A comprehensive model of wind‐generated bubbles in the ocean and predictions of the effects on sound propagation at frequencies up to 40 kHz

A new expression is proposed for the population density spectrum of wind‐generated bubbles in the sea based on measurements made by Johnson and Cooke [B. D. Johnson and R. C. Cooke, J. Geophys. Res. 84, 3761–3766 (1979)] and by Thorpe [S. A. Thorpe, Phil. Trans. R. Soc. London Ser. A 304, 155–210 (1982)]. The main departures from existing expressions are the narrowing of the radius spectrum with increasing depth and the conclusion from Thorpe’s data that the bubble density at the surface is proportional to the cube of the wind speed. For acoustic propagation at a given frequency, useful expressions for the resonant bubble radius, damping coefficient, the complex sound speed, attenuation, and the refraction spreading loss are presented. Predicted results for each of these parameters are calculated for frequencies of 0 Hz and from 1.25 to 40 kHz in octave steps. As frequency is increased, the dominant cause of loss changes from refraction to attenuation. For a wind speed of around 15 m/s, the transmission a...