Measurements of Wave Breaking and Dissipation over the Continental Shelf

The primary aims of this research are to measure the kinematics and dynamics of breaking waves in the transition zone between deep-water breaking and depth-limited breaking on the continental shelf, and provide models of dissipation due to breaking for use in wind-wave models. The geometry, kinematics, and statistics of breaking leading to whitecaps will be measured using video imagery from light aircraft. Image sequence analysis will be used to determine L(c)dc,the length per unit area of breaking crests in the velocity range (c, c+dc). This fundamental statistical distribution function and its moments will be correlated with bottom topography and with wind and wave variables, including the wave directional spectrum. It will also be used along with inertial estimates of dissipation rates to remotely infer dissipation due to breaking.

Direct measurements of dissipation in the surface wave zone boundary layer along with acoustic measurements of the incidence of breaking will be made from a spar buoy and will be used to confirm the association between enhanced dissipation and wave breaking, and to bound model estimates of dissipation due to breaking. The field measurements of breaking statistics will be combined with available laboratory measurements of breaking dynamics to model dissipation on the shelf. The predictions of the model will be compared with field measurements of dissipation in the wave-zone boundary layer.