A modified empirical model for soil moisture estimation in vegetated areas using SAR data

Among the major models developed for soil moisture retrieval, the empirical model developed by Dubois et al. in 1995 proves to be a good choice, because of its accuracy and simplicity of implementation. The model provides quite good results for the estimation in bare soil areas. However, it does not explicitly incorporate vegetation backscatter effects and does not provide good results for vegetated areas with a cross-polarization ratio greater than -11dB. A modified empirical model is developed to address this concern. The water-cloud model is used to introduce vegetation effects into the VV backscatter coefficient, which is further used in the inversion model. The modified model is applied to the Washita 1994 SIR-C data and a correlation of 0.81 is obtained between the ground based measurements and the soil moisture estimated from radar data