July 1993 ARSRP acoustics experiments: Some results from R/V Al l i a n c e

Abstract

In July 1993 SACLANTCEN participated in an experiment for the Acoustic Reverberation Special Research Program (ARSRP). The primary objective was to take high-resolution measurements to shed light on the detailed physical processes dominating the low-frequency scattering from rough topographic features and from deep sediment pond areas. A very detailed set of monostatic and bistatic scattering experiments were conducted (using frequencies from 150–1500 Hz) just west of the Mid-Atlantic Ridge near 26 °N and 47 °W. Results are presented that show monostatic and bistatic scattering from selected bathymetric features using both pulses and shots as sources. Area water depths ranged from 3300 to greater than 5200 m. The receivers were a horizontal array of 128 elements spaced at 0.5, 1, and 2 m, and a vertical array with 32 elements and the same spacings. Source depths varied from 120 to 1200 m and receiver depths ranged from 400 to 500 m. Received reverberation levels and scattering strength values are presented as functions of the estimated scatterer position on area bathymetry maps. Estimates of monostatic bottom scattering strengths are given using parabolic equation propagation models to interpret the data. Finally, comparisons of measured reverberation and modeled reverberation are presented.