Accession Number:

AD0728745

Title:

Bistatic Acoustic Scattering from the Ocean Bottom.

Descriptive Note:

Interim rept.,

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON D C

Report Date:

1971-08-05

Pagination or Media Count:

22.0

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 Lamberts scattering law and did not correspond with either or with a combination of both. Author

Subject Categories:

  • Physical and Dynamic Oceanography
  • Acoustic Detection and Detectors
  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE