The Atlantic Meridional Overturning Circulation and the Cabbeling Effect
The Atlantic Meridional Overturning Circulation and the Cabbeling Effect
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DOI：
10.1175/jpo-d-20-0085.1
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发表时间：
2020-09
影响因子：
3.5
通讯作者：
F. Schloesser
中科院分区：
文献类型：
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作者：
F. Schloesser
北大西洋经向密度梯度是大西洋经向翻转环流（AMOC）的主要驱动因素。由于串带效应，这些密度梯度越来越受变暖海洋温度梯度的支配，北大西洋平均温度与AMOC强度之间存在直接联系。本文在Stommel和Gnanadesikan模型中量化了这一机制的影响。由于包括不同的反馈机制，北大西洋平均海洋温度每升高1°C，在Gnanadesikan模式和Stommel模式中AMOC分别增强3%和8%。在Gnanadesikan模式中，这种增加相当于南半球风增强4%，可以补偿水循环增加14%。此外，平均温度强烈地控制了强AMOC状态的淡水强迫阈值，这表明需要考虑电缆效应来解释过去和未来的AMOC变化。
North Atlantic meridional density gradients have been identified as a main driver of the Atlantic meridional overturning circulation (AMOC). Due to the cabbeling effect, these density gradients are increasingly dominated by temperature gradients in a warming ocean, and a direct link exists between North Atlantic mean temperature and AMOC strength. This paper quantifies the impact of this mechanism in the Stommel and Gnanadesikan models. Owing to different feedback mechanisms being included, a 1°C warming of North Atlantic mean ocean temperature strengthens the AMOC by 3% in the Gnanadesikan model and 8% in the Stommel model. In the Gnanadesikan model that increase is equivalent to a 4% strengthening of Southern Hemisphere winds and can compensate for a 14% increase in the hydrological cycle. Furthermore, mean temperature strongly controls a freshwater forcing threshold for the strong AMOC state, suggesting that the cabbeling effect needs to be considered to explain past and future AMOC variability.