Discussion “A probability distribution for hydrological drought duration”

Abstract

Song et al. (2021) deals with drought duration probabilistic modeling treatment based on Bernoulli-independent and lag-one Mar-kov process modeling procedures. However, calculations are based on percentages, not probabilities, and therefore the formulations are not hydrologically valid as drought length probabilities. The authors used the enumeration method for percentage calculations, not probability principles. Drought calculation has been established in the literature by scientific studies of different researchers based on probability principles (Feller, 1966; Yevjevich, 1963; S ̧en, 1976, 1978, 1980). The presenta-tion by Song et al (2021) is not based on probabilistic principles such as mutually exclusive and independence principles for Bernoulli events. In order to distinguish the difference of the probability and percentage concepts, it is worth paying attention to the following points.