南极冰盖的物质平衡研究:进展与展望

PROGRESS AND PROSPECT IN MASS BALANCE STUDIES OF ANTARCTIC ICE SHEET

南极冰盖物质平衡最新的研究进展表明,西南极洲表现出两种变化模式,西部在增厚,而北面在更快地减薄。西南极冰盖总体可能正在减薄,其物质损失的速率可能足以使海平面每年上升近0.2mm。东南极冰盖物质不平衡可能很小,甚至其符号还不能被确定。南极半岛正在经历着快速变化。目前还不能可靠地估算南极冰盖的物质平衡状态。同时,大型冰川的停滞,一些冰川流速加快,冰盖大范围加速减薄,冰架大面积的快速崩解和支流冰川的加速,以及着地线强烈的底部融化等显示出南极冰盖存在快速变化。南极冰盖物质平衡未来的重点研究领域是开展冰盖表面高程变化的监测与模拟,确定表面物质平衡及其在各冰流盆地的分布,着地线的冰流通量,冰架底部的融化,了解冰后期冰盖退缩的动力过程,以及开发、对比和改进与冰盖物质平衡模拟和预测相关的各种模型。

Recent advances in the study on the mass balance of Antarctic Ice Sheet show that the West Antarctic Ice Sheet exhibits a bimodal behavior, with thickening in the west and more rapid thinning to the north, but is probably losing mass overall at a rate sufficient to raise sea level by almost 0.2 mm·a -1 . The East Antarctic Ice Sheet seems to be close to balance, but it is still impossible to determine even the sign of its mass balance. The state of Antarctic Ice Sheet mass balance is still unknown at present. Meanwhile, stoppage of huge glaciers, acceleration of others, rapid thinning of large sectors of ice sheet, rapid breakup of vast areas of ice shelf and acceleration of tributary glaciers, and vigorous bottom melting near grounding lines show substantial changes on relatively short time scales are commonplace on Antarctic Ice Sheet. The following key future research fields are needed to understand and predict Antarctic Ice Sheet mass balance: Observation and modeling of the surface elevation changes, determination of surface mass balance and its distribution over drainage basins as well as fluxes at the grounding lines and the bottom melting underneath ice shelves, understanding of the deglaciation history, development, comparison and improvement of all kinds of models related to modeling and prediction of ice sheet mass balance.