### ASA 126th Meeting Denver 1993 October 4-8

## 2pAO3. Relation between waveguide and nonwaveguide (half-space) scattering
from a rough interface.

**T. F. Gao
**

**
**
*Inst. of Acoust., Academia Sinica, Beijing, People's Republic of China
*

*
*
**E. C. Shang
**

**
**
*Univ. of Colorado/NOAA/Wave Propagation, Boulder, CO 80303
*

*
*
A formal solution of the scattering field from a rough interface has been
derived. Under the Bass perturbation theory, both waveguide and nonwaveguide
(half-space) scattering from a rough interface (the sea bottom) can be
calculated analytically. By using an identical definition of ``scattering
coefficient,'' a relation between the waveguide scattering (the modal S matrix)
M[sub lj][sup s] and the nonwaveguide scattering (conventional plane-wave
scattering) coefficient m[sub s] has been found: M[sub lj][sup s]=(2(pi))[sup
2]m[sub s]/|V((theta)[sub l])V((theta)[sub j ])|, where V((theta)[sub l]) and
V((theta)[sub j]) represent the reflection coefficients of the plane interface
for the modal incident angles (theta)[sub l] and (theta)[sub j], respectively.
Consequently, based on this relation, the m[sub s] data measured in the
conventional sense (half-space) can be bridged into a shallow water
reverberation prediction or vice versa.