to limit long-term drifts. The climate simulated by CNRM-CM6-1 is then evaluated using CMIP6 historical and Diagnostic, Evaluation and Characterization of Klima (DECK) experiments in comparison with CMIP5 CNRM-CM5.1 equivalent experiments. Overall, the mean surface biases are of similar magnitude but with different spatial patterns. Deep ocean biases are generally reduced, whereas sea ice is too thin in the Arctic. Although the simulated climate variability remains roughly consistent with CNRM-CM5.1, its sensitivity to rising CO2 has increased: the equilibrium climate sensitivity is 4.9 K, which is now close to the upper bound of the range estimated from CMIP5 models.},
author = {Voldoire, A. and Saint-Martin, D. and S{\'{e}}n{\'{e}}si, S. and Decharme, B. and Alias, A. and Chevallier, M. and Colin, J. and Gu{\'{e}}r{\'{e}}my, J. F. and Michou, M. and Moine, M. P. and Nabat, P. and Roehrig, R. and {Salas y M{\'{e}}lia}, D. and S{\'{e}}f{\'{e}}rian, R. and Valcke, S. and Beau, I. and Belamari, S. and Berthet, S. and Cassou, C. and Cattiaux, J. and Deshayes, J. and Douville, H. and Eth{\'{e}}, C. and Franchist{\'{e}}guy, L. and Geoffroy, O. and L{\'{e}}vy, C. and Madec, G. and Meurdesoif, Y. and Msadek, R. and Ribes, A. and Sanchez-Gomez, E. and Terray, L. and Waldman, R.},
doi = {10.1029/2019MS001683},
issn = {19422466},
journal = {Journal of Advances in Modeling Earth Systems},
keywords = {CMIP6 DECK,CNRM-CM6-1,climate model},
month = {jul},
number = {7},
pages = {2177--2213},
title = {{Evaluation of CMIP6 DECK Experiments With CNRM-CM6-1}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019MS001683},
volume = {11},
year = {2019}
}
@article{Voldoire2019,
author = {Voldoire, Aurore and Exarchou, Eleftheria and Sanchez-Gomez, Emilia and Demissie, Teferi and Deppenmeier, Anna-Lena and Frauen, Claudia and Goubanova, Katerina and Hazeleger, Wilco and Keenlyside, Noel and Koseki, Shunya and Prodhomme, Chlo{\'{e}} and Shonk, Jonathan and Toniazzo, Thomas and Traor{\'{e}}, Abdoul-Khadre},
doi = {10.1007/s00382-019-04717-0},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {sep},
number = {5-6},
pages = {3481--3504},
title = {{Role of wind stress in driving SST biases in the Tropical Atlantic}},
volume = {53},
year = {2019}
}
@article{Volpi2020,
author = {Volpi, Danila and Batt{\'{e}}, Lauriane and Gu{\'{e}}r{\'{e}}my, Jean-Fran{\c{c}}ois and D{\'{e}}qu{\'{e}}, Michel},
doi = {10.1007/s00382-020-05327-x},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {sep},
number = {5-6},
pages = {1353--1365},
title = {{Teleconnection-based evaluation of seasonal forecast quality}},
url = {http://link.springer.com/10.1007/s00382-020-05327-x},
volume = {55},
year = {2020}
}
@article{VonSchuckmann2016,
abstract = {The current Earth's energy imbalance (EEI) is mostly caused by human activity, and is driving global warming. The absolute value of EEI represents the most fundamental metric defining the status of global climate change, and will be more useful than using global surface temperature. EEI can best be estimated from changes in ocean heat content, complemented by radiation measurements from space. Sustained observations from the Argo array of autonomous profiling floats and further development of the ocean observing system to sample the deep ocean, marginal seas and sea ice regions are crucial to refining future estimates of EEI. Combining multiple measurements in an optimal way holds considerable promise for estimating EEI and thus assessing the status of global climate change, improving climate syntheses and models, and testing the effectiveness of mitigation actions. Progress can be achieved with a concerted international effort.},
author = {von Schuckmann, K. and Palmer, M. D. and Trenberth, K. E. and Cazenave, A. and Chambers, D. and Champollion, N. and Hansen, J. and Josey, S. A. and Loeb, N. and Mathieu, P. P. and Meyssignac, B. and Wild, M.},
doi = {10.1038/nclimate2876},
issn = {17586798},
journal = {Nature Climate Change},
keywords = {asl736,energy,imbalance,monitoring},
month = {feb},
number = {2},
pages = {138--144},
title = {{An imperative to monitor Earth's energy imbalance}},
url = {citeulike-article-id:14533822 http://dx.doi.org/10.1038/nclimate2876},
volume = {6},
year = {2016}
}
@article{essd-12-2013-2020,
author = {von Schuckmann, K and Cheng, L and Palmer, M D and Hansen, J and Tassone, C and Aich, V and Adusumilli, S and Beltrami, H and Boyer, T and Cuesta-Valero, F J and Desbruy{\`{e}}res, D and Domingues, C and Garc$\backslash$'$\backslash$ia-Garc$\backslash$'$\backslash$ia, A and Gentine, P and Gilson, J and Gorfer, M and Haimberger, L and Ishii, M and Johnson, G C and Killick, R and King, B A and Kirchengast, G and Kolodziejczyk, N and Lyman, J and Marzeion, B and Mayer, M and Monier, M and Monselesan, D P and Purkey, S and Roemmich, D and Schweiger, A and Seneviratne, S I and Shepherd, A and Slater, D A and Steiner, A K and Straneo, F and Timmermans, M.-L. and Wijffels, S E},
doi = {10.5194/essd-12-2013-2020},
journal = {Earth System Science Data},
number = {3},
pages = {2013--2041},
title = {{Heat stored in the Earth system: where does the energy go?}},
url = {https://essd.copernicus.org/articles/12/2013/2020/},
volume = {12},
year = {2020}
}
@article{VonStorch2016,
abstract = {Using a suite of simulations with the Max Planck Institute Ocean Model (MPIOM) at resolutions of about 0.1°, 0.4° and 1.5°, we study the impact of resolved and parameterized vertical eddy fluxes on the long-standing biases obtained when running MPIOM at low resolutions. In the 0.1° simulation, the eddy heat and salt fluxes have three features in common. First, their horizontal area averages are both upward, counteracting the downward fluxes due to time-mean circulations. Second, their divergences at intermediate depths are both negative, acting to cool and to freshen water masses, thereby reducing the major long-standing warm and saline biases of the low-resolution MPIOM at these depths. Third, both the heat and salt budgets are dominated by a balance between the divergence of eddy flux and that of mean flux. The vertical profiles of the tendency forcing due to parameterized eddies resemble those due to resolved eddies. This resemblance does not guarantee a bias reduction, as the tendency forcing terms are much less well compensated in the 0.4°- and 1.5°-simulation than in the 0.1°-simulation. When concentrating on the eddy-induced transports, we identify two situations in which the eddy effect is not appropriately represented by the GM-parameterization. One emphasizes the importance of the mean tracer distribution and the other the importance of the simulated isoneutral slope in determining the eddy-induced transports. Given the mean salinity distribution in the Southern ocean, characterized by a tongue of fresh Antarctic Intermediate Water, the salinity advection via eddy-induced transport tends to strengthen, rather than to weaken, the saline biases. Due to the density biases in a widened region of the Agulhas current in the low-resolution runs, the isoneutral slope vectors are erroneous and the large parameterized eddy-induced transports do not occur where they should.},
author = {von Storch, Jin-Song and Haak, Helmuth and Hertwig, Eileen and Fast, Irina},
doi = {10.1016/J.OCEMOD.2016.10.001},
issn = {1463-5003},
journal = {Ocean Modelling},
month = {dec},
pages = {1--19},
publisher = {Elsevier},
title = {{Vertical heat and salt fluxes due to resolved and parameterized meso-scale Eddies}},
url = {https://www.sciencedirect.com/science/article/abs/pii/S1463500316301111},
volume = {108},
year = {2016}
}
@article{Wainwright2019,
abstract = {The biannual seasonal rainfall regime over the southern part of West Africa is characterised by two wet seasons, separated by the ‘Little Dry Season' in July–August. Lower rainfall totals during this intervening dry season may be detrimental for crop yields over a region with a dense population that depends on agricultural output. Coupled Model Intercomparison Project Phase 5 (CMIP5) models do not correctly capture this seasonal regime, and instead generate a single wet season, peaking at the observed timing of the Little Dry Season. Hence, the realism of future climate projections over this region is questionable. Here, the representation of the Little Dry Season in coupled model simulations is investigated, to elucidate factors leading to this misrepresentation. The Global Ocean Mixed Layer configuration of the Met Office Unified Model is particularly useful for exploring this misrepresentation, as it enables separating the effects of coupled model ocean biases in different ocean basins while maintaining air–sea coupling. Atlantic Ocean SST biases cause the incorrect seasonal regime over southern West Africa. Upper level descent in August reduces ascent along the coastline, which is associated with the observed reduction in rainfall during the Little Dry Season. When coupled model Atlantic Ocean biases are introduced, ascent over the coastline is deeper and rainfall totals are higher during July–August. Hence, this study indicates detrimental impacts introduced by Atlantic Ocean biases, and highlights an area of model development required for production of meaningful climate change projections over the West Africa region.},
author = {Wainwright, Caroline M. and Hirons, Linda C. and Klingaman, Nicholas P. and Allan, Richard P. and Black, Emily and Turner, Andrew G.},
doi = {10.1007/s00382-019-04973-0},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {dec},
number = {11},
pages = {7027--7044},
title = {{The impact of air–sea coupling and ocean biases on the seasonal cycle of southern West African precipitation}},
url = {http://link.springer.com/10.1007/s00382-019-04973-0},
volume = {53},
year = {2019}
}
@article{Wallace2014a,
abstract = {Increased nutrient loading into estuaries causes the accumulation of algal biomass, and microbial degradation of this organic matter decreases oxygen levels and contributes towards hypoxia. A second, often overlooked consequence of microbial degradation of organic matter is the production of carbon dioxide (CO2) and a lowering of seawater pH. To assess the potential for acidification in eutrophic estuaries, the levels of dissolved oxygen (DO), pH, the partial pressure of carbon dioxide (pCO2), and the saturation state for aragonite ($\Omega$aragonite) were horizontally and vertically assessed during the onset, peak, and demise of low oxygen conditions in systems across the northeast US including Narragansett Bay (RI), Long Island Sound (CT–NY), Jamaica Bay (NY), and Hempstead Bay (NY). Low pH conditions ({\textless}7.4) were detected in all systems during summer and fall months concurrent with the decline in DO concentrations. While hypoxic waters and/or regions in close proximity to sewage discharge had extremely high levels of pCO2, ({\textgreater}3000 $\mu$atm), were acidic pH ({\textless}7.0), and were undersaturated with regard to aragonite ($\Omega$aragonite {\textless} 1), even near-normoxic but eutrophic regions of these estuaries were often relatively acidified (pH {\textless} 7.7) during late summer and/or early fall. The close spatial and temporal correspondence between DO and pH and the occurrence of extremes in these conditions in regions with the most intense nutrient loading indicated that they were primarily driven by microbial respiration. Given that coastal acidification is promoted by nutrient-enhanced organic matter loading and reaches levels that have previously been shown to negatively impact the growth and survival of marine organisms, it may be considered an additional symptom of eutrophication that warrants managerial attention.},
author = {Wallace, Ryan B. and Baumann, Hannes and Grear, Jason S. and Aller, Robert C. and Gobler, Christopher J.},
doi = {10.1016/J.ECSS.2014.05.027},
issn = {0272-7714},
journal = {Estuarine, Coastal and Shelf Science},
month = {jul},
pages = {1--13},
publisher = {Academic Press},
title = {{Coastal ocean acidification: The other eutrophication problem}},
url = {https://www.sciencedirect.com/science/article/pii/S0272771414001553},
volume = {148},
year = {2014}
}
@article{Wan2015,
abstract = {Using an optimal fingerprinting method and improved observations, we compare observed and CMIP5 model simulated annual, cold season and warm season (semi-annual) precipitation over northern high-latitude (north of 50{\{}$\backslash$textdegree{\}}N) land over 1966--2005. We find that the multi-model simulated responses to the effect of anthropogenic forcing or the effect of anthropogenic and natural forcing combined are consistent with observed changes. We also find that the influence of anthropogenic forcing may be separately detected from that of natural forcings, though the effect of natural forcing cannot be robustly detected. This study confirms our early finding that anthropogenic influence in high-latitude precipitation is detectable. However, in contrast with the previous study, the evidence now indicates that the models do not underestimated observed changes. The difference in the latter aspect is most likely due to improvement in the spatial--temporal coverage of the data used in this study, as well as the details of data processing procedures.},
author = {Wan, Hui and Zhang, Xuebin and Zwiers, Francis and Min, Seung-Ki},
doi = {10.1007/s00382-014-2423-y},
issn = {1432-0894},
journal = {Climate Dynamics},
number = {7},
pages = {1713--1726},
title = {{Attributing northern high-latitude precipitation change over the period 1966–2005 to human influence}},
url = {https://doi.org/10.1007/s00382-014-2423-y},
volume = {45},
year = {2015}
}
@article{Wang2017a,
abstract = {The impact of internal tropical Pacific variability on global mean surface temperature (GMST) is quantified using a multimodel ensemble. A tropical Pacific index (TPI) is defined to track tropical Pacific sea surface temperature (SST) variability. The simulated GMST is highly correlated with TPI on the interannual time scale but this correlation weakens on the decadal time scale. The time-scale dependency is such that the GMST regression equation derived from the observations, which are dominated by interannual variability, would underestimate the magnitude of decadal GMST response to tropical Pacific variability. The surface air temperature response to tropical Pacific variability is strong in the tropics but weakens in the extratropics. The regression coefficient of GMST against TPI shows considerable intermodel variations, primarily because of differences in high latitudes. The results have important implications for the planned intercomparison of pacemaker experiments that force Pacific variability to follow the observed evolution. The model dependency of the GMST regression suggests that in pacemaker experiments—model performance in simulating the recent “slowdown” in global warming—will vary substantially among models. It also highlights the need to develop observational constraints and to quantify the TPI effect on the decadal variability of GMST.},
author = {Wang, Chuan-Yang and Xie, Shang-Ping and Kosaka, Yu and Liu, Qinyu and Zheng, Xiao-Tong},
doi = {10.1175/JCLI-D-15-0496.1},
issn = {0894-8755},
journal = {Journal of Climate},
keywords = {Climate change,Decadal variability,Interannual variability,Model evaluation/performance},
month = {apr},
number = {7},
pages = {2679--2695},
title = {{Global Influence of Tropical Pacific Variability with Implications for Global Warming Slowdown}},
url = {https://journals.ametsoc.org/doi/10.1175/JCLI-D-15-0496.1},
volume = {30},
year = {2017}
}
@article{Wang2013d,
author = {Wang, B. and Liu, J. and Kim, H.-J. and Webster, P. J. and Yim, S.-Y. and Xiang, B.},
doi = {10.1073/pnas.1219405110},
issn = {0027-8424},
journal = {Proceedings of the National Academy of Sciences},
month = {apr},
number = {14},
pages = {5347--5352},
title = {{Northern Hemisphere summer monsoon intensified by mega-El Ni{\~{n}}o/southern oscillation and Atlantic multidecadal oscillation}},
url = {http://www.pnas.org/cgi/doi/10.1073/pnas.1219405110},
volume = {110},
year = {2013}
}
@article{Wang2018b,
author = {Wang, Bin and Li, Juan and Cane, Mark A. and Liu, Jian and Webster, Peter J. and Xiang, Baoqiang and Kim, Hye-Mi and Cao, Jian and Ha, Kyung-Ja},
doi = {10.1175/JCLI-D-17-0521.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {apr},
number = {7},
pages = {2699--2714},
title = {{Toward Predicting Changes in the Land Monsoon Rainfall a Decade in Advance}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-17-0521.1},
volume = {31},
year = {2018}
}
@article{Wang2019a,
abstract = {After exhibiting an upward trend since 1979, Antarctic sea ice extent (SIE) declined dramatically during austral spring 2016, reaching a record low by December 2016. Here we show that a combination of atmospheric and oceanic phenomena played primary roles for this decline. The anomalous atmospheric circulation was initially driven by record strength tropical convection over the Indian and western Pacific Oceans, which resulted in a wave-3 circulation pattern around Antarctica that acted to reduce SIE in the Indian Ocean, Ross and Bellingshausen Sea sectors. Subsequently, the polar stratospheric vortex weakened significantly, resulting in record weakening of the circumpolar surface westerlies that acted to decrease SIE in the Indian Ocean and Pacific Ocean sectors. These processes appear to reflect unusual internal atmosphere-ocean variability. However, the warming trend of the tropical Indian Ocean, which may partly stem from anthropogenic forcing, may have contributed to the severity of the 2016 SIE decline.},
author = {Wang, Guomin and Hendon, Harry H and Arblaster, Julie M and Lim, Eun-Pa and Abhik, S and van Rensch, Peter},
doi = {10.1038/s41467-018-07689-7},
issn = {2041-1723},
journal = {Nature Communications},
number = {1},
pages = {13},
title = {{Compounding tropical and stratospheric forcing of the record low Antarctic sea-ice in 2016}},
