Breaking wind waves as a source of ambient noise.

A theoretical model for the prediction of ambient noise level due to collective oscillations of air bubbles under breaking wind waves is presented. The model uses a budget of the energy flux from the breaking waves to quantify acoustic power radiation by a bubble cloud. A shift of the noise spectra to lower frequency due to collective bubble oscillation is assumed. The model derives good estimates of the magnitude, slope, and frequency range of the noise spectra using the wind speed or height of breaking waves.