Changes in surface soil mositure during freeze-thaw process under different vegetated status using Sentinel-1A in Beiluhe北大核心CSCD

Beiluhe basin lies in a permafrost region where is located in the interior of Tibetan Plateau. Ecosystem in the area is subjected to the freeze-thaw process of the active tjaele，and there is conspicuous correlation between soil moisture（SM）and vegetation coverage. To retrieve the soil moisture content of Beiluhe basin with a total area of 2 037. 94 km2，a synergistic method，which combined improved water cloud model，Oh，Dubois and Topp model，was presented in this paper base on Sentinel-1A multi-polarization SAR and Landsat-8 time series images data. The accuracy was validated with the in-situ point SM data：Adjusted-R2 of the regression equation is 0. 6848，and RMSE is 0. 039 cm3·cm-3. The analysis of correlation among freeze-thaw process，SM and vegetation cover from macro watershed scale manifests：Vegetation coverage has a significant delayed effect on the freeze-thaw process of the active tjaele，that is，the higher vegetation coverage，the more lagging freeze-thaw time；These study results are basically consistent with predecessors in-situ observation data，verifying the feasibility of studying correlation among soil freeze-thaw process，SM，and vegetation coverage from the macro watershed scale based on Sentinel-1A annual time series data. © 2022 Science Press (China).

Changes in surface soil mositure during freeze-thaw process under different vegetated status using Sentinel-1A in Beiluhe

Beiluhe basin lies in a permafrost region where is located in the interior of Tibetan Plateau. Ecosystem in the area is subjected to the freeze-thaw process of the active tjaele， and there is conspicuous correlation between soil moisture （SM） and vegetation coverage. To retrieve the soil moisture content of Beiluhe basin with a total area of 2 037.94 km²， a synergistic method， which combined improved water cloud model， Oh， Dubois and Topp model， was presented in this paper base on Sentinel-1A multi-polarization SAR and Landsat-8 time series images data. The accuracy was validated with the in-situ point SM data： Adjusted-R² of the regression equation is 0.6848， and RMSE is 0.039 cm³·cm^-3. The analysis of correlation among freeze-thaw process， SM and vegetation cover from macro watershed scale manifests： Vegetation coverage has a significant delayed effect on the freeze-thaw process of the active tjaele， that is， the higher vegetation coverage， the more lagging freeze-thaw time； These study results are basically consistent with predecessors in-situ observation data， verifying the feasibility of studying correlation among soil freeze-thaw process， SM， and vegetation coverage from the macro watershed scale based on Sentinel-1A annual time series data.