ASA 128th Meeting - Austin, Texas - 1994 Nov 28 .. Dec 02

1pUW12. Shallow-water ambient noise due to surf.

Marc Stewart

Combat Syst. Sci. and Technol. Curriculum

O. B. Wilson

J. H. Wilson

R. H. Bourke

Naval Postgraduate School, Monterey, CA 93943

Forecasting levels and directionality of ambient noise in the littoral environment is important for predicting performance of acoustic sensor systems and developing naval warfare tactics for that environment. Noise due to waves breaking at the beach contributes significantly to the low-frequency ambient noise in shallow water, as shown by the observations of O. B. Wilson, S. N. Wolf, and F. Ingenito [J. Acoust. Soc. Am. 78, 190--195 (1985)]. At some geographic points worldwide, unique geoacoustic features contribute to the detectability of ``surf point noise'' (a term coined by submariners) dozens of kilometers out to sea. The objective of this work is to apply more recently developed and powerful shallow-water propagation loss models and the increased knowledge of the geoacoustic properties of the seabed to obtain a quantitative understanding of observations reported by O. B. Wilson et al., and to make possible the prediction of the noise fields from surf in other locations. The results of the use of the SNAP programs applied to the Monterey Bay environment will be presented.