Observations of Wave Transformation near Breaking

Abstract

Analysis of the change in the spectrum of wind waves over a 5-km reach just prior to the surf zone during a major extratropical storm indicates that significant shifts in the spectral distribution of wave energy occur. For both onshore and offshore winds, the midrange of the spectrum loses up to 40% of the energy content, while the lowand high-frequency ranges have an energy gain. In the onshore case, gain in the high-frequency range dominates, and in the offshore wind case (predominant wave energy propagation is still shoreward), gain in the low-frequency region dominates.