Figure 3.30. Changes in winter (December–March) surface pressure, temperature, and precipitation corresponding to a unit deviation of the NAO index over 1900 to 2005. (Top left) Mean sea level pressure (0.1 hPa). Values greater than 0.5 hPa are stippled and values less than −0.5 hPa are hatched. (Top right) Land-surface air and sea surface temperatures (0.1°C; contour increment 0.2°C). Temperature changes greater than 0.1°C are indicated by stippling, those less than –0.1°C are indicated by hatching, and regions of insufficient data (e.g., over much of the Arctic) are not contoured. (Bottom left) Precipitation for 1979 to 2003 based on GPCP (0.1 mm per day; contour interval 0.6 mm per day). Stippling indicates values greater than 0.3 mm per day and hatching values less than –0.3 mm per day. Adapted and updated from Hurrell et al. (2003).