Vegetation influence level on the water resources effectiveness over China

Abstract Water resources play an extremely important role in sustainable development. The hydrological processes from evapotranspiration to precipitation reshape the distribution of surface water resources, and a thorough understanding of these processes can contribute to water resources management. China has experienced vegetation greening in recent years. How China's evapotranspiration, particularly vegetation-related evapotranspiration (transpiration and interception loss), regulates its own water resources effectiveness and the precipitation in surrounding countries remains unclear. Using a high-quality global atmospheric moisture connectivity, evapotranspiration, and precipitation dataset, we find that the regulatory effect of evapotranspiration on precipitation is most pronounced in summer. Annually in China, 57% of the moisture generated by evapotranspiration stays within China, accounting for 39.54% of precipitation sources. The remaining moisture is transported abroad, providing an important source of precipitation for the neighboring countries, especially North Korea and Mongolia. Although grass and bare ecosystems contribute much less moisture than farm and forest ecosystems, they serve as critical moisture sources for the arid interior of China and Mongolia. Vegetation in China has a negative net hydrological effect domestically, which tends to increase across most parts of the country from 2000 to 2020. This research highlights the critical role of vegetation in the transboundary distribution of water resources through moisture transport and provides new insights for sustainable development of water resources.