The Effect of Extreme Sea Ice Variations on the Climatology of the Goddard General Circulation Model
We have computed two different January-February climatologies with the Goddard general circulation model corresponding to hypothetical maximum and minimum sea conditions in the north and south polar regions. The largest dif-ferences in sea ice extent were specified in the Davis Straits, the Bering S...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.486.8314 http://itia.ntua.gr:80/hsj/redbooks/124/iahs_124_0207.pdf |
| Summary: | We have computed two different January-February climatologies with the Goddard general circulation model corresponding to hypothetical maximum and minimum sea conditions in the north and south polar regions. The largest dif-ferences in sea ice extent were specified in the Davis Straits, the Bering Sea, the Greenland, Norwegian, and Barents seas, the Sea of Okhotsk, and in the ocean peripheral to the Antarctic continent. The largest differences in the Northern Hemisphere were found in the follow-ing fields: zonally averaged temperature, which was up to 5°C cooler in the lower troposphere between 50°N and 70°N; and vertically integrated eddy energy flux, which was approximately 13 % larger at 50°N with maximum ice conditions. In the surface energy balance, sensible and latent heat fluxes and the solar radiation absorbed at the surface were greatly reduced where the ice margin was increased. With the maximum ice, storage terms in the atmospheric energy cycle were increased up to 10%, and conversion terms up to 17%, although these differences are smaller than the uncertainty associated with their calculation from observations. There are local differences in the 500 mb geopotential height field and 850 mb temperature field that are more than twice as large as the standard deviations of these fields obtained in predictability experiments with the Goddard GCM. We conclude that the calculated differences between model simulations for the two ice conditions are greater than the inherent variability of the model. |
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