Accession Number : AD0782274
Title : A Review of Low-Frequency Sound Attenuation in the Ocean.
Descriptive Note : Technical memo.,
Corporate Author : NAVAL UNDERWATER SYSTEMS CENTER NEWPORT R I
Personal Author(s) : Thorp,W. H. ; Browning,D. G. ; Jones,E. N. ; Mellen,R. H.
Report Date : 18 JUN 1971
Pagination or Media Count : 9
Abstract : The trend to lower sonar frequencies following WW 2 has revealed the existence of two and possibly more regimes of excess attenuation of sound in the oceans. The first of these, identified as a relaxation absorption caused by the MgSO4 content in sea water and, below 100 kHz, results in an increase in the absorption coefficient over fresh water by roughly a factor of 20. The second shows a further increase by a factor of 10 below 1 kHz. A number of hypotheses, including a second relaxation, have been proposed to explain the excess attenuation anomaly. Experimental techniques, data analysis, and mathematical models are discussed. (Author)
Descriptors : *Underwater sound, *Acoustic attenuation, Sea water, Low frequency, Sonar signals, Regression analysis, Magnesium compounds, Sulfates
Subject Categories : Acoustic Detection and Detectors
Distribution Statement : APPROVED FOR PUBLIC RELEASE