Design Tropical Cyclone Wind Speed when Considering Climate Change

Abstract

This paper investigated the evolution of tropical cyclone (TC) wind threat from the past into the future and discussed its implications for the building code specifications for two vulnerable coastal cities (Hangzhou and Shanghai) in China. Large samples of synthetic TCs were generated from reanalysis data and climate-model projections over the years 1979–2098. The synthetic data were evaluated with terrain-corrected historical TC wind speed data. Extreme value analysis was applied to the generated data set to estimate the return period of extreme winds. Most climate models considered (five of six) projected that the return period of TC winds for Hangzhou and Shanghai would significantly decrease over the 21st century. Because the traditional return-period-targeted estimation of the design wind speed is no longer appropriate in the context of a nonstationary climate, an alternative method based on the lifetime exceedance probability (LEP) was proposed to estimate the design wind speed. Most climate models considered (five of six) yielded significantly larger design wind speeds than the traditional stationary method, attributable to both projected increase in TC activity in the future climate and the applied nonstationary LEP method. The code-recommended design wind speeds for Shanghai and Hangzhou are smaller than the climatic design wind speeds projected by some (three of six) climate models considered in this study.