Rough surface scattering from an elastic scale model of an ocean bottom

Monostatic and bistatic scattering strength measurements with a rough PVC surface were collected during two experiments in an acoustic tank facility at the Allied Geophysical Laboratories in the University of Houston. The PVC surface was analogous to limestone ocean bottoms in its two-dimensional power-law roughness spectrum and its large dependence of scattering strength on the roughness parameters. The experiments represent an initial effort to use physical models with ground-truth measurements of roughness and compressional/shear speeds and attenuations to verify the predicted effects of interface scattering models, e.g., the small-slope model developed at the Naval Research Laboratory for elastic bottoms. Comparisons between the small-slope model, perturbation theory, and the observed data are shown for the various geometries using acoustic transmissions in the 100–400 kHz band. The success in obtaining a good model-data fit is shown to be directly related to the ensonification of an area that represents a sufficient statistical sample of the roughness. Plans for a series of tank experiments with physical models for verifying predictions of rough surface scattering theories and elastic PE are described. [Work supported by ONR.]