| Recent acoustic reverberation experiments in the Florida Strait region have been performed for investigation of the contribution of sediment volume scattering to measured backscatter levels. Each site was analyzed for bottom backscattering level in both the radial and azimuthal directions. A spectrally based volume scattering model was employed, and compared to, the composite roughness interface scattering model for data taken at the South Florida sites as well as data taken by others in various regions. Using input environmental parameters taken by cross well tomography, the volume scattering model agreed well with the Florida data. Comparison of model predictions showed mid grazing angle regions to be largely dominated by volume scattering, while high grazing angles were consistently dominated by surface roughness scattering. Low grazing angle regions were shown to be controlled by the interface sound speed ratio. In areas where the interface sound speed ratio exceeded one, below the critical angle, roughness scattering tended to control the backscattered level.;Inversion of the measured backscatter data was performed using a genetic optimization algorithm developed around the volume scattering model. Inverse results were found to agree well with measured data sets and measured environmental parameters which describe the scattering volume. Discussions of the inversion technique, forward volume scattering model, roughness model and experimental equipment and procedures are given. |
