Indo-Pacific warming induced by a weakening of the Atlantic Meridional Overturning Circulation
Indo-Pacific warming induced by a weakening of the Atlantic Meridional Overturning Circulation
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DOI：
10.1175/jcli-d-21-0346.1
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发表时间：
2021-11
影响因子：
4.9
通讯作者：
Shantong Sun;A. Thompson;S. Xie;Shang‐min Long
中科院分区：
文献类型：
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作者：
Shantong Sun;A. Thompson;S. Xie;Shang‐min Long
大西洋经向翻转环流（AMOC）的重组通常与地球气候的变化有关。这些AMOC变化通过波过程传达到印度洋-太平洋海盆，并引起翻转环流异常，在十年到百年的时间尺度上反对大西洋的变化。我们研究的作用，这种短暂的，跨盆地翻转响应，驱动的AMOC减弱，无论是在一个只有海洋的模型与理想化的几何形状和耦合的CO2翻两番的实验，其中海洋变暖两个不同的时间尺度：一个快速的十年表面变暖和缓慢的百年地下变暖。我们表明，瞬态盆地间翻转产生了大西洋和印度洋-太平洋盆地之间的纬向热量再分配。在AMOC减弱后，印度洋-太平洋地区出现异常的北向热输送，这基本上补偿了大西洋向南的热输送异常。这种纬向热量再分配表现为高纬度北大西洋和次表层印度洋-太平洋之间的热盆间跷跷板，有助于解释为什么南极温度记录通常显示出比北方半球在末次冰期更渐进的变化。在耦合CO2翻两番的实验中，我们发现，由于减弱AMOC的盆地间热传输大大有助于在印度太平洋缓慢的百年次表层变暖，占一半以上的热含量增加和海平面上升。因此，我们的研究结果表明，瞬态流域间翻转环流是全球海洋热收支在气候变化的一个关键组成部分。
The reorganization of the Atlantic Meridional Overturning Circulation (AMOC) is often associated with changes in Earth’s climate. These AMOC changes are communicated to the Indo-Pacific basins via wave processes and induce an overturning circulation anomaly that opposes the Atlantic changes on decadal to centennial time scales. We examine the role of this transient, inter-basin overturning response, driven by an AMOC weakening, both in an ocean-only model with idealized geometry and in a coupled CO2 quadrupling experiment, in which the ocean warms on two distinct timescales: a fast decadal surface warming and a slow centennial subsurface warming. We show that the transient inter-basin overturning produces a zonal heat redistribution between the Atlantic and Indo-Pacific basins. Following a weakened AMOC, an anomalous northward heat transport emerges in the Indo-Pacific, which substantially compensates for the Atlantic southward heat transport anomaly. This zonal heat redistribution manifests as a thermal inter-basin seesaw between the high-latitude North Atlantic and the subsurface Indo-Pacific and helps to explain why Antarctic temperature records generally show more gradual changes than the Northern Hemisphere during the last glacial period. In the coupled CO2 quadrupling experiment, we find that the inter-basin heat transport due to a weakened AMOC contributes substantially to the slow centennial subsurface warming in the Indo-Pacific, accounting for more than half of the heat content increase and sea level rise. Thus, our results suggest that the transient inter-basin overturning circulation is a key component of the global ocean heat budget in a changing climate.