APPLICATION OF RADIAL-BASIS FUNCTION NETWORK TO CHARACTERIZE FUTURE RAINFALL PRONE TO SEDIMENT HAZARDS IN A CHANGING CLIMATE

抄録

 In this study, as a first attempt, we utilize the method of Radial-Basis Function Network (RBFN) to examine hourly rainfall intensity and soil-water index obtained from climate projections for investigating features of future rainfall under climate change influences. Our study area is focused on Rokko Mountain in Hyogo prefecture. The 1-km MLIT 3^rd-mesh system is adopted in our analysis. The 2-km and 5-km Non-Hydrostatic Regional Climate Models (NHRCM) under RCP2.6 and RCP8.5 scenarios are used as future climate projections. A transformation matrix is used to quantify geometrical changes of RBFN contours. The characteristics of cumulative rainfall amount and rainfall duration of hazardous rainfall events are also examined. The analysis results show that soil-water index is much enlarged while hourly rainfall is a bit enlarged under RCP2.6, but, reversely, soil-water index remains unchanged while hourly rainfall is much intensified on the mountain side facing Osaka Bay under RCP8.5 in 2-km NHRCM. The hazardous rainfall events in 2-km NHRCM have shorter durations and smaller cumulative amount comparing to the ones in 5-km NHRCM.