Figure 9.4: Intercomparison
statistics for seasonal and annual (a) temperature and (b) precipitation changes
in nineteen CMIP2 experiments at the doubling of CO2 (years 61 to 80). The total
length of the bars shows the mean squared amplitude of the simulated local temperature
and precipitation changes averaged over all experiments and over the whole world.
The lowermost part of each bar represents a nominally unbiased “common signal”,
the mid-part directly model-related variance and the top part the inter-experiment
variance attributed to internal variability. Precipitation changes are defined
as 100% x (PG-PCTRL) / Max(PCTRL, 0.25 mm/day),
where the lower limit of 0.25 mm/day is used to reduce the sensitivity of the
global statistics to areas with very little control run precipitation.