Sea-ice loss in Eurasian Arctic coast intensifies heavy Meiyu-Baiu rainfall associated with Indian Ocean warming

Heavy Meiyu-Baiu rainfall, a significant weather phenomenon in East Asia, poses a considerable threat due to catastrophic flooding. While previous studies linked Indian Ocean (IO) warming to this rainfall, they failed to predict the record-breaking rainfall in July 2020. This study integrates observational analysis, large-ensemble climate simulations, and atmospheric simulations to demonstrate that sea-ice loss in the Kara Sea in May intensifies IO warming-induced heavy Meiyu-Baiu rainfall, accurately explaining the 2020 event. Sea-ice loss, under the condition of IO warming, prolongs the Meiyu-Baiu season, strengthens convective activity, and enhances rainfall by ~50%, doubling the risk of extreme events like that of 2020. A statistical model further confirms that incorporating Arctic sea ice significantly improves seasonal prediction of extreme Meiyu-Baiu rainfall.

Xiaodan Chen, Zhiping Wen, Jiping Liu, Wei Mei, Ruonan Zhang, Sihua Huang, Yuanyuan Guo, Juncong Li