基于广义极值分布的设计基本风速及其置信限计算

引入涵盖Gumbel,Frechet,W eibull三类极值渐近分布的广义极值分布(GED)模型,给出该模型参数的极大似然估计的计算公式,并由此导出设计基本风速及其置信上限的计算方法.采用南通气象观测站的年最大风速资料进行实证研究,分别用似然比法和Kolmogorv统计量检验分布的拟合优度,得出南通气象观测站年最大风速符合Frechet分布,而由样本值构造的经验分布与理论分布曲线基本相吻合.因此,由GED模型导出的计算方法明显优于采用单一分布的方法.

Computation of design basic wind velocity and its confidence limits based on generalized extreme value distribution

Generalized extreme distribution(GED) model,which summarizes three gradually approximate distribution,i.e.Gumbel,Frechet and Weibull distribution,is introduced and the calculating formulas of GED's parameters by using maximum likelihood estimate method are given.Furthermore,the computing methods of design basic wind velocity and its higher confidence limits are derived in this paper.Finally,the wind velocity data of Nantong observatory are used to verify the methods above-mentioned,and the likelihood ratio method and Kolmogorov statistic are used to test the fitness of the distribution.It is obtained that the distribution of yearly extreme wind velocity of the observatory is in keeping with Frechet distribution,and the experimental distribution form from samples basically coincides with the theoretical ones.Therefore,compared with the individual extreme distribution,the algorithm derived from GED model is obviously preferable.