基于Copula函数的设计洪水过程线方法

Derivation of design flood hydrograph based on Copula function

采用Copula函数构造边缘分布为PIII分布的联合分布,用以描述年最大洪峰和年最大时段洪量,并介绍两变量情形下的重现期定义,根据建立的联合分布和两变量的重现期提出基于两变量联合分布的设计洪水过程线推求方法.研究有助于进一步认识设计洪水过程线的推求方法,并为设计洪水过程线推求提供了一种新思路.

A new design flood hydrograph （DFH） derivation method based on Copula function is proposed and developed. In this method, Copula function is used to obtain the bivariate joint distribution of flood peak and volume with Pearson Type III （Pill） distribution margins~ and the bivariate return period of the flood peak-volume pair is also defined. The proposed method can guarantee that the whole design flood hydrograph has the same return period. Application of the proposed DFH method to the Geheyan Reservoir is demonstrated and discussed. Case study results indicate that the DFH derived by the proposed method has a more reasonable shape than that based on the conventional univariate method. It provides an alternative way for derivation of DFH when flood peak and flood volume both play important role in the hydraulic engineering practice.