Numerical experiments on subaqueous melting of Greenland tidewater glaciers in response to ocean warming and enhanced subglacial discharge
Numerical experiments on subaqueous melting of Greenland tidewater glaciers in response to ocean warming and enhanced subglacial discharge
复制标题
格陵兰岛潮水冰川水下融化响应海洋变暖和冰下排放增加的数值实验
DOI：
10.3189/2012aog60a139
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发表时间：
2012
影响因子：
2.9
通讯作者：
M. Koppes
中科院分区：
文献类型：
--
作者：
Yun Xu;E. Rignot;D. Menemenlis;M. Koppes
格陵兰岛最大的冰排放源是冰川，这些冰川终止于海洋，与海水接触后融化。冰盖/海洋相互作用的研究主要集中在近水平的浮冰架下的融化。对于冰川，融化反而发生在沿着崩解锋的垂直面。在这里，我们修改了马萨诸塞州理工学院的大气环流模式（MITgcm），包括冰融化从一个冰解面与淡水流出冰川接地线。我们使用该模型来预测融化率和海洋热强迫和冰下放电的敏感性。我们发现，融化率增加约冰下水通量的三分之一的权力，并与海洋热强迫线性增加。我们的模拟结果表明，与有限的现场数据一致，融化停止时，冰下放电被关闭，并达到每天数米时，冰下放电是在夏季高。这些结果是一个更现实的代表性的冰下放电和海洋热力强迫的数值海洋模式中的冰川融化的水下的第一步。我们的研究结果表明，冰锋融化过程是复杂的和强烈的时间依赖性。
Abstract The largest dischargers of ice in Greenland are glaciers that terminate in the ocean and melt in contact with sea water. Studies of ice-sheet/ocean interactions have mostly focused on melting beneath near-horizontal floating ice shelves. For tidewater glaciers, melting instead takes place along the vertical face of the calving front. Here we modify the Massachusetts Institute of Technology general circulation model (MITgcm) to include ice melting from a calving face with the freshwater outflow at the glacier grounding line. We use the model to predict melt rates and their sensitivity to ocean thermal forcing and to subglacial discharge. We find that melt rates increase with approximately the one-third power of the subglacial water flux, and increase linearly with ocean thermal forcing. Our simulations indicate that, consistent with limited field data, melting ceases when subglacial discharge is shut off, and reaches several meters per day when subglacial discharge is high in the summer. These results are a first step toward a more realistic representation of subglacial discharge and of ocean thermal forcing on the subaqueous melting of tidewater glaciers in a numerical ocean model. Our results illustrate that the ice-front melting process is both complex and strongly time-dependent.