Accession Number : AD0852507

Title :   Bottom Reverberation Measurements in the Norwegian Sea and North Atlantic Ocean.

Descriptive Note : Informal rept.,

Corporate Author : NAVAL OCEANOGRAPHIC OFFICE NSTL STATION MS

Personal Author(s) : Schmidt, Peter B.

Report Date : 21 MAR 1969

Pagination or Media Count : 32

Abstract : Measurements of bottom reverberation were made at six locations in the Norwegian Sea and North Atlantic Ocean, and scattering strengths determined for grazing angles between 83 deg 30 min and 35 deg 30 min, and one-third octave frequencies from 2.5 to 12.5 kHz. In general, the data are consistent with the concept of Volovova and Zhitovskiy (1965), in which the bottom is considered to be composed of roughness elements much greater and much smaller than the wavelengths of the incident sound, with each type of roughness producing characteristic effects in the reverberation. Among these effects, evident in the analyzed data, are a small dependence of scattering strength on frequency at high grazing angles, and a greater dependence at low grazing angles. Scattering strengths at the higher frequencies do not decrease as much with decreasing grazing angles as do those at the lower frequencies. Standard deviations of scattering strengths are greatest at high grazing angles and low frequencies. Contrary to the data presented by Randlett and Urick (1968), no clear relationships between bottom scattering strength and physiographic province are evident, but this is perhaps due to the small number of stations studied. (Author)

Descriptors :   (*UNDERWATER SOUND, NORWEGIAN SEA), (*ECHO RANGING, ATLANTIC OCEAN), REVERBERATION, SOUND TRANSMISSION, MEASUREMENT, SCATTERING, VERY LOW FREQUENCY, SITE SELECTION, OCEANOGRAPHIC DATA, UNDERWATER SOUND SIGNALS, OCEAN BOTTOM TOPOGRAPHY, GRAPHICS.

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE