Energy dissipation and the spectral distribution of whitecaps

[1] Energy dissipation by breaking water waves is quantified indirectly using remote observations (digital video recordings) and directly using in situ observations (acoustic Doppler velocity profiles). The analysis is the first validation using field data to test the Duncan-Phillips formulation relating energy dissipation to the spectral distribution of whitecap speeds and lengths. Energy dissipation estimates are in agreement over two orders of magnitude, and demonstrate a promising method for routine observation of wave breaking dynamics. Breaking statistics are partitioned into contributions from waves at the peak of the wave-height spectrum and waves at higher frequencies in the spectrum. Peak waves are found to be only 10% of the total breaking rate, however peak waves contribute up to 75% of the total dissipation rate. In addition, breaking statistics are found to depend on the peak wave steepness and the energy input by the wind.

[1]  Spectrally Resolved Energy Dissipation Rate and Momentum Flux of Breaking Waves , 2008 .

[2]  Johannes Gemmrich,et al.  On the Energy Input from Wind to Surface Waves , 1994 .

[3]  W. Kendall Melville,et al.  Distribution of breaking waves at the ocean surface , 2002, Nature.

[4]  Christopher W. Fairall,et al.  A study of the inertial‐dissipation method for computing air‐sea fluxes , 1991 .

[5]  K..  THE ROLE OF SURFACE-WAVE BREAKING IN AIR-SEA INTERACTION , 2007 .

[6]  M. Banner.  Equilibrium Spectra of Wind Waves , 1990 .

[7]  J. Simpson,et al.  A novel technique for measuring the rate of turbulent dissipation in the marine environment , 2006 .

[8]  K. Katsaros,et al.  Wind stress and surface waves observed on Lake Washington , 1999 .

[9]  D. Peregrine,et al.  Wave Breaking in Deep Water , 1993 .

[10]  J. Holyer.  The stability of long steady three-dimensional salt fingers to long-wavelength perturbations , 1985, Journal of Fluid Mechanics.

[11]  R. Holman,et al.  An optical technique for the measurement of longshore currents , 2003 .

[12]  J. P. Hansen,et al.  High Range Resolution Radar Measurements of the Speed Distribution of Breaking Events in Wind-Generated Ocean Waves: Surface Impulse and Wave Energy Dissipation Rates , 2001 .

[13]  W. Melville,et al.  Inertial scaling of dissipation in unsteady breaking waves , 2008, Journal of Fluid Mechanics.

[14]  James D. Dykes,et al.  Global and Regional Wave Modeling Activities , 2002 .

[15]  Albert J. Williams,et al.  Estimates of Kinetic Energy Dissipation under Breaking Waves , 1996 .

[16]  Andrew T. Jessup,et al.  Measurement of the geometric and kinematic properties of microscale breaking waves from infrared imagery using a PIV algorithm , 2005 .

[17]  A Fourier-Based Method for the Distribution of Breaking Crests from Video Observations , 2009 .

[18]  J. Duncan,et al.  An experimental investigation of breaking waves produced by a towed hydrofoil , 1981, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[19]  Alexander V. Babanin,et al.  Breaking Probability for Dominant Waves on the Sea Surface , 2000 .

[20]  O. Phillips.  Spectral and statistical properties of the equilibrium range in wind-generated gravity waves , 1985, Journal of Fluid Mechanics.