关键词: 冰架, 底部融化, 冰腔, 冰架水, 南极

Abstract:

Recent advances in the research of ice shelf–ocean interactions in Antarctica are reviewed in this paper. Basal melt rate of ice shelves exceeds calving flux, making bottom melt the dominant cause of mass loss in Antarctic ice sheets. Cavities under ice shelves can be classified into cold cavities—basal melt is driven by dense shelf water—and warm cavities—basal melt is driven by modified Circumpolar Deep Water. The giant Filchner–Ronne and Ross Ice Shelves in the Weddell and Ross Seas cover two-thirds of the total ice shelf area in Antarctica but mass loss from their cold cavities accounts for only 15% of the net melting of all ice shelves combined. Half of the net melting comes from several small, warm-cavity ice shelves in the Amundsen and Bellingshausen Seas in the Southeast Pacific sector, which cover 8% of the total ice shelf area. Modified Circumpolar Deep Water has been found to cause melting in the cold cavities under the Totten and Amery Ice Shelves in East Antarctica. Ice shelves cool and freshen seawater in their cavities. Ice shelf water from cavities is at a very low temperature and will modify shelf waters and even contribute to the formation of Antarctic Bottom Water. The recently observed freshening of Antarctic Bottom Water in the Pacific and Indian sectors might be attributed to the enhanced basal melting of upstream ice shelves.

Key words: ice shelf, basal melt, cavity, ice shelf water, Antarctic