基于广义极值分布的设计波高推算

Calculation of design wave heights based on generalized extreme value distribution

简介了广义极值分布函数及其3种参数估计方法,包括极大似然(ML)、线性矩(LM)和间隔最大积(MPS)估计的计算方法。使用广义极值分布函数推算了北部湾涠洲岛海域3个波向的年波高极值序列设计波高,并与Weibull分布、Gumbel分布和皮尔逊Ⅲ型分布的推算结果加以对比。分析表明,涠洲岛海域极值波高服从于广义极值Ⅲ型分布,拟合优度检验结果表明广义极值分布能更好地拟合极值波高;MPS方法是一种优良的参数估计法,推算的设计波高可作为海岸环境工程设计的首要参考值。

Three parameter estimation methods on generalized extreme value distribution function were briefly introduced in the paper,which included the maximum-likelihood estimation（ML）,the linear moment estimation（LM） and the maximum product of spacing estimation（MPS）.The design wave heights based on the generalized extreme value distribution function are calculated by using largest annual wave heights of three wave directions measured in the sea waters near Weizhou Island of Beibu Gulf.And then the results were compared by goodness fit test on design wave heights calculated by the Gumbel dis-tribution,Weibull distribution and Pearson Ⅲ.It indicated that the annual extreme wave heights obeyed the generalized ex-treme value distribution type three.The extreme wave heights were better fitted by generalized extreme value distribution function.The parameter estimation of maximum product of spacing was the best method compared with the others.The design wave heights calculated by MPS parameter estimation of the generalized extreme value distribution can be as the first refer-ence value in the coastal engineering design.