基于Copula函数的永翠河流域降雨径流特征分析

Analysis of rainfall-runoff characteristics in Yongcui River Basin based on Copula function

基于永翠河流域带岭(二)站1964—1987及1995—2014年共44年逐月降水径流数据,利用非参数法确定水文要素边缘分布,运用3种Archimedean Copula函数构建出降雨-径流的联合分布,选取最优Copula函数并进行流域内降雨径流的相关性分析。结果表明:利用非参数随机模型的核密度估计方法生成的边缘分布符合精度要求;3种常用Archimedean Copula函数中,对流域降雨-径流联合分布拟合效果最好的是Gumbel Copula函数;永翠河流域降雨量和径流量之间存在较强的上尾相关性。该研究对流域水资源管理有重要意义,也可为该流域径流随机模拟提供理论支撑。

Based on the monthly precipitation runoff data of 44 years from 1964 to 1987 and from 1995 to 2014 at the Dailing Station in Yongcui River Basin,the marginal distribution of hydrological elements was determined by nonparametric method,the joint distribution of rainfall-runoff was constructed by using 3 Archimedean Copula functions,the optimal Copula function was selected and the correlation analysis of rainfall runoff in the basin was carried out.The results show that the edge distribution generated by the kernel density estimation method of the non-parametric stochastic model meets the accuracy requirements,and among the three commonly used Archimedean Copula functions,the best fit effect on the combined distribution of rainfall-runoff in the basin is the Gumbel Copula function,and there is a strong upper-tail correlation between rainfall and runoff in the Yongcui River Basin.This study is of great significance to water resources management and provides theoretical support for stochastic simulation of runoff in the watershed.