Study On Typhoon Wind Field Model In Xiamen Area

China is one of the region most severely influenced by typhoon in the world, which suffers significant casualties and huge economic losses from typhoon-caused disasters every year. Recent years, The booming economy and the fast growing population in urban areas make costal cities and buildings more vulnerable to typhoon-caused disasters.To reduce economic losses caused by typhoons, assessing typhoon risks in the coastal area, especially key coastal cities in typhoon-prone regions, seems more important than ever. The researches on typhoon wind field model and risk assessment are main aspects of easing typhoon-caused disaster losses. Based on the wind field model (physical model) of mature typhoons and data of typhoon key parameters, the method of analyzing wind-speeds simulated by numerical simulation is now a well-accepted means to analyze the typhoon risks in coastal areas. xiamen was used as case studies to demonstrate the applicability of this risk analysis method in the region. Probability track model and weakening model of loading typhoon in typhoon risk assessment were also discussed in this paper. The main contents of the paper are as following:Firstly, the probability models of typhoon occurrence and typhoon key parameters in China's xiamen region were studied. Then the rate of typhoon occurrence and the key parameters of direction of typhoon motion, speed of typhoon translation, radius to maximum wind speeds, difference between atmospheric pressure at the center and at the periphery of the typhoon, and minimum distance were extracted by analyzing historical typhoon data. Given the available statistical information on the climatological characteristics of typhoons, the applicability of probabilistic model was estimated for each of these parameters by using the goodness of fit test.On the basis of the probability models, Monte Carlo stochastic sampling method was employed to produce the parameters of typhoon simulation Yearly extreme wind speed serials in long return period (100-year,200-year,500-year and 1000-year) were obtained by means of wind field simulation. Extreme value of wind speeds for different return periods and surface roughness were predicted by analyzing the simulated yearly extreme value of wind speed serials with risk assessment method. The results were consistent with the wind speed records and the wind speeds deduced from observed data.Finally, using the mesh generation, the probabilistic model and the wind speed attenuation model were established, using the historical data statistical analysis and the numerical analysis, the typhoon landing probability of Xiamen area was obtained, analysising the probability along typhoon path of each area which attacks. Wind speed attenuation model along the path of loaded typhoon was established, in order to access the risk of typhoon in Xiamen area.This paper presented a feasible way to assess typhoon risks and determine the design wind loads with the scarcity of observed wind data in typhoon-prone areas of Southeast China, and also gave scientific information of wind loads on the designing and planning of civil infrastructures, disaster mitigation and prevention in such areas. In addition, the paper research the law of typhoon wind speed attenuation along the path ,combined with the probability of loading typhoon along the path, providing a more reasonable basis to assess the local area building economic loss based on the incident typhoon.