Marine heatwaves (MHWs) and cold-spells (MCSs) are extreme sea surface temperature events with significant impacts on marine ecosystems. However, the connection between these events and mixed layer depth (MLD) variations, as well as how their intensity relates to MLD changes, remains unclear. Integrating OISST V2.1 data with Argo profiles, this analysis finds that during MHWs, MLD decreases by 8.10% globally, while during MCSs, it increases by 8.13%. In 5° × 5° bins, 80.46% of ocean regions show MLD shallowing during MHWs, while 67.69% show deepening during MCSs. A significant global correlation between the intensity of MHWs/MCSs and MLD changes, with coefficients of −0.85 and −0.86, respectively. MHWs are more common in mesoscale anticyclonic eddies (AEs) (19.45%) than in cyclonic eddies (CEs) (10.11%). For MCSs, the pattern reverses, with 8.57% in AEs and 20.82% in CEs. Restratification and mesoscale eddies are two important factors driving MLD changes during these events.

中文翻译：

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与全球混合层深度变化相关的海洋热浪/寒潮


海洋热浪 （MHW） 和寒潮 （MCS） 是极端的海面温度事件，对海洋生态系统有重大影响。然而，这些事件与混合层深度 （MLD） 变化之间的联系，以及它们的强度与 MLD 变化的关系，仍不清楚。将 OISST V2.1 数据与 Argo 配置文件相结合，该分析发现，在 MHW 期间，全球 MLD 下降了 8.10%，而在 MCS 期间，它增加了 8.13%。在 5° × 5° 区间中，80.46% 的海洋区域在 MHW 期间显示 MLD 变浅，而 67.69% 的海洋区域在 MCS 期间显示加深。MHWs/MCS 的强度与 MLD 变化之间存在显著的全局相关性，系数分别为 -0.85 和 -0.86。MHW 在中尺度反气旋涡流 （AE） （19.45%） 中比在气旋涡流 （CE） （10.11%） 中更常见。对于 MCS，模式相反，AE 为 8.57%，CE 为 20.82%。再分层和中尺度涡流是这些事件期间驱动 MLD 变化的两个重要因素。