关于水文同频率地区组成法中相应洪量频率的探讨

Discussion on the corresponding flood frequency in the Hydrological Equivalent Frequency Regional Composition method

水文中往往需要研究水文变量在空间上的分配规律,同频率地区组成法是目前解决该问题的一个重要方法,但其中仍有一些理论问题悬而未解。以"上下同频、区间相应"的组成方案为例,区间相应量的频率C与"同频"中设计频率P之间的大小关系,无法判断,目前尚无理论证明。因此,对正态分布和P-Ⅲ分布,分别通过理论推导和统计试验途径,明确了C与P之间关系。对设计洪水问题,根据"上下同频、区间相应"求得的区间相应洪量,其频率C将大于设计频率P;对径流或枯水设计问题而言,区间径流量的频率C将小于设计保证率P。研究结果从理论上进一步明晰了同频率地区组成法中相应量的频率问题。

The spatial distribution rules of hydrological variables are often studied in hydrology.The Equivalent Frequency Regional Composition（EFRC）method is an important approach to solving this problem at present.However,there are still some theoretical issues that remain unsolved.Take as an example the composition scheme of ＂ same design frequencies at upstream and downstream,with corresponding value at the interval＂,we cannot determine which is larger between the frequency of the interval area（C）and the design flood frequency（P）at both upstream and downstream due to a lack of theoretical proof.In this study,we investigated the relationships between Cand P for the normal and Pearson type III（PE3）distributions by means of theoretical derivation and Monte Carlo（MC）experiment.Results showed that Cis larger than Pfor the design flood problem,while for the design problem of runoff or low flow,Pis larger than C.Therefore,this study has clarified in theory the design frequency of corresponding value at the interval for the EFRC method.