Renmin Zhujiang (Jan 2024)
Study on Response Probability of Meteorological and Hydrological Drought Characteristics during Drought Recovery Period in Upper Hanjiang River
Abstract
It is of great reference significance for drought recovery and water resources management to explore the response rules of meteorological and hydrological drought characteristics during the drought recovery period. In this study, standardized precipitation evapotranspiration index (SPEI) and standardized runoff index (SRI) were used to characterize meteorological and hydrological drought in the upper Hanjiang River basin from 1961 to 2019, respectively. First, the Pearson correlation coefficient method was used to calculate the response time of meteorological and hydrological drought, and the time overlap method was used to match meteorological and hydrological drought events. Furthermore, the characteristics of meteorological and hydrological drought during the drought recovery period were obtained. Finally, a probability model of meteorological and hydrological drought recovery responses based on the Copula function coupled with Bayesian network was established to explore the relationship between meteorological and hydrological drought characteristics during the drought recovery period. The results show that: ① from June to November, the response time of hydrological drought to meteorological drought in the basin is the shortest, which is only two months. The response time of January is the longest, which is eight months. The response time of April, May, and December is about five months. ② The optimal marginal distributions for the response probabilities of meteorological and hydrological drought durations during the drought recovery period were LogL distributions, while the optimal distributions for the intensities of meteorological and hydrological droughts were Kernel and LogL distributions. Furthermore, the optimal joint distribution functions for both duration and intensity were the Gumbel Copula function. ③With the increase in characteristic value of meteorological drought recovery, the response probability of hydrological drought recovery characteristic also increases. For example, when the meteorological drought recovery lasts more than two, three, four, five, and six months, the probability of hydrological drought recovery lasting more than four months is 34.8%, 38.5%, 42.8%, 47.0%, and 50.7%, respectively. The change rate of response probability of hydrological drought recovery characteristics accelerates with the increase in meteorological drought recovery characteristics. The research results can provide an important reference for further understanding of drought recovery mechanisms and drought prevention and early warning in the upper Hanjiang River.
