[A-AS04] Extreme Events and Mesoscale Weather: Observations and Modeling

[AAS04-P11] Local-scale circulation associated with enhanced poleward moisture transport for Meiyu-Baiu heavy rainfall over western Japan

*Satoshi Iizuka¹, Shinji Matsumura¹ (1.National Research Institute for Earth Science and Disaster Resilience)

Keywords:Heavy rainfall, SST, Kuroshio

Heavy rainfall events in western Japan during early July have become more frequent, yet the underlying mechanism behind this trend during the late stage of the Meiyu-Baiu rainy season remains unclear. Our long-term analysis of short-duration events revealed that a quasi-stationary Rossby wave train enhances the poleward transport of moisture from the western Pacific, contributing to the frequent occurrence of heavy rainfall events over western Japan. The local-scale circulation over the East China Sea plays a substantial role in producing this quasi-stationary Rossby wave train, which is closely linked to enhanced deep convection over the Kuroshio warm current, characterized by a distinct sea surface temperature (SST) front.