Export and circulation of ice cavity water in Pine Island Bay, West Antarctica
Export and circulation of ice cavity water in Pine Island Bay, West Antarctica
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南极洲西部松岛湾冰腔水的输出和循环
DOI：
10.1002/2013jc009307
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发表时间：
2014
影响因子：
--
通讯作者：
C. F. Giulivi
中科院分区：
文献类型：
--
作者：
A. Thurnherr;S. Jacobs;P. Dutrieux;C. F. Giulivi
南极冰盖的大部分地区很容易受到边缘冰架底部融化增加的影响，融化速度取决于海洋温度和冰下空腔的环流。在这里，我们分析了海洋学数据集在2009年夏季在松岛湾，这是有界的阿蒙森海的快速移动的松岛冰架的崩解前在东部。在无冰湾的上层海洋速度场占主导地位的700米深，50公里宽的环流1.5西弗的水顺时针循环周围的海湾。冰腔水被观察到在一个表面增强和向南增强的边界流沿着冰锋，并在一个小冰湾在南部剪切边缘的冰架的结束。在海湾的重复测量显示，在10天的采样期间，持续的空腔水出口为10.25 Sv。在冰草案以上的海湾中的垂直速度占主导地位的浮力频率振荡的振幅为几厘米/秒，但没有显着的净上升流。结合海水的性质，这一观察表明，大部分的上升流发生在海湾附近的断裂冰，可能有助于削弱冰架剪切边缘。
Large sectors of the Antarctic ice sheet are vulnerable to increases in melting at the bases of fringing ice shelves, with melt rates depending on ocean temperatures and circulations in the sub-ice cavities. Here we analyze an oceanographic data set obtained in austral summer 2009 in Pine Island Bay, which is bounded in the east by the calving front of the Amundsen Sea's fast-moving Pine Island Ice Shelf. The upper-ocean velocity field in the ice-free bay was dominated by a 700 m deep and 50 km wide gyre circulating 1.5 Sv of water clockwise around the bay. Ice cavity water was observed in a surface-intensified and southward-intensified boundary current along the ice front, and in a small ice cove at the end of the southern shear margin of the ice shelf. Repeat measurements in the cove reveal persistent cavity water export of ≈ 0.25 Sv during 10 days of sampling. Vertical velocities in the cove above the ice draft were dominated by buoyancy-frequency oscillations with amplitudes of several cm/s but without significant net upwelling. In combination with the seawater properties, this observation indicates that much of the upwelling occurs within fractured ice near the cove, potentially contributing to weakening the ice shelf shear margin.