Evolution Characteristics and Impact Evaluation of Meteorological and Hydrological Drought in the Jinsha River Basin

The Jinsha River Basin (JRB) is situated on the eastern edge of the Tibetan Plateau and is a significant water source for the Yangtze River. An in-depth understanding of its drought evolution and propagation is a crucial guide for drought identification and risk assessment in the plateau and the entire Yangtze River. Hence, this paper analyzed the trend pattern of meteorological elements in the JRB and explored the dynamics of meteorological and hydrological drought. The results indicated that precipitation in the JRB fluctuated and increased at a rate of 8.01 mm/10a on average, and the average temperature increased by around 1.82 °C over the past 61 years, with both indicating a higher value downstream than upstream. Meteorological droughts were mainly focused in the 1970s, 1980s, and mid-1990s, with an overall reduction in meteorological droughts on a 12-month time scales. There were differences in the hydrological drought trends at different stations, Zhimenda and Shigu stations decreased and Pingshan station increased. In addition, the JRB was dominated by mild drought, with an average frequency of 13% for meteorological drought and 30% for hydrological drought, and the correlation between SRI and SPI was most significant in the upstream area where human activities were less frequent. The hydrological drought was about 9–10 months later than the meteorological drought due to climate change, subsurface change and human activity. The findings could be utilized as a reference for regional water resource management and basin drought hazard warning.