Simulations of Present Arctic Climate and Future Regional Projections

John E. Walsh
International Arctic Research Center, University of Alaska Fairbanks

Abstract

Projections of changes in permafrost require credible projections of the atmosphere that overlies terrestrial regions containing permafrost. The critical atmospheric variables for permafrost are surface air temperature and precipitation, especially snowfall. In this study, global climate models used in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report are ranked on the basis of their simulations of regional Arctic temperature, precipitation and sea level pressure. When evaluated by the root-mean-square error relative to an atmospheric reanalysis, the models that perform best over the pan-Arctic and broader Northern Hemisphere domains are generally found to have the smallest errors over permafrost areas (e.g., Alaska). However, even the highest ranking model has some areas in which its simulations are problematic. The changes of temperature and precipitation projected by the highest ranking models are generally larger than the changes projected by the other models used by the IPCC.

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