Abstract:In this paper, we proposed a modified crop scattering model to inverse soil moisture for low vegetation. According to the scattering characteristics of winter wheat, the model retained the direct scattering contribution of vegetation layer and the coupling component between vegetation and surface ground on the basis of the original model, but considered the direct scattering contribution of the underlying ground and separated the scattering effects between vegetation and surface bare soil by introducing an empirical weight. Combined with RADARSAT-2 radar data and ground measurements of farmland experimental area in Yangling District, Shaanxi Province, the values of structural parameters of the modified model were calculated and then the model was verified and analyzed. The results showed that the simulation accuracy of the modified model was significantly improved than the original model, withR2 of more than 80% in both HH and VV polarizations. In order to verify the effectiveness of the modified model algorithm and soil moisture inversion, soil moistures inversed by the modified model were compared with those by the TVDI optical model and the simplified MIMICS model, and the results showed that the modified model was better, with R2 and RMSE of 84.3% and 0.028 cm3/cm3, respectively. The simplified MIMICS model was better than TVDI, but the inversion accuracy was not high, withR2 of 66.9% and the RMSE of 0.043 cm3/cm3, respectively. In conclusion, the modified model is sensitive to surface vegetation, can effectively distinguish the influences of winter wheat and bare soil on radar signal, thus can create conditions for inversing surface soil moisture in vegetation-covered area and provide strong technical support for large-area and large-scale surface soil moisture inversion.