RS Data

We obtained multispectral Landsat images from Google Earth Engine (GEE) cloud platform for over 30 years (1990, 2000, 2010, 2020 and 2024), all images have been pre-processed and de-clouded. The open-access remote sensing data employed in this study were systematically processed to extract three critical indicators: vegetation coverage, salinization detection index, and bare rocky rate. Topographic data were obtained from the Shuttle Radar Topography Mission (SRTM) V3 product, which can accessible through the GEE platform. The SRTM dataset covers 80% of the Earth’s land surface between 60°N and 56°S, provides a global digital elevation model (DEM) with 1" (approximately 30 meters) spatial resolution. Precipitation data were sourced from the Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS), with a spatial resolution of 0.05°. This quasi-global dataset covers 50°S to 50°N, provides daily to annual precipitation time series from 1981 to present. Soil data were derived from the Harmonized World Soil Database (HWSD) version 1.2. The HWSD is a 30-arc-second raster database with over 15,000 soil mapping units. Land use/cover data and nighttime light data originated from the National Tibetan Plateau Scientific Data Centre, with a 30m and 1km spatial resolution. Details of these data are shown in Table 1.