Experimental study of the modulation of the radar cross section due to long waves at incidence angles around 14° and 34°

Observations from the airborne radar Ressac (C-Band HH polarization, real-aperture) in two modes have been used. From the first mode which corresponds to a mean incidence angle of 14°, directional spectra of the waves have been derived assuming the usual tilt model to relate the cross-section modulations to the slopes of the long waves. Using the same tilt model, observations from the second mode (mean incidence angle≈34°) have also been processed. The comparison of the two sets of results is then used to estimate the contribution of the hydrodynamic modulation in the 34° incidence case