Multi-polarization scatterometer measurements of long surface gravity wave breaking

The possibility of detecting breaking long surface gravity waves in S-band radar backscatter measurements is being investigated using multi-polarization scatterometer measurements. To detect breaking waves the change in the spectral shape of the radar Doppler spectra was analyzed with respect to possible indicators for wave breaking events. They are identified here using the ratio of the second and fourth spectral moments after normalization by the squared radar frequency. A comparison with simultaneous estimates of the fractional area of whitecaps suggests that a normalized spectral moment ratio might be used as one indicator for events of breaking surface gravity waves.