2.1.3 Subsurface data
The subsurface data were acquired from the China Land Cover Ratio dataset, which was provided by the National Tibetan Plateau Science Data Centre (https://data.tpdc.ac.cn/) in tif format. The dataset has a spatial resolution of 1 km. For this study, four types of feature ratios were chosen: grass-irrigation ratio, forest ratio, cropland ratio, and bare ground ratio.