2:00 PM - 2:15 PM
[AAS03-14] A Numerical Simulation of a Heavy Rainfall Event in Yamagata and Niigata Prefectures on 3 August 2022
Keywords:Heavy rainfall event, Numerical simulation
A numerical simulation was conducted to reproduce and analyze the localized heavy rainfall event that occurred in Niigata and Yamagata Prefectures on August 3, 2022. The simulation, performed at a horizontal resolution of 2 km, successfully captured key features of the convective systems that repeatedly propagated into the affected regions. The analysis demonstrated that extremely warm and moist air in the lower troposphere was advected into Niigata and Yamagata, converging along the southern flank of a low-pressure system located over the Sea of Japan, which facilitated the development of intense rainfall. The temporal evolution of the vertical structure of the precipitation systems revealed that, despite the presence of dry air in the mid-to-upper troposphere, the high equivalent potential temperature in the lower troposphere was transported upward, triggering deep convection. A backward trajectory analysis was performed to determine the origin of the air parcels feeding the convective system. The analysis identified two primary air parcel sources: one originating from the East China Sea, passing through the Tsushima Strait and entering from the Sea of Japan, and another crossing the Korean Peninsula, traveling over the Sea of Japan, and advecting into the Niigata and Yamagata regions. Future studies will focus on conducting a more detailed investigation into the mechanisms sustaining the heavy rainfall event and the associated processes.