Low‐frequency wind‐generated noise produced by the impact of spray with the ocean’s surface

Ambient noise measurements for frequencies from 50 to 1000 Hz indicate that wind‐generated noise is a significant source of the total ambient noise field during high‐wind/sea‐state conditions. The acoustic source spectrum levels for the physical mechanism involving the impact of water droplets from ocean spray, streaks, and white caps were derived as a function of wind speed. An empirical approach using the results of Franz and measurements of Morris were used in this analysis. A full analytical derivation of the wind‐generated source level using Franz’s results was not possible because knowlege of certain parameters such as size and impact velocity of ocean spray as a function of wind speed is currently unknown. Recent measurements of the ’’white capping index’’ as a function of wind speed were used in conjunction with Morris measurements and Franz’s results to derive the source spectrum levels for wind‐generated noise in this frequency interval. The acoustic noise from bubble oscillation in white caps w...