Risk zoning of typhoon disasters in Zhejiang Province, China

Abstract: We analyze the characteristics of typhoon disasters and the factors causing them using precipitation and wind data at the county level in Zhejiang Province from 2004 to 2012. Using canonical correlation analysis, we develop an intensity index for the factors causing typhoon disasters and calculate a population vulnerability index for Zhejiang by principal components analysis. Combining these two indexes, a comprehensive risk index for typhoon disasters is obtained and used to zone areas of risk in Zhejiang Province. Southeastern Zhejiang Province is the area most affected by typhoon disasters. The frequency ratio of daily rainfall > 50 mm decreases from the southeast coast to inland areas and is at a maximum in the boundary region between Fujian and Zhejiang, which has the highest risk of rainstorms. Southeastern Zhejiang and the boundary region between Zhejiang and Fujian and the Hangzhou Bay area are most frequently affected by extreme winds and have the highest risk of wind damage. The population of southwestern Zhejiang Province is the most vulnerable to typhoons as a result of the relatively undeveloped economy in this region, the mountainous terrain and the high risk of geological disasters. Vulnerability is lower in the cities and coastal areas due to better disaster prevention and reduction strategies and a more highly educated population. The southeast coastal areas face the highest risk, especially in the boundary region between Taizhou and Ningbo cities. Although the inland mountainous areas are not directly affected by the typhoons, they are in the medium-risk category for vulnerability.