url = {https://doi.org/10.1038/s41467-018-07689-7},
volume = {10},
year = {2019}
}
@article{Wang2008b,
author = {Wang, Bin and Ding, Qinghua},
doi = {10.1016/j.dynatmoce.2007.05.002},
issn = {03770265},
journal = {Dynamics of Atmospheres and Oceans},
month = {mar},
number = {3-4},
pages = {165--183},
title = {{Global monsoon: Dominant mode of annual variation in the tropics}},
url = {https://linkinghub.elsevier.com/retrieve/pii/S0377026508000055},
volume = {44},
year = {2008}
}
@article{Wang2014,
author = {Wang, Chunzai and Zhang, Liping and Lee, Sang-Ki and Wu, Lixin and Mechoso, Carlos R},
doi = {10.1038/nclimate2118},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {mar},
number = {3},
pages = {201--205},
publisher = {Nature Publishing Group},
title = {{A global perspective on CMIP5 climate model biases}},
url = {http://www.nature.com/articles/nclimate2118},
volume = {4},
year = {2014}
}
@article{Wang2019b,
abstract = {Sea salt aerosols were assumed to be homogeneous spheres in most climate models. However, observations show that sea salt particles are inhomogeneous during the deliquesce and crystallization processes. Using a two-layer sphere model, we found that backscattering of solar radiation associated with sea salts is underestimated in homogeneous sea salt models. The Community Earth System Model is used to assess the inhomogeneity effect on direct radiative forcing. For global climate model simulation, the inhomogeneity effect on radiative transfer is found to be small as high RHs over widespread oceans suppress the impact of inhomogeneity. On the other hand, in coastal regions, the inhomogeneity effect can cause up to 10{\%} radiative forcing difference of sea salt aerosols. The inhomogeneity effect of sea salt aerosols has to be considered over coastal regions, especially in the Mediterranean, Australia, and the eastern coast of South America.},
author = {Wang, Zheng and Bi, Lei and Yi, Bingqi and Zhang, Xiaoyu},
doi = {10.1029/2018GL081193},
issn = {19448007},
journal = {Geophysical Research Letters},
keywords = {light scattering,radiative forcing,sea salt},
month = {feb},
number = {3},
pages = {1805--1813},
title = {{How the Inhomogeneity of Wet Sea Salt Aerosols Affects Direct Radiative Forcing}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GL081193},
volume = {46},
year = {2019}
}
@article{Wang2017h,
author = {Wang, Jianglin and Yang, Bao and Ljungqvist, Fredrik Charpentier and Luterbacher, J{\"{u}}rg and Osborn, Timothy J. and Briffa, Keith R. and Zorita, Eduardo},
doi = {10.1038/ngeo2962},
issn = {1752-0894},
journal = {Nature Geoscience},
month = {jul},
number = {7},
pages = {512--517},
title = {{Internal and external forcing of multidecadal Atlantic climate variability over the past 1,200 years}},
url = {http://www.nature.com/articles/ngeo2962},
volume = {10},
year = {2017}
}
@article{Wang2017i,
author = {Wang, Xiaofan and Li, Jianping and Sun, Cheng and Liu, Ting},
doi = {10.1002/2016JD025979},
issn = {2169897X},
journal = {Journal of Geophysical Research: Atmospheres},
month = {apr},
number = {8},
pages = {4202--4227},
title = {{NAO and its relationship with the Northern Hemisphere mean surface temperature in CMIP5 simulations}},
url = {http://doi.wiley.com/10.1002/2016JD025979},
volume = {122},
year = {2017}
}
@article{Wang2014f,
abstract = {Abstract. Monsoon has earned increasing attention from the climate community since the last century, yet only recently have regional monsoons been recognized as a global system. It remains a debated issue, however, as to what extent and at which timescales the global monsoon can be viewed as a major mode of climate variability. For this purpose, a PAGES (Past Global Changes) working group (WG) was set up to investigate the concept of the global monsoon and its future research directions. The WG's synthesis is presented here. On the basis of observation and proxy data, the WG found that the regional monsoons can vary coherently, although not perfectly, at various timescales, varying between interannual, interdecadal, centennial, millennial, orbital and tectonic timescales, conforming to the global monsoon concept across timescales. Within the global monsoon system, each subsystem has its own features, depending on its geographic and topographic conditions. Discrimination between global and regional components in the monsoon system is a key to revealing the driving factors in monsoon variations; hence, the global monsoon concept helps to enhance our understanding and to improve future projections of the regional monsoons. This paper starts with a historical review of the global monsoon concept in both modern and paleo-climatology, and an assessment of monsoon proxies used in regional and global scales. The main body of the paper is devoted to a summary of observation data at various timescales, providing evidence of the coherent global monsoon system. The paper concludes with a projection of future monsoon shifts in a warming world. The synthesis will be followed by a companion paper addressing driving mechanisms and outstanding issues in global monsoon studies.},
author = {Wang, P. X. and Wang, B. and Cheng, H. and Fasullo, J. and Guo, Z. T. and Kiefer, T. and Liu, Z. Y.},
doi = {10.5194/cp-10-2007-2014},
issn = {1814-9332},
journal = {Climate of the Past},
month = {nov},
number = {6},
pages = {2007--2052},
title = {{The global monsoon across timescales: coherent variability of regional monsoons}},
url = {https://cp.copernicus.org/articles/10/2007/2014/},
volume = {10},
year = {2014}
}
@article{Wang2020a,
abstract = {Changing amplitude of the seasonal cycle of atmospheric CO2 (SCA) in the northern hemisphere is an emerging carbon cycle property. Mauna Loa (MLO) station (20°N, 156°W), which has the longest continuous northern hemisphere CO2 record, shows an increasing SCA before the 1980s (p {\textless}.01), followed by no significant change thereafter. We analyzed the potential driving factors of SCA slowing-down, with an ensemble of dynamic global vegetation models (DGVMs) coupled with an atmospheric transport model. We found that slowing-down of SCA at MLO is primarily explained by response of net biome productivity (NBP) to climate change, and by changes in atmospheric circulations. Through NBP, climate change increases SCA at MLO before the 1980s and decreases it afterwards. The effect of climate change on the slowing-down of SCA at MLO is mainly exerted by intensified drought stress acting to offset the acceleration driven by CO2 fertilization. This challenges the view that CO2 fertilization is the dominant cause of emergent SCA trends at northern sites south of 40°N. The contribution of agricultural intensification on the deceleration of SCA at MLO was elusive according to land–atmosphere CO2 flux estimated by DGVMs and atmospheric inversions. Our results also show the necessity to adequately account for changing circulation patterns in understanding carbon cycle dynamics observed from atmospheric observations and in using these observations to benchmark DGVMs.},
author = {Wang, Kai and Wang, Yilong and Wang, Xuhui and He, Yue and Li, Xiangyi and Keeling, Ralph F. and Ciais, Philippe and Heimann, Martin and Peng, Shushi and Chevallier, Fr{\'{e}}d{\'{e}}ric and Friedlingstein, Pierre and Sitch, Stephen and Buermann, Wolfgang and Arora, Vivek K. and Haverd, Vanessa and Jain, Atul K. and Kato, Etsushi and Lienert, Sebastian and Lombardozzi, Danica and Nabel, Julia E. M. S. and Poulter, Benjamin and Vuichard, Nicolas and Wiltshire, Andy and Zeng, Ning and Zhu, Dan and Piao, Shilong},
doi = {10.1111/gcb.15162},
issn = {1354-1013},
journal = {Global Change Biology},
month = {aug},
number = {8},
pages = {4462--4477},
title = {{Causes of slowing‐down seasonal CO2 amplitude at Mauna Loa}},
url = {https://onlinelibrary.wiley.com/doi/10.1111/gcb.15162},
volume = {26},
year = {2020}
}
@article{Wang2020c,
abstract = {The 2019/20 Australian black summer bushfires were particularly severe in many respects, including its early commencement, large spatial coverage, and large number of burning days, preceded by record dry and hot anomalies. Determining whether greenhouse warming has played a role is an important issue. Here, we examine known modes of tropical climate variability that contribute to droughts in Australia to provide a gauge. We find that a two-year consecutive concurrence of the 2018 and 2019 positive Indian Ocean Dipole and the 2018 and 2019 Central Pacific El Ni{\~{n}}o, with the former affecting Southeast Australia, and the latter influencing eastern and northeastern Australia, may explain many characteristics of the fires. Such consecutive events occurred only once in the observations since 1911. Using two generations of state-of-the-art climate models under historical and a business-as-usual emission scenario, we show that the frequency of such consecutive concurrences increases slightly, but rainfall anomalies during such events are stronger in the future climate, and there are drying trends across Australia. The impact of the stronger rainfall anomalies during such events under drying trends is likely to be exacerbated by greenhouse warming-induced rise in temperatures, making such events in the future even more extreme.},
author = {Wang, Guojian and Cai, Wenju},
doi = {10.1186/s40562-020-00168-2},
issn = {2196-4092},
journal = {Geoscience Letters},
month = {dec},
number = {1},
pages = {19},
title = {{Two-year consecutive concurrences of positive Indian Ocean Dipole and Central Pacific El Ni{\~{n}}o preconditioned the 2019/2020 Australian “black summer” bushfires}},
url = {https://geoscienceletters.springeropen.com/articles/10.1186/s40562-020-00168-2},
volume = {7},
year = {2020}
}
@article{Wang2020d,
abstract = {Projecting future change of monsoon rainfall is essential for water resource management, food security, disaster mitigation, and infrastructure planning. Here we assess the future change and explore the causes of the changes using 15 models that participated in phase 6 of the Coupled Model Intercomparison Project (CMIP6). The multimodel ensemble projects that, under the shared socioeconomic pathway (SSP) 2–4.5, the total land monsoon rainfall will likely increase in the Northern Hemisphere (NH) by about 2.8{\%} per one degree Celsius of global warming (2.8{\%} °C −1 ) in contrast to little change in the Southern Hemisphere (SH; −0.3{\%} °C −1 ). In addition, in the future the Asian–northern African monsoon likely becomes wetter while the North American monsoon becomes drier. Since the humidity increase is nearly uniform in all summer monsoon regions, the dynamic processes must play a fundamental role in shaping the spatial patterns of the global monsoon changes. Greenhouse gas (GHG) radiative forcing induces a “NH-warmer-than-SH” pattern, which favors increasing the NH monsoon rainfall and prolonging the NH monsoon rainy season while reducing the SH monsoon rainfall and shortening the SH monsoon rainy season. The GHG forcing induces a “land-warmer-than-ocean” pattern, which enhances Asian monsoon low pressure and increases Asian and northern African monsoon rainfall, and an El Ni{\~{n}}o–like warming, which reduces North American monsoon rainfall. The uncertainties in the projected monsoon precipitation changes are significantly related to the models' projected hemispheric and land–ocean thermal contrasts as well as to the eastern Pacific Ocean warming. The CMIP6 models' common biases and the processes by which convective heating drives monsoon circulation are also discussed.},
author = {Wang, Bin and Jin, Chunhan and Liu, Jian},
doi = {10.1175/JCLI-D-19-0993.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {aug},
number = {15},
pages = {6471--6489},
title = {{Understanding Future Change of Global Monsoons Projected by CMIP6 Models}},
url = {https://journals.ametsoc.org/doi/10.1175/JCLI-D-19-0993.1},
volume = {33},
year = {2020}
}
@article{Watanabe2020,
abstract = {The equatorial Pacific zonal sea surface temperature (SST) gradient, known to be a pacemaker of global warming, has strengthened since the mid-twentieth century. However, the cause is controversial because a majority of Coupled Model Intercomparison Project Phase 5 (CMIP5) models suggest weakening of the zonal SST gradient from the past to the future. Reconciling this discrepancy is important for the climate change attribution and climate sensitivity assessment. Here we use the CMIP5 ensemble and large ensemble simulations by four climate models to show that the intensifying SST gradient observed during 1951–2010 could arise from internal climate variability. Models and members that simulate historical strengthening of the SST gradient commonly exhibit reversed future trends. Using these models as a constraint, the rate of global-mean temperature rise is amplified by 9–30{\%}, with higher values occurring in low-emission scenarios, because internal variability has a greater impact when the externally forced response is smaller.},
author = {Watanabe, Masahiro and Dufresne, Jean-Louis and Kosaka, Yu and Mauritsen, Thorsten and Tatebe, Hiroaki},
doi = {10.1038/s41558-020-00933-3},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {jan},
number = {1},
pages = {33--37},
title = {{Enhanced warming constrained by past trends in equatorial Pacific sea surface temperature gradient}},
url = {http://www.nature.com/articles/s41558-020-00933-3},
volume = {11},
year = {2021}
}
@article{Watanabe2014,
abstract = {Reasons for the apparent pause in the rise of global-mean surface air temperature (SAT) after the turn of the century has been a mystery, undermining confidence in climate projections. Recent climate model simulations indicate this warming hiatus originated from eastern equatorial Pacific cooling associated with strengthening of trade winds. Using a climate model that overrides tropical wind stress anomalies with observations for 1958–2012, we show that decadal-mean anomalies of global SAT referenced to the period 1961–1990 are changed by 0.11, 0.13 and −0.11 °C in the 1980s, 1990s and 2000s, respectively, without variation in human-induced radiative forcing. They account for about 47{\%}, 38{\%} and 27{\%} of the respective temperature change. The dominant wind stress variability consistent with this warming/cooling represents the deceleration/acceleration of the Pacific trade winds, which can be robustly reproduced by atmospheric model simulations forced by observed sea surface temperature excluding anthropogenic warming components. Results indicate that inherent decadal climate variability contributes considerably to the observed global-mean SAT time series, but that its influence on decadal-mean SAT has gradually decreased relative to the rising anthropogenic warming signal.},
author = {Watanabe, Masahiro and Shiogama, Hideo and Tatebe, Hiroaki and Hayashi, Michiya and Ishii, Masayoshi and Kimoto, Masahide},
doi = {10.1038/nclimate2355},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {oct},
number = {10},
pages = {893--897},
title = {{Contribution of natural decadal variability to global warming acceleration and hiatus}},
url = {http://www.nature.com/articles/nclimate2355},
volume = {4},
year = {2014}
}
@article{Watanabe2019,
author = {Watanabe, Masahiro and Tatebe, Hiroaki},
doi = {10.1007/s00382-019-04811-3},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {oct},
number = {7-8},
pages = {4651--4665},
title = {{Reconciling roles of sulphate aerosol forcing and internal variability in Atlantic multidecadal climate changes}},
url = {http://link.springer.com/10.1007/s00382-019-04811-3},
volume = {53},
year = {2019}
}
@article{Waugh2008a,
abstract = {A set of performance metrics is applied to stratospheric-resolving chemistry- climate models (CCMs) to quantify their ability to reproduce key processes relevant for stratospheric ozone. The same metrics are used to assign a quantitative measure of performance ("grade") to each model- observations comparison shown in Eyring et al. (2006). A wide range of grades is obtained, both for different diagnostics applied to a single model and for the same diagnostic applied to different models, highlighting the wide range in ability of the CCMs to simulate key processes in the stratosphere. No model scores high or low on all tests, but differences in the performance of models can be seen, especially for processes that are mainly determined by transport where several models get low grades on multiple tests. The grades are used to assign relative weights to the CCM projections of 21st century total ozone. For the diagnostics used here there are generally only small differences between weighted and unweighted multi-model mean and variances of total ozone projections. This study raises several issues with the grading and weighting of CCMs that need further examination. However, it does provide a framework and benchmarks that will enable quantification of model improvements and assignment of relative weights to the model projections.},
author = {Waugh, D. W. and Eyring, V.},
doi = {10.5194/acp-8-5699-2008},
isbn = {1680-7316},
issn = {16807324},
journal = {Atmospheric Chemistry and Physics},
number = {18},
pages = {5699--5713},
pmid = {17158515},
title = {{Quantitative performance metrics for stratospheric-resolving chemistry-climate models}},
volume = {8},
year = {2008}
}
@article{Weijer2020,
abstract = {We explore the representation of the Atlantic Meridional Overturning Circulation (AMOC) in 27 models from the CMIP6 multimodel ensemble. Comparison with RAPID and SAMBA observations suggests that the ensemble mean represents the AMOC strength and vertical profile reasonably well. Linear trends over the entire historical period (1850–2014) are generally neutral, but many models exhibit an AMOC peak around the 1980s. Ensemble mean AMOC decline in future (SSP) scenarios is stronger in CMIP6 than CMIP5 models. In fact, AMOC decline in CMIP6 is surprisingly insensitive to the scenario at least up to 2060.We find an emergent relationship among a majority of models between AMOC strength and 21st century AMOC decline. Constraining this relationship with RAPID observations suggests that the AMOC might decline between 6 and 8 Sv (34–45{\%}) by 2100. A smaller group of models projects much less AMOC weakening of only up to 30{\%}.},
