Abstract:

Multi-variable frequency distribution is becoming increasingly important for hydrological design and risk management. Traditional multi-variable distribution has severe restrictions because all component margins must be from the same distribution family. The Copula method is a newly emerging approach to generating multi-variable distribution that overcome this limitation. In this study, the Osmaniye province's rain station was calculated using the drought analysis copy function with long-term data. First, the duration and severity of drought with dryness parameters are obtained using the SPI method. For the observed drought period, Lognormal was found as the most suitable marginal distribution for the severity of drought, while Weibull was found as the most suitable marginal distribution. After the single variable distribution function for each drought parameter has been obtained, the Gumbel copule is selected among the 10 determined copule functions, taking into account the Akaike Information Criterion (AIC), the Bayes Information Criterion (BIC), the Maximum Probability (MLE) methods and the corner dependency. Lastly, Osmaniye or drought has been calculated the common return period, and it provides useful information on topics such as the water supply system, hydraulic design and water management that is considered to be done.

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