Research on the Joint Probability Distribution of Flood Peak and Period Flood Volume based on Three-dimensional Asymmetric Copula Function

In this paper,the joint probability distribution of flood peak and period flood volume was constructed based on three-dimensional asymmetric Copula function. And the probabilistic characteristics between the flood peak and period flood volume were discussed by joint probability distribution.. First,the joint probability distribution of flood peak,3 days flood volume and 7 days flood volume was established based on the threedimensional asymmetric Gumbel Copula function,and then maximum likelihood method was used to estimate the parameters of the three-dimensional asymmetric Gumbel Copula function,finally the conditional probability distribution between flood peak and period flood volume was deduced and the probabilistic characteristics between the flood peak and volume were analyzed. This method was applied in the Dadu River using flood peak,3 days flood volume and 7 days flood volume datas( 1960—2013) from the Dajinchuan hydrological station. These results will provide a newapproach for the study of correlation between flood peak and flood volume.