Drought duration and severity are two properties that are usually needed for drought analysis. To characterize the correlation between the two drought properties, a bivariate distribution is needed. A new method based on entropy theory is proposed for constructing the bivariate distribution that is capable of modeling drought duration and severity with different marginal distributions. Parameters of the joint distribution are estimated with Newton’s method. Monthly streamflow data from Brazos River at Waco, Texas, are employed to illustrate the application of the proposed method to model drought duration and severity for drought analysis.
drought analysis, joint distribution, entropy theory, principle of maximum entropy
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