Shan Xuan, Sun Shantong, Wu Lixin, Spall Michael
Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Physical Oceanography, Ocean University of China, Qingdao, China.
Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
Nat Commun. 2024 Aug 27;15(1):7361. doi: 10.1038/s41467-024-51449-9.
Anthropogenic warming is projected to enhance Arctic freshwater exportation into the Labrador Sea. This extra freshwater may weaken deep convection and contribute to the Atlantic Meridional Overturning Circulation (AMOC) decline. Here, by analyzing an unprecedented high-resolution climate model simulation for the 21st century, we show that the Labrador Current strongly restricts the lateral spread of freshwater from the Arctic Ocean into the open ocean such that the freshwater input has a limited role in weakening the overturning circulation. In contrast, in the absence of a strong Labrador Current in a climate model with lower resolution, the extra freshwater is allowed to spread into the interior region and eventually shut down deep convection in the Labrador Sea. Given that the Labrador Sea overturning makes a significant contribution to the AMOC in many climate models, our results suggest that the AMOC decline during the 21st century could be overestimated in these models due to the poorly resolved Labrador Current.
预计人为变暖将增强北极淡水向拉布拉多海的输出。这些额外的淡水可能会削弱深层对流，并导致大西洋经向翻转环流（AMOC）减弱。在此，通过分析一个前所未有的21世纪高分辨率气候模型模拟，我们表明拉布拉多海流强烈限制了北冰洋淡水向公海的横向扩散，因此淡水输入对减弱翻转环流的作用有限。相比之下，在一个分辨率较低的气候模型中，若没有强大的拉布拉多海流，额外的淡水会扩散到内部区域，并最终导致拉布拉多海深层对流停止。鉴于在许多气候模型中，拉布拉多海的翻转对AMOC有重大贡献，我们的结果表明，在这些模型中，由于对拉布拉多海流的分辨率较低，21世纪AMOC的减弱可能被高估了。
