RISK ASSESSMENT OF WIND DISASTERS IN URBAN DISTRICTS UNDER GLOBAL WARMING

Abstract

This study investigated the risks of disasters from strong winds in urban districts under global warming by conducting pseudo-global warming (PGW) experiments with a regional meteorological model and large eddy simulations (LESs) as well as by using urban geometrical features. Both the Weather Research and Forecasting (WRF) model and a simplified axisymmetric model were used to conduct PGW experiments on typhoons, while LESs were conducted for airflows in an urban district of Osaka City. Urban geometrical features were derived from a high-resolution digital surface model dataset. From the LES analysis, statistical relationships between wind gustiness and urban geometrical features under various stability conditions were obtained. The PGW experiments indicated how the external forcing of intense typhoons changed in a future climate. A combination of the meteorological, LES, and urban geometrical feature analyses demonstrated that risk of wind disasters in urban districts would increase by 10 % under +4K global warming scenario.