ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

5pUW13. Modeling of backscattering by bottom volumetric inhomogeneities.

Dajun Tang

Dept. of Appl. Ocean Phys. & Eng., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543

It has been recognized that when a sound wave encounters the ocean bottom, part of the energy will be scattered by volumetric inhomogeneities in the bottom. To simplify the mathematics, previous efforts in modeling the volumetric scattering process invoke some forms of plane-wave approximation to either or both of the forward and backward propagating fields. Since the ocean bottom has different acoustic properties from that of the water column, particularly since it often has a more complicated structure, introduction of the plane-wave approximation casts clouds on the validity of the modeling results. Here an approach is presented that uses the exact forward and backward propagating fields and calculates the backscattering strength numerically in the spatial domain. The bottom is assumed to be generally layered with superimposed random scatterers which have given correlation functions. Finally the validity of this model and its range of applicability will be discussed.