A Super Cluster of extreme rainfall event over North China in July 2023: role of typhoon-monsoon interaction

In July 2023, a super cluster of extreme rainfall event attacked North China during the decaying phase of Typhoon Doksuri, which induced a severe flood, causing great damage and people death. Our results show that this event is mainly caused by the cross-time scale interaction between the enhanced anticyclone over the Sea of Japan, the decaying Typhoon Doksuri, and the developing Typhoon Khanun. The anomalous anticyclone exhibits significant 10−30-day and 30–90-day time scales. It interacted with Typhoon Doksuri, providing moisture advection via southeasterly flow. The anticyclone was enhanced by the combination of wave energy dispersed from Typhoons Doksuri and Khanun in the lower troposphere and eastward propagation of Rossby waves in the upper troposphere, which jointly resulted in the local moisture convergence and vertical motion during the flooding. As a result, the 10–30-day and 30–90-day intraseasonal oscillations of the anticyclone play an important role as an initial atmospheric condition. It bridges the East Asian summer monsoon and Typhoons of Doksuri and Khanun, showing an important source of subseasonal predictability of extreme heavy rainfall events in North China.