Evidence from ice shelves for channelized meltwater flow beneath the Antarctic Ice Sheet
Evidence from ice shelves for channelized meltwater flow beneath the Antarctic Ice Sheet
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DOI：
10.1038/ngeo1977
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发表时间：
2013-11-01
影响因子：
18.3
通讯作者：
Siegert, Martin J.
中科院分区：
文献类型：
--
作者：
Le Brocq, Anne M.;Ross, Neil;Siegert, Martin J.
南极冰盖下产生的融水对冰流的速度有很大的影响，特别是对主要的冰流（1，2）。冰下融水也影响冰架下的海洋环流，引发融水羽流，夹带温暖的海水，导致高融化率（3）。然而，尽管它的重要性，水文系统的性质下的接地冰盖仍然很差的特点。在这里，我们提出的证据，从卫星和航空遥感，在南极洲西部的浮动Filchner-Ronne冰架下的大通道，我们建议提供一种手段，调查水文系统下的接地冰盖。我们从卫星图像上观察冰架表面的特征，并使用雷达测量，表明它们与冰架下方的通道相对应。我们还表明，子冰架通道与预测的冰下融水流出的位置对齐。这一协议表明，冰架下的渠道是由融水羽流形成的，由冰下水以集中（渠道化）的方式离开上游接地冰盖。渠化水文系统的存在对南极洲冰流接地线附近的冰盖和冰架的行为和动态有影响。
Meltwater generated beneath the Antarctic Ice Sheet exerts a strong influence on the speed of ice flow, in particular for major ice streams(1,2). The subglacial meltwater also influences ocean circulation beneath ice shelves, initiating meltwater plumes that entrain warmer ocean water and cause high rates of melting(3). However, despite its importance, the nature of the hydrological system beneath the grounded ice sheet remains poorly characterized. Here we present evidence, from satellite and airborne remote sensing, for large channels beneath the floating Filchner-Ronne Ice Shelf in West Antarctica, which we propose provide a means for investigating the hydrological system beneath the grounded ice sheet. We observe features on the surface of the ice shelf from satellite imagery and, using radar measurements, show that they correspond with channels beneath the ice shelf. We also show that the sub-ice-shelf channels are aligned with locations where the outflow of subglacial meltwater has been predicted. This agreement indicates that the sub-ice-shelf channels are formed by meltwater plumes, initiated by subglacial water exiting the upstream grounded ice sheet in a focused (channelized) manner. The existence of a channelized hydrological system has implications for the behaviour and dynamics of ice sheets and ice shelves near the grounding lines of ice streams in Antarctica.