基于极值同频率法的非一致性年径流过程设计方法--以跳跃变异为例

由于气候系统变化和高强度人类活动的影响,天然年径流序列失去了一致性。为了适应变化环境对工程水文分析计算的新要求,本文以跳跃变异为例提出了基于极值同频率法的非一致性年径流过程设计方法:首先,采用水文变异诊断系统对不同时间尺度径流序列进行年际和年内分配情势变异分析;其次,根据年际变异和年内分配情势变异的时间点,将径流序列分段;再次,基于径流年际变异诊断结果,采用变化环境下非一致性水文频率计算方法计算不同时间尺度径流量变异前后过去不同保证率下的设计值;最后,基于径流年内分配变异诊断结果,在径流年内分配变异前后利用极值同频率法进行年径流过程设计。以东江岭下站为例,进行了非一致性年径流过程设计,并与未考虑"非一致性"影响的年径流过程设计结果进行了比较,发现岭下站设计年径流过程受"非一致性"影响显著,该结果可为东江流域水利工程的规划设计提供参考和依据。

Inconsistent annual runoff process design method based on extreme value with common frequency:A case study in jump variation

Owing to the effects of human activities and climate change, the natural hydrological series lost their consistency. In order to adapt to a changing environment demanding for hydraulic engineering design, inconsistent annual runoff process design method based on extreme value with common frequency was proposed. Firstly,the hydrological variation diagnosis system(HVDS)was used to analyze the variation of different time scales runoff series and their annual distribution features. Secondly, according to the variation point, annual average flow series was divided into several time periods. Thirdly, the frequency distributions of different time scales runoff series before and after the change-point were conducted based on the hydrological frequency calculation theory for inconsistent series (HFCT) and the difference of means and various frequency characteristic values were analyzed. Finally, the method of extreme value with common frequency was used to calculate the annual runoff process in each time period. This study was applied at Lingxia station in Dongjiang River, and the inconsistent annual runoff process was designed. The difference of designed annual runoff process before and after the change-point at Lingxia station was analyzed. The results are valuable for the planning and design of hydraulic engineering in Dongjiang river basin.