淮河流域极端降水概率分布模型及其应用

Probability Distribution Model and its Application on Extreme Precipitation in Huaihe River Basin

[目的]研究淮河流域极端降水最优概率分布模型,旨在为洪水计算规范修改和调整提供参考。[方法]基于淮河流域110个气象站点1959—2008年的日降水资料,通过年最大值法(AM)及超门限峰法(POT)分别建立极端降水AM及POT序列,比较两者捕捉极端降水的适用性,建立淮河流域极端降水最优概率分布模型,并对其应用进行探讨。[结果](1)在研究流域极端降水空间分布上,POT序列适用性更强,能较好捕捉降水极值。在研究极端降水时间变化上,AM序列更合理;(2)经K-S法检验,Wakeby函数是AM及POT序列的最优概率分布模型,优于水利工程标准曲线PearsonⅢ函数,且Wakeby函数的中部拟合效果比尾部更优。[结论]最优概率分布模型在气候变化的研究中得到较好地应用,近25a来淮河流域极端降水强度呈增长趋势,且频率增大,需加强对该流域极端降水灾害的防治减灾工作。

[Objective]Studying the optimal probability distribution model of extreme precipitation in order to provide basis for the standard modification of flood calculation method.[Methods]Based on the daily precipitation data from 110 meteorological stations during 1959—2008in the Huaihe River basin,annual maximum series（AM）and peak over threshold series（POT）were established to compare the applicability of them.The optimal probability distribution models of extreme precipitation for AM and POT were established and the applications were discussed.[Results]In the study of spatial distribution of extreme precipitation,POT was proved to be more reasonable than AM.In dealing with temporal sequence,AM was more reasonable.Checked by K-S method,Wakeby was the optimal function for the two kinds of series.The estimation accuracy of Wakeby was higher than the performance of PearsonⅢ,which is regarded as the standard frequency curve in the water conservancy project;especially,the middle part of Wakeby fitted better than its tail did.[Conclusion]The probability distribution model can get a better application in the climate change.The extreme precipitation showed an increasing trend during 1984—2008and the frequency is increasing.Thegovernment needs to take some measures to deal with extreme precipitation disasters.