Links Between the Amundsen Sea Low and the Sea Ice Variability in the Ross Sea.

Abstract:

The Amundsen Sea Low (ASL) is a climatological low pressure center located generally in the region between the Antarctic Peninsula and the Ross Sea. The Ross Sea is the primary area of the Southern Ocean where sea ice is expanding, an expansion shown to be due to the earlier advance and later retreat of the ice. It is suggested that the ASL is the primary large/regional scale atmospheric circulation feature contributing to the variability of sea ice in the Ross Sea during the advance and retreat periods of the ice. Using observed sea ice concentration data, geopotential height, and indices describing the depth and location of the ASL this research establishes statistical links between the variability of the ASL during the advance and retreat periods of the ice. The results clarify which characteristic of the ASL exerts the strongest influence on the variability of ice in the Ross Sea and also in the Amundsen and Bellingshausen Seas. The ASL is projected to deepen in future decades and the effect of this deepening on sea ice in the Ross is also examined.