Temporal and spatial evolution of water yield in the lower reaches of the Yarlung Zangbo River and its response to climate and land use change

The lower reaches of the Yarlung Zangbo River are the largest water vapor channels in the Qinghai-Tibet Plateau, and the precipitation is exceptionally abundant. Hence, it is of great importance for the development, utilization, and management of water resources in this area to master the temporal and spatial characteristics and their change response to water yield. Based on the water yield module of the InVEST model and scenario analysis method, the water yield of the lower reaches of the Yarlung Zangbo River in 2000, 2010, and 2020 were evaluated, and the temporal and spatial evolution of water yield and its response to climate and land use change in the recent 20 years were analyzed. The results show the following. First, the spatial pattern of water yield in the lower reaches of the Yarlung Zangbo River basin was similar each year but varied significantly in different regions. The water yield decreases rapidly from south to north in the horizontal direction and decreases rapidly with the elevation in the vertical direction. Second, the water yield in 2000, 2010, and 2020 is 411 × 10⁸ m³, 392 × 10⁸ m³, and 360 × 10⁸ m³, respectively. The water yield exhibited an overall downward trend, and the decreasing range increased. Third, from 2000 to 2020, precipitation change significantly influenced water yield, while land use change had little influence on water yield.