Antarctic circumpolar currentʹs role in the Antarctic ice system: An overview

The Antarctic Circumpolar Current (ACC) provides fundamental control on the Antarctic ice system. The tilt of the isopycnals of the ACC, in response to strong westerlies, serves to thermally isolate the Antarctic continent from directly receiving the overwhelming subtropical ocean surface heat. This same tilt provides the northern boundary of the polar seas; as such it “contains” the statically stable cold fresh surface polar waters required for sea ice formation. In this manner it effectively sets the northern limit for seasonal sea ice formation. The isopycnal tilt also allows warm deep water to upwell to the surface near the continental margin in western Antarctica where the ACC skirts the continental shelf, leading to excessive ocean heat flux to the atmosphere in winter, and providing heat to melt the underside of the glacial ice.