author = {Weijer, W. and Cheng, W. and Garuba, O. A. and Hu, A. and Nadiga, B. T.},
doi = {10.1029/2019GL086075},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {jun},
number = {12},
pages = {e2019GL086075},
title = {{CMIP6 Models Predict Significant 21st Century Decline of the Atlantic Meridional Overturning Circulation}},
url = {https://doi.org/10.{\%}0D1029/2019GL086075 https://onlinelibrary.wiley.com/doi/10.1029/2019GL086075},
volume = {47},
year = {2020}
}
@article{Weisheimer2020,
abstract = {Forecasts of seasonal climate anomalies using physically based global circulation models are routinely made at operational meteorological centers around the world. A crucial component of any seasonal forecast system is the set of retrospective forecasts, or hindcasts, from past years that are used to estimate skill and to calibrate the forecasts. Hindcasts are usually produced over a period of around 20–30 years. However, recent studies have demonstrated that seasonal forecast skill can undergo pronounced multidecadal variations. These results imply that relatively short hindcasts are not adequate for reliably testing seasonal forecasts and that small hindcast sample sizes can potentially lead to skill estimates that are not robust. Here we present new and unprecedented 110-year-long coupled hindcasts of the next season over the period 1901–2010. Their performance for the recent period is in good agreement with those of operational forecast models. While skill for ENSO is very high during recent decades, it is markedly reduced during the 1930s–1950s. Skill at the beginning of the twentieth century is, however, as high as for recent high-skill periods. Consistent with findings in atmosphere-only hindcasts, a midcentury drop in forecast skill is found for a range of atmospheric fields, including large-scale indices such as the NAO and the PNA patterns. As with ENSO, skill scores for these indices recover in the early twentieth century, suggesting that the midcentury drop in skill is not due to a lack of good observational data. A public dissemination platform for our hindcast data is available, and we invite the scientific community to explore them.},
author = {Weisheimer, Antje and Befort, Daniel J. and MacLeod, Dave and Palmer, Tim and O'Reilly, Chris and Str{\o}mmen, Kristian},
doi = {10.1175/BAMS-D-19-0019.1},
issn = {0003-0007},
journal = {Bulletin of the American Meteorological Society},
month = {aug},
number = {8},
pages = {E1413--E1426},
title = {{Seasonal Forecasts of the Twentieth Century}},
url = {https://journals.ametsoc.org/bams/article/101/8/E1413/345578/Seasonal-Forecasts-of-the-Twentieth-Century},
volume = {101},
year = {2020}
}
@article{Weller2016d,
abstract = {Multi-model attribution of upper-ocean temperature changes using an isothermal approach},
author = {Weller, Evan and Min, Seung-Ki and Palmer, Matthew D. and Lee, Donghyun and Yim, Bo Young and Yeh, Sang-Wook},
doi = {10.1038/srep26926},
issn = {2045-2322},
journal = {Scientific Reports},
keywords = {Attribution,Physical oceanography},
month = {jul},
number = {1},
pages = {26926},
publisher = {Nature Publishing Group},
title = {{Multi-model attribution of upper-ocean temperature changes using an isothermal approach}},
url = {http://www.nature.com/articles/srep26926},
volume = {6},
year = {2016}
}
@article{Weller2020,
abstract = {This study provides the first quantitative assessment of observed long-term changes in summer-season timing and length in the Southern Hemisphere (SH) and its subregions over the past 60 years, enabling a global completeness by complementing such characteristics previously reported for the Northern Hemisphere (NH). Using an objective algorithm that is based on temperature indices, relative measures of summer onset, withdrawal, and duration are determined at each land location over the period 1953–2012. Significant widespread summer-season lengthening, due to earlier onset and delayed withdrawal, has occurred across the SH, a longer period for extreme heat-wave events and wildfires to potentially occur. The asymmetric magnitude (onset vs withdrawal) in summer-season lengthening is slightly less over the SH than over the NH. Contributions of anthropogenic and natural factors to the observed trends in summer-season characteristics were investigated using phase 5 of the Coupled Model Intercomparison Project (CMIP5) multimodel simulations integrated with observed external forcings [anthropogenic plus natural (ALL)], greenhouse gas forcing only (GHG), and natural forcing only [solar and volcanic activities (NAT)]. Overall, consistent with the NH, increased greenhouse gases were the main cause of observed changes in the SH, with negligible contribution from other external forcings. ALL and GHG simulations also reproduced a slight tendency for earlier summer onset to contribute more to summer lengthening. Proportions of observed regional trends in summer-season indices attributable to trends in long-term internal variability in the SH, namely, the interdecadal Pacific oscillation (IPO) and southern annular mode (SAM), suggests such variability can only explain up to {\~{}}12{\%}, supporting the dominant role of greenhouse gas forcing.},
author = {Weller, Evan and Park, Bo-Joung and Min, Seung-Ki},
doi = {10.1175/JCLI-D-20-0084.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {dec},
number = {24},
pages = {10539--10553},
title = {{Anthropogenic and Natural Contributions to the Lengthening of the Southern Hemisphere Summer Season}},
url = {https://journals.ametsoc.org/doi/10.1175/JCLI-D-20-0084.1},
volume = {33},
year = {2020}
}
@article{Wenzel2016b,
abstract = {Uncertainties in the response of vegetation to rising atmospheric CO 2 concentrations contribute to the large spread in projections of future climate change. Climate-carbon cycle models generally agree that elevated atmospheric CO 2 concentrations will enhance terrestrial gross primary productivity (GPP). However, the magnitude of this CO 2 fertilization effect varies from a 20 per cent to a 60 per cent increase in GPP for a doubling of atmospheric CO 2 concentrations in model studies. Here we demonstrate emergent constraints on large-scale CO 2 fertilization using observed changes in the amplitude of the atmospheric CO 2 seasonal cycle that are thought to be the result of increasing terrestrial GPP. Our comparison of atmospheric CO 2 measurements from Point Barrow in Alaska and Cape Kumukahi in Hawaii with historical simulations of the latest climate-carbon cycle models demonstrates that the increase in the amplitude of the CO 2 seasonal cycle at both measurement sites is consistent with increasing annual mean GPP, driven in part by climate warming, but with differences in CO 2 fertilization controlling the spread among the model trends. As a result, the relationship between the amplitude of the CO 2 seasonal cycle and the magnitude of CO 2 fertilization of GPP is almost linear across the entire ensemble of models. When combined with the observed trends in the seasonal CO 2 amplitude, these relationships lead to consistent emergent constraints on the CO 2 fertilization of GPP. Overall, we estimate a GPP increase of 37 ± 9 per cent for high-latitude ecosystems and 32 ± 9 per cent for extratropical ecosystems under a doubling of atmospheric CO 2 concentrations on the basis of the Point Barrow and Cape Kumukahi records, respectively.},
author = {Wenzel, Sabrina and Cox, Peter M. and Eyring, Veronika and Friedlingstein, Pierre},
doi = {10.1038/nature19772},
issn = {0028-0836},
journal = {Nature},
month = {oct},
number = {7626},
pages = {499--501},
title = {{Projected land photosynthesis constrained by changes in the seasonal cycle of atmospheric CO2}},
url = {http://www.nature.com/articles/nature19772},
volume = {538},
year = {2016}
}
@article{west2013co,
author = {West, J Jason and Smith, Steven J and Silva, Raquel A and Naik, Vaishali and Zhang, Yuqiang and Adelman, Zachariah and Fry, Meridith M and Anenberg, Susan and Horowitz, Larry W and Lamarque, Jean-Francois},
doi = {10.1038/nclimate2009},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {oct},
number = {10},
pages = {885--889},
publisher = {Nature Publishing Group},
title = {{Co-benefits of mitigating global greenhouse gas emissions for future air quality and human health}},
url = {http://www.nature.com/articles/nclimate2009},
volume = {3},
year = {2013}
}
@article{Wieder2019,
abstract = {Land models are often used to simulate terrestrial responses to future environmental changes, but these models are not commonly evaluated with data from experimental manipulations. Results from experimental manipulations can identify and evaluate model assumptions that are consistent with appropriate ecosystem responses to future environmental change. We conducted simulations using three coupled carbon-nitrogen versions of the Community Land Model (CLM, versions 4, 4.5, and—the newly developed—5), and compared the simulated response to nitrogen (N) and atmospheric carbon dioxide (CO2) enrichment with meta-analyses of observations from similar experimental manipulations. In control simulations, successive versions of CLM showed a poleward increase in gross primary productivity and an overall bias reduction, compared to FLUXNET-MTE observations. Simulations with N and CO2 enrichment demonstrate that CLM transitioned from a model that exhibited strong nitrogen limitation of the terrestrial carbon cycle (CLM4) to a model that showed greater responsiveness to elevated concentrations of CO2 in the atmosphere (CLM5). Overall, CLM5 simulations showed better agreement with observed ecosystem responses to experimental N and CO2 enrichment than previous versions of the model. These simulations also exposed shortcomings in structural assumptions and parameterizations. Specifically, no version of CLM captures changes in plant physiology, allocation, and nutrient uptake that are likely important aspects of terrestrial ecosystems' responses to environmental change. These highlight priority areas that should be addressed in future model developments. Moving forward, incorporating results from experimental manipulations into model benchmarking tools that are used to evaluate model performance will help increase confidence in terrestrial carbon cycle projections.},
author = {Wieder, William R. and Lawrence, David M. and Fisher, Rosie A. and Bonan, Gordon B. and Cheng, Susan J. and Goodale, Christine L. and Grandy, A. Stuart and Koven, Charles D. and Lombardozzi, Danica L. and Oleson, Keith W. and Thomas, R. Quinn},
doi = {10.1029/2018GB006141},
issn = {0886-6236},
journal = {Global Biogeochemical Cycles},
month = {oct},
number = {10},
pages = {1289--1309},
title = {{Beyond Static Benchmarking: Using Experimental Manipulations to Evaluate Land Model Assumptions}},
url = {https://onlinelibrary.wiley.com/doi/10.1029/2018GB006141},
volume = {33},
year = {2019}
}
@article{Willet2014,
abstract = {Abstract. HadISDH.2.0.0 is the first gridded, multi-variable humidity and temperature in situ observations-only climate-data product that is homogenised and annually updated. It provides physically consistent estimates for specific humidity, vapour pressure, relative humidity, dew point temperature, wet bulb temperature, dew point depression and temperature. It is a monthly mean gridded (5° by 5°) product with uncertainty estimates that account for spatio-temporal sampling, climatology calculation, homogenisation and irreducible random measurement effects. It provides a tool for the long-term monitoring of a variety of humidity-related variables which have different impacts and implications for society. It is also useful for climate model evaluation and reanalyses validation. HadISDH.2.0.0 is shown to be in good agreement both with other estimates and with theoretical understanding. The data set is available from 1973 to the present. The theme common to all variables is of a warming world with more water vapour present in the atmosphere. The largest increases in water vapour are found over the tropics and the Mediterranean. Over the tropics and high northern latitudes the surface air over land is becoming more saturated. However, despite increasing water vapour over the mid-latitudes and Mediterranean, the surface air over land is becoming less saturated. These observed features may be due to atmospheric circulation changes, land–sea warming disparities and reduced water availability or changed land surface properties.},
author = {Willett, K. M. and Dunn, R J H and Thorne, Peter W and Bell, S and de Podesta, M and Parker, David E. and Jones, P. D. and {Williams Jr.}, C. N.},
doi = {10.5194/cp-10-1983-2014},
issn = {1814-9332},
journal = {Climate of the Past},
month = {nov},
number = {6},
pages = {1983--2006},
title = {{HadISDH land surface multi-variable humidity and temperature record for climate monitoring}},
url = {https://doi.org/10.5194/cp-10-1983-2014 https://cp.copernicus.org/articles/10/1983/2014/},
volume = {10},
year = {2014}
}
@article{Williams2015a,
abstract = {Asuite of climate data sets andmultiple representations of atmosphericmoisture demand are used to calculate many estimates of the self-calibrated Palmer Drought Severity Index, a proxy for near-surface soil moisture, across California from1901 to 2014 at high spatial resolution. Based on the ensemble of calculations, California drought conditions were record breaking in 2014, but probably not record breaking in 2012–2014, contrary to prior findings. Regionally, the 2012–2014 droughtwas record breaking in the agriculturally important southern Central Valley and highly populated coastal areas. Contributions of individual climate variables to recent drought are also examined, including the temperature component associated with anthropogenic warming. Precipitation is the primary driver of drought variability but anthropogenic warming is estimated to have accounted for 8–27{\%} of the observed drought anomaly in 2012–2014 and 5–18{\%} in 2014. Although natural variability dominates, anthropogenic warming has substantially increased the overall likelihood of extreme California droughts. 1.},
author = {Williams, A. Park and Seager, Richard and Abatzoglou, John T. and Cook, Benjamin I. and Smerdon, Jason E. and Cook, Edward R.},
doi = {10.1002/2015GL064924},
isbn = {1944-8007},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {aug},
number = {16},
pages = {6819--6828},
title = {{Contribution of anthropogenic warming to California drought during 2012–2014}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2015GL064924},
volume = {42},
year = {2015}
}
@article{Williams2020,
abstract = {Severe and persistent 21st-century drought in southwestern North America (SWNA) motivates comparisons to medieval megadroughts and questions about the role of anthropogenic climate change. We use hydrological modeling and new 1200-year tree-ring reconstructions of summer soil moisture to demonstrate that the 2000-2018 SWNA drought was the second driest 19-year period since 800 CE, exceeded only by a late-1500s megadrought. The megadrought-like trajectory of 2000-2018 soil moisture was driven by natural variability superimposed on drying due to anthropogenic warming. Anthropogenic trends in temperature, relative humidity, and precipitation estimated from 31 climate models account for 47{\%} (model interquartiles of 35 to 105{\%}) of the 2000-2018 drought severity, pushing an otherwise moderate drought onto a trajectory comparable to the worst SWNA megadroughts since 800 CE.},
author = {Williams, A. Park and Cook, Edward R. and Smerdon, Jason E. and Cook, Benjamin I. and Abatzoglou, John T. and Bolles, Kasey and Baek, Seung H. and Badger, Andrew M. and Livneh, Ben},
doi = {10.1126/science.aaz9600},
issn = {10959203},
journal = {Science},
number = {6488},
pages = {314--318},
pmid = {32299953},
title = {{Large contribution from anthropogenic warming to an emerging North American megadrought}},
volume = {368},
year = {2020}
}
@article{Wills2019c,
author = {Wills, Robert C. J. and Armour, Kyle C. and Battisti, David S. and Hartmann, Dennis L.},
doi = {10.1175/JCLI-D-18-0269.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jan},
number = {1},
pages = {251--272},
title = {{Ocean–Atmosphere Dynamical Coupling Fundamental to the Atlantic Multidecadal Oscillation}},
volume = {32},
year = {2019}
}
@article{Winkler2019b,
abstract = {Most Earth system models agree that land will continue to store carbon due to the physiological effects of rising CO 2 concentration and climatic changes favoring plant growth in temperature-limited regions. But they largely disagree on the amount of carbon uptake. The historical CO 2 increase has resulted in enhanced photosynthetic carbon fixation (Gross Primary Production, GPP), as can be evidenced from atmospheric CO 2 concentration and satellite leaf area index measurements. Here, we use leaf area sensitivity to ambient CO 2 from the past 36 years of satellite measurements to obtain an Emergent Constraint (EC) estimate of GPP enhancement in the northern high latitudes at two-times the pre-industrial CO 2 concentration (3.4 ± 0.2 Pg C yr −1 ). We derive three independent comparable estimates from CO 2 measurements and atmospheric inversions. Our EC estimate is 60{\%} larger than the conventionally used multi-model average (44{\%} higher at the global scale). This suggests that most models largely underestimate photosynthetic carbon fixation and therefore likely overestimate future atmospheric CO 2 abundance and ensuing climate change, though not proportionately.},
author = {Winkler, Alexander J. and Myneni, Ranga B. and Alexandrov, Georgii A. and Brovkin, Victor},
