| Summary: | 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. The coarse resolution of both the model and SST data may hinder the ability of climate simulations to capture the local-scale circulation, underscoring the importance of quasi-stationary atmospheric circulation for a better understanding of heavy rainfall events through poleward moisture transport.
|
|---|