变化环境下石羊河流域年径流频率计算

受气候变化与人类活动的影响,水文序列一致性遭到破坏,传统的频率计算方法受到挑战。针对石羊河流域8条河流年径流量序列,在基于水文变异诊断系统进行变异分析的基础上,采用条件概率分布法和混合分布法进行了变化环境下的年径流频率计算。结果表明,石羊河流域年径流量序列以向下跳跃变异为主,变异年份多集中在1960年附近;变异序列的两种分布均通过K-S检验,最优分布的拟合效率系数均大于0.97;对比由考虑变异的理论分布与不考虑变异的一致性P-III型分布确定的设计年径流量,当设计频率高于90%时,大靖河与西营河的设计年径流量值相差较大。因此,石羊河流域新建水利工程的规划设计,应适当考虑水文资料的变异特性,选择合理的频率分析方法确定设计年径流量。

Frequency Analysis of Annual Runoff for Shiyanghe River in A Changing Environment

With the impact of climate change and human activities, the consistency of hydrological series is destroyed. Thus, traditional frequency calculation methods are challenged. The variation characteristics of 8 river annual runoff series in the Shiyanghe River Basin were detected using the hydrological alteration diagnosis system, conditional probability distribution and mixed distribu - tion methods were employed to calculate the frequency of annual runoff. The results indicate that the dominant variation type of annual runoff series in Shiyanghe River Basin is a downward jump and the aberrance years are mainly around 1960; the two kinds of distributions of variant series pass the K-S test with all the efficiency coefficients of optimal distributions exceeding 0.97; when design frequency is more than 90%, the design annual runoff of the Dajinghe River and Xiyinghe River derived from the theoretical distribution considering variation has a great difference from that obtained by consistent P -III distribution without regard to variation. Therefore, during the planning design phase of newly-built water projects, the emphasis is analyzing variation features of hydrological data appropriately and selecting rational frequency calculation method for design annual runoff.