Prediction of typhoon design wind speed with cholesky decomposition method

Abstract

Typhoon simulation method that integrates typhoon wind field model, probability distributions of typhoon key parameters, and Monte Carlo simulation method has long been used to predict typhoon design wind speeds of structures. In the research, the empirical typhoon wind field model with a novel parameter B model of Holland's radial pressure profile is first introduced and validated with typhoon Hagupit's simulation. The results show that relatively good typhoons can be simulated with this empirical typhoon wind field model. Then, the cholesky decomposition method used in typhoon simulation method is proposed that allows achieving all correlated typhoon key parameters simultaneously. Finally, the cholesky decomposition method is used to generating typhoon key parameters in Hong Kong, and typhoon design wind speeds for different return periods are predicted with typhoon simulation method. In addition, typhoon design wind speeds derived from historical typhoon key parameters and typhoon key parameters generated without considering cholesky decomposition method are also predicted, respectively. The predicted typhoon design wind speeds are compared and the results demonstrate that the cholesky decomposition method should be incorporated into typhoon simulation method. KEYWORDS cholesky decomposition method, design wind speed, Monte Carlo simulation, typhoon simulation method, typhoon key parameters, typhoon wind field modelIn typhoon prone regions, the optimal prediction of typhoon design wind speed is using extreme wind speed analysis on the basis of annual maximum typhoon wind speeds derived from wind measurement data. However, normally, only a few decades wind measurement data can be used and this is not enough for a reliable prediction of typhoon design wind speed. [1][2][3] Therefore, typhoon simulation method that integrates typhoon wind field model, probability distributions of typhoon key parameters, and Monte Carlo simulation method was developed for the prediction of typhoon design wind speed and was widely used in engineering applications. [4][5][6][7][8] Within this method, probability distributions of typhoon key parameters, including central pressure difference Δp 0 , radius to maximum wind r m , translation velocity c, approach angle θ, and minimum of closest distance d min , are first determined by using historical typhoon wind data obtained from Observatory. Typhoon wind field model with/without filling wind field model after landfall in conjunction with Monte Carlo simulation method is then used to generate a series of typhoons. Typhoon design wind speeds for different return periods in the concerned region are finally determined with extreme wind speed analysis.Typhoon wind field models proposed by Vickery and Twisdale [9] and Meng et al. [10] were widely used in typhoon simulation method. They developed the typhoon wind field model from the momentum equation of three-dimensional Navier-Stokes equations, but then Vickery and the optimum fit method [10] or the empirical statistical model [14] was app...

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