He Qingyou, Zhan Weikang, Cai Shuqun, Du Yan, Chen Zhiwu, Tang Shilin, Zhan Haigang
State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China.
Proc Natl Acad Sci U S A. 2023 Sep 26;120(39):e2302292120. doi: 10.1073/pnas.2302292120. Epub 2023 Sep 18.
As a major sink of anthropogenic heat and carbon, the Southern Ocean experienced pronounced warming with increasing extreme temperature events over the past decades. Mesoscale eddies that strongly influence the uptake, redistribution, and storage of heat in the ocean are expected to play important roles in these changes, yet observational evidence remains limited. Here, we employ a comprehensive analysis of over 500,000 historical hydrographic profile measurements combined with satellite-based eddy observations to show enhanced thermal eddy imprints in the Southern Ocean. Our observations reveal that anticyclonic (cyclonic) eddies are responsible for nearly half of the subsurface high (low)-temperature extremes detected, although only 10% of the profiles are located in eddy interiors. Over the past decade (2006 to 2019), both mean and extreme temperature anomalies within eddies in the Antarctic Circumpolar Current increased significantly, promoting the rise in subsurface ocean temperature variability. This enhanced role of eddies is likely a result of enhanced eddy pumping due to the increase in eddy intensity and ocean stratification caused by ocean warming. Our analysis underscores the crucial role of eddies in amplifying ocean temperature variability and extremes, with their effects expected to be even more pronounced as global warming persists.
作为人为热量和碳的主要汇聚地，南大洋在过去几十年经历了显著变暖，极端温度事件不断增加。中尺度涡旋对海洋中热量的吸收、重新分布和储存有强烈影响，预计在这些变化中发挥重要作用，但观测证据仍然有限。在此，我们对50多万次历史水文剖面测量数据进行综合分析，并结合基于卫星的涡旋观测，以显示南大洋中热涡印记增强。我们的观测结果表明，反气旋（气旋）涡旋造成了近一半检测到的次表层高温（低温）极端情况，尽管只有10%的剖面位于涡旋内部。在过去十年（2006年至2019年），南极绕极流中涡旋内的平均温度异常和极端温度异常均显著增加，推动了次表层海洋温度变率的上升。涡旋作用的增强可能是由于涡旋强度增加以及海洋变暖导致海洋层结加剧，进而增强了涡旋抽吸作用的结果。我们的分析强调了涡旋在放大海洋温度变率和极端情况方面的关键作用，随着全球变暖持续，其影响预计将更加显著。
