Retrieval of height and topography of corn fields by polarimetric SAR interferometry

Polarimetric SAR interferometry (Pol-InSAR) has been applied successfully to retrieve biophysical parameters from forest areas. This technique employs a scene model composed of a random volume over the ground. However, that model is based on the assumption that the wave propagation through the vegetation canopy is independent of polarization, which is not valid for agricultural crops because the medium shows a strong anisotropic behavior. In this work we have studied the implications of the polarization dependence of the extinction coefficients, and a redefinition of the line fit inversion model is proposed and validated with indoor measurements. As we will show, provided that agricultural vegetation is short, the influence of the different extinction coefficient is minor. Consequently, it is demonstrated that an accurate inversion of the vegetation height and the underlying topography is still possible. However, it is also shown that the model is not sensitive to changes in the extinction coefficient, so this parameter is not well estimated. Implications about the necessity of fully or partially polarimetric data have been also analyzed