Effect of coherent surface water wave patterns on electromagnetic scattering of sea surface
Résumé
The problem of identifying and quantifying of coherent surface water wave patterns is considered basing on unique data of laboratory experiment in Luminy wind-wave tank (Caulliez, Collard 1999). Intensities of electromagnetic scattering are calculated within the small perturbation approximation for series of spatial reconstructions of water wave surface. This approximation allows for quantifying interference effect of EM scattering in an explicit form. The interference effect of a series of wave profiles due to persistent phase relations of water wave components can be characterized by the ratio of the mean scattering intensity to the intensity of ‘a surrogate wave field' with completely random phases as it is supposed by the so-called random phase approximation. This characteristic is found to be indicative for coherent water wave patterns under study in a wide range of ‘inner parameters' — lengths and directions of incident EM waves. The presence of coherent wave patterns as it is indicated by the calculations of EM scattering is found to be consistent with the dynamics of water wave patterns as it has been observed by Caulliez & Collard (1999). The observed interference of EM scattering and, hence, persistent water wave phase relations are associated with the forced harmonics of water waves and can be treated effectively within the weakly nonlinear approach.