Interaction between Arctic sea ice and the Atlantic meridional overturning circulation in a warming climate
Interaction between Arctic sea ice and the Atlantic meridional overturning circulation in a warming climate
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DOI：
10.1007/s00382-021-05993-5
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发表时间：
2021-10-20
期刊：
影响因子：
4.6
通讯作者：
Fedorov, Alexey
中科院分区：
文献类型：
--
作者：
Liu, Wei;Fedorov, Alexey
初步证据表明，北极海冰的收缩和大西洋经向翻转环流（AMOC）的放缓可能已经在 1970 或 1980 年代开始，这提出了一个问题：这两个关键气候组成部分的变化如何在不同的时间尺度上相互关联。在这里，我们使用广泛的模型和气候模拟（包括来自 CMIP5 和 CMIP6 数据集的模型和气候模拟）研究北极海冰和 AMOC 变化之间的双向相互作用。我们对工业化前模拟的分析表明，北极海冰损失可以在数十年的延迟后导致 AMOC 放缓，主要是通过正浮力（温暖/低盐度）异常的下游传播从北极传播到近极地北大西洋并抑制深层对流。另一方面，AMOC 的减弱会通过北向海洋热传输的减少，在几年内扩大北极海冰覆盖范围。通过分析温室变暖模拟，我们进一步表明，这些相互作用应该在人为全球变暖的情况下发挥作用，影响北极海冰和 AMOC 的未来预测。
Tentative evidence suggests that the contraction of Arctic sea ice and the slowdown of the Atlantic meridional overturning circulation (AMOC) may have already started in the 1970 or 1980s, which raises the question of how changes in these two key climate components are connected across different timescales. Here, we investigate two-way interactions between Arctic sea ice and AMOC variations using a broad suite of models and climate simulations, including those from the CMIP5 and CMIP6 datasets. Our analysis of preindustrial simulations suggests that Arctic sea ice loss can drive an AMOC slowdown after a multi-decadal delay primarily through the downstream propagation of positive buoyancy (warm/low salinity) anomalies spreading from the Arctic to the subpolar North Atlantic and suppressing deep convection. The AMOC weakening on the other hand acts to expand Arctic sea ice cover within several years via a reduction in northward oceanic heat transport. Analyzing greenhouse-warming simulations, further we show that these interactions should operate under anthropogenic global warming, affecting future projections for Arctic sea ice and the AMOC.