Accession Number : ADA324436

Title :   Bottom Scattering Strengths Measured in Deep and Shallow Water Using the Deep Towed Acoustics/Geophysics System.

Descriptive Note : Final rept. 1994-1996,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC ACOUSTICS SYSTEMS BRANCH

Personal Author(s) : Jeffery, Joseph ; Ogden, Peter M.

PDF Url : ADA324436

Report Date : 30 APR 1997

Pagination or Media Count : 25

Abstract : The Deep Towed Acoustics/Geophysics System (DTAGS) has been used for some years by Naval Research Laboratory investigators to examine the structure of ocean bottom sediments. With the replacement of the DTAGS horizontal array by a vertical array, it became possible to use the system to measure bottom scattering strengths in both deep and shallow water. The first DTAGS scattering measurements with the vertical array were taken in two general locations: in deep water near the MidAtlantic Ridge, and in shallow water near the Hudson Canyon. Analysis of the deep water results shows scattering strengths from a thicldy sedimented area to he somewhat lower than Mackenzie scattering levels, with a relatively flat dependence on grazing angle. The scattering strengths decrease slightly as frequency increases from 300 to 540 Hz, consistent with other measurements of this type. Scattering strength measurements were successfully carried out in shallow water as well. Although aspects of the data collection led to low confidence in the absolute levels, the feasibility of the low frequency measurement approach was demonstrated.

Descriptors :   *GEOACOUSTICS, *ACOUSTIC SCATTERING, *OCEAN BOTTOM SOILS, BACKSCATTERING, DEPTH, SEDIMENTS, MIDATLANTIC RIDGE, GRAZING ANGLES.

Subject Categories : Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE