Impacts of wind stress on the Antarctic Circumpolar Current fronts and associated subduction
Impacts of wind stress on the Antarctic Circumpolar Current fronts and associated subduction
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DOI：
10.1029/2011gl047668
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发表时间：
2011-06-14
影响因子：
5.2
通讯作者：
Farneti, R.
中科院分区：
文献类型：
--
作者：
Downes, S. M.;Budnick, A. S.;Farneti, R.
最近的研究表明，在南极绕极流（ACC）地区的翻转环流显示了一个弱的敏感性，叠加风应力的变化，由于平衡的变化，涡诱导和欧拉平均输送。使用涡允许耦合气候模式，我们分析了ACC运输的响应，以及相关的水团俯冲率，在响应一个理想化的极移和西风带的强化。在以前的研究中，我们发现一个小的增加，在净ACC运输，并在ACC流的平均位置向极移动。然而，ACC被重组，亚季风锋（SAF）和极锋（PF）分支向极地移动0.9度和2.5度之间的纬度，导致在SAF和PF区的ACC流较弱。风应力异常驱动一个较强的向北Ekman输送冷表面沃茨，加深冬季混合层，并导致12.7 Sv的增加，在俯冲的亚南极模式水（SAMW）的SAF区北部和6.5 Sv的增加，在俯冲的南极中层水（AAIW）的SAF和PF区。我们的研究结果表明，在风应力的变化重构南大洋大尺度环流，包括流动的ACC在其主要的射流，这会影响SAMW和AAIW在这个复杂的区域的形成率。作者：Downes，S. M.，A. S. Budnick，J. L. Sarmiento和R. Farneti（2011），Impacts of wind stress on the Antarctic Circumpolar Current fronts and associated subduction，Geophys.保留信函：38，L11605，doi：10.1029/2011GL047668。
Recent studies suggest that the overturning circulation in the Antarctic Circumpolar Current (ACC) region shows a weak sensitivity to overlying wind stress changes, due to balancing of changes in the eddy-induced and Eulerian mean transports. Using an eddy-permitting coupled climate model, we analyze the response of the ACC transport, and associated water mass subduction rates, in response to an idealized poleward shift and intensification of the westerlies. As in previous studies, we find a small increase in the net ACC transport, and a poleward shift in the mean position of the ACC flow. However, the ACC is restructured, with the Subantarctic Front (SAF) and Polar Front (PF) branches shifting poleward by between 0.9 degrees and 2.5 degrees of latitude, resulting in a weaker ACC flow in both the SAF and PF zones. The wind stress anomaly drives a stronger northward Ekman transport of cool surface waters, deepening the winter mixed layer and causing a 12.7 Sv increase in the subduction of Subantarctic Mode Water (SAMW) north of the SAF zone and a 6.5 Sv increase in the subduction of Antarctic Intermediate Water (AAIW) within the SAF and PF zones. Our results suggest that changes in the wind stress restructure the Southern Ocean large-scale circulation, including the flow of the ACC in its primary jets, and that this affects the formation rates of SAMW and AAIW in this complex region. Citation: Downes, S. M., A. S. Budnick, J. L. Sarmiento, and R. Farneti (2011), Impacts of wind stress on the Antarctic Circumpolar Current fronts and associated subduction, Geophys. Res. Lett., 38, L11605, doi:10.1029/2011GL047668.