High-Frequency Bistatic Scattering Model for Elastic Seafloors
Abstract
A model for bistatic acoustic scattering at high frequencies (10-100 kHz) from elastic seafloors is developed by combining the elastic small-slope roughness scattering model of Yang and Broschat with the elastic volume scattering model of Ivakin. The combined model is applicable to a variety of seafloors, including clays, silts, sands, gravel, and rock. Although elastic effects are negligible in sands and finer sediments, they are essential in treating reflection and scattering by rock, which cannot be usefully represented by a fluid model. Use of the small-slope approximation makes it possible to avoid the cumber-some interpolation between the Kirchhoff and perturbation approximations employed in the previous APL-UW backscattering model and allows larger levels of roughness than are permitted with conventional scattering approximations. The model results agree with those of the APL-UW backscattering model and with those of the APL-UW bistatic model for clays, silts, and sands. The inclusion of elastic effects attributes the high levels of scattering observed for cobble and rock seafloors to a combination of roughness and volume scattering, and replaces the empirical treatment of cobble and rock seafloors previously used in the APL-UW backscattering model by a physical one. For these cases, the new model sometimes produces unphysical results for scattering near the specular direction, indicating the need for further work on this problem.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2000
- Accession Number
- ADA373575
Entities
People
- Darrell R. Jackson
Organizations
- University of Washington