OBSERVATIONS OF BREAKING SURFACE-WAVE STATISTICS

Breaking surface waves were observed during the Surface Wave Processes Program with a novel acoustical instrument that makes use of underwat er ambient sound to track individual breaking events. The spatial and temporal statistics of breaking waves such as duration, velocity, spac ing, and breaking probability were determined under various wind and w ave conditions. Statistical models are developed to assess and where a ppropriate, correct for any bias resulting from limitations of the mea surement approach. Empirical relations of these with wind speed are ob tained. Comparison of the observed distributions with simultaneously m easured directional wave spectra suggests that wave breaking occurs at multiple scales and that the mean scale of breaking is substantially smaller than the scale associated with the dominant wind wave componen t. Preliminary analysis indicates that the dependence of breaking prob ability on the fourth moment of the wave spectrum is consistent with a linear statistical model.