基于Copula函数的嘉陵江流域干支流洪水遭遇分析 Flood Coincidence Probability Analysis for Mainstream and Tributaries of the Jialing River Basin Based on Copula Function

Abstract

洪水遭遇是一个多变量水文事件，目前研究多限于对实测资料进行统计分析。基于二维copula函数分别建立嘉陵江干流北碚站与支流小河坝站、罗渡溪站、武胜站洪峰流量的联合分布。计算各站不同重现期的设计洪水，推求出对应的洪水遭遇概率。结果表明，嘉陵江流域低重现期洪水遭遇概率大于高重现期；同一重现期下，嘉陵江各支流与干流(北碚站)的洪水遭遇概率，渠江大于嘉陵江，涪江最低。此方法为计算洪水遭遇分析计算提供了一条新途径。 Flood coincidence probability is a multivariable hydrologic event. At present, the research is mostly limited to the statistical analysis of observed data. In this study, the annual maximum flood peak data of four hydrological stations in Jialing River and its tributaries, including the Beibei, Xiaoheba, Luoduxi and Wusheng station, are selected for case study. The bivariate copula functions are introduced and used to construct the joint distributions of flood peak. The design flood and flood coincidence probability are computed for different return periods. The result shows that the flood coincidence probability of high return periods is smaller than low return periods. The flood coincidence probability of Jialing River and its tributaries in the same return periods, Qujiang River is greater than Jialing River, and Fujiang River is among the smallest. This study will provide a new approach for Flood encounter analysis.