Accession Number:

AD0651706

Title:

EFFECT OF GEOMETRY ON ACOUSTIC MONOSTATIC SCATTERING FROM THE OCEAN BOTTOM,

Descriptive Note:

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s):

Report Date:

1967-03-16

Pagination or Media Count:

34.0

Abstract:

An investigation was made to determine the degree of correspondence between measured returns scattered from the ocean bottom and an extended model of isotropic scattering from a boundary. The isotropic scattering model was applied to yield the form of the scattered intensity as a function of time for the monostatic geometry in which a circular symmetric beam function is employed. An experiment was conducted in the Blake Plateau area with a piston transducer operated at 19.5 kHz and having a beamwidth of approximately 8 degrees at the half-power points. Measured signal intensities from the relatively flat bottom in this area were averaged and compared with those of the model. These comparisons were made for depression angles between 15 and 90 degrees, and for pulse lengths between 2 and 3000 msec. Measured and computed curves were found to be essentially congruent for the range of pulse lengths and depression angles employed. However, for a given depression angle it is found that scattering strength, the acoustic constant used to characterize the boundary, varies with pulse length. This indicates that scattering from the Blake Plateau bottom is not isotropic. Measurements of scattering strength versus grazing angle for the Blake Plateau area were obtained. Author

Subject Categories:

  • Physical and Dynamic Oceanography
  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE