Azimuthal variability of acoustic backscatter from 3 to 8 kHz on the New Jersey continental shelf

The acoustic backscattering strength of the seabed has been demonstrated to be one of the key inputs required in sonar performance prediction (SPP) models. Extending range independent SPP models to full 3-dimensional—or even the simpler N×2-dimensional—models requires measurements of the azimuthal variability of the backscattering strength. DRDC Atlantic’s Wide Band Sonar (WBS) system, which consists of a parametric transmitter and a superdirective receiver, is ideally suited to make these measurements. In the spring of 2003 the system was used to measure the azimuthal variability of acoustic backscatter at a site referred to as the New Jersey Strataform. Data were collected at 3, 5, and 8 kHz at grazing angles spanning 10–40. Interpretation of the data set is enhanced with swath bathymetry measurements made during the experiment as well as 3-D seismic profiles made by other researchers [C. S. Duncan, J. A. Goff, J. A. Austin, Jr., and C. S. Fulthorpe, Marine Geology 170, 395–421 (2000)]. In this paper the experimental geometry is described and the backscatter measurements are presented.