Variability of basal melt beneath the Pine Island Glacier ice shelf, West Antarctica

被引:76
作者
Bindschadler, Robert [1 ,2 ]
Vaughan, David G. [3 ]
Vornberger, Patricia [4 ]
机构
[1] NASA, Greenbelt, MD 20771 USA
[2] Univ Maryland Baltimore Cty, NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA
[3] British Antarctic Survey, Nat Environm Res Council, Cambridge CB3 0ET, England
[4] Sci Applicat Int Corp, Beltsville, MD 20705 USA
基金
美国国家科学基金会;
关键词
SHEET; ACCELERATION; COLLAPSE;
D O I
10.3189/002214311797409802
中图分类号
P9 [自然地理学];
学科分类号
0705 ; 070501 ;
摘要
Observations from satellite and airborne platforms are combined with model calculations to infer the nature and efficiency of basal melting of the Pine Island Glacier ice shelf, West Antarctica, by ocean waters. Satellite imagery shows surface features that suggest ice-shelf-wide changes to the ocean's influence on the ice shelf as the grounding line retreated. Longitudinal profiles of ice surface and bottom elevations are analyzed to reveal a spatially dependent pattern of basal melt with an annual melt flux of 40.5 Gt a(-1). One profile captures a persistent set of surface waves that correlates with quasi-annual variations of atmospheric forcing of Amundsen Sea circulation patterns, establishing a direct connection between atmospheric variability and sub-ice-shelf melting. Ice surface troughs are hydrostatically compensated by ice-bottom voids up to 150 m deep. Voids form dynamically at the grounding line, triggered by enhanced melting when warmer-than-average water arrives. Subsequent enlargement of the voids is thermally inefficient (4% or less) compared with an overall melting efficiency beneath the ice shelf of 22%. Residual warm water is believed to cause three persistent polynyas at the ice-shelf front seen in Landsat imagery. Landsat thermal imagery confirms the occurrence of warm water at the same locations.
引用
收藏
页码:581 / 595
页数:15
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