Stronger ocean circulation and increased melting under Pine Island Glacier ice shelf
Stronger ocean circulation and increased melting under Pine Island Glacier ice shelf
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DOI：
10.1038/ngeo1188
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发表时间：
2011-08-01
影响因子：
18.3
通讯作者：
Dutrieux, Pierre
中科院分区：
文献类型：
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作者：
Jacobs, Stanley S.;Jenkins, Adrian;Dutrieux, Pierre
1994年，南极洲松岛冰川附近的海洋测量表明，支撑冰川的冰架正在迅速融化(1)。这种融化归因于阿蒙森海大陆架上相对温暖的深水的存在。热、盐和冰的预算以及海洋模型提供了稳定的产犊和融化速率（2,3）。随后的卫星观测和模拟显示了较大的系统失衡，包括冰架变薄和更剧烈的融化、冰川加速和流域退缩（4-10）。在这里，我们将早期的数据与2009年的测量结果结合起来，表明松岛湾深水的温度和体积都在增加。冰架附近的海洋运输和示踪剂计算显示，自1994年以来，融水产量增加了约50%。更快的融化似乎主要是由于更强的冰架下环流，因为变薄的冰增加了冰川原来所在的海底湖岸上方的间隙（11）。我们得出的结论是，基底融化超过了冰流入的增加，导致冰架下形成和扩大了一个内腔，在这个内腔中，冰点以上近4摄氏度的海水现在更容易进入接地区。
In 1994, ocean measurements near Antarctica's Pine Island Glacier showed that the ice shelf buttressing the glacier was melting rapidly(1). This melting was attributed to the presence of relatively warm, deep water on the Amundsen Sea continental shelf. Heat, salt and ice budgets along with ocean modelling provided steady-state calving and melting rates(2,3). Subsequent satellite observations and modelling have indicated large system imbalances, including ice-shelf thinning and more intense melting, glacier acceleration and drainage basin drawdown(4-10). Here we combine our earlier data with measurements taken in 2009 to show that the temperature and volume of deep water in Pine Island Bay have increased. Ocean transport and tracer calculations near the ice shelf reveal a rise in meltwater production by about 50% since 1994. The faster melting seems to result mainly from stronger sub-ice-shelf circulation, as thinning ice has increased the gap above an underlying submarine bank on which the glacier was formerly grounded(11). We conclude that the basal melting has exceeded the increase in ice inflow, leading to the formation and enlargement of an inner cavity under the ice shelf within which sea water nearly 4 degrees C above freezing can now more readily access the grounding zone.