Study on the Joint Distribution of Annual Maximum Flood of Changzhou Reservoir Based on Copula Function

Abstract

The annual maximum flood magnitude and occurrence time are of great significance to the safe flood control and comprehensive benefits of reservoirs.Taking Changzhou reservoir as the example,this paper uses Von Mises function distribution and Pearson Type Ⅲ distribution to describe the time probability distribution of flood and probability distribution of peak discharge respectively,establishes the joint distribution of the two variables of the occurrence time and magnitudes of the annual maximum flood based on Frank Copula function,and describes the occurrence time distribution characteristics,joint return period and conditional return period of annual maximum flood in Changzhou reservoir.The results show that the joint distribution function based on Frank Copula function can fit both occurrence time and magnitudes of the annual maximum flood well,and can effectively mine the information of inflow flood,which can provide reference for the optimal dispatching and risk management.

Keywords

• Copula function
• bivariate joint distribution
• annual maximum flood
• Changzhou reservoir