Development of high-resolution monthly precipitation datasets for geomorphological applications in the Tianshan Mountains from 2000 to 2050

Precipitation has a fundamental influence on landscape evolution and erosion rates. Accurate predictions of precipitation changes are crucial for landscape evolution modelling and erosion modelling. The Tianshan Mountains are known as the ‘Water Tower in Central Asia’, where precipitation is the main water supply for the surrounding lakes and rivers and also supports the population and economic development in the plain areas. This study developed a global climate model (GCM) and digital elevation model (DEM)-based downscaling method and simulated high-resolution monthly precipitation in Tianshan from 2000 to 2050, with a resolution of 90 m. The datasets developed from 30 surface observation stations had a high degree of precision and simulated the precipitation processes well in the historical period. The simulation results indicated that precipitation will increase at a rate of 11 mm/decade under the SSP245 scenario and 5 mm/decade under the RCP4.5 scenario from 2022 to 2050. Spatially, precipitation was projected to increase in the central and eastern regions and decrease in the western region. In the Kaidu, Urumqi and Manas river basins in the central Tianshan Mountains, precipitation was projected to increase at a rate of 20 mm/decade. The datasets developed here have important theoretical and practical implications for water resource management, and sustainable development in Central Asia.