Bistatic Acoustic Scattering from the Ocean Bottom.

Abstract

To obtain the intensity field of sound scattered from a relatively rough region of ocean bottom, pulsed 19.5-kHz transmissions were directed toward the bottom from a ship as it approached and passed a special radio sonobuoy. Sets of data were taken with the beam incident on the bottom at grazing angles between 30 and 90 degrees. Bottom scatter returns in the monostatic direction were received on the source transducer, while reception in other directions was made by the buoy. Te source was a tiltable piston transducer with a beamwidth of approximately 8 degrees. The buoy hydrophone was omnidirectional in the horizontal plane with a rejection of surface-reflected signals n the vertical plane. The data were analyzed on the basis of an isotropic-scatter model, taking the velocity gradient into consideration. Polar plots were made of bottom scattering strength. These intensity fields have been obtained from areas east of Bermuda for two bottom types, mud-coral and ooze, in water depths of approximately 750 and 1250 fathoms respectively. The results were compared with geometric reflection and Lambert's scattering law and did not correspond with either or with a combination of both. (Author)

Document Details

Document Type
Technical Report
Publication Date
Aug 05, 1971
Accession Number
AD0728745

Entities

People

  • B. G. Hurdle
  • K. D. Flowers
  • K. P. Thompson

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Acoustic Scattering
  • Buoys
  • Grazing
  • Grazing Angles
  • Hydrophones
  • Intensity
  • Low Angles
  • Omnidirectional
  • Reflection
  • Rejection
  • Scattering
  • Seabed
  • Sonobuoys
  • Transducers

Fields of Study

  • Physics

Readers

  • Acoustical Oceanography.
  • Electromagnetic Wave Scattering and Antenna Radiation Engineering
  • Oceanography.