Arctic sea-ice decline weakens the Atlantic Meridional Overturning Circulation
Arctic sea-ice decline weakens the Atlantic Meridional Overturning Circulation
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DOI：
10.1038/nclimate3353
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发表时间：
2017-08-01
影响因子：
30.7
通讯作者：
Liu, Wei
中科院分区：
文献类型：
--
作者：
Sevellec, Florian;Fedorov, Alexey V.;Liu, Wei
北极海冰的持续减少使海洋面临异常的表面热量和淡水通量，导致正浮力异常，从而影响海洋环流。在这项研究中，我们使用最佳通量扰动框架和综合气候模型模拟来估计大西洋经向翻转环流（AMOC）对北极和全球浮力强迫的敏感性，更普遍的是对海冰下降的敏感性。研究发现，在年代际时间尺度上，北大西洋副极地的通量异常对AMOC影响最大，而在数十年时间尺度上（超过20年），北极地区的通量异常变得更加重要。这些正浮力异常扩散到北大西洋，削弱了 AMOC 及其向极地的热传输。因此，北极海冰的减少可以解释AMOC的放缓和北大西洋副极地地区持续存在的“暖洞”。
The ongoing decline of Arctic sea ice exposes the ocean to anomalous surface heat and freshwater fluxes, resulting in positive buoyancy anomalies that can affect ocean circulation. In this study, we use an optimal flux perturbation framework and comprehensive climate model simulations to estimate the sensitivity of the Atlantic Meridional Overturning Circulation (AMOC) to such buoyancy forcing over the Arctic and globally, and more generally to sea-ice decline. It is found that on decadal timescales, flux anomalies over the subpolar North Atlantic have the largest impact on the AMOC, while on multidecadal timescales (longer than 20 years), flux anomalies in the Arctic become more important. These positive buoyancy anomalies spread to the North Atlantic, weakening the AMOC and its poleward heat transport. Therefore, the Arctic sea-ice decline may explain the suggested slow-down of the AMOC and the 'Warming Hole' persisting in the subpolar North Atlantic.