Influence of resolution cell size for surface parameters retrieval from polarimetric SAR data

This paper introduces a study of the influence of the size of SAR resolution cell on polarimetric scattering characteristics over rough surfaces. Surface scattering is shown to be dependent on the cell size to correlation length ratio. SAR resolution is taken into account by dividing a surface spectrum in two parts: a low-frequency spectrum corresponding to local slopes and a high-frequency component, defining the roughness inside a resolution cell. Backscattering coefficients are calculated for each resolution cell with the IEM model using local incidence angles. Surface scattering is characterized with three polarimetric indicators H/A/α_, highly related to the soil characteristics. These models are validated on indoor polarimetric SAR measurements acquired at the JRC laboratory.