Antarctic ice-sheet loss driven by basal melting of ice shelves
Antarctic ice-sheet loss driven by basal melting of ice shelves
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DOI：
10.1038/nature10968
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发表时间：
2012-04-26
期刊：
影响因子：
64.8
通讯作者：
Padman, L.
中科院分区：
文献类型：
--
作者：
Pritchard, H. D.;Ligtenberg, S. R. M.;Padman, L.
要准确预测全球海平面上升，我们必须了解最近沿沿着南极冰盖海岸边缘（3）冰川加速的原因。大气和海洋作用力有可能减少浮冰架的厚度和范围，从而可能限制其支持地面支流冰川流动的能力。事实上，最近的冰架崩溃导致了南极半岛上几个冰川的退缩和加速（5）。但是，冰架厚度变化的范围和幅度，这种变化的根本原因，以及它与冰川流速的联系是如此的知之甚少，以至于它对冰盖的未来影响还无法预测（3）。在这里，我们使用卫星激光测高和模拟的表面积雪层，以揭示环南极模式的冰架变薄，通过增加基底融化。我们推断，这种增加的融化是南极冰盖损失的主要控制因素，通过减少邻近冰盖的支撑作用导致冰川流动加速（2）。最高的减薄率发生在深层的温水可以通过穿越大陆架的海底槽进入厚冰架的地方。风的作用力可以通过阿蒙森海（6）和别林斯高晋海（7）的海洋上升流以及南极半岛的大气变暖（8）来解释南极冰架的基底融化和表面融化和崩溃的主要模式。这意味着，通过改变风的气候强迫影响南极冰盖质量平衡，从而影响全球海平面，在年度到十年的时间尺度。
Accurate prediction of global sea-level rise requires that we understand the cause of recent, widespread and intensifying(1,2) glacier acceleration along Antarctic ice-sheet coastal margins(3). Atmospheric and oceanic forcing have the potential to reduce the thickness and extent of floating ice shelves, potentially limiting their ability to buttress the flow of grounded tributary glaciers(4). Indeed, recent ice-shelf collapse led to retreat and acceleration of several glaciers on the Antarctic Peninsula(5). But the extent and magnitude of ice-shelf thickness change, the underlying causes of such change, and its link to glacier flow rate are so poorly understood that its future impact on the ice sheets cannot yet be predicted(3). Here we use satellite laser altimetry and modelling of the surface firn layer to reveal the circum-Antarctic pattern of ice-shelf thinning through increased basal melt. We deduce that this increased melt is the primary control of Antarctic ice-sheet loss, through a reduction in buttressing of the adjacent ice sheet leading to accelerated glacier flow(2). The highest thinning rates occur where warm water at depth can access thick ice shelves via submarine troughs crossing the continental shelf. Wind forcing could explain the dominant patterns of both basal melting and the surface melting and collapse of Antarctic ice shelves, through ocean upwelling in the Amundsen(6) and Bellingshausen(7) seas, and atmospheric warming on the Antarctic Peninsula(8). This implies that climate forcing through changing winds influences Antarctic ice-sheet mass balance, and hence global sea level, on annual to decadal timescales.