Retrieving Soil Moisture in the Permafrost Environment by Sentinel-1/2 Temporal Data on the Qinghai–Tibet Plateau

Soil moisture (SM) products presently available in permafrost regions, especially on the Qinghai–Tibet Plateau (QTP), hardly meet demands of evaluating and modeling climatic, hydrological, ecological processes, due to their significant bias low spatial resolution. This study developed an algorithm generate high-spatial-resolution SM during thawing season using Sentinel-1 (S1) Sentinel-2 (S2) temporal data environment. utilizes seasonal backscatter differences reduce effect surface roughness uses normalized difference vegetation index (NDVI) (NDMI) characterize contribution. Then, map with a grid spacing 50 m × hinterland QTP area 505 km 246 was generated. The results were independently validated based situ from active layer monitoring sites. It shows that this can retrieve well area. coefficient determination (R2) root-mean-square error (RMSE) are 0.82 0.06 m3/m3, respectively. analyzed distribution different types: alpine swamp meadow had largest 0.26 followed by (0.23), steppe (0.2), desert (0.16), taking Tuotuo River basin as example. We also found significantly negative correlation between variation (CV) area, variability is higher drier environments lower wetter environments. comparison ERA5-Land, GLDAS, ESA CCI showed proposed method provide more details achieve better performance areas QTP. indicated has potential be applied entire regions