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

2pUW1. Time and angle spreads due to scattering by bottom roughness and sediment volume inhomogeneity.

Darrell R. Jackson

Kevin L. Williams

Appl. Phys. Lab., College of Ocean and Fishery Sciences, Univ. of Washington, Seattle, WA 98105

A bistatic scattering model that treats both roughness and sediment volume scattering is used to infer time and angle spreading for sedimentary seabeds. This model is embedded in a simulation code that predicts the received intensity time series taking account of single-bounce bistatic geometry as well as transmitter and receiver directivity. Roughness scattering is treated in the Kirchhoff approximation without invoking the stationary-phase approximation. Sediment volume scattering is treated in the perturbation approximation. Both roughness and volume inhomogeneity are assumed to be random processes with power-law spectra. The relative importance of roughness and sediment volume scattering as spreading mechanisms and the energy loss due to forward scattering are examined for a range of sediment types.