镇江市中长历时设计暴雨计算

Medium and long duration design rainstorm calculation in Zhenjiang City

基于丹徒站1981—2016年长系列实测降雨资料,采用Mann-Kendall检验分析了3 h、6 h、12 h、24 h共4种中长历时的年最大降水量的变化趋势,采用模糊识别法识别了4种历时暴雨的雨型特征,并基于优选得到的分布函数计算不同历时、不同重现期的设计面雨量;依据5场典型场次暴雨,分别应用同频率法和P&C(Pilgrim&Cordery)法推求相应的设计暴雨过程并进行了对比分析。结果表明:4种历时的年最大降水量虽均呈现不同程度的增加趋势,但仅6 h和12 h的年最大降水量通过了90%的显著性检验;4种历时暴雨的雨型均以雨峰偏前的单峰型为主;P-Ⅲ型分布函数在降雨频率分析中拟合最优;与P&C法相比,同频率法推求得到的设计暴雨过程峰值更大,有利于保障防洪安全。

Based on the long series of measured precipitation data of Dantu station from 1981 to 2016,Mann-Kendall test was used to analyze the variation trend of maximum annual precipitation with four medium and long durations of 3,6,12 and 24 hours.Fuzzy identification method was adopted to identify the rainfall pattern characteristics of four duration rainstorms.The design rainfall in different durations and return periods was calculated based on the optimized distribution function.According to five typical rainstorms,the same frequency method and Pilgrim&Cordery method were used to deduce the corresponding design rainstorm process and comparative analysis was conducted.The results show that although the maximum annual precipitation of four durations all showed increasing trends to different degrees,only the maximum annual precipitation of 6 h and 12 h passed the 90% significance test.The rainfall patterns of four duration rainstorms were all dominated by single peak with a slight front.P-Ⅲ distribution function fitted optimally in rainfall frequency analysis.The peak value obtained by the same frequency method was larger than that obtained by Pilgrim&Cordery method,which was beneficial to ensure flood control safety.