doi = {10.1038/s41467-019-08633-z},
issn = {2041-1723},
journal = {Nature Communications},
month = {dec},
number = {1},
pages = {885},
title = {{Earth system models underestimate carbon fixation by plants in the high latitudes}},
url = {http://www.nature.com/articles/s41467-019-08633-z},
volume = {10},
year = {2019}
}
@article{Winton2020,
abstract = {Abstract GFDL's new CM4.0 climate model has high transient and equilibrium climate sensitivities near the middle of the upper half of CMIP5 models. The CMIP5 models have been criticized for excessive sensitivity based on observations of present-day warming and heat uptake and estimates of radiative forcing. An ensemble of historical simulations with CM4.0 produces warming and heat uptake that are consistent with these observations under forcing that is at the middle of the assessed distribution. Energy budget-based methods for estimating sensitivities based on these quantities underestimate CM4.0's sensitivities when applied to its historical simulations. However, we argue using a simple attribution procedure that CM4.0's warming evolution indicates excessive transient sensitivity to greenhouse gases. This excessive sensitivity is offset prior to recent decades by excessive response to aerosol and land use changes.},
annote = {https://doi.org/10.1029/2019MS001838},
author = {Winton, M and Adcroft, A and Dunne, J P and Held, I M and Shevliakova, E and Zhao, M and Guo, H and Hurlin, W and Krasting, J and Knutson, T and Paynter, D and Silvers, L G and Zhang, R},
doi = {10.1029/2019MS001838},
issn = {1942-2466},
journal = {Journal of Advances in Modeling Earth Systems},
month = {jan},
number = {1},
pages = {e2019MS001838},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Climate Sensitivity of GFDL's CM4.0}},
url = {https://doi.org/10.1029/2019MS001838},
volume = {12},
year = {2020}
}
@incollection{WMO2018b,
address = {Geneva, Switzerland},
author = {WMO},
booktitle = {Scientific Assessment of Ozone Depletion: 2018},
doi = {https://csl.noaa.gov/assessments/ozone/2018/downloads/},
pages = {ES.1--ES.67},
publisher = {World Meteorological Organization (WMO)},
series = {Global Ozone Research and Monitoring Project – Report No. 58},
title = {{Executive Summary}},
url = {https://csl.noaa.gov/assessments/ozone/2018/downloads/},
year = {2018}
}
@article{Woollings2015,
author = {Woollings, T. and Franzke, C. and Hodson, D. L. R. and Dong, B. and Barnes, E. A. and Raible, C. C. and Pinto, J. G.},
doi = {10.1007/s00382-014-2237-y},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jul},
number = {1-2},
pages = {539--556},
title = {{Contrasting interannual and multidecadal NAO variability}},
url = {http://link.springer.com/10.1007/s00382-014-2237-y},
volume = {45},
year = {2015}
}
@article{Woollings2018a,
author = {Woollings, Tim and Barnes, Elizabeth and Hoskins, Brian and Kwon, Young-Oh and Lee, Robert W. and Li, Camille and Madonna, Erica and McGraw, Marie and Parker, Tess and Rodrigues, Regina and Spensberger, Clemens and Williams, Keith},
doi = {10.1175/JCLI-D-17-0286.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {feb},
number = {4},
pages = {1297--1314},
title = {{Daily to Decadal Modulation of Jet Variability}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-17-0286.1},
volume = {31},
year = {2018}
}
@article{Woollings2018,
abstract = {Atmospheric blocking events represent some of the most high-impact weather patterns in the mid-latitudes, yet they have often been a cause for concern in future climate projections. There has been low confidence in predicted future changes in blocking, despite relatively good agreement between climate models on a decline in blocking. This is due to the lack of a comprehensive theory of blocking and a pervasive underestimation of blocking occurrence by models. This paper reviews the state of knowledge regarding blocking under climate change, with the aim of providing an overview for those working in related fields.},
author = {Woollings, Tim and Barriopedro, David and Methven, John and Son, Seok-Woo and Martius, Olivia and Harvey, Ben and Sillmann, Jana and Lupo, Anthony R and Seneviratne, Sonia},
doi = {10.1007/s40641-018-0108-z},
issn = {2198-6061},
journal = {Current Climate Change Reports},
month = {sep},
number = {3},
pages = {287--300},
title = {{Blocking and its Response to Climate Change}},
volume = {4},
year = {2018}
}
@article{Wouters2012,
author = {Wouters, Bert and Drijfhout, Sybren and Hazeleger, Wilco},
doi = {10.1007/s00382-012-1366-4},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {dec},
number = {11},
pages = {2695--2712},
title = {{Interdecadal North-Atlantic meridional overturning circulation variability in EC-EARTH}},
url = {http://link.springer.com/10.1007/s00382-012-1366-4},
volume = {39},
year = {2012}
}
@article{gmd-12-1573-2019,
author = {Wu, T and Lu, Y and Fang, Y and Xin, X and Li, L and Li, W and Jie, W and Zhang, J and Liu, Y and Zhang, L and Zhang, F and Zhang, Y and Wu, F and Li, J and Chu, M and Wang, Z and Shi, X and Liu, X and Wei, M and Huang, A and Zhang, Y and Liu, X},
doi = {10.5194/gmd-12-1573-2019},
journal = {Geoscientific Model Development},
number = {4},
pages = {1573--1600},
title = {{The Beijing Climate Center Climate System Model (BCC-CSM): the main progress from CMIP5 to CMIP6}},
url = {https://www.geosci-model-dev.net/12/1573/2019/},
volume = {12},
year = {2019}
}
@article{Wu2013a,
author = {Wu, Peili and Christidis, Nikolaos and Stott, Peter},
doi = {10.1038/nclimate1932},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {sep},
number = {9},
pages = {807--810},
title = {{Anthropogenic impact on Earth's hydrological cycle}},
url = {http://www.nature.com/articles/nclimate1932},
volume = {3},
year = {2013}
}
@article{doi:10.1002/qj.3618,
abstract = {Abstract Climate modes as simulated by global climate models are often found to be considerably weaker than are observed. One possibility is that coarse-resolution climate models do not capture turbulent air–sea fluxes sufficiently. Ensemble experiments with the same atmospheric configuration of the Met Office Hadley Centre climate model, forced with observed sea-surface temperatures (SST) and at three different horizontal model resolutions (approximately 130, 60 and 25 km), are used to test the sensitivity of air–sea surface heat and moisture fluxes. We find that, although global mean budgets at the three resolutions are very similar, substantial differences appear in regional air–sea flux patterns. Increased model resolution consistently enhances zonal-mean air–sea fluxes in the mid–high latitudes while suppressing heat fluxes in the low latitudes and weakening the Hadley Circulation. In the North Atlantic, annual mean surface heat fluxes into the atmosphere along the Gulf Stream/North Atlantic Current and over the sub-polar gyre can increase by up to 10 W/m2 when atmospheric model resolution increases from 130 to 60 km. In the Pacific, increased model resolution tends to weaken the Walker Circulation with increased heat fluxes from the east but markedly reduced fluxes from the western Pacific, leading to significantly improved precipitation over the tropical western Pacific and the Maritime Continent. Changes in air–sea heat fluxes come about mainly as a result of changed near-surface ventilation. Generally, increasing resolution strengthens surface winds and reduces specific humidity in the mid–high latitudes while weakening surface winds over the Tropics and subtropics.},
author = {Wu, Peili and Roberts, Malcolm and Martin, Gill and Chen, Xiaolong and Zhou, Tianjun and Vidale, Pier L},
doi = {10.1002/qj.3618},
journal = {Quarterly Journal of the Royal Meteorological Society},
keywords = {air–sea fluxes,climate modelling,model resolution effect},
number = {724},
pages = {3271--3283},
title = {{The impact of horizontal atmospheric resolution in modelling air–sea heat fluxes}},
url = {https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/qj.3618},
volume = {145},
year = {2019}
}
@article{Wu2019b,
author = {Wu, Tongwen and Hu, Aixue and Gao, Feng and Zhang, Jie and Meehl, Gerald A.},
doi = {10.1038/s41612-019-0075-7},
issn = {2397-3722},
journal = {npj Climate and Atmospheric Science},
month = {dec},
number = {1},
pages = {18},
title = {{New insights into natural variability and anthropogenic forcing of global/regional climate evolution}},
url = {http://www.nature.com/articles/s41612-019-0075-7},
volume = {2},
year = {2019}
}
@article{gmd-13-977-2020,
author = {Wu, T and Zhang, F and Zhang, J and Jie, W and Zhang, Y and Wu, F and Li, L and Yan, J and Liu, X and Lu, X and Tan, H and Zhang, L and Wang, J and Hu, A},
doi = {10.5194/gmd-13-977-2020},
journal = {Geoscientific Model Development},
number = {3},
pages = {977--1005},
title = {{Beijing Climate Center Earth System Model version 1 (BCC-ESM1): model description and evaluation of aerosol simulations}},
url = {https://gmd.copernicus.org/articles/13/977/2020/},
volume = {13},
year = {2020}
}
@article{VariationsintheFrequencyofStratosphericSuddenWarmingsinCMIP5andCMIP6andPossibleCauses,
address = {Boston MA, USA},
author = {Wu, Zheng and Reichler, Thomas},
doi = {10.1175/JCLI-D-20-0104.1},
journal = {Journal of Climate},
number = {23},
pages = {10305--10320},
publisher = {American Meteorological Society},
title = {{Variations in the Frequency of Stratospheric Sudden Warmings in CMIP5 and CMIP6 and Possible Causes}},
url = {https://journals.ametsoc.org/view/journals/clim/33/23/jcliD200104.xml},
volume = {33},
year = {2020}
}
@article{rs9090883,
author = {Xiao, Lin and Che, Tao and Chen, Linling and Xie, Hongjie and Dai, Liyun},
doi = {10.3390/rs9090883},
issn = {2072-4292},
journal = {Remote Sensing},
month = {aug},
number = {9},
pages = {883},
title = {{Quantifying Snow Albedo Radiative Forcing and Its Feedback during 2003–2016}},
url = {http://www.mdpi.com/2072-4292/9/9/883},
volume = {9},
year = {2017}
}
@article{Xie2010,
abstract = {Spatial variations in sea surface temperature (SST) and rainfall changes over the tropics are investigated based on ensemble simulations for the first half of the twenty-first century under the greenhouse gas (GHG) emission scenario A1B with coupled ocean–atmosphere general circulation models of the Geophysical Fluid Dynamics Laboratory (GFDL) and National Center for Atmospheric Research (NCAR). Despite a GHG increase that is nearly uniform in space, pronounced patterns emerge in both SST and precipitation. Regional differences in SST warming can be as large as the tropical-mean warming. Specifically, the tropical Pacific warming features a conspicuous maximum along the equator and a minimum in the southeast subtropics. The former is associated with westerly wind anomalies whereas the latter is linked to intensified southeast trade winds, suggestive of wind–evaporation–SST feedback. There is a tendency for a greater warming in the northern subtropics than in the southern subtropics in accordance with asymmetries in trade wind changes. Over the equatorial Indian Ocean, surface wind anomalies are easterly, the thermocline shoals, and the warming is reduced in the east, indicative of Bjerknes feedback. In the midlatitudes, ocean circulation changes generate narrow banded structures in SST warming. The warming is negatively correlated with wind speed change over the tropics and positively correlated with ocean heat transport change in the northern extratropics. A diagnostic method based on the ocean mixed layer heat budget is developed to investigate mechanisms for SST pattern formation.},
author = {Xie, Shang-Ping and Deser, Clara and Vecchi, Gabriel A. and Ma, Jian and Teng, Haiyan and Wittenberg, Andrew T.},
doi = {10.1175/2009JCLI3329.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {feb},
number = {4},
pages = {966--986},
title = {{Global Warming Pattern Formation: Sea Surface Temperature and Rainfall}},
url = {http://journals.ametsoc.org/doi/10.1175/2009JCLI3329.1},
volume = {23},
year = {2010}
}
@article{Xu2014c,
author = {Xu, Zhao and Chang, Ping and Richter, Ingo and Kim, Who and Tang, Guanglin},
doi = {10.1007/s00382-014-2247-9},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {dec},
number = {11},
pages = {3123--3145},
title = {{Diagnosing southeast tropical Atlantic SST and ocean circulation biases in the CMIP5 ensemble}},
volume = {43},
year = {2014}
}
@article{Xu2018d,
author = {Xu, Yangyang and Hu, Aixue},
doi = {10.1175/JCLI-D-17-0319.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {feb},
number = {4},
pages = {1547--1563},
title = {{How Would the Twenty-First-Century Warming Influence Pacific Decadal Variability and Its Connection to North American Rainfall: Assessment Based on a Revised Procedure for the IPO/PDO}},
volume = {31},
year = {2018}
}
@article{Xu2018b,
author = {Xu, Tingting and Shi, Zhengguo and An, Zhisheng},
doi = {10.1016/j.quaint.2017.12.038},
issn = {10406182},
journal = {Quaternary International},
month = {sep},
pages = {99--111},
title = {{Responses of ENSO and NAO to the external radiative forcing during the last millennium: Results from CCSM4 and MPI-ESM-P simulations}},
url = {https://linkinghub.elsevier.com/retrieve/pii/S1040618217309527},
volume = {487},
year = {2018}
}
@article{Yan2018,
abstract = {Abstract The Atlantic Meridional Overturning Circulation (AMOC) has profound impacts on various climate phenomena. Using both observations and simulations from the Coupled Model Intercomparison Project Phase 3 and 5, here we show that most models underestimate the amplitude of low-frequency AMOC variability. We further show that stronger low-frequency AMOC variability leads to stronger linkages between the AMOC and key variables associated with the Atlantic multidecadal variability (AMV), and between the subpolar AMV signal and northern hemisphere surface air temperature. Low-frequency extratropical northern hemisphere surface air temperature variability might increase with the amplitude of low-frequency AMOC variability. Atlantic decadal predictability is much higher in models with stronger low-frequency AMOC variability and much lower in models with weaker or without AMOC variability. Our results suggest that simulating realistic low-frequency AMOC variability is very important, both for simulating realistic linkages between AMOC and AMV-related variables and for achieving substantially higher Atlantic decadal predictability.},
annote = {doi: 10.1029/2018GL077378},
author = {Yan, Xiaoqin and Zhang, Rong and Knutson, Thomas R},
doi = {10.1029/2018GL077378},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {Atlantic Meridional Overturning Circulation,Atlantic Multidecadal Variation,Decadal predictability,Low-frequency,Northern hemisphere temperature},
month = {apr},
number = {9},
pages = {4319--4328},
publisher = {Wiley-Blackwell},
title = {{Underestimated AMOC Variability and Implications for AMV and Predictability in CMIP Models}},
url = {https://doi.org/10.1029/2018GL077378},
volume = {45},
year = {2018}
}
@article{doi:10.1175/JCLI-D-15-0667.1,
abstract = { AbstractThis paper shows that joint temperature–precipitation information over a global domain provides a more accurate estimate of aerosol forced responses in climate models than does any other combination of temperature, precipitation, or sea level pressure. This fact is demonstrated using a new quantity called potential detectability, which measures the extent to which a forced response can be detected in a model. In particular, this measure can be evaluated independently of observations and therefore permits efficient exploration of a large number of variable combinations before performing optimal fingerprinting on observations. This paper also shows that the response to anthropogenic aerosol forcing can be separated from that of other forcings using only spatial structure alone, leaving the time variation of the response to be inferred from data, thereby demonstrating that temporal information is not necessary for detection. The spatial structure of the forced response is derived by maximizing the signal-to-noise ratio. For single variables, the north–south hemispheric gradient and equator-to-pole latitudinal gradient are important spatial structures for detecting anthropogenic aerosols in some models but not all. Sea level pressure is not an independent detection variable because it is derived partly from surface temperature. In no case does sea level pressure significantly enhance potential detectability beyond that already possible using surface temperature. Including seasonal or land–sea contrast information does not significantly enhance detectability of anthropogenic aerosol responses relative to annual means over global domains. },
author = {Yan, Xiaoqin and DelSole, Timothy and Tippett, Michael K},
doi = {10.1175/JCLI-D-15-0667.1},
journal = {Journal of Climate},
number = {11},
pages = {4165--4184},
title = {{What Surface Observations Are Important for Separating the Influences of Anthropogenic Aerosols from Other Forcings?}},
url = {https://doi.org/10.1175/JCLI-D-15-0667.1},
volume = {29},
year = {2016}
}
@article{Yan2016a,
author = {Yan, Mi and Wang, Bin and Liu, Jian},
doi = {10.1007/s00382-015-2841-5},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jul},
number = {1-2},
pages = {359--374},
title = {{Global monsoon change during the Last Glacial Maximum: a multi-model study}},
volume = {47},
year = {2016}
}
@article{Yan2016b,
