Quantitative Analysis of the Influence of Climate Change and Human Activities on Monthly and Seasonal Hydrological Drought in the Upper Yangtze River, China

Abstract

Climate change and human activities are significantly altering hydrological systems, intensifying extreme events such as hydrological drought patterns. These changes pose critical challenges for water sustainability, requiring a deeper understanding of prolonged hydrological droughts. Under the complex changing environment, hydrological drought in the Upper Yangtze River is becoming increasingly severe. Using monthly scale meteorological and hydrological data, this study quantitatively conducted an attribution analysis of hydrological drought in the Upper Yangtze River through a multi-method framework combining mutation analysis, a hydrological model, and machine learning. The results showed that: (1) the coupled model had higher precision and better applicability in a basin with more complex changing environments. (2) Climate change was the dominant factor for most months of monthly scale hydrological drought in the Wujiang, Jialing, and Upper Yangtze River Basins, while human activities were the main cause of hydrological drought in most months in the Tongtian River. (3) The dominant factor for seasonal hydrological drought in the Wujiang and Upper Yangtze River Basins was climate change. The seasonal hydrological drought in the Tongtian River and Jialing River basins was jointly affected by climate change and human activities.