SPATIOTEMPORAL STRUCTURE AND ENVIRONMENTAL FIELD OF THE PRECIPITATION SYSTEM INDUCING THE HEAVY RAINFALL EVENT IN KYOTO CITY

Abstract

 Kyoto is one of the most flood-prone cities in the Kansai region. It is essential to understand the precipitation system that causes heavy rainfall for disaster prevention and mitigation. In this study, we analyzed the spatiotemporal structure and environmental field of the precipitation system inducing the heavy rainfall event in Kyoto city by using radar AMeDAS rainfall data and GPV-MSM reanalysis data. We defined the two thresholds for extracting the heavy rainfall event in different temporal scales; (1) daily maximum 1-hour precipitation exceeds 20 mm and (2) daily maximum 10-minute precipitation exceeds 10 mm. The events meeting only (1) threshold are characterized by a line-shaped precipitation system originating from Mt. Rokko. These are associated with a developed low-pressure system with a trough at 850hPa. In contrast, the events meeting only (2) threshold are localized precipitation systems over Kyoto city, suggesting convective precipitation with warmer surface temperature in the Kansai area due to the expansion of the Pacific high to the west.