abstract = {Global mean surface temperatures (GMST) exhibited a smaller rate of warming during 1998–2013, compared to the warming in the latter half of the 20th Century. Although, not a “true” hiatus in the strict definition of the word, this has been termed the “global warming hiatus” by IPCC (2013). There have been other periods that have also been defined as the “hiatus” depending on the analysis. There are a number of uncertainties and knowledge gaps regarding the “hiatus.” This report reviews these issues and also posits insights from a collective set of diverse information that helps us understand what we do and do not know. One salient insight is that the GMST phenomenon is a surface characteristic that does not represent a slowdown in warming of the climate system but rather is an energy redistribution within the oceans. Improved understanding of the ocean distribution and redistribution of heat will help better monitor Earth's energy budget and its consequences. A review of recent scientific publications on the “hiatus” shows the difficulty and complexities in pinpointing the oceanic sink of the “missing heat” from the atmosphere and the upper layer of the oceans, which defines the “hiatus.” Advances in “hiatus” research and outlooks (recommendations) are given in this report.},
author = {Yan, Xiao Hai and Boyer, Tim and Trenberth, Kevin and Karl, Thomas R. and Xie, Shang Ping and Nieves, Veronica and Tung, Ka Kit and Roemmich, Dean},
doi = {10.1002/2016EF000417},
isbn = {2328-4277},
issn = {23284277},
journal = {Earth's Future},
keywords = {Global warming hiatus,Heat energy,Ocean monitoring},
month = {nov},
number = {11},
pages = {472--482},
publisher = {Wiley-Blackwell},
title = {{The global warming hiatus: Slowdown or redistribution?}},
url = {http://doi.wiley.com/10.1002/2016EF000417},
volume = {4},
year = {2016}
}
@article{ISI:000428305800001,
abstract = {We examine the capability of thirteen Coupled Model Intercomparison Project (CMIP) phase 5 (CMIP5) models in simulating climatology and interannual variability of Winter North Pacific Storm Track (WNPST). It is found that nearly half of the selected models can reproduce the spatial pattern of WNPST climatology. However, the strength and spatial variation of WNPST climatology are weak in most of the models. Most differences among the models are in the northeast of the simulated multi-model ensemble (MME) climatology, while it is more consistent in the south. The MME can reflect not only the center position, but also the strength and spatial distribution of interannual variation of the WNPST amplitude. Except for CNRM-CM5, the interannual standard deviations of simulated WNPST strength and spatial variation in all other models are weak. ACCESS1-3 and CanESM2 have a better capability in simulating the spatial modes of WNPST, while the simulated second and third modes in some models are in opposite order with those in NCEP (National Centers for Environmental Prediction) reanalysis. Only five models and MME can capture ``midwinter suppression{\{}''{\}} feature in their simulations. Compared with NCEP reanalysis, the winter longitude index is larger and latitude index is smaller in most of the models, indicating the simulated storm track is further east and south. CNRM-CM5, MME and CMCC-CM could be used to evaluate interannual variation of strength index, longitude index and latitude index respectively. Nevertheless, only INM-CM4 and CNRM-CM5 can simulate southward drift of WNPST.},
address = {ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND},
annote = {Some shortcomings in simulating the Western North Pacific Storm Track.},
author = {Yang, Minghao and Li, Xin and Zuo, Ruiting and Chen, Xiong and Wang, Liqiong},
doi = {10.3390/atmos9030079},
issn = {2073-4433},
journal = {Atmosphere},
keywords = {CMIP5,Winter North Pacific Storm Track,interannu},
month = {feb},
number = {3},
pages = {79},
publisher = {MDPI},
title = {{Climatology and Interannual Variability of Winter North Pacific Storm Track in CMIP5 Models}},
type = {Article},
url = {http://www.mdpi.com/2073-4433/9/3/79},
volume = {9},
year = {2018}
}
@article{Yang2017,
author = {Yang, Yun and Xie, Shang-Ping and Wu, Lixin and Kosaka, Yu and Li, Jianping},
doi = {10.1175/JCLI-D-16-0866.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {aug},
number = {16},
pages = {6171--6182},
title = {{Causes of Enhanced SST Variability over the Equatorial Atlantic and Its Relationship to the Atlantic Zonal Mode in CMIP5}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-16-0866.1},
volume = {30},
year = {2017}
}
@article{Yang2018a,
abstract = {Many studies on drought consider precipitation and potential evapotranspiration (PET) impacts. However, catchment water retention is a factor affecting the interception of precipitation and slowing down runoff which also plays a critical role in determining the risks of hydrological drought. The Budyko framework links retention to the partitioning of precipitation into runoff or evapotranspiration. Applied worldwide, we demonstrate that retention changes are the dominant contribution to measured runoff changes in 21 of 33 major catchments. Similarly, assessing climate simulations for the historical period suggests that models substantially underestimate observed runoff changes due to unrepresented water management processes. Climate models show that water retention (without direct water management) generally decreases by the end of the 21st century, except in dry central Asia and northwestern China. Such decreases raise runoff, mainly driven by precipitation intensity increases (RCP4.5 scenario) and additionally by CO2-induced stomata closure (RCP8.5). This mitigates runoff deficits (generally from raised PET under warming) by increasing global mean runoff from -2.77 mm yr-1 to +3.81 mm yr-1 (RCP4.5), and -6.98 mm yr-1 to +5.11 mm yr-1 (RCP8.5).},
author = {Yang, Hui and Piao, Shilong and Huntingford, Chris and Ciais, Philippe and Li, Yue and Wang, Tao and Peng, Shushi and Yang, Yuting and Yang, Dawen and Chang, Jinfeng},
doi = {10.1088/1748-9326/aadd32},
issn = {1748-9326},
journal = {Environmental Research Letters},
keywords = {atmosphericCO2,climate change,drought risk,hydrological cycle,runoff,water retention},
month = {sep},
number = {9},
pages = {094019},
title = {{Changing the retention properties of catchments and their influence on runoff under climate change}},
url = {https://iopscience.iop.org/article/10.1088/1748-9326/aadd32},
volume = {13},
year = {2018}
}
@article{Yang2020,
author = {Yang, Jun-Chao and Lin, Xiaopei and Xie, Shang-Ping and Zhang, Yu and Kosaka, Yu and Li, Ziguang},
doi = {10.1038/s41558-020-0753-9},
issn = {1758-678X},
journal = {Nature Climate Change},
month = {may},
number = {5},
pages = {422--427},
title = {{Synchronized tropical Pacific and extratropical variability during the past three decades}},
url = {http://www.nature.com/articles/s41558-020-0753-9},
volume = {10},
year = {2020}
}
@article{Yang2017a,
abstract = {{\textcopyright}2017. American Geophysical Union.In the recent Intergovernmental Panel on Climate Change assessment, multimodel ensembles (arithmetic model averaging, AMA) were constructed with equal weights given to Earth system models, without considering the performance of each model at reproducing current conditions. Here we use Bayesian model averaging (BMA) to construct a weighted model ensemble for runoff projections. Higher weights are given to models with better performance in estimating historical decadal mean runoff. Using the BMA method, we find that by the end of this century, the increase of global runoff (9.8 ± 1.5{\%}) under Representative Concentration Pathway 8.5 is significantly lower than estimated from AMA (12.2 ± 1.3{\%}). BMA presents a less severe runoff increase than AMA at northern high latitudes and a more severe decrease in Amazonia. Runoff decrease in Amazonia is stronger than the intermodel difference. The intermodel difference in runoff changes is mainly caused not only by precipitation differences among models, but also by evapotranspiration differences at the high northern latitudes.},
author = {Yang, Hui and Zhou, Feng and Piao, Shilong and Huang, Mengtian and Chen, Anping and Ciais, Philippe and Li, Yue and Lian, Xu and Peng, Shushi and Zeng, Zhenzhong},
doi = {10.1002/2017GL073454},
isbn = {0094-8276},
issn = {19448007},
journal = {Geophysical Research Letters},
number = {11},
pages = {5540--5549},
title = {{Regional patterns of future runoff changes from Earth system models constrained by observation}},
volume = {44},
year = {2017}
}
@article{Yeh2009a,
author = {Yeh, Sang-Wook and Kug, Jong-Seong and Dewitte, Boris and Kwon, Min-Ho and Kirtman, Ben P and Jin, Fei-Fei},
doi = {10.1038/nature08316},
journal = {Nature},
month = {sep},
pages = {511},
publisher = {Macmillan Publishers Limited. All rights reserved},
title = {{El Ni{\~{n}}o in a changing climate}},
url = {https://doi.org/10.1038/nature08316 http://10.0.4.14/nature08316 https://www.nature.com/articles/nature08316{\#}supplementary-information},
volume = {461},
year = {2009}
}
@article{Yeh2018,
author = {Yeh, Sang-Wook and Cai, Wenju and Min, Seung-Ki and McPhaden, Michael J. and Dommenget, Dietmar and Dewitte, Boris and Collins, Matthew and Ashok, Karumuri and An, Soon-Il and Yim, Bo-Young and Kug, Jong-Seong},
doi = {10.1002/2017RG000568},
issn = {87551209},
journal = {Reviews of Geophysics},
month = {mar},
number = {1},
pages = {185--206},
title = {{ENSO Atmospheric Teleconnections and Their Response to Greenhouse Gas Forcing}},
url = {http://doi.wiley.com/10.1002/2017RG000568},
volume = {56},
year = {2018}
}
@article{Yin2018,
author = {Yin, Jianjun and Overpeck, Jonathan and Peyser, Cheryl and Stouffer, Ronald},
doi = {10.1002/2017GL076500},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {jan},
number = {2},
pages = {1069--1078},
title = {{Big Jump of Record Warm Global Mean Surface Temperature in 2014-2016 Related to Unusually Large Oceanic Heat Releases}},
url = {http://doi.wiley.com/10.1002/2017GL076500},
volume = {45},
year = {2018}
}
@article{doi:10.3878/j.issn.1674-2834.13.0058,
abstract = {AbstractThe authors evaluate the performance of models from Coupled Model Intercomparison Project Phase 5 (CMIP5) in simulating the historical (1951–2000) modes of interannual variability in the seasonal mean Northern Hemisphere (NH) 500 hPa geopotential height during winter (December-January-February, DJF). The analysis is done by using a variance decomposition method, which is suitable for studying patterns of inter-annual variability arising from intraseasonal variability and slow variability (time scales of a season or longer). Overall, compared with reanalysis data, the spatial structure and variance of the leading modes in the intraseasonal component are generally well reproduced by the CMIP5 models, with few clear differences between the models. However, there are systematic discrepancies among the models in their reproduction of the leading modes in the slow component. These modes include the dominant slow patterns, which can be seen as features of the Pacific-North American pattern, the North Atlantic Oscillation/Arctic Oscillation, and the Western Pacific pattern. An overall score is calculated to quantify how well models reproduce the three leading slow modes of variability. Ten models that reproduce the slow modes of variability relatively well are identified.},
annote = {CMIP5 model reproduction of leading modes of intraseasonal and interannual-longer variability in NH winter
- CMIP5 historical, 1951-2000
- 20CR, HadISST
- DJF, REOFs of intraseasonal and interannual (and longer) components of z500 over the NH (Zheng and Frederiksen 2004 method)

- Intraseasonal: 9 modes, PNA, EA, EA/WR, TNH, SCA and blocking patterns
{\ldots} Intraseasonal modes are well reproduces
- Longer time scales: 3 modes, PNA, NAM, WP (=NPO)
{\ldots} PNA is overall well reproduced in spatial structure and association of SST anomalies
NAM, WP are not reproduced reasonablly well in spatial structure},
author = {Ying, Kai-Ran and Zhao, Tian-Bao and Zheng, Xiao-Gu},
doi = {10.3878/j.issn.1674-2834.13.0058},
journal = {Atmospheric and Oceanic Science Letters},
number = {1},
pages = {34--41},
publisher = {Taylor {\&} Francis},
title = {{Slow and Intraseasonal Modes of the Boreal Winter Atmospheric Circulation Simulated by CMIP5 Models}},
url = {https://www.tandfonline.com/doi/abs/10.3878/j.issn.1674-2834.13.0058},
volume = {7},
year = {2014}
}
@article{cp-15-1375-2019,
author = {Yoshimori, M and Suzuki, M},
doi = {10.5194/cp-15-1375-2019},
journal = {Climate of the Past},
number = {4},
pages = {1375--1394},
title = {{The relevance of mid-Holocene Arctic warming to the future}},
url = {https://www.clim-past.net/15/1375/2019/},
volume = {15},
year = {2019}
}
@article{Young2013,
abstract = {We present a comparison of temperature trends using different satellite and radiosonde observations and climate (GCM) and chemistry-climate model (CCM) outputs, focusing on the role of photochemical ozone depletion in the Antarctic lower stratosphere during the second half of the twentieth century. Ozone-induced stratospheric cooling peaks during November at an altitude of approximately 100 hPa in radiosonde observations, with 1969 to 1998 trends in the range of -3.8 to -4.7 K/dec. This stratospheric cooling trend is more than 50{\%} greater than the previously estimated value of -2.4 K/dec, which suggested that the CCMs were overestimating the stratospheric cooling, and that the less complex GCMs forced by prescribed ozone were matching observations better. Corresponding ensemble mean model trends are -3.8K/dec for the CCMs, -3.5K/dec for the CMIP5 GCMs, and -2.7K/dec for the CMIP3 GCMs. Accounting for various sources of uncertainty-including sampling uncertainty, measurement error, model spread, and trend confidence intervals-observations and CCM and GCM ensembles are consistent in this new analysis. This consistency does not apply to each individual that makes up the GCM and CCM ensembles, and some do not show significant ozone-induced cooling. Nonetheless, analysis of the joint ozone and temperature trends in the CCMs suggests that the modeled cooling/ozone-depletion relationship is within the range of observations. Overall, this study emphasizes the need to use a wide range of observations for model validation as well as sufficient accounting of uncertainty in both models and measurements. {\textcopyright} 2012. American Geophysical Union.},
author = {Young, P.J. and Butler, A.H. and Calvo, N. and Haimberger, L. and Kushner, P.J. and Marsh, D.R. and Randel, W.J. and Rosenlof, K.H.},
doi = {10.1002/jgrd.50126},
journal = {Journal of Geophysical Research: Atmospheres},
number = {2},
pages = {605--613},
title = {{Agreement in late twentieth century southern hemisphere stratospheric temperature trends in observations and ccmval-2, CMIP3, and CMIP5 models}},
volume = {118},
year = {2013}
}
@article{zaehle2015nitrogen,
author = {Zaehle, S{\"{o}}nke and Jones, Chris D and Houlton, Benjamin and Lamarque, Jean-Francois and Robertson, Eddy},
journal = {Journal of Climate},
number = {6},
pages = {2494--2511},
title = {{Nitrogen availability reduces CMIP5 projections of twenty-first-century land carbon uptake}},
volume = {28},
year = {2015}
}
@article{Zanchettin2014,
author = {Zanchettin, Davide and Bothe, Oliver and M{\"{u}}ller, Wolfgang and Bader, J{\"{u}}rgen and Jungclaus, Johann H.},
doi = {10.1007/s00382-013-1669-0},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jan},
number = {1-2},
pages = {381--399},
title = {{Different flavors of the Atlantic Multidecadal Variability}},
url = {http://link.springer.com/10.1007/s00382-013-1669-0},
volume = {42},
year = {2014}
}
@article{Zanchettin2013,
author = {Zanchettin, Davide and Bothe, Oliver and Graf, Hans F. and Lorenz, Stephan J. and Luterbacher, Juerg and Timmreck, Claudia and Jungclaus, Johann H.},
doi = {10.1002/jgrd.50229},
issn = {2169897X},
journal = {Journal of Geophysical Research: Atmospheres},
month = {may},
number = {10},
pages = {4090--4106},
title = {{Background conditions influence the decadal climate response to strong volcanic eruptions}},
url = {http://doi.wiley.com/10.1002/jgrd.50229},
volume = {118},
year = {2013}
}
@article{Zang2019,
author = {Zang, Christian S. and Jochner-Oette, Susanne and Cort{\'{e}}s, Jos{\'{e}} and Rammig, Anja and Menzel, Annette},
doi = {10.1007/s00382-018-4524-5},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {jun},
number = {11},
pages = {6463--6473},
title = {{Regional trend changes in recent surface warming}},
url = {http://link.springer.com/10.1007/s00382-018-4524-5},
volume = {52},
year = {2019}
}
@article{Zanna2019a,
abstract = {Most of the excess energy stored in the climate system due to anthropogenic greenhouse gas emissions has been taken up by the oceans, leading to thermal expansion and sea-level rise. The oceans thus have an important role in the Earth's energy imbalance. Observational constraints on future anthropogenic warming critically depend on accurate estimates of past ocean heat content (OHC) change. We present a reconstruction of OHC since 1871, with global coverage of the full ocean depth. Our estimates combine timeseries of observed sea surface temperatures with much longer historical coverage than those in the ocean interior together with a representation (a Green's function) of time-independent ocean transport processes. For 1955–2017, our estimates are comparable with direct estimates made by infilling the available 3D time-dependent ocean temperature observations. We find that the global ocean absorbed heat during this period at a rate of 0.30 ± 0.06 W/m 2 in the upper 2,000 m and 0.028 ± 0.026 W/m 2 below 2,000 m, with large decadal fluctuations. The total OHC change since 1871 is estimated at 436 ± 91 × 10 21 J, with an increase during 1921–1946 (145 ± 62 × 10 21 J) that is as large as during 1990–2015. By comparing with direct estimates, we also infer that, during 1955–2017, up to one-half of the Atlantic Ocean warming and thermosteric sea-level rise at low latitudes to midlatitudes emerged due to heat convergence from changes in ocean transport.},
author = {Zanna, Laure and Khatiwala, Samar and Gregory, Jonathan M. and Ison, Jonathan and Heimbach, Patrick},
doi = {10.1073/pnas.1808838115},
issn = {10916490},
journal = {Proceedings of the National Academy of Sciences},
keywords = {Climate change,Earth's energy imbalance,Ocean  Ocean processes,Sea-level rise},
