Surface roughness characterization for SAR applications

In this paper is proposed an alternative description of the roughness state of bare soil surfaces at the scale of the "homogenous" agricultural field. As a first step, the roughness power spectra of experimental profiles acquired over various test-sites in Europe are thoroughly investigated to characterize the main features of the different tillage states. Then, a novel roughness parameter is obtained by integrating the filtered power spectral density of the surface over a frequency band centered on the resonant Bragg frequency. This parameter can describe the roughness effectively seen by the SAR sensor at the scale of the field. Finally, the roughness parameter stability and its impact on the backscattered σ° are assessed with a view on investigating issues of parameters retrieval.