Role of Stationary wave feedback in shaping the glacial ice sheets

Abstract:

The large northern hemisphere ice sheets significantly affected the atmospheric circulation and in return, their evolution and geographical pattern is influenced by the changed atmospheric circulation. In this work, we suggest that the atmospheric stationary planetary wave feedback leads to the contrasting asymmetrical evolution of ice sheet in the Northern Hemisphere during the glacial cycles. Model results suggest that the stationary wave induced by the glacial ice sheet topography suppresses the cooling of the land in the central Asia and prevents the ice sheet growth of the east-southern part of the Fennoscandian ice sheet and enables its faster retreat at the ice age termination. Because of the smaller eccentricity during the last 120 ka compared to the penultimate glacial during 230 to 130 ka, the Laurentide ice sheet grew to a larger size at the Last Glacial Maximum (LGM) than the Penultimate Glacial Maximum (PGM). This, in turn, resulted in the Fennoscandian ice sheet to be smaller in LGM than PGM through the stationary wave feedback mechanism.