In this study, the Yangtze River Basin which located in the East Asian monsoon region is choosed as the study area, we collect stable water isotope measurments of precipitation events in the basin(sampling site in Hengyang) and using daily retrievals of H2O, HDO from TES on NASA’s Aura spacecraft. On the one hand, a quantitative assessment of secondary evaporation such as raindrop evaporation and moisture recycling is achieved by using the deuterium excess of precipitation events. On the other hand, Backward trajectories of water vapor, both c...