Accession Number : AD0906165

Title :   Determination of Acoustic Parameters Using Normal Mode Theory.

Descriptive Note : Technical rept.,

Corporate Author : NAVAL UNDERWATER SYSTEMS CENTER NEWPORT RI

Personal Author(s) : Kanabis, William G. ; Arens, Hans J.

Report Date : 14 NOV 1972

Pagination or Media Count : 78

Abstract : A computer-oriented procedure based on normal mode theory can be used to determine values of acoustic parameters. Such a procedure was utilized in the analysis of shallow water acoustic data taken in the Block Island Fishers Island range. Short pulses were utilized to determine the relative strength of the modes composing the sound field. The measured vertical amplitude distribution of the sound was applied to determine the velocity of sound in the bottom. The measured propagation loss as a function of range and depth served to determine bottom loss. Also considered were the effect of seasonal variations in velocity profile upon bottom loss and the effects of different bottom types and discontinuities in channel stratification upon propagation.

Descriptors :   (*UNDERWATER SOUND SIGNALS, SHALLOW WATER), BLOCK ISLAND SOUND, SOUND TRANSMISSION, PROPAGATION, VELOCITY, OCEAN BOTