金沙江流域极端强降水分布拟合

Distribution fitting of extreme precipitation in Jinsha River Basin

极端降水的统计分布研究是当前国内外极端水文事件研究的前沿方向之一。根据金沙江流域45个气象站的长系列日降水资料,采用年极大值抽样方法建立了不同统计时段(最大1 d、最大3 d、最大7 d等)的降水极值系列,通过比选11种常见的概率分布函数确定了金沙江流域极端强降水的最优分布。对基于站点与面暴雨的2套极端强降水序列的频率分析表明,韦克比分布是拟合金沙江流域极端强降水发生概率的最优分布形式。

Study on statistical distribution of extreme precipitation is one frontier of hydrologic events research at home and a -broad. This paper assesses the probability distribution of extreme precipitation events by using long - series daily precipitation da-ta from 45 stations in Jinsha River Basin. By using the annual maximum sampling method, three extreme precipitation series of different statistical interval, including AM_1 （annual 1 - day maximum precipitation） , AM_3 （ annual 3 - day maximum precipi-tation） and AM_7 （annual 7 - day maximum precipitation） , were established. Through evaluating the performances of reprodu-cing extreme precipitation events by 11 commonly used probability distributions, we determined the optimum distribution of ex-treme precipitation in Jinsha River Basin. The frequency analysis of two extreme precipitation series, a site - based and a areal rainstorm - based, shows that the Wakeby distribution is the optimal probability distribution of extreme precipitations in the Jinsha River Basin.