In 2023, the global temperature rose significantly, triggering a marine heatwave (MHW) in the East China Sea (ECS) from August 12 to October 13. Unlike the typical July onset, this event was delayed. Here we investigate the mechanisms behind the late onset and prolonged duration of the 2023 MHW in the ECS and its potential linkage to global warming. The early phase was driven by shortwave radiation and ocean dynamics, while the later phase saw reduced northerly winds, allowing warmer, more humid southerlies to dominate. This shift decreased the air-sea humidity difference, enhancing downward latent heat fluxes. Future CMIP6 projections also suggest that delayed MHWs are linked to weak heat exchanges, limiting the oceanic heat transport to the atmosphere. Our findings highlight the increasing risk of prolonged MHWs in the ECS and the urgent need for improved climate preparedness.

2023 年，全球气温大幅上升，引发 8 月 12 日至 10 月 13 日东海海洋热浪 （MHW）。与典型的 7 月发病不同，这一事件被推迟了。在这里，我们研究了 ECS 中 2023 MHW 晚发和持续时间延长的机制及其与全球变暖的潜在联系。早期阶段由短波辐射和海洋动力学驱动，而后期阶段的北风减弱，使更温暖、更潮湿的南风占主导地位。这种变化减小了气-海湿度差，增强了向下的潜热通量。未来的 CMIP6 预测还表明，延迟的 MHW 与弱热交换有关，从而限制了海洋向大气的热量传输。我们的研究结果强调了 ECS 中 MHW 延长的风险增加，以及改善气候准备的迫切需求。