Wind-induced low-frequency ambient sea noise: Mechanism and modeling

Abstract

A study has been made on the wind-induced ambient sea noise in the frequency range of 1–10 Hz. The noise generating mechanisms due to wind turbulence, surface wave, and wave turbulence are analyzed as the possible causes for the wind-induced ambient sea noise observed in the deep ocean. Based on the assumption of a stationary ocean surface disturbance, the noise power spectra due to the aforementioned noise-generating mechanisms are derived; furthermore, with the incorporation of propagation condition and bottom loss, a relationship between wind speed and ambient noise level in a certain water depth is formulated. The ambient noise level predicted by the theory agrees in order of magnitude with the reported experimental data obtained in Bermuda and Grand Bank areas. Analysis of noise spectrum level and wind speed variation has also been made in the determination of the dominant parameters affecting the wind induced noise. As a result of this study, a semiempirical wind noise model is suggested for the purpose of data comparison and as a guideline in wind noise level prediction. [Work supported by ONR.]