Site dependence of wind-dominated ambient noise in shallow water

Abstract

A survey of ambient noise data taken under wind-dominated conditions in shallow water shows substantial differences in spectrum level (often greater than 10 dB) under the same windspeed and sea-state conditions. This area-dependent effect, which is evident even in long-term averaged data, is caused by differences in ocean bottom properties, water depth, and sound-speed profile. A shallow-water, wind-noise model is used to remove propagation effects from selected data sets that cover a broad range of bottom types, water depths, and sound-speed profiles. These reduced data exhibit less variability, and it is concluded that the model is capable of predicting the effect of the shallow-water environment on the spectrum level of wind-dominated ambient noise. The results also suggest that commonly used universal ambient noise curves that do not take into account environmental differences are inferior to the model predictions in shallow water.