Surf Zone Wave Breaking Identification Using Marine Radar

This paper presents a novel combination of synchronous, large coverage marine radar, calibrated pulsed Doppler radar, and video remote sensing observations from a nearshore field site. The data enable the analysis of the evolution and characteristics of the remotely observed signals from surf zone waves. The combination of different remote sensors allows a better discrimination between breaking and non-breaking waves, such a discrimination method offers the potential of more quantitative analyses of the wave breaking roller at field scales. In the present work, we concentrate on quantifying the contribution of the wave breaking roller to the total microwave backscatter and optical intensity signals. Analysis of the power outputs of both breaking and non-breaking events demonstrates that the backscatter from the wave roller is distinguishable from relict foam and appears to be independent of environmental conditions. Finally, we test a volumetric scattering model against the wave breaking observations. This is a new application for this type of scattering model. The model treats the wave roller as a multi-phase body where most of the scattering arises from a layer of water droplets representing the wave roller. The model shows an improved agreement with the data as compared to the traditional surface scattering model.