Drought analysis is important for water resources planning and management. Drought duration and severity are two main characteristics that have often been used for drought analysis, which can be defined using run theory with hydrological variables (e. g., streamflow).

A traditional way to characterize the drought duration or severity is based on fitting a probability density function. The drought duration can be modeled by a geometric distribution (discrete) or an exponential distribution (continuous). The gamma distribution is generally used to model drought severity.

Bivariate drought analysis is often needed to characterize the correlation between drought duration and severity. This article proposes a new method for constructing the joint density function of drought duration and severity with different marginal distributions based on the principle of maximum entropy. The proposed method is applied for drought analysis based on the monthly streamflow of Brazos River at Waco, Texas.


drought analysis, streamflow, Texas

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