Spatiotemporal evolution and future trends in vegetation productivity in Xinjiang driven by vapor pressure deficit and potential evapotranspiration

Under climate change, extreme drought events have become increasingly frequent; however, the regulatory mechanisms through which atmospheric drought affects vegetation productivity in arid regions remain unclear. Understanding the spatiotemporal relationships between vegetation productivity, vapor pressure deficit (VPD), and potential evapotranspiration (PET) is essential for assessing ecosystem responses to climate change. Using remote-sensing normalized difference vegetation index (NDVI), gross primary productivity (GPP), and meteorological VPD and PET data for Xinjiang from 2004 to 2023, this study employed trend analysis, the Hurst exponent, and eXtreme Gradient Boosting (XGBoost) to investigate vegetation responses to atmospheric drought stress and the persistence of future trends. GPP increased significantly in 22% of the study area and NDVI in 8.9%, mainly along the Tarim Basin margins, whereas localized vegetation degradation occurred in northern Xinjiang. VPD and PET were primary statistical contributors, with substantially higher relative importance than other factors. Temporally, both were negatively correlated with vegetation productivity; spatially, positive correlations occurred in southern oasis regions, whereas negative correlations predominated in northern Xinjiang. Strong temporal persistence in vegetation productivity was observed in only 8.6% of the vegetated areas. GPP is projected to decline after peaking in 2019, reaching approximately 197.62 g C m −2 yr −1 by 2033, while XGBoost achieved relatively high predictive accuracy (R 2 = 0.78). Overall, atmospheric drought substantially constrained vegetation productivity and weakened ecosystem stability, highlighting the need for differentiated management strategies in southern and northern Xinjiang to mitigate the risk of regional vegetation productivity decline.