基于广义Pareto分布的波高极值序列频率分析

Frequency analysis for extreme sequence of wave heights based on generalized Pareto distribution

应用广义Pareto分布(GPD)分析超阈值波高序列的设计值。以位于美国北卡罗来纳州的FRF历时32年连续测量的逐日波高序列为例,检验了不同波高阈值样本的泊松分布,采用多种方法综合确定最佳阈值的拟合优度指标。对最优广义Pareto分布和GEV分布及P-Ⅲ分布推算的波高重现水平做了对比分析。得到以下结论:(1)波高的GPD属于短尾型分布;(2)拟合优度指标表明构建的波高GPD模型普遍优于GEV和P-Ⅲ型;(3)GPD的参数估计方法对设计波高的计算结果有较大影响。

Generalized Pareto distribution(GPD)was used to analyze the design value of the peak over threshold wave height sequence.Taking the daily wave height sequence 32 years continuously measured by Field Research Facility(FRF)in north Carolina of the USA as an example,the Poisson distribution under different wave height thresholds samples was tested,and the fitting optimization index of the best threshold was used to comprehensively determine the optimal generalized Pareto distribution.A comparative analysis was made of the return period wave heights among the optimal generalized Pareto distribution,GEV distribution and P-Ⅲdistribution.The following conclusions are obtained:(1)the GPD of wave heights belongs to the short-tailed distribution;(2)the goodness of fit test indicates that the wave height GPD model constructed is generally superior to GEV and P-Ⅲmodels;(3)the parameter estimation method of GPD has a great influence on the calculation results of designed wave heights.