ASA 124th Meeting New Orleans 1992 October

5aUW11. Scattering from rough surfaces over a layered media.

John Dubberley

NRL Code 7821, Stennis Space Center, MS 39529-5004

It has been observed in both the recent surface acoustic backscatter experiments and the well-cited Chapman--Harris experiments that at certain frequency ranges and sea state conditions backscatter is enhanced over that which would be expected from rough surface scattering alone. One explanation for this anomaly is that a diffuse layer of bubbles may be affecting the low grazing angle backscatter by steepening the incident wave through refraction. A model for testing this theory in one dimension will be presented. The operator expansion surface scattering method will be tied to a simple one-way anisotropic media propagation model to examine the backscatter behavior. This model will be compared to some experimental data as well as to benchmark examples.