Maximum Precipitation Scenarios of Line-Shaped Mesoscale Convective Systems in a Warming Climate: Numerical Model-Based Estimation

This study aims to estimate a PMP scenario with considering climate change for line-shaped mesoscale convective systems (MCSs), called “Senjo-Kousuitai” in Japanese. The numerical model-based method was employed to estimate PMP at the target watersheds in Japan. The August 2022 event in northern Japan was selected as the target rainfall event, which brought recorded greatest rainfall amount in observation history at many rain-gauge stations in the region. The storm transposition method (i.e., atmospheric initial and boundary condition shifting method) successfully transposed the target MCS, resulting in significant increase in rainfall at the Akagawa watershed. Climate change effects were incorporated by means of pseudo-global warming method, showing the high sensitivity of rainfall to warming scenarios. This study provides important insights on modernizing PMP with considering climate change. The estimated PMP scenarios under climate change will play a critical role in flood risk management in the region.