Synergistic dynamics and driving mechanisms of land cover and evapotranspiration under multi-scenario projections from the Pearl River Basin

Study region The Pearl River Basin (China). Study focus This study examined the synergistic dynamics between land cover and evapotranspiration (ET) components, including evaporation (E), transpiration (T), under three scenarios—business as usual (BAU), carbon neutrality target (CNT), and economic development priority (EDP) from 2021 to 2050. Using the Shuttleworth-Wallace-Hu (SWH) model, we simulated E, T and ET at high resolution and quantified the contributions of E and T to ET variations, as well as the interactions among vegetation, climate variables, and topography. New hydrogeological insights from the region The study reveals pronounced synergy between land-cover change and ET dynamics across the basin. Under CNT, marked expansion of forest and water bodies coincides with only modest increases in ET, whereas conversion of farmland to urban land in the Greater Bay Area elevates E with negligible change in T. T accounts for a larger share of ET variability than E, indicating T’s central role in regional water–energy coupling. Interaction analysis shows vegetation dominates through synergistic effects with temperature, precipitation and elevation, suggesting a “vegetation–climate–topography” co-regulation mechanism of T. These findings offer empirical evidence and a practical framework for integrated watershed water-resource management and scenario-informed planning.