[M-IS05] 南大洋・南極氷床が駆動する全球気候変動

[MIS05-13] Antarctic Slope Current modulates warm ocean heat intrusions towards Totten Glacier

* 中山 佳洋¹、Greene Chad²、Paolo Fernando ²、Mensah Vigan¹、Zhang Hong²、柏瀬 陽彦³、清水 大輔³、Greenbaum Jamin⁴、Blankenship Donald⁵、阿部 彩子⁶、青木 茂¹ (1.Institute of Low Temperature Science, Hokkaido University, Japan、2.NASA Jet Propulsion Laboratory, California, USA、3.National Institute of Polar Research, Tokyo, Japan、4.Scripps Institution of Oceanography, University of California, CA USA、5.Institute for Geophysics, University of Texas at Austin, Texas, USA、6.Atmosphere and Ocean Research Institute, The University of Tokyo, Tokyo, Japan)

キーワード：南大洋、棚氷海洋相互作用、周極深層水

The Totten Glacier in East Antarctica has received increasing attention in recent years for its ice loss and warm oceanographic conditions observed at the ice shelf front. Here, we developed satellite estimates of temporally varying Totten Ice Shelf (TIS) melt rates and a high-resolution ocean model. We show that the Antarctic Slope Current (ASC) impedes ocean heat intrusions onto the continental shelf, whereas on-shelf intrusions are enhanced when the ASC weakens. Our findings suggest that atmospheric and oceanic conditions beyond our regional model domain play a greater role than local wind stress curl or other factors in driving interannual variability of the ASC. We further show that heat intrusions towards the TIS are enhanced with coastal freshening, suggesting a positive feedback whereby even freshening due to ice loss in West Antarctica could start a chain reaction, leading to increased melt in East Antarctica, and further coastal freshening.