Ambient Sea‐Noise Model

A model of ambient sea noise is developed under the assumption of a surface distribution of noise sources. Volume absorption and the effects of refraction and reflection over long‐range paths are included. The derived directional noise field is expressed as a function of vertical arrival angle, with the parameters being velocity profile, surface distribution, bottom‐reflection coefficient, surface‐reflection coefficient, and frequency. Several forms of surface source directionality are considered. In an example representative of deep‐water and low‐sea‐state conditions, the model predicts that most of the low frequency acoustic energy at the ocean bottom should arrive over nearly horizontal paths. This is in agreement with reported measurements. Methods of incorporating the effects of sea state into the model are discussed.