Multivariable Frequency Analysis of Flood Based on Copulas

Bivariate probability distribution models were constructed based on Copulas to study the joint probability and return period of various combinations of flood peak and flood volume,flood volume and flood duration.The results showed the Copula models had no limitation to marginal distribution,and they were more suitable for various hydrological frequency than other bivariate probability models.The flood hazards not only relied on the univariate quantity of flood peak,flood volume,and flood duration,but the joint probability of the variables.When the variables exceeded certain quantity jointly,floods would be in higher risk.The Bivariate probability distribution model was used to analyze the joint probability and return period of flood peak,flood volume and flood duration.