Extended GO modeling of microwave backscattering from measured breaking wave crests

In previous work, an extension to geometrical optics (EGO) that allows the application to reflecting surfaces that have radii of curvature less than the electromagnetic was used to model the microwave backscattering from numerically simulated breaking water wave crests. The same approach has now been applied to plunging wave crest profiles that were directly measured in a wave tank, and the modeled backscattering compared to reference scattering found using moment-method based numerical techniques. When considering the directly measured two-dimensional cross-sections of the breaker, EGO successfully predicts the reduction in the vertically polarized backscatter (VV) observed in the reference scattering through the interference of reflections from the breaker jet itself and the cavity under the jet. A similar reduction is not seen at horizontal polarization (HH), giving a large HH-to-VV ratio at certain times in the breaking process. A three-dimensional scattering profile was synthesized from the 2-D measurements. The EGO-modeled interference of reflections from several different points on the 3-D wave yields a deep in the VV backscattering that matches the observed in the reference scattering. Again no interference is observed in the HH scattering.