ASA 126th Meeting Denver 1993 October 4-8

3aUW11. Ambient noise predictions from deep to shallow water.

J. Ernest Breeding, Jr.

Naval Res. Lab., Stennis Space Center, MS 39529-5004

Marshall Bradley Melanie Hebert

Planning Systems, Inc., Slidell, LA 70458

The RANDI-III noise model is used to make predictions of the omni noise level, horizontal noise field, and the vertical noise field for real world examples of broad and narrow transects from deep to shallow water. For comparison, some noise predictions are also made with the ANDES-II noise model. This is of interest since these two noise models are fundamentally different in several ways, including the methods used to propagate noise and the approaches used to treat ship sources. It is found that at the deeper water portions of the transects, the RANDI-III and ANDES-II predictions of the omni noise levels and the horizontal noise fields can be similar. However, the RANDI-III and ANDES-II predictions of the vertical noise field at these same water depths are quite different. At the shallow water sites the predictions of noise are not possible with ANDES-II. Examples illustrating the differences and similarities of the RANDI-III and ANDES-II predictions, as well as the RANDI-III predicted variations in the noise along the transects from deep to shallow water will be presented. [Research supported by The Office of Naval Research, Program Element 62435N with technical management provided by the Naval Research Laboratory, Stennis Space Center, MS.]