On the Influence of Surface Roughness on Radarsat-2 Polarimetric Observations

Radar based surface soil moisture retrieval has been subject of intense research during the last decades. However, the space-borne radar sensors available so far provided single configuration observations where the influence of surface roughness generally caused the solution of the backscattering process to be ill posed. The availability of SAR sensors with polarimetric capabilities, such as RADARSAT-2, brings new expectations for an operational estimation of soil moisture and surface roughness from remote observations. In this paper a preliminary analysis of the influence of surface roughness on polarimetric parameters is carried out. The aim is to evaluate the ability of several polarimetric variables for the separation of fields with different roughness conditions. The results obtained are not very promising since low separabilities between rough and smooth fields are obtained with most polarimetric variables tested. In the near future, the role of tillage direction and topography on the roughness separability will be studied in more detail.