Dynamics of atmospheric water resources over the Yangtze River Basin: Historical patterns and future projections

Yangtze River Basin (YRB), the longest river in Asia, holds ∼40% of the China's population and GDP. As climate warms, the amount of water vapor increases in the atmosphere which prompting alterations in the regional water cycle and intensifying the occurrence of precipitation extremes. Extensive research has been conducted in the YRB on its terrestrial water sources, however, insufficient attention has been given to its atmospheric water resources. Thus, this study aims to provide a comprehensive investigation into the dynamics of atmospheric water (AW) over the YRB, covering both historical (1979–2022) and future (2023–2099) periods. Our results reveal a declining trend in atmospheric water content (AWC) across the middle to western YRB before approximately 2011 (1979–2010). After this point (2011–2022), the trends suddenly reverse to a significant increase in nearly all the sub-basins within the YRB. This is closely linked to the enhancement of atmospheric water transport (AWT) from the southwestern directions. The historical increasing trends in AWC across the YRB will continue in the future (2023–2099). However, the future raising trends are expected to decelerate (accelerate) from the near term to the far term under SSP1–2.6/SSP2–4.5 (SSP5–8.5). The AWT to the YRB from the southwestern directions will also maintain its raising trends in the future.