Division Into Districts On Wind Disaster Risk Of Hangzhou

Strong wind disaster is the global high frequent and serious influence. Strong wind often causes casualties, farmland disaster and the Houses collapsed. Hence, it seriously restricts the development of social economy and the protection of environmental resources. Hangzhou which is located in the northeast coast of Zhejiang is one of the most serious Strong wind disaster areas in China. According to Hangzhou meteorological related data and statistical analysis, the yearly maximum wind speed extremum is34.7m/s which is recorded in1988.Meanwhile, the yearly longest strong wind days is16d which is recorded in1981._There are High value regions in Apri、July and August for the monthly distribution of average maximum wind speed and strong wind days.Based on the formation of strong wind, there are Typhoon wind, strong convective wind and other wind three types. Because it has occured more and affect longer, the proportion of strong convective wind days is much higher.According to the1984-2008strong wind disaster data, this paper assesses the strong wind disasters caused loss through the selection of three indexes which are the number of death, the number of injury and the direct economic losses. It shows a quantitative evaluation on the situation of strong wind disaster damage and space losses based on the grey relation model. Based on the precipitation data from Hangzhou City during the period from1959to2010and combined with the natural geographic and the society economic factors, according to the natural disaster system theory, this study builds a set strong wind disaster assessment model of hazard factors, hazard including environment, hazard-affected body and disaster prevention ability.In this paper, it uses the GIS spatial analysis technique to study space laminated analysis of the index and uses the fuzzy comprehensive evaluation method to analyze strong wind disaster risk situation in the selected area on the base of theory of strong wind disaster formation, strong wind disaster development and the spread of the disaster and proper disaster risk evaluation index. The author produces the Hangzhou municipal strong wind disaster risk diagram with the1km*1km grid for basic evaluation unit and divides Hangzhou into five risk categories which are high, secondary high, medium, secondary low and low respectively.Division results show that there is a southwest lower than northeast situation of Hangzhou strong wind disaster.Xiaoshan district, Yuhang district,urban of Hangzhou city and The northern mountains of Linan show relatively higher risk level. However, hilly areas of southern and southwestern regions show slightly lower risk level. Finally, according to the strong wind disaster data in Hangzhou, the verified evidence shows that the risk division results are in accordance with the regional disaster distribution.