### ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

## 5aUW9. Sound scattering at a rough water--sediment interface in shallow
water.

**X. Tang
**

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F. D. Tappert
**

**
**
*Appl. Marine Phys., Univ. Miami, RSMAS, 4600 Rickenbacker Cswy., Miami, FL
33149
*

*
*
The method of smoothing is used to study sound propagation and scattering
in a realistic shallow-water environment with a randomly rough water--sediment
interface. A mean field wave equation for the coherent acoustic field is
obtained that has a complex-valued attenuation coefficient that is localized at
the mean interface. The solution of the mean field equation, under highly
idealized conditions, is derived and discussed. The branch point and pole
singularities are found to be related to the head wave mode and the
Biot--Tolstoy rough boundary wave mode, respectively. Also obtained is the
coherent plane-wave reflection coefficient which is found to vanish when the
acoustic frequency and the incident angle of the plane wave satisfy a certain
resonant condition. For testing the mean field equation, a stochastic full-wave
forward propagation PE model is developed for Monte Carlo simulations. The
numerical results show that the coherent field obtained by an ensemble average
over many realizations is in agreement with that obtained by solving the mean
field equation just once. The Monte Carlo simulations also yield additional
useful information about higher-order moments of the acoustic field. [Work
supported by ONR.]