Scenario Simulation And Risk Assessment Of Typhoon Storm Surge Disaster In Different Spatial Scales

The eastern coastal area of China is located in the northwestern margin of the Pacific storm basin. Typhoon storm surge occurred frequently and caused great loss, especially for Shanghai, the country’s economic and financial center. The existing researches of typhoon storm surge mostly focused on the simulation of reproducing the storm surge history events. There are still a lot of work to do in building a perfect method system for risk researches and sovling the spatial scale problem. This paper built a method system for typhoon storm surge risk evaluation using probabilistic method and GIS space modeling and studied space scale effects of typhoon storm surge disaster risk.This study was supported by the National Natural Science Foundation of China (NO.40730526), the Innovation Project of Shanghai Education Committee (NO.13ZZ035), Technology Venus Project (NO.09QA1401800) and the Key Scientific Research Projects of ECNU and Shanghai Science. In this paper, the eastern coastal area of China and Shanghai were selected as the two kinds of spatial scale empirical study areas. Typhoon hazard scenario generation tool, DHI MIKE21and ArcGIS were used to carry out risk assessment in two spatial scales. Then put forward the risk prevention measures and studied the spatial scale effects of typhoon storm surge risk. The work and results of this study are as follows:1. Constructed two models of typhoon storm surge disaster risk on different spatial scales and proposed a perfect method system for disaster risk assessment:(1) Analysed2118typhoons data, generated9typhoons (W20, W50, W100, WN20, WN50, WN100, S20, S50, SI00) relying on the typhoon risk scenario generation tool and built the typhoon storm surge risk models on DHI MIKE21(2) Put forward the method system for typhoon storm surge disaster risk assessment. The system included:generating typhoons, the simulation of typhoon storm surge and risk assessment.2. Typhoon storm surge risk assessments in eastern coast of China:(1) Typhoon storm surges in west scenarios mainly affected Guangdong and Hainan, northwest influenced Fujian and Zhejiang and steering impacted Zhejiang, Shanghai and Jiangsu. Flooded areas in extreme scenarios (100-year frequency) were10124、17915and23916km2for west、 northwest and steering typhoon storm surges.(2) Typhoon storm surge disaster vulnerability grades were1or2in W100, WN100scenarios and higher in S100scenario which existed4in Shanghai.(3) High risk areas were Leizhou city, Southeast of Zhejiang province, the Gulf of Hangzhou and the southern Jiangsu, medium risk area was eastern Shanghai.(4) The typhoon storm surge risk prevention work should focus on strategy and policy guidance, such as adjust social development mode and promote economic sustainable development.3. Typhoon storm surge risk assessments in Shanghai:(1)3typhoon storm surges of steering type affected southern Chongming Island, coastal area in Changxing Island, western Hengsha Island, coast in Baoshan, Pudong, Fengxian and Jinshan. Flooded area in extreme scenarios (S100) was351km2.(2) High-grade vulnerability existed mainly in south bank of Chongming Island, Changxing Island, the coastal areas of Baoshan, Pudong and south coast of Jinshan.(3) The very high risk areas were southern Chongming Island, Baoshan, Pudong and Jinshan.(4) Risk prevention should focus on risk management and city planning. Carry out engineering and biological prevention work, such as in Baoshan, Pudong and Jinshan and reinforce seawall constructions.4. Studied the spatial scale effects of typhoon storm surge risk based on the empirical researches of China’s east coast and Shanghai:(1) The spatial scale effects of hazard was mainly reflected in the construction method of scenarios. The large scale used all9typhoon scenarios, while mesoscale selected3of them. In addition, the open boundary of the large scale model is much larger than the mesoscale’s and the accuracy of simulation in mesoscale is better than the large scale.(2) The spatial scale effects of vulnerability included two aspects: methods and results. The large scale vulnerability assessment used the first level of land types as hazard-affected bodies, while the mesoscale used the second level of land types, therefore the typhoon storm surge vulnerability assessment in mesoscale was more accurate.(3) The spatial scale effects of typhoon storm disaster risk zoning were different results by using the same method.(4) Used spatial downscaling method to construct the coupled model, including data coupling, method coupling and zoning coupling. The main features and innovations are as follows:(1) Emphasized the scientific and rational hazard scenarios. In order to establish a scientific risk scenario, this paper used probability statistics method to analyse the typhoon data of recent50years in eastern coastal areas of China.(2) Pay attention to the study of tools and methods for typhoon storm surge risk. This study established the scientific methods system, including the typhoon risk scenarios construction, the storm surge disaster risk simulation driven by typhoons and risk assessment of typhoon storm surge.(3) Made a research on the spatial scale effects of typhoon storm surge risk. In the construction of the spatial coupling model, the paper tried to use the results of large scale simulation as the boundary conditions of mesoscale simulation.