Vegetation and Wind Speed Dominate Precipitation-Evaporation Recycling Processes during 1980–2021

Atmospheric moisture plays a crucial role in connecting global water and energy exchanges within the water cycle. Using a water recycling model, this study examines the spatiotemporal characteristics of precipitation and evaporation recycling ratios (PRR and ERR) across 200 river basins worldwide from 1980 to 2021, with data fused from three reanalysis datasets. The results reveal that regions near the equator exhibit higher PRR values, signifying strong moisture self-sufficiency, whereas arid, high-latitude, and inland regions show lower PRR values, indicating a higher dependence on external water vapor. Temporal trends indicate a decline in PRR and ERR in regions such as North America, South Africa, and Australia, while some areas in Central Asia and Europe have experienced increases. Structural Equation Modeling reveals that land cover, especially the Leaf Area Index (LAI), and wind speed are key drivers of spatial and temporal variability in water recycling ratios. The study classifies river basins into four categories based on their water recycling trends: ‘Enhanced Exchange Basins,’ ‘Beneficial Basins,’ ‘Shrinkage Basins,’ and ‘Reduced Exchange Basins.’ These classifications provide valuable insights into regional water cycles and can inform targeted water resource management strategies, crucial for addressing challenges like water scarcity and ecosystem restoration.