A multimodel, multiresolution ensemble using Coupled Model Intercomparison Project Phase 6 (CMIP6) High Resolution Model Intercomparison Project (HighResMIP) coupled experiments is used to assess the performance of key aspects of the North Atlantic circulation. The Atlantic Meridional Overturning Circulation (AMOC), and related heat transport, tends to become stronger as ocean model resolution is enhanced, better agreeing with observations at 26.5°N. However, for most models the circulation remains too shallow compared to observations and has a smaller temperature contrast between the northward and southward limbs of the AMOC. These biases cause the northward heat transport to be systematically too low for a given overturning strength. The higher‐resolution models also tend to have too much deep mixing in the subpolar gyre. In the period 2015–2050 the overturning circulation tends to decline more rapidly in the higher‐resolution models, which is related to both the mean state and to the subpolar gyre contribution to deep water formation. The main part of the decline comes from the Florida Current component of the circulation. Such large declines in AMOC are not seen in the models with resolutions more typically used for climate studies, suggesting an enhanced risk for Northern Hemisphere climate change. However, only a small number of different ocean models are included in the study.

中文翻译：

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大西洋子午线翻转环流对CMIP6 HighResMIP模拟中模型分辨率的敏感性及其对未来变化的启示

使用耦合模型比对项目第六阶段（CMIP6）高分辨率模型比对项目（HighResMIP）耦合实验的多模型，多分辨率合奏用于评估北大西洋环流关键方面的性能。随着海洋模型分辨率的提高，大西洋子午倾覆环流（AMOC）和相关的热传输趋于增强，与26.5°N处的观测结果更加吻合。但是，对于大多数模型，与观测相比，环流仍然太浅，并且AMOC的南北向之间的温度差较小。对于给定的倾覆强度，这些偏差会导致北向热传输系统地过低。高分辨率模型也倾向于在亚极回旋中进行过多的深度混合。在2015-2050年期间，高分辨率模式的倾覆环流趋于更快地下降，这与平均状态和亚极回旋对深水形成的贡献有关。下降的主要部分来自环流的佛罗里达电流部分。在模型中没有看到AMOC如此大的下降，其分辨率更通常用于气候研究，这表明北半球气候变化的风险增加了。但是，该研究仅包含少量不同的海洋模型。在模型中没有看到AMOC如此大的下降，其分辨率更通常用于气候研究，这表明北半球气候变化的风险增加了。但是，该研究仅包含少量不同的海洋模型。在模型中没有看到AMOC如此大的下降，其分辨率更通常用于气候研究，这表明北半球气候变化的风险增加了。但是，该研究仅包含少量不同的海洋模型。