Stochastic generation of daily rainfall events: A single-site rainfall model with Copula-based joint simulation of rainfall characteristics and classification and simulation of rainfall patterns

Abstract

Rainfall event simulation can be very useful in many hydrological and hydraulic practices such as dam design. The aim of this study is to propose a new single-site stochastic model for generating daily rainfall events. The model has two components: Copula-based joint simulation of rainfall characteristics and rainfall temporal pattern simulation. Compared with prevailing stochastic rainfall models, this new model can not only preserve the dependence relationship between rainfall duration and rainfall depth by using Copula functions, but also take different temporal rainfall patterns that can cause various hydrological responses of watersheds into consideration. Additionally, the internal clustering validation index is introduced in this study to objectively determine the number of representative rainfall patterns in this model. Lastly, a framework is designed to apply the developed stochastic model to 39 gauged meteorological stations in Zhejiang Province, East China and to extend its application to one ungauged site for validation. The final validation results were sound and indicated that the developed stochastic model is robust and can be applied at both gauged stations and ungauged sites for generating long rainfall records.