The evolution trend of evapotranspiration and dry–wet conditions in the Yangtze River Basin

ABSTRACT Graphical Abstract: In light of the current state of global climate change, this study examined the spatiotemporal variations in seasonal and interannual evapotranspiration and water conditions in the Yangtze River Basin from 1970 to 2014, as well as their underlying causes, and projected future evapotranspiration and water conditions in the basin. This provides valuable insights into the hydrometeorological dynamics of the Yangtze River Basin and its potential future trends. Evapotranspiration, as well as dry–wet conditions, can measure changes of water volume in a region and are important factors affecting atmospheric circulation. With global climate change, the dry–wet conditions in the Yangtze River Basin have undergone profound changes. This study investigates spatiotemporal variations of evapotranspiration and dry–wet conditions in the Yangtze River Basin (1970–2014) using the Penman–Monteith equation and surface moisture index. Results reveal an overall increasing trend in annual evapotranspiration across most stations, with more pronounced increases in spring and autumn compared with winter and summer. Dry conditions dominated the Yangtze River Basin, particularly in spring, autumn, and winter, while summer showed slight wetting trends. Notably, middle-lower reaches exhibited significant aridification. Range/Standard Deviation (R/S) analysis suggests these observed trends in both evapotranspiration and moisture indices are likely to persist. The findings highlight the basin's evolving hydrological patterns under climate change, with implications for water resource management. The seasonal and spatial variations in evapotranspiration and dry–wet conditions provide valuable insights for understanding regional climate dynamics and their potential future trajectories.