month = {jan},
number = {4},
pages = {1126--1131},
pmid = {30617081},
title = {{Global reconstruction of historical ocean heat storage and transport}},
url = {http://www.pnas.org/content/116/4/1126.abstract},
volume = {116},
year = {2019}
}
@article{ISI:000332990200023,
abstract = {The relationship between biases in Northern Hemisphere (NH) atmospheric blocking frequency and extratropical cyclone track density is investigated in 12 CMIP5 climate models to identify mechanisms underlying climate model biases and inform future model development. Biases in the Greenland blocking and summer Pacific blocking frequencies are associated with biases in the storm track latitudes while biases in winter European blocking frequency are related to the North Atlantic storm track tilt and Mediterranean cyclone density. However, biases in summer European and winter Pacific blocking appear less related with cyclone track density. Furthermore, the models with smaller biases in winter European blocking frequency have smallerbiases in the cyclone density in Europe, which suggests that they are different aspects of the same bias. This is not found elsewhere in the NH. The summer North Atlantic and the North Pacific mean CMIP5 track density and blocking biases mighttherefore have different origins.},
address = {2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA},
annote = {Biases in the Greenland blocking and summer Pacific blocking frequencies
are associated with biases in the storm track latitudes, while biases in
winter European blocking frequency are related to the North Atlantic
storm track tilt and Mediterranean cyclone density. The models with smaller biases in
winter European blocking frequency have smaller biases in the cyclone
density in Europe, which suggests that they are different aspects of the
same bias.},
author = {Zappa, G. and Masato, G. and Shaffrey, L. and Woollings, T. and Hodges, K.},
doi = {10.1002/2013GL058480},
isbn = {1944-8007},
issn = {00948276},
journal = {Geophysical Research Letters},
keywords = {CMIP5,biases,blocking,climate models,extratropical cyclones,storm tracks},
month = {jan},
number = {1},
pages = {135--139},
publisher = {AMER GEOPHYSICAL UNION},
title = {{Linking Northern Hemisphere blocking and storm track biases in the CMIP5 climate models}},
type = {Letter},
volume = {41},
year = {2014}
}
@article{Zappa2013,
abstract = {The ability of the climate models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5) to simulate North Atlantic extratropical cyclones in winter [December–February (DJF)] and summer [June–August (JJA)] is investigated in detail. Cyclones are identified as maxima in T42 vorticity at 850 hPa and their propagation is tracked using an objective feature-tracking algorithm. By comparing the historical CMIP5 simulations (1976–2005) and the ECMWF Interim Re-Analysis (ERA-Interim; 1979–2008), the authors find that systematic biases affect the number and intensity of North Atlantic cyclones in CMIP5 models. In DJF, the North Atlantic storm track tends to be either too zonal or displaced southward, thus leading to too few and weak cyclones over the Norwegian Sea and too many cyclones in central Europe. In JJA, the position of the North Atlantic storm track is generally well captured but some CMIP5 models underestimate the total number of cyclones. The dynamical intensity of cyclone...},
address = {45 BEACON ST},
author = {Zappa, Giuseppe and Shaffrey, Len C. and Hodges, Kevin I.},
doi = {10.1175/JCLI-D-12-00501.1},
isbn = {10.1175/JCLI-D-12-00501.1},
issn = {08948755},
journal = {Journal of Climate},
month = {aug},
number = {15},
pages = {5379--5396},
publisher = {AMER METEOROLOGICAL SOC},
title = {{The ability of CMIP5 models to simulate North Atlantic extratropical cyclones}},
volume = {26},
year = {2013}
}
@article{Zeng2014a,
abstract = {The atmospheric carbon dioxide (CO2) record displays a prominent seasonal cycle that arises mainly from changes in vegetation growth and the corresponding CO2 uptake during the boreal spring and summer growing seasons and CO2 release during the autumn and winter seasons. The CO2 seasonal amplitude has increased over the past five decades, suggesting an increase in Northern Hemisphere biospheric activity. It has been proposed that vegetation growth may have been stimulated by higher concentrations of CO2 as well as by warming in recent decades, but such mechanisms have been unable to explain the full range and magnitude of the observed increase in CO2 seasonal amplitude. Here we suggest that the intensification of agriculture (the Green Revolution, in which much greater crop yield per unit area was achieved by hybridization, irrigation and fertilization) during the past five decades is a driver of changes in the seasonal characteristics of the global carbon cycle. Our analysis of CO2 data and atmospheric inversions shows a robust 15 per cent long-term increase in CO2 seasonal amplitude from 1961 to 2010, punctuated by large decadal and interannual variations. Using a terrestrial carbon cycle model that takes into account high-yield cultivars, fertilizer use and irrigation, we find that the long-term increase in CO2 seasonal amplitude arises from two major regions: the mid-latitude cropland between 25° N and 60° N and the high-latitude natural vegetation between 50° N and 70° N. The long-term trend of seasonal amplitude increase is 0.311 ± 0.027 per cent per year, of which sensitivity experiments attribute 45, 29 and 26 per cent to land-use change, climate variability and change, and increased productivity due to CO2 fertilization, respectively. Vegetation growth was earlier by one to two weeks, as measured by the mid-point of vegetation carbon uptake, and took up 0.5 petagrams more carbon in July, the height of the growing season, during 2001–2010 than in 1961–1970, suggesting that human land use and management contribute to seasonal changes in the CO2 exchange between the biosphere and the atmosphere.},
author = {Zeng, Ning and Zhao, Fang and Collatz, George J. and Kalnay, Eugenia and Salawitch, Ross J. and West, Tristram O. and Guanter, Luis},
doi = {10.1038/nature13893},
isbn = {0028-0836},
issn = {14764687},
journal = {Nature},
month = {nov},
number = {7527},
pages = {394--397},
pmid = {25409829},
publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.},
title = {{Agricultural Green Revolution as a driver of increasing atmospheric CO 2 seasonal amplitude}},
volume = {515},
year = {2014}
}
@article{Zhang2007,
author = {Zhang, Xuebin and Zwiers, Francis W and Hegerl, Gabriele C and Lambert, F Hugo and Gillett, Nathan P and Solomon, Susan and Stott, Peter A and Nozawa, Toru},
doi = {10.1038/nature06025},
issn = {0028-0836},
journal = {Nature},
month = {jul},
number = {7152},
pages = {461--465},
publisher = {Nature Publishing Group},
title = {{Detection of human influence on twentieth-century precipitation trends}},
url = {http://www.nature.com/articles/nature06025},
volume = {448},
year = {2007}
}
@article{Zhang2018a,
abstract = {The sensitivity of the representation of the global monsoon annual cycle to horizontal resolution is compared in three AGCMs: the Met Office Unified Model-Global Atmosphere 3.0; the Meteorological Research Institute AGCM3; and the Global High Resolution AGCM from the Geophysical Fluid Dynamics Laboratory. For each model, we use two horizontal resolution configurations for the period 1998–2008. Increasing resolution consistently improves simulated precipitation and low-level circulation of the annual mean and the first two annual cycle modes, as measured by the pattern correlation coefficient and equitable threat score. Improvements in simulating the summer monsoon onset and withdrawal are region-dependent. No consistent response to resolution is found in simulating summer monsoon retreat. Regionally, increased resolution reduces the positive bias in simulated annual mean precipitation, the two annual-cycle modes over the West African monsoon and Northwestern Pacific monsoon. An overestimation of the solstitial mode and an underestimation of the equinoctial asymmetric mode of the East Asian monsoon are reduced in all high-resolution configurations. Systematic errors exist in lower-resolution models for simulating the onset and withdrawal of the summer monsoon. Higher resolution models consistently improve the early summer monsoon onset over East Asia and West Africa, but substantial differences exist in the responses over the Indian monsoon region, where biases differ across the three low-resolution AGCMs. This study demonstrates the importance of a multi-model comparison when examining the added value of resolution and the importance of model physical parameterizations for simulation of the Indian monsoon.},
author = {Zhang, Lixia and Zhou, Tianjun and Klingaman, Nicholas P and Wu, Peili and Roberts, Malcolm},
doi = {10.1007/s00376-018-7273-9},
issn = {1861-9533},
journal = {Advances in Atmospheric Sciences},
number = {8},
pages = {1003--1020},
title = {{Effect of Horizontal Resolution on the Representation of the Global Monsoon Annual Cycle in AGCMs}},
url = {https://doi.org/10.1007/s00376-018-7273-9},
volume = {35},
year = {2018}
}
@article{doi:10.1175/JCLI-D-17-0445.1,
abstract = { AbstractObservations show that decadal (10–20 yr) to interdecadal ({\textgreater}20 yr) variability of the tropical Indian Ocean (TIO) sea surface temperature (SST) closely follows that of the Pacific until the 1960s. Since then, the TIO SST exhibits a persistent warming trend, whereas the Pacific SST shows large-amplitude fluctuations associated with the interdecadal Pacific oscillation (IPO), and the decadal variability of the TIO SST is out of phase with that of the Pacific after around 1980. Here causes for the changing behavior of the TIO SST are explored, by analyzing multiple observational datasets and the recently available large-ensemble simulations from two climate models. It is found that on interdecadal time scales, the persistent TIO warming trend is caused by emergence of anthropogenic warming overcoming internal variability, while the time of emergence occurs much later in the Pacific. On decadal time scales, two major tropical volcanic eruptions occurred in the 1980s and 1990s causing decadal SST cooling over the TIO during which the IPO was in warm phase, yielding the out-of-phase relation. The more evident fingerprints of external forcing in the TIO compared to the Pacific result from the much weaker TIO internal decadal–interdecadal variability, making the TIO prone to the external forcing. These results imply that the ongoing warming and natural external forcing may make the Indian Ocean more active, playing an increasingly important role in affecting regional and global climate. },
annote = {Relationship between IO decadal SST variability and IPO
- CESM1 40-member large ensemble and MPI 100-member large ensemble
- HadISST, ERSSTv4, Kaplan SST
- For models, inter-member variability -{\textgreater} 8-yr low-pass
- For Obs, linear detrending

- The IPO-TIO relationship changed from highly positive to highly negative around 1980
- This is due to volcanic and GHG radiative forcing since the 1980s, whose influence on SST is detectable better in the TIO than tropical Pacific due to difference in magnitude of internal variability
- Occurrence of 15-yr TIO cooling, which should be 50{\%} in the absence of external forcing, is {\textless} 5{\%} after around 2000 in CESM1 (with RCP8.5)
- By contrast, it is only after 2040 that occurrence of 15-yr Pacific cooling is {\textless} 5{\%}},
author = {Zhang, Lei and Han, Weiqing and Sienz, Frank},
doi = {10.1175/JCLI-D-17-0445.1},
journal = {Journal of Climate},
number = {6},
pages = {2377--2388},
title = {{Unraveling Causes for the Changing Behavior of the Tropical Indian Ocean in the Past Few Decades}},
url = {https://doi.org/10.1175/JCLI-D-17-0445.1},
volume = {31},
year = {2018}
}
@article{Zhang2012,
abstract = {The recent study demonstrated the existence of a sys- tematical narrow bias in the simulated El Ni{\~{n}}o-Southern Oscillation (ENSO) meridional width of surface temperature anomaly (SSTA) of ENSO by the models participating in Phase 3 of the Coupled Model Inter-comparison Project (CMIP3). The current models developed for Phase 5 of the CMIP (CMIP5) still have this narrow bias in ENSO width relative to the observation, but with a modest improvement over previous models. The improvement can partly be attributed to a better simulation in trade wind, and partly to a better simulation in ENSO period. It has also been demon- strated that the models with a better performance in ENSO width tend to simulate the precipitation response to ENSO over the off-equatorial eastern Pacific more realistically.},
author = {Zhang, Wenjun and Jin, Fei Fei},
doi = {10.1029/2012GL053588},
isbn = {1944-8007},
issn = {19448007},
journal = {Geophysical Research Letters},
number = {23},
pages = {1--5},
title = {{Improvements in the CMIP5 simulations of ENSO-SSTA meridional width}},
volume = {39},
year = {2012}
}
@article{Zhang2014,
abstract = {AbstractThe El Ni{\~{n}}o–La Ni{\~{n}}a asymmetry is evaluated in 14 coupled models from phase 5 of the Coupled Model Intercomparison Project (CMIP5). The results show that an underestimate of ENSO asymmetry, a common problem noted in CMIP3 models, remains a common problem in CMIP5 coupled models. The weaker ENSO asymmetry in the models primarily results from a weaker SST warm anomaly over the eastern Pacific and a westward shift of the center of the anomaly. In contrast, SST anomalies for the La Ni{\~{n}}a phase are close to observations.Corresponding Atmospheric Model Intercomparison Project (AMIP) runs are analyzed to understand the causes of the underestimate of ENSO asymmetry in coupled models. The analysis reveals that during the warm phase, precipitation anomalies are weaker over the eastern Pacific, and westerly wind anomalies are confined more to the west in most models. The time-mean zonal winds are stronger over the equatorial central and eastern Pacific for most models. Wind-forced ocean GCM experiments suggest...},
author = {Zhang, Tao and Sun, De Zheng},
doi = {10.1175/JCLI-D-13-00454.1},
isbn = {0894-8755, 1520-0442},
issn = {08948755},
journal = {Journal of Climate},
number = {11},
pages = {4070--4093},
title = {{ENSO asymmetry in CMIP5 models}},
volume = {27},
year = {2014}
}
@article{Zhang2013,
abstract = {In this paper, simulated variability of the Atlantic Multidecadal Oscillation (AMO) and the Atlantic Meridional Overturning Circulation (AMOC) and their relationship has been investigated. For the first time, climate models of the Coupled Model Intercomparison Project phase 5 (CMIP5) provided to the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC-AR5) in historical simulations have been used for this purpose. The models show the most energetic variability on the multidecadal timescale band both with respect to the AMO and AMOC, but with a large model spread in both amplitude and frequency. The relationship between the AMO and AMOC in most of the models resembles the delayed advective oscillation proposed for the AMOC on multidecadal timescales. A speed up (slow down) of the AMOC is in favor of generating a warm (cold) phase of the AMO by the anomalous northward (southward) heat transport in the upper ocean, which reversely leads to a weakening (strengthening) of the AMOC through changes in the meridional density gradient after a delayed time of ocean adjustment. This suggests that on multidecadal timescales the AMO and AMOC are related and interact with each other.},
annote = {doi: 10.1002/jgrc.20390},
author = {Zhang, Liping and Wang, Chunzai},
doi = {10.1002/jgrc.20390},
issn = {2169-9275},
journal = {Journal of Geophysical Research: Oceans},
keywords = {AMO,AMOC},
month = {sep},
number = {10},
pages = {5772--5791},
publisher = {Wiley-Blackwell},
title = {{Multidecadal North Atlantic sea surface temperature and Atlantic meridional overturning circulation variability in CMIP5 historical simulations}},
url = {https://doi.org/10.1002/jgrc.20390},
volume = {118},
year = {2013}
}
@article{Zhang2016,
author = {Zhang, Rong and Sutton, Rowan and Danabasoglu, Gokhan and Delworth, Thomas L. and Kim, Who M. and Robson, Jon and Yeager, Stephen G.},
doi = {10.1126/science.aaf1660},
issn = {0036-8075},
journal = {Science},
language = {en},
month = {jun},
number = {6293},
pages = {1527--1527},
title = {{Comment on “The Atlantic Multidecadal Oscillation without a role for ocean circulation”}},
url = {https://www.science.org/doi/10.1126/science.aaf1660},
volume = {352},
year = {2016}
}
@article{Zhang1997a,
abstract = {Abstract A number of recent studies have reported an ENSO-like EOF mode in the global sea surface temperature (SST) field, whose time variability is marked by an abrupt change toward a warmer tropical eastern Pacific and a colder extratropical central North Pacific in 1976?77. The present study compares this pattern with the structure of the interannual variability associated with the ENSO cycle and documents its time history back to 1900. The analysis is primarily based on the leading EOFs of the SST anomaly and ?anomaly deviation? fields in various domains and the associated expansion coefficient (or principal component) time series, which are used to construct global regression maps of SST, sea level pressure (SLP), and a number of related variables. The use of ?anomaly deviations? (i.e., departures of local SST anomalies from the concurrent global-mean SST anomaly) reduces the influence of global-mean SST trends upon the structure of the EOFs and their expansion coefficient time series. An important auxiliary time series used in this study is a ?Southern Oscillation index? based on marine surface observations. By means of several different analysis techniques, the time variability of the leading EOF of the global SST field is separated into two components: one identified with the ?ENSO cycle-related? variability on the interannual timescale, and the other a linearly independent ?residual? comprising all the interdecadal variability in the record. The two components exhibit rather similar spatial signatures in the global SST, SLP, and wind stress fields. The SST signature in the residual variability is less equatorially confined in the eastern Pacific and it is relatively more prominent over the extratropical North Pacific. The corresponding SLP signature is also stronger over the extratropical North Pacific, and its counterpart in the cold season 500-mb height field more closely resembles the PNA pattern. The amplitude time series of the ENSO-like pattern in the residual variability reflects the above-mentioned shift in 1976?77, as well as a number of other prominent features, including a shift of opposite polarity during the 1940s.},
