Potential of ERS and Radarsat data for surface roughness monitoring over bare agricultural fields: application to catchments in Northern France

The potential of synthetic aperture radar (SAR) data for monitoring roughness states over bare agricultural fields has been investigated using one ERS image (23degrees) and two Radarsat images (39degrees and 47degrees). The relationships between the backscattering coefficient, incidence angle, soil surface roughness and row direction have been examined so as to determine the best SAR configuration for such monitoring. The results indicate a strong dependence of incidence angle on the discrimination between radar return over areas of different surface roughness. At a high incidence angle (47degrees), the influence of soil roughness on radar return predominates over the influence of other soil parameters, making it possible to discriminate and map various surface roughness classes (smooth, medium and rough) over agricultural fields.