Contribution of C-Band Radar Data to the Description of Vegetation Dynamics in the Surface Soil Moisture Retrieval in Semi-Arid Region

To retrieve the surface soil moisture using the radar data, several works performed the inversion of the Water Cloud Model (WCM) where the Normalized Vegetation Difference Index (NDVI) was used as vegetation descriptor.In the case of cloud presence, the optical data availability is limited. Therefore, in the present work, we compared the potential of the NDVI and the cross-polarization ratio and its normalized index (IN) calculated from Sentinel-1 data to describe the wheat dynamic in the soil moisture retrieve process. After the calibration and the validation of WCM, the inversion results were characterized by RMSE values varying between 5.6 vol.% and 7.4 vol.% with the outperformance of the NDVI use. Relatively close accuracy characterized the estimation of soil moisture using the radar derived descriptors.