author = {Zhang, Yuan and Wallace, John M and Battisti, David S},
doi = {10.1175/1520-0442(1997)010<1004:ELIV>2.0.CO;2},
issn = {0894-8755},
journal = {Journal of Climate},
month = {may},
number = {5},
pages = {1004--1020},
publisher = {American Meteorological Society},
title = {{ENSO-like Interdecadal Variability: 1900–93}},
url = {https://doi.org/10.1175/1520-0442(1997)010{\%}3C1004:ELIV{\%}3E2.0.CO http://0.0.0.2},
volume = {10},
year = {1997}
}
@article{Zhang2017d,
abstract = {AbstractThis study explores the potential predictability of the Southern Ocean (SO) climate on decadal time scales as represented in the GFDL CM2.1 model using prognostic methods. Perfect model predictability experiments are conducted starting from 10 different initial states, showing potentially predictable variations of Antarctic bottom water (AABW) formation rates on time scales as long as 20 years. The associated Weddell Sea (WS) subsurface temperatures and Antarctic sea ice have potential predictability comparable to that of the AABW cell. The predictability of sea surface temperature (SST) variations over the WS and the SO is somewhat smaller, with predictable scales out to a decade. This reduced predictability is likely associated with stronger damping from air?sea interaction. As a complement to this perfect predictability study, the authors also make hindcasts of SO decadal variability using the GFDL CM2.1 decadal prediction system. Significant predictive skill for SO SST on multiyear time scales is found in the hindcast system. The success of the hindcasts, especially in reproducing observed surface cooling trends, is largely due to initializing the state of the AABW cell. A weak state of the AABW cell leads to cooler surface conditions and more extensive sea ice. Although there are considerable uncertainties regarding the observational data used to initialize the hindcasts, the consistency between the perfect model experiments and the decadal hindcasts at least gives some indication as to where and to what extent skillful decadal SO forecasts might be possible.},
author = {Zhang, Liping and Delworth, Thomas L and Yang, Xiaosong and Gudgel, Richard G and Jia, Liwei and Vecchi, Gabriel A and Zeng, Fanrong},
doi = {10.1175/JCLI-D-16-0840.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {mar},
number = {14},
pages = {5187--5203},
publisher = {American Meteorological Society},
title = {{Estimating Decadal Predictability for the Southern Ocean Using the GFDL CM2.1 Model}},
volume = {30},
year = {2017}
}
@article{Zhang2013a,
author = {Zhang, Rong and Delworth, Thomas L. and Sutton, Rowan and Hodson, Daniel L. R. and Dixon, Keith W. and Held, Isaac M. and Kushnir, Yochanan and Marshall, John and Ming, Yi and Msadek, Rym and Robson, Jon and Rosati, Anthony J. and Ting, MingFang and Vecchi, Gabriel A.},
doi = {10.1175/JAS-D-12-0331.1},
issn = {0022-4928},
journal = {Journal of the Atmospheric Sciences},
month = {apr},
number = {4},
pages = {1135--1144},
title = {{Have Aerosols Caused the Observed Atlantic Multidecadal Variability?}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/JAS-D-12-0331.1},
volume = {70},
year = {2013}
}
@article{Zhang2013h,
abstract = {Abstract. Based on simulations with 15 climate models in the Pliocene Model Intercomparison Project (PlioMIP), the regional climate of East Asia (focusing on China) during the mid-Pliocene is investigated in this study. Compared to the pre-industrial, the multi-model ensemble mean (MMM) of all models shows the East Asian summer winds (EASWs) largely strengthen in monsoon China, and the East Asian winter winds (EAWWs) strengthen in south monsoon China but slightly weaken in north monsoon China in the mid-Pliocene. The MMM of all models also illustrates a warmer and wetter mid-Pliocene climate in China. The simulated weakened mid-Pliocene EAWWs in north monsoon China and intensified EASWs in monsoon China agree well with geological reconstructions. However, there is a large model–model discrepancy in simulating mid-Pliocene EAWW, which should be further addressed in the future work of PlioMIP.},
author = {Zhang, R. and Yan, Q. and Zhang, Z. S. and Jiang, D. and Otto-Bliesner, B. L. and Haywood, A. M. and Hill, D. J. and Dolan, A. M. and Stepanek, C. and Lohmann, G. and Contoux, C. and Bragg, F. and Chan, W.-L. and Chandler, M. A. and Jost, A. and Kamae, Y. and Abe-Ouchi, A. and Ramstein, G. and Rosenbloom, N. A. and Sohl, L. and Ueda, H.},
doi = {10.5194/cp-9-2085-2013},
issn = {1814-9332},
journal = {Climate of the Past},
month = {sep},
number = {5},
pages = {2085--2099},
title = {{Mid-Pliocene East Asian monsoon climate simulated in the PlioMIP}},
url = {https://cp.copernicus.org/articles/9/2085/2013/},
volume = {9},
year = {2013}
}
@article{Zhang2018c,
author = {Zhang, Yanfang and Guo, Yan and Dong, Wenjie and Li, Chunxiang},
doi = {10.1002/joc.5699},
issn = {08998418},
journal = {International Journal of Climatology},
month = {nov},
number = {13},
pages = {4818--4829},
title = {{What drives the decadal variation of global land monsoon precipitation over the past 50 years?}},
url = {http://doi.wiley.com/10.1002/joc.5699},
volume = {38},
year = {2018}
}
@article{zhang2019natural,
abstract = {Observed Southern Ocean surface cooling and sea-ice expansion over the past several decades are inconsistent with many historical simulations from climate models. Here we show that natural multidecadal variability involving Southern Ocean convection may have contributed strongly to the observed temperature and sea-ice trends. These observed trends are consistent with a particular phase of natural variability of the Southern Ocean as derived from climate model simulations. Ensembles of simulations are conducted starting from differing phases of this variability. The observed spatial pattern of trends is reproduced in simulations that start from an active phase of Southern Ocean convection. Simulations starting from a neutral phase do not reproduce the observed changes, similarly to the multimodel mean results of CMIP5 models. The long timescales associated with this natural variability show potential for skilful decadal prediction.},
author = {Zhang, Liping and Delworth, Thomas L. and Cooke, William and Yang, Xiaosong},
doi = {10.1038/s41558-018-0350-3},
issn = {17586798},
journal = {Nature Climate Change},
number = {1},
pages = {59--65},
publisher = {Nature Publishing Group},
title = {{Natural variability of Southern Ocean convection as a driver of observed climate trends}},
volume = {9},
year = {2019}
}
@article{Zhang2015,
author = {Zhang, Ran and Jiang, Dabang and Zhang, Zhongshi},
doi = {10.1007/s00376-014-4183-3},
issn = {0256-1530},
journal = {Advances in Atmospheric Sciences},
month = {jul},
number = {7},
pages = {1016--1026},
title = {{Causes of mid-Pliocene strengthened summer and weakened winter monsoons over East Asia}},
url = {http://link.springer.com/10.1007/s00376-014-4183-3},
volume = {32},
year = {2015}
}
@article{Zhang2017c,
author = {Zhang, Rong},
doi = {10.1002/2017GL074342},
issn = {00948276},
journal = {Geophysical Research Letters},
month = {aug},
number = {15},
pages = {7865--7875},
title = {{On the persistence and coherence of subpolar sea surface temperature and salinity anomalies associated with the Atlantic multidecadal variability}},
url = {http://doi.wiley.com/10.1002/2017GL074342},
volume = {44},
year = {2017}
}
@article{Zhang2019d,
author = {Zhang, Wei and Kirtman, Ben},
doi = {10.1029/2019GL085159},
issn = {0094-8276},
journal = {Geophysical Research Letters},
month = {nov},
number = {22},
pages = {13308--13317},
title = {{Understanding the Signal‐to‐Noise Paradox with a Simple Markov Model}},
url = {https://onlinelibrary.wiley.com/doi/10.1029/2019GL085159},
volume = {46},
year = {2019}
}
@article{Zhang2019b,
author = {Zhang, Ran and Jiang, Dabang and Zhang, Zhongshi and Yan, Qing and Li, Xiangyu},
doi = {10.1007/s00382-019-04834-w},
issn = {0930-7575},
journal = {Climate Dynamics},
month = {oct},
number = {7-8},
pages = {4871--4886},
title = {{Modeling the late Pliocene global monsoon response to individual boundary conditions}},
url = {http://link.springer.com/10.1007/s00382-019-04834-w},
volume = {53},
year = {2019}
}
@article{Zhang2013i,
author = {Zhang, Rong and Knutson, Thomas R},
doi = {10.1175/BAMS-D-13-00085.1},
journal = {Bulletin of the American Meteorological Society},
number = {9},
pages = {S23--S26},
publisher = {American Meteorological Society},
title = {{The role of global climate change in the extreme low summer Arctic sea ice extent in 2012 [in “Explaining Extreme Events of 2012 from a Climate Perspective”]}},
volume = {94},
year = {2013}
}
@article{zhao2017environmental,
author = {Zhao, D F and Buchholz, Angela and Tillmann, Ralf and Kleist, Einhard and Wu, Cheng and Rubach, Florian and Kiendler-Scharr, Astrid and Rudich, Yinon and Wildt, J{\"{u}}rgen and Mentel, Th F},
doi = {10.1038/ncomms14067},
issn = {2041-1723},
journal = {Nature Communications},
month = {apr},
number = {1},
pages = {14067},
publisher = {Nature Publishing Group},
title = {{Environmental conditions regulate the impact of plants on cloud formation}},
url = {http://www.nature.com/articles/ncomms14067},
volume = {8},
year = {2017}
}
@article{Zheng2013a,
author = {Zheng, Fei and Li, Jianping and Clark, Robin T. and Nnamchi, Hyacinth C.},
doi = {10.1175/JCLI-D-13-00204.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {dec},
number = {24},
pages = {9860--9879},
title = {{Simulation and Projection of the Southern Hemisphere Annular Mode in CMIP5 Models}},
url = {http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-13-00204.1},
volume = {26},
year = {2013}
}
@article{Zheng2016,
author = {Zheng, Xiao-Tong and Gao, Lihui and Li, Gen and Du, Yan},
doi = {10.1007/s00376-015-5076-9},
issn = {0256-1530},
journal = {Advances in Atmospheric Sciences},
month = {apr},
number = {4},
pages = {489--503},
title = {{The Southwest Indian Ocean thermocline dome in CMIP5 models: Historical simulation and future projection}},
url = {http://link.springer.com/10.1007/s00376-015-5076-9},
volume = {33},
year = {2016}
}
@article{Zhou2020a,
author = {Zhou, Shijie and Huang, Gang and Huang, Ping},
doi = {10.1175/JCLI-D-19-0922.1},
journal = {Journal of Climate},
number = {12},
pages = {5305--5316},
title = {{Excessive ITCZ but Negative SST Biases in the Tropical Pacific Simulated by CMIP5/6 Models: The Role of the Meridional Pattern of SST Bias}},
volume = {33},
year = {2020}
}
@article{Zhou2020,
author = {Zhou, Tianjun and Zhang, Wenxia and Zhang, Lixia and Zhang, Xuebin and Qian, Yun and Peng, Dongdong and Ma, Shuangmei and Dong, Buwen},
doi = {10.1007/s11430-019-9613-9},
issn = {1674-7313},
journal = {Science China Earth Sciences},
month = {jul},
number = {7},
pages = {919--933},
title = {{The dynamic and thermodynamic processes dominating the reduction of global land monsoon precipitation driven by anthropogenic aerosols emission}},
url = {http://link.springer.com/10.1007/s11430-019-9613-9},
volume = {63},
year = {2020}
}
@article{https://doi.org/10.1029/2020GL091220,
abstract = {AbstractThe upper end of the equilibrium climate sensitivity (ECS) has increased substantially in the latest Coupled Model Intercomparison Projects phase 6 with eight models (as of this writing) reporting an ECS {\textgreater} 5°C. The Community Earth System Model version 2 (CESM2) is one such high-ECS model. Here we perform paleoclimate simulations of the Last Glacial Maximum (LGM) using CESM2 to examine whether its high ECS is realistic. We find that the simulated LGM global mean temperature decrease exceeds 11°C, greater than both the cooling estimated from proxies and simulated by an earlier model version (CESM1). The large LGM cooling in CESM2 is attributed to a strong shortwave cloud feedback in the newest atmosphere model. Our results indicate that the high ECS of CESM2 is incompatible with LGM constraints and that the projected future warming in CESM2, and models with a similarly high ECS, is thus likely too large.},
annote = {e2020GL091220 2020GL091220},
author = {Zhu, Jiang and Otto‐Bliesner, Bette L. and Brady, Esther C and Poulsen, Christopher J and Tierney, Jessica E and Lofverstrom, Marcus and DiNezio, Pedro},
doi = {10.1029/2020GL091220},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {cloud feedback,equilibrium climate sensitivity,last glacial maximum},
month = {feb},
number = {3},
pages = {e2020GL091220},
title = {{Assessment of Equilibrium Climate Sensitivity of the Community Earth System Model Version 2 Through Simulation of the Last Glacial Maximum}},
url = {https://onlinelibrary.wiley.com/doi/10.1029/2020GL091220},
volume = {48},
year = {2021}
}
@article{Zhu2020a,
abstract = {Abstract Explosive volcanism imposes impulse-like radiative forcing on the climate system, providing a natural experiment to study the climate response to perturbation. Previous studies have identified disagreements between paleoclimate reconstructions and climate model simulations with respect to the magnitude and recovery from volcanic cooling, questioning the fidelity of climate model simulations, reconstructions, or both. Using the paleoenvironmental data assimilation framework of the Last Millennium Reanalysis, this study investigates the causes of the disagreements, using both real and simulated data. We demonstrate that discrepancies since 1600 CE can be largely resolved by assimilating tree-ring density records only, targeting growing season temperature instead of annual temperature, and performing the comparison at proxy locales. Simulations of eruptions earlier in the last millennium may also reflect uncertainties in forcing and modeled aerosol microphysics.},
annote = {https://doi.org/10.1029/2019GL086908},
author = {Zhu, Feng and Emile-Geay, Julien and Hakim, Gregory J and King, Jonathan and Anchukaitis, Kevin J},
doi = {10.1029/2019GL086908},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {Last Millennium Reanalysis,Superposed Epoch Analysis,paleoclimate data assimilation,simulation-reconstruction comparison,temperature response,volcanic eruptions},
month = {apr},
number = {8},
pages = {e2019GL086908},
publisher = {John Wiley {\&} Sons, Ltd},
title = {{Resolving the Differences in the Simulated and Reconstructed Temperature Response to Volcanism}},
url = {https://doi.org/10.1029/2019GL086908},
volume = {47},
year = {2020}
}
@article{Zhu2018,
abstract = {Model biases are substantial in ocean and coupled ocean-atmosphere simulations in the tropical Pacific Ocean, including a too cold tongue and too diffuse thermocline. These biases can be partly attributed to vertical mixing parameterizations in which the background diffusivity depiction has great uncertainties. Here based on the fine-scale parameterization, the Argo data are used to derive the spatially varying background diffusivity, with a magnitude of O(10−6 m2 s−1) in the most area of tropical Pacific. This new scheme is then employed into the version 5.1 of the Modular Ocean Model-based ocean-only and coupled models, resulting in substantial improvements in ocean simulations, including a more realistic cold tongue and equatorial thermocline. The improved simulations can be attributed to the reduced cooling effects induced by weakened equatorial upwelling. Additionally, the subsurface cooling effect is attributed to the reduced heat transfer from the upper layer to the subsurface layer and the convergence of the colder water from off the equator.},
author = {Zhu, Yuchao and Zhang, Rong Hua},
doi = {10.1002/2017GL076269},
isbn = {1944-8007},
issn = {19448007},
journal = {Geophysical Research Letters},
keywords = {MOM5,diapycnal diffusivity,fine-scale parameterizations},
month = {feb},
number = {3},
pages = {1509--1517},
publisher = {Wiley-Blackwell},
title = {{An Argo-Derived Background Diffusivity Parameterization for Improved Ocean Simulations in the Tropical Pacific}},
url = {http://doi.wiley.com/10.1002/2017GL076269},
volume = {45},
year = {2018}
}
@article{Zhu2016a,
abstract = {Global environmental change is rapidly altering the dynamics of terrestrial vegetation, with consequences for the functioning of the Earth system and provision of ecosystem services1,2. Yet how global vegetation is responding to the changing environment is not well established. Here we use three long-term satellite leaf area index (LAI) records and ten global ecosystem models to investigate four key drivers of LAI trends during 1982–2009. We show a persistent and widespread increase of growing season integrated LAI (greening) over 25{\%} to 50{\%} of the global vegetated area, whereas less than 4{\%} of the globe shows decreasing LAI (browning). Factorial simulations with multiple global ecosystem models suggest that CO2 fertilization eects explain 70{\%} of the observed greening trend, followed by nitrogen deposition (9{\%}), climate change (8{\%}) and land cover change (LCC) (4{\%}). CO2 fertilization eects explain most of the greening trends in the tropics, whereas climate change resulted in greening of the high latitudes and the Tibetan Plateau. LCC contributed most to the regional greening observed in southeast China and the eastern United States. The regional eects of unexplained factors suggest that the next generation of ecosystem models will need to explore the impacts of forest demography, dierences in regional management intensities for cropland andpastures,andother emerging productivity constraints such as phosphorus availability.},
author = {Zhu, Zaichun and Piao, Shilong and Myneni, Ranga B. and Huang, Mengtian and Zeng, Zhenzhong and Canadell, Josep G. and Ciais, Philippe and Sitch, Stephen and Friedlingstein, Pierre and Arneth, Almut and Cao, Chunxiang and Cheng, Lei and Kato, Etsushi and Koven, Charles and Li, Yue and Lian, Xu and Liu, Yongwen and Liu, Ronggao and Mao, Jiafu and Pan, Yaozhong and Peng, Shushi and Peuelas, Josep and Poulter, Benjamin and Pugh, Thomas A.M. and Stocker, Benjamin D. and Viovy, Nicolas and Wang, Xuhui and Wang, Yingping and Xiao, Zhiqiang and Yang, Hui and Zaehle, S{\"{o}}nke and Zeng, Ning},
doi = {10.1038/nclimate3004},
isbn = {1758-6798},
issn = {17586798},
journal = {Nature Climate Change},
number = {8},
pages = {791--795},
title = {{Greening of the Earth and its drivers}},
url = {https://www.nature.com/articles/nclimate3004},
volume = {6},
year = {2016}
}
@article{doi:10.1111/gcb.13723,
abstract = {Abstract Significant increases in remotely sensed vegetation indices in the northern latitudes since the 1980s have been detected and attributed at annual and growing season scales. However, we presently lack a systematic understanding of how vegetation responds to asymmetric seasonal environmental changes. In this study, we first investigated trends in the seasonal mean leaf area index (LAI) at northern latitudes (north of 30°N) between 1982 and 2009 using three remotely sensed long-term LAI data sets. The most significant LAI increases occurred in summer (0.009 m2 m−2 year−1, p {\textless} .01), followed by autumn (0.005 m2 m−2 year−1, p {\textless} .01) and spring (0.003 m2 m−2 year−1, p {\textless} .01). We then quantified the contribution of elevating atmospheric CO2 concentration (eCO2), climate change, nitrogen deposition, and land cover change to seasonal LAI increases based on factorial simulations from 10 state-of-the-art ecosystem models. Unlike previous studies that used multimodel ensemble mean (MME), we used the Bayesian model averaging (BMA) to optimize the integration of model ensemble. The optimally integrated ensemble LAI changes are significantly closer to the observed seasonal LAI changes than the traditional MME results. The BMA factorial simulations suggest that eCO2 provides the greatest contribution to increasing LAI trends in all seasons (0.003–0.007 m2 m−2 year−1), and is the main factor driving asymmetric seasonal LAI trends. Climate change controls the spatial pattern of seasonal LAI trends and dominates the increase in seasonal LAI in the northern high latitudes. The effects of nitrogen deposition and land use change are relatively small in all seasons (around 0.0002 m2 m−2 year−1 and 0.0001–0.001 m2 m−2 year−1, respectively). Our analysis of the seasonal LAI responses to the interactions between seasonal changes in environmental factors offers a new perspective on the response of global vegetation to environmental changes.},
author = {Zhu, Zaichun and Piao, Shilong and Lian, Xu and Myneni, Ranga B and Peng, Shushi and Yang, Hui},
doi = {10.1111/gcb.13723},
journal = {Global Change Biology},
keywords = {Bayesian model averaging,attribution,climate change,remote sensing,seasonal change,vegetation greening},
number = {11},
pages = {4798--4813},
title = {{Attribution of seasonal leaf area index trends in the northern latitudes with “optimally” integrated ecosystem models}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.13723},
volume = {23},
year = {2017}
}
@article{Zhu8728,
abstract = {Climate models are foundational to formulations of climate policy and must successfully reproduce key features of the climate system. The temporal spectrum of observed global surface temperature is one such critical benchmark. This spectrum is known to obey scaling laws connecting astronomical forcings, from orbital to annual scales. We provide evidence that the current hierarchy of climate models is capable of reproducing the increase in variance in global-mean temperature at low frequencies. We suggest that successful climate predictions at decadal-to-centennial horizons hinge critically on the accuracy of initial and boundary conditions, particularly for the deep ocean state.Climate records exhibit scaling behavior with large exponents, resulting in larger fluctuations at longer timescales. It is unclear whether climate models are capable of simulating these fluctuations, which draws into question their ability to simulate such variability in the coming decades and centuries. Using the latest simulations and data syntheses, we find agreement for spectra derived from observations and models on timescales ranging from interannual to multimillennial. Our results confirm the existence of a scaling break between orbital and annual peaks, occurring around millennial periodicities. That both simple and comprehensive ocean{\{}$\backslash$textendash{\}}atmosphere models can reproduce these features suggests that long-range persistence is a consequence of the oceanic integration of both gradual and abrupt climate forcings. This result implies that Holocene low-frequency variability is partly a consequence of the climate system{\{}$\backslash$textquoteright{\}}s integrated memory of orbital forcing. We conclude that climate models appear to contain the essential physics to correctly simulate the spectral continuum of global-mean temperature; however, regional discrepancies remain unresolved. A critical element of successfully simulating suborbital climate variability involves, we hypothesize, initial conditions of the deep ocean state that are consistent with observations of the recent past.},
author = {Zhu, Feng and Emile-Geay, Julien and McKay, Nicholas P and Hakim, Gregory J and Khider, Deborah and Ault, Toby R and Steig, Eric J and Dee, Sylvia and Kirchner, James W},
doi = {10.1073/pnas.1809959116},
issn = {0027-8424},
journal = {Proceedings of the National Academy of Sciences},
number = {18},
pages = {8728--8733},
publisher = {National Academy of Sciences},
title = {{Climate models can correctly simulate the continuum of global-average temperature variability}},
url = {https://www.pnas.org/content/116/18/8728},
volume = {116},
year = {2019}
}
@article{Zhu2020,
abstract = {{\textless}p{\textgreater}Substantial model biases are still prominent even in the latest CMIP6 simulations; attributing their causes is defined as one of the three main scientific questions addressed in CMIP6. In this paper, cold temperature biases in the North Pacific subtropics are investigated using simulations from the newly released CMIP6 models, together with other related modeling products. In addition, ocean-only sensitivity experiments are performed to characterize the biases, with a focus on the role of oceanic vertical mixing schemes. Based on the Argo-derived diffusivity, idealized vertical diffusivity fields are designed to mimic the seasonality of vertical mixing in this region, and are employed in ocean-only simulations to test the sensitivity of this cold bias to oceanic vertical mixing. It is demonstrated that the cold temperature biases can be reduced when the mixing strength is enhanced within and beneath the surface boundary layer. Additionally, the temperature simulations are rather sensitive to the parameterization of static instability, and the cold biases can be reduced when the vertical diffusivity for convection is increased. These indicate that the cold temperature biases in the North Pacific can be largely attributed to biases in oceanic vertical mixing within ocean-only simulations, which likely contribute to the even larger biases seen in coupled simulations. This study therefore highlights the need for improved oceanic vertical mixing in order to reduce these persistent cold temperature biases seen across several CMIP models.{\textless}/p{\textgreater}},
author = {Zhu, Yuchao and Zhang, Rong-Hua and Sun, Jichang},
doi = {10.1175/JCLI-D-19-0654.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {sep},
number = {17},
pages = {7523--7538},
publisher = {American Meteorological Society},
title = {{North Pacific Upper-Ocean Cold Temperature Biases in CMIP6 Simulations and the Role of Regional Vertical Mixing}},
url = {https://journals.ametsoc.org/jcli/article/33/17/7523/347586/North-Pacific-UpperOcean-Cold-Temperature-Biases},
volume = {33},
year = {2020}
}
@article{Ziehn2020a,
author = {Ziehn, Tilo and Chamberlain, Matthew A. and Law, Rachel M. and Lenton, Andrew and Bodman, Roger W. and Dix, Martin and Stevens, Lauren and Wang, Ying-Ping and Jhan, Srbinovsky},
doi = {10.1071/ES19035},
journal = {Journal of Southern Hemisphere Earth Systems Science},
pages = {193--214},
title = {{The Australian Earth System Model: ACCESS-ESM1.5}},
url = {https://doi.org/10.1071/ES19035},
volume = {70},
year = {2020}
}
@article{Zika2015,
abstract = {The global water cycle leaves an imprint on ocean salinity through evaporation and precipitation. It has been proposed that observed changes in salinity can be used to infer changes in the water cycle. Here salinity is characterized by the distribution of water masses in salinity coordinates. Only mixing and sources and sinks of freshwater and salt can modify this distribution. Mixing acts to collapse the distribution, making saline waters fresher and fresh waters more saline. Hence, in steady state, there must be net precipitation over fresh waters and net evaporation over saline waters. A simple model is developed to describe the relationship between the breadth of the distribution, the water cycle, and mixing?the latter being characterized by an e-folding time scale. In both observations and a state-of-the-art ocean model, the water cycle maintains a salinity distribution in steady state with a mixing time scale of the order of 50 yr. The same simple model predicts the response of the salinity distribution to a change in the water cycle. This study suggests that observations of changes in ocean salinity could be used to infer changes in the hydrological cycle.},
author = {Zika, Jan D. and Skliris, Nikolaos and Nurser, A. J. George and Josey, Simon A. and Mudryk, Lawrence and Lalibert{\'{e}}, Fr{\'{e}}d{\'{e}}ric and Marsh, Robert},
doi = {10.1175/JCLI-D-15-0273.1},
isbn = {0894-8755},
issn = {08948755},
journal = {Journal of Climate},
keywords = {Climate change,Evaporation,Hydrologic cycle,Precipitation,Salinity,Water masses},
month = {dec},
number = {24},
pages = {9550--9560},
title = {{Maintenance and broadening of the ocean's salinity distribution by the water cycle}},
url = {http://journals.ametsoc.org/doi/10.1175/JCLI-D-15-0273.1},
volume = {28},
year = {2015}
}
@article{Zika2018,
abstract = {Changes in the global water cycle critically impact environmental, agricultural, and energy systems relied upon by humanity (Jim{\'{e}}nez Cisneros et al 2014 Climate Change 2014: Impacts, Adaptation, and Vulnerability (Cambridge: Cambridge University Press)). Understanding recent water cycle change is essential in constraining future projections. Warming-induced water cycle change is expected to amplify the pattern of sea surface salinity (Durack et al 2012 Science 336 455–8). A puzzle has, however, emerged. The surface salinity pattern has amplified by 5{\%}–8{\%} since the 1950s (Durack et al 2012 Science 336 455–8, Skliris et al 2014 Clim. Dyn. 43 709–36) while the water cycle is thought to have amplified at close to half that rate (Durack et al 2012 Science 336 455–8, Skliris et al 2016 Sci. Rep. 6 752). This discrepancy is also replicated in climate projections of the 21st century (Durack et al 2012 Science 336 455–8). Using targeted numerical ocean model experiments we find that, while surface water fluxes due to water cycle change and ice mass loss amplify the surface salinity pattern, ocean warming exerts a substantial influence. Warming increases near-surface stratification, inhibiting the decay of existing salinity contrasts and further amplifying surface salinity patterns. Observed ocean warming can explain approximately half of observed surface salinity pattern changes from 1957–2016 with ice mass loss playing a minor role. Water cycle change of 3.6{\%} ± 2.1{\%} per degree Celsius of surface air temperature change is sufficient to explain the remaining observed salinity pattern change.},
author = {Zika, Jan D. and Skliris, Nikolaos and Blaker, Adam T. and Marsh, Robert and Nurser, A. J.George and Josey, Simon A.},
doi = {10.1088/1748-9326/aace42},
issn = {17489326},
journal = {Environmental Research Letters},
keywords = {Climate change,Ocean salinity,Ocean warming,Water cycle},
month = {jul},
number = {7},
pages = {074036},
publisher = {IOP Publishing},
title = {{Improved estimates of water cycle change from ocean salinity: The key role of ocean warming}},
url = {http://stacks.iop.org/1748-9326/13/i=7/a=074036?key=crossref.d9ae3f534b60365d6f2a9c5bf3fdcf02 http://iopscience.iop.org/article/10.1088/1748-9326/aace42},
volume = {13},
year = {2018}
}
@article{tc-7-451-2013,
author = {Zunz, V and Goosse, H and Massonnet, F},
doi = {10.5194/tc-7-451-2013},
journal = {The Cryosphere},
number = {2},
pages = {451--468},
title = {{How does internal variability influence the ability of CMIP5 models to reproduce the recent trend in Southern Ocean sea ice extent?}},
url = {https://www.the-cryosphere.net/7/451/2013/},
volume = {7},
year = {2013}
}
@article{Zuo2013,
abstract = {The temporal variability and spatial pattern of the Arctic Oscillation (AO) simulated in the historical experiment of 26 coupled climate models participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5) are evaluated. Spectral analysis of the monthly AO index indicates that 23 out of the 26 CMIP5 models exhibit no statistically significant spectral peak in the historical experiment, as seen in the observations. These models are able to reproduce the AO pattern in the sea level pressure anomaly field during boreal winter, but the intensity of the AO pattern tends to be overestimated in all the models. The zonal-mean zonal wind anomalies associated with the AO is dominated by a meridional dipole in the mid-high latitudes of the Northern Hemisphere during boreal winter, which is well reproduced by only a few models. Most models show significant biases in both strength and location of the dipole compared to the observation. In considering the temporal variability as well as spatial structures in both horizontal and vertical directions, the MPI-ESM-P model reproduces an AO pattern that resembles the observation the best.},
annote = {AO in CMIP5 models
- CMIP5 historical vs HadSLP2, NCEP/NCAR
- Monthly EOF of SLP 20-90N for 1950-2005
- Patterns are only for DJF

- All models (except those from Hadley Centre) reproduces AO structure
- North Pacific SLP center is too emphasized
- All overestimate amplitude (at least partly due to overly strong Pacific signal)
- Associated zonal-mean zonal wind anomaly structure is biased in variaous manner (in magnitude, relative strength of dipole, meridional shift, vertical tilt)},
author = {Zuo, Jin-Qing and Li, Wei-Jing and Ren, Hong-Li},
doi = {10.3724/SP.J.1248.2013.242},
journal = {Advances in Climate Change Research},
keywords = {Arctic Oscillation,CMIP5,coupled climate model,model evaluation},
number = {4},
pages = {242--249},
title = {{Representation of the Arctic Oscillation in the CMIP5 Models}},
volume = {4},
year = {2013}
}
@article{Zuo2019,
abstract = {Understanding the influence of volcanic eruptions on the hydroclimate over global monsoon regions is of great scientific and social importance. However, the link between the latitude of volcanic eruptions and related hydroclimate changes over global monsoon regions in the last millennium remains inconclusive. Here we show divergent hydroclimate responses after different volcanic eruptions based on large sets of reconstructions, observations, and climate model simulation. Both the proxy and observations show that Northern Hemispheric (Southern Hemispheric) monsoon precipitation is weakened by northern (southern) and tropical eruptions but is enhanced by the southern (northern) eruptions. A similar relationship is found in coupled model simulations driven by volcanic forcing. The model evidence indicates that the dynamic processes related to changes in atmospheric circulation play a dominant role in precipitation responses. The dry conditions over the Northern Hemisphere (Southern Hemisphere) and global monsoon regions following northern (southern) and tropical eruptions are induced through weakened monsoon circulation. The wet conditions over Northern Hemispheric (Southern Hemispheric) monsoon regions after southern (northern) eruptions are caused by the enhanced cross-equator flow. We extend our model simulation analysis from mean state precipitation to extreme precipitation and find that the response of the extreme precipitation is consistent with that of the mean precipitation but is more sensitive over monsoon regions. The response of surface runoff and net primary production is stronger than that of precipitation over some submonsoon regions. Our results imply that it is imperative to consider the potential volcanic eruptions at different hemispheres in the design of near-term decadal climate prediction experiments.},
author = {Zuo, Meng and Zhou, Tianjun and Man, Wenmin},
doi = {10.1175/JCLI-D-18-0707.1},
issn = {0894-8755},
journal = {Journal of Climate},
month = {jul},
number = {14},
pages = {4367--4385},
title = {{Hydroclimate Responses over Global Monsoon Regions Following Volcanic Eruptions at Different Latitudes}},
url = {https://journals.ametsoc.org/jcli/article/32/14/4367/344058/Hydroclimate-Responses-over-Global-Monsoon-Regions},
volume = {32},
year = {2019}
}