Accession Number : AD0906178

Title :   Volume Reverberation Measurements in the Gulf of Alaska.

Descriptive Note : Research and development rept. May 71-Apr 72,

Corporate Author : NAVAL UNDERSEA CENTER SAN DIEGO CA

Personal Author(s) : Reese, J. W. ; Keir, D. L.

Report Date : NOV 1972

Pagination or Media Count : 27

Abstract : This report is a data compilation on the temporal and geographical variations of scattering in various areas of the Pacific Ocean. Scattering strengths were measured from May to August 1971 in the Gulf of Alaska using continuous-wave pulses and explosive charges. Significant geographical variations in volume reverberation were observed for frequencies from 1.6 through 12.5 kHz. There was good agreement between the explosive methods and the pulsed continuous-wave measurements, although the velocity gradients affected the results at frequencies where deep layers were absent and for long integration times. Although near-surface scattering (less than 300 yd) was significant during night hours, the major contributions to the low-frequency column strengths for both day and night were from deep layers (greater than 500 yd). The results of the measurements also showed that predictions of sonar volume reverberation, based solely on column strength, will be marginal in the measured areas because of the presence of very deep scattering layers. (Author)

Descriptors :   *ALASKA GULF), (*REVERBERATION, (*UNDERWATER SOUND, REVERBERATION), MEASUREMENT, ECHO RANGING, SOUND TRANSMISSION, SONAR SIGNALS, UNDERWATER SOUND GENERATORS, UNDERWATER SOUND SIGNALS, SCATTERING, PERIODIC VARIATIONS, PULSES, UNDERWATER EXPLOSIONS, PHYSICAL PROPERTIES, OCEANOGRAPHY.

Subject Categories : Physical and Dynamic Oceanography
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE