基于时变矩GEV频率分布模型的设计暴雨推求

Calculation of Design Storm Based on The Time-Varying Moment GEV Frequency Distribution Model

受频繁人类活动和气候变化的影响,暴雨序列呈现出不同程度的非一致性,常规频率分布模型在设计暴雨、设计洪水分析计算中不再适用。本研究以最大三日暴雨为例,采用时变矩的GEV频率分布模型,与基于一致性假设的常规模型所得设计暴雨成果进行对比,结果表明:当暴雨资料不满足一致性假设时,时变矩模型相比常规频率模型具有更好的适用性与复杂性;并且时变矩模型求解得到的设计值及其超越概率明显不同于常规频率分布模型;面对不满足一致性假设的暴雨资料推求设计洪水时,应当对非一致性做处理,避免产生较大偏差,影响防洪安全和造成工程投资的浪费。

As storm time series show varying degrees of inconsistency because of the impacts of frequent human activities and climate change,the conventional hydrological frequency analysis model is not ap⁃plicable for calculating design storm and design flood any more.Taking Maximum three-day rainstorm for example,this paper compares design storm calculated with the time-varying moment GEV frequency distribution model with the calculation of traditional hydrological frequency analysis method based on the consistent assumption.The result shows that:Compared with the traditional frequency analysis method,the time-varying moment model present better reliability and complexity,the design value and its exceeding probability calculated with the time-varying moment model are obviously different from those calculated with the traditional frequency analysis method.In order to avoid large deviation,affect⁃ing the flood control safety and causing waste of project investment,the inconsistency should be pro⁃cessed when calculating design flood from storm time series which are not applicable of consistent as⁃sumption.