Infrared remote sensing of microscale breaking waves and near-surface flow fields

We report the results from a series of wind-wave flume experiments, in which microscale breaking waves were detected using an infrared (111) imager and two-dimensional velocity fields were measured simultaneously using particle image velocimetry (PIV). Careful measurements of the water surface profile enabled us to make accurate estimates of near-surface velocities using PIV. We show that strong vortic are generated behind the leading edge of microscale breaking waves. These vortices disrupt the cool skin layer, which appears as wake in the IR image. The near-surface vorticity was correlated with the fractional area coverage of microscale breaking waves providing convincing evidence that the wakes produced by microscale breaking waves are regions of high near-surface vorticity.