Prediction Of Typhoon Extreme Wind Speeds Based On Improved Typhoon Key Parameters

Along with the rapid development of the society and economy of China, especially the fast development of the ecnomy in the southeast coast, a lot of structures such as the high-rise buildings, skyscrapers and long-span bridges which are susceptible to the wind loading come forth. The safer and more convenient life is required and China's southeast coast is one of the regions most severely influenced by typhoons in the world, which suffers significant casualties and huge economic losses from typhoon-caused disasters every year. Consequently, the method of numerical simulation is used to analyze the typhoon risks and to predict the extreme wind, which gives important information of wind loads on the designing and disaster mitigation in the China'southeast coast.The probabilistic modeling of typhoon key parameters, which include speed of typhoon translation, minimum approach distance, difference between atmospheric pressure at the center and at the periphery of the typhoon, direction of typhoon motion and radius to maximum wind speeds, is the basis for typhoon numerical simulation. Speed of typhoon translation, radius to maximum wind speeds and difference between atmospheric pressure at the center and at the periphery of the typhoon are used to simulate the typhoon wind velocity, while minimum approach distance and direction of typhoon motion are used to model the effect of typhoon on the specific site. The main contents of the paper are as following:Firstly , the fitness test of probabilistic models are made and then the probabilistic models of typhoon key parameters of China southeast coastal cities are obtained by analyzing historical data from the typhoon annuals with computer programs. Meanwhile, Holland parameter B is also regarded as a typhoon key parameter and the historical data is analyzed to estimate the parametric values of parameter B.Secondly, considering that typhoon will decay during the development of itself as a result of the reduction of the potential heat in the ocean vapor and the convective cloud, to better simulate the effect of typhoon on the specific site, a new parameter named"maximum risk distance"is presented which is defined as the distance where the maximum wind speeds of the specific site are produced by typhoon during the development of typhoon. Then the probabilistic distribution of this new parameter is derived and the comparison between this paramenter and the minimum approach distance is also performed.Finally, based on the historical data of typhoon occurred in the China'southeast coast and the Shapiro-based wind field model, the serials of the maximum wind speed are simulated and the extreme wind speeds in the southeast coast during different return periods such as thirty years, fifty years and one hundred years are predicted by means of risk assessment, which will provide significant information for risk assessment of typhoon in the coastal cities and the risk mitigation.