Trivariate joint frequency analysis of water resources deficiency signatures using vine copulas

Abstract Investigating the interaction of water resources such as rainfall, river flow and groundwater level can be useful to know behavior balance in a basin. In this study, using deficiency signatures for 60-day duration, accuracy vine copulas was investigated by joint frequency analysis. First, while investigating correlation pair-variables, tree sequences C-, D- R-vine were investigated. The results evaluated AIC, Log likelihood BIC statistics. Finally, according physics problem evaluation criteria, D-vine copula selected best relevant sequence introduced. Kendall’s tau test used evaluate pair-signatures. showed that pair-signatures studied have good correlation. Using its conditional structure, return period signature affected rainfall main changes is between 0.3 2 m, which due corresponding deficiency, periods will less than 5 years. Copula-based simulations investigate analysis signatures. data signatures, simulated sequence. acceptable simulating values signature. After confirming copula, probability occurrence obtained from other This method general drought monitoring system better management