Sea surface dipole sound source dependence on wave-breaking variables

Estimates of the surface dipole sound source spectrum per unit water surface area were obtained from 40–4000 Hz and related to environmental parameters characterizing the wind and wave fields. The results give additional credence to the role of entrapped air bubbles and bubble clouds in the generation of acoustic ambient and indicate a change in the entrainment mechanism when the water surface transitions from aerodynamically ‘‘smooth’’ to ‘‘rough.’’ The measured dipole sound source spectrum, when scaled by the gravity wave equilibrium range wave-breaking rate of energy dissipation appears to be a self-similar function dependent only on the acoustic frequency nondimensionalized by the frequency of peak acoustic spectral level.