Analysis of rainfall abundance and drought occurrence and probability of flood and drought occurrence in Yellow River Basin based on Copula function family

Abstract

Study region

The Yellow River Basin, China.

Study focus

Using Copula joint distribution models, this study delves into the analysis of wetness-dryness encounters and their evolving patterns in the all three reaches. The research specifically explores the probability of asynchronous and synchronous wetness-dryness encounters, providing valuable insights into the hydrological dynamics of the region. Additionally, the study constructs and simulates a Bayesian network model for flood and drought management based on the observed wetness-dryness patterns.

New hydrological insights for the region

The findings of this study reveal several noteworthy insights. Firstly, there is no significant trend in rainfall in the all three reaches, but periodic cycles of 5 years, 4 years, and 16 years are identified. Secondly, the probability of asynchronous wetness-dryness encounters is higher than synchronous encounters, with annual asynchronous probabilities of 54.46 %, 80.65 %, and 62.9 % in the upper, middle, and lower reaches, respectively. Thirdly, the overall probability of synchronous wetness-dryness encounters is relatively low, with concurrent dryness having the highest probability. Lastly, the study indicates an overall 50 % probability of floods and droughts in the Yellow River. The simulation results further highlight a 91 % probability of floods during wet years and an equal probability of droughts during dry years. These findings contribute to a theoretical foundation for optimizing and allocating water resources in the Yellow River Basin.