AGU: Geophysical Research Letters

 

Editors' Highlight

The Arctic influences subpolar wind patterns and European climate

In the Arctic, fluctuations in sea ice extent will affect the Earth's albedo, or the fraction of incident sunlight that is reflected by the Earth. This feedback mechanism is likely the most important factor for the polar amplification of global warming. To look for such feedbacks, Dethloff et al. (2006) used an atmosphere-ocean general circulation model run over 500 years that, compared with past models, includes improved parameterizations of snow cover over land, sea ice cover, and melt ponds. Detailed analysis of the first 9 years of simulations showed that though warming may occur in the midlatitudes, Arctic cooling will result from a polar vortex churning cold air from the Rockies northward. This indicated that the Arctic exerts a strong influence on the middle- and high-latitude climate because of its ability to modulate the strength of subpolar westerlies and storm tracks. Moreover, the improved parameterization revealed Arctic Oscillation–like fluctuations in the middle troposphere and in middle latitudes that can strongly affect European climate.

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