OS54A-02
Wave breaking turbulence in the ocean surface layer
Friday, 18 December 2015: 16:15
3009 (Moscone West)
James M Thomson1, Johannes Gemmrich2, Michael Schwendeman3, Seth Zippel3, Saeed Moghimi4 and William Rogers5, (1)Applied Physics Lab (UW), Seattle, WA, United States, (2)University of Victoria, Victoria, BC, Canada, (3)Applied Physics Laboratory University of Washington, Seattle, WA, United States, (4)Oregon State University, Corvallis, OR, United States, (5)US Naval Research Laboratory, Washington, DC, United States
Abstract:
We present observations of turbulent dissipation rate beneath ocean waves measured from a wave following, Lagrangian, reference frame. We find that the strong turbulence associated with wave breaking is isolated to a small region (nominally less than one meter) beneath the surface. However, this strong turbulence is advected vertically by the orbital motions of the dominant waves, and thus, in an Eulerian reference frame, the strong turbulence penetrates below the wave trough level. We also test several scalings for the turbulent dissipation rates caused by wave breaking, and we conclude that the conventional scaling by the cube of the wind speed (or wind friction velocity) is biased, particularly in high winds. A formulation using a transfer velocity associated with the short waves and the wind stress is more successful in scaling the observations.
