Extremes of the Amundsen Sea Low and Their Impact on Climate

Abstract:

The Amundsen Sea Low is an important feature of the high latitude atmospheric circulation over the western Antarctic. It influences the climate of the region including sea ice. There have been periods in the 40-year record when the ASL has been extremely strong and extremely weak. Using the Actual Central pressure (ACP), an index of the depth of the Amundsen Sea Low, we examine the frequency with which such extremes occur. Using sea level pressure and surface winds we examine the characteristics of the Amundsen Sea Low, when it is exhibiting such extremes. We show that there are preferred times of year when these extremes occur, as well as preferred locations. We also examine the impact of these extremes on the Antarctic climate in particular the sea ice distribution, and the surface temperature of Western Antarctica and the Antarctic Peninsula.