IMPACTS OF GLOBAL WARMING ON HEAVY PRECIPITATION FREQUENCY AND FLOOD RISK

Abstract

We describe impacts of global warming on heavy precipitation characteristics and flood risk using the 2-day precipitation of the 12 General Circulation Models. The frequency analysis based on partial duration series was carried out. The model ensemble average 200-year quantiles in Tokyo during 2050-2300 under the climate condition of IPCC SRES-A1B scenario were 1.07-1.20 times as large as the one under the present climate condition. Those influences on runoff discharge and flood risk in the Tama river basin were investigated using the numerical simulations. The estimated high water discharge rise by 10-26%, and the flood volume increased by 46-131% if the precipitation with a 200-year return period occurred.