Reversal of ocean gyres near ice shelves in the Amundsen Sea caused by the interaction of sea ice and wind
Reversal of ocean gyres near ice shelves in the Amundsen Sea caused by the interaction of sea ice and wind
复制标题
海冰和风的相互作用导致阿蒙森海冰架附近的海洋环流逆转
DOI：
10.5194/tc-2021-390
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
B. Queste
中科院分区：
文献类型：
--
作者：
Y. Zheng;D. Stevens;K. Heywood;B. Webber;B. Queste
抽象的。漂浮的冰架支撑着南极冰盖，主要由于海洋融化和相关的冰川动力学破坏，冰盖正在迅速失去质量。因此，冰架附近的局部海洋环流对于预测未来冰量损失和相关的海平面上升非常重要，因为它决定了冰架下的水质量交换、热量输送以及由此产生的融化。然而，控制近海岸环流的动力学尚未完全了解。在松岛冰架前的气旋（即顺时针方向）环流（半径27公里）先前已被确定在数值模式和速度观测。在这里，我们介绍了从2019年到Thwaites冰架以西的船基观测结果，在这个习惯性冰覆盖的地区首次揭示了另一个环流（半径13公里），尽管有类似的风强迫，但与松岛冰架附近的环流相反（反气旋，反气旋）方向旋转。我们使用一个理想化的配置MITgcm，与理想化的强迫ERA-5气候风场和简化海冰条件的基础上，从MODIS卫星图像，重现观察到的环流附近的松岛冰架和Thwaites冰架的主要功能。在冰的存在下，单独由风强迫驱动的模式可以再现两个环流的水平结构和方向。我们表明，模拟的环流方向取决于海洋表面应力的空间差异，这可以受到所施加的风应力旋度场，通过冰传递的风应力的百分比，以及风向和海冰边缘之间的角度。冰的存在，无论是阻挡风影响的快速冰/冰架，还是增强风影响的移动的海冰，都有可能使环流方向相对于无冰条件发生逆转。
Abstract. Floating ice shelves buttress the Antarctic Ice Sheet, which is losing mass rapidly mainly due to ocean-driven melting and the associated disruption to glacial dynamics. The local ocean circulation near ice shelves is therefore important for the prediction of future ice mass loss and related sea-level rise as it determines the water mass exchange, heat transport under the ice shelf and the resultant melting. However, the dynamics controlling the near-coastal circulation are not fully understood. A cyclonic (i.e. clockwise) gyre circulation (27 km radius) in front of the Pine Island Ice Shelf has previously been identified in both numerical models and velocity observations. Here we present ship-based observations from 2019 to the west of Thwaites Ice Shelf, revealing another gyre (13 km radius) for the first time in this habitually ice-covered region, rotating in the opposite (anticyclonic, anticlockwise) direction to the gyre near Pine Island Ice Shelf, despite similar wind forcing. We use an idealised configuration of MITgcm, with idealised forcing based on ERA-5 climatological wind fields and simplified sea ice conditions from MODIS satellite images, to reproduce key features of the observed gyres near Pine Island Ice Shelf and Thwaites Ice Shelf. The model driven solely by wind forcing in the presence of ice can reproduce the horizontal structure and direction of both gyres. We show that the modelled gyre direction depends upon the spatial difference in the ocean surface stress, which can be affected by the applied wind stress curl filed, the percentage of wind stress transferred through the ice, and the angle between the wind direction and the sea ice edge. The presence of ice, either it is fast ice/ice shelves blocking the effect of wind, or the mobile sea ice enhancing the effect of wind, has the potential to reverse the gyre direction relative to ice-free conditions.
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影响因子：
13.6
作者：
Wåhlin AK;Graham AGC;Hogan KA;Queste BY;Boehme L;Larter RD;Pettit EC;Wellner J;Heywood KJ
通讯作者：
Heywood KJ
影响因子：
3.6
作者：
Biddle, Louise C.;Loose, Brice;Heywood, Karen J.
通讯作者：
Heywood, Karen J.
DOI：
10.1073/pnas.1817205116
发表时间：
2019-06-04
影响因子：
11.1
作者：
Bamber, Jonathan L.;Oppenheimer, Michael;Cooke, Roger M.
通讯作者：
Cooke, Roger M.
影响因子：
6.3
作者：
Elvidge, A. D.;Renfrew, I. A.;King, J. C.
通讯作者：
King, J. C.
影响因子：
16.6
作者：
Yoon ST;Lee WS;Nam S;Lee CK;Yun S;Heywood K;Boehme L;Zheng Y;Lee I;Choi Y;Jenkins A;Jin EK;Larter R;Wellner J;Dutrieux P;Bradley AT
通讯作者：
Bradley AT