An unprecedented marine heatwave (MHW) event occurred in the middle-high latitudes of the western North Pacific during the summer of 2022. This study demonstrates that excessive precipitation thousands of kilometers away fueled this extreme MHW event in July 2022. A persistent atmospheric blocking system over the MHW region reduced cloud cover and increased shortwave radiation at the ocean surface, leading to high sea surface temperatures. Atmospheric perturbations induced by latent heat release from extreme precipitation in the Indian summer monsoon region enhanced this atmospheric blocking through the propagation of quasi-stationary Rossby waves. A numerical model forced with observed atmospheric anomalous diabatic heating verified this hypothesis. This study clarifies how a subtropical extreme event can fuel another extreme event at middle-high latitudes through an atmospheric teleconnection.

Qianghua Song, Chunzai Wang, Yulong Yao, Hanjie Fan