Impacts of Continuous Water Diversions by the South-To-North Water Diversion Project on Increased Precipitation and Decreased Temperature in Water-Receiving Areas

Abstract

Climate impacts of the South-to-North water diversion project in China on water-receiving areas (WRA) is simulated by the Weather Research and Forecasting (WRF) model. The results show that during the 2015–2022 water diversion period, the WRA experiences increased precipitation and decreased temperature. Annual precipitation increased by 2.8 mm, mainly dominated by non-convective precipitation (1.92 mm). Although the upwind region receives more water, the increase in water vapor flux is more dramatic in the downwind region due to the spring northwest monsoon; The decreased temperature effect is most pronounced in spring (over 0.15°C), and over 10 mm of evaporation increase in the downwind region. The sensible heat flux decrease is less pronounced than the latent heat flux increase, mainly because of the insulating effect, which prevented evaporative cooling reduction. This study advances our understanding of the mechanisms by which large-scale water diversion affects WRA climates.