A new semi-empirical radar backscattering model for bare soil surfaces: Baghdadi model
Un nouveau modèle de rétrodiffusion radar semi-empirique pour les sols nus : le modèle de Baghdadi
Résumé
The aim of this paper is to develop a new semi-empirical radar backscattering model (Baghdadi model) based on the Dubois model using a wide dataset of SAR data and experimental soil measurements for bare soil surfaces in HH, VV and HV polarizations. This dataset contains radar data in L-, C- and X-bands, with incidence angles ranged between 18° and 57°. The proposed model uses a formulation of radar signals based on physical principles that were validated in numerous studies. In comparison to Dubois model, results obtained with the new model are more accurate. The bias and the RMSE decrease for both HH and VV polarizations. The RMSE decreases from 3.8 dB to 2.0 dB for HH and from 2.8 dB to 1.9 dB for VV. In addition, the high over- and under-estimations of radar backscattering coefficients observed with the Dubois model according to soil moisture, surface roughness and radar incidence angle are clearly eliminated with the new model. Based on the same type of expression as that used for HH and VV, a radar signal in HV polarization was also proposed.