Figure 1

The location of the sample area. Note:Maps were created in ArcGIS 10.8, the Ningxia Hui Autonomous Region map (in .json format) was sourced from aliyun data visualisation platform https://datav.aliyun.com/portal/school/atlas/area_selector and the format conversion to shapefile was at mapshaper https://mapshaper.org/. DEM was sourced from Geospatial Data Cloud https://www.gscloud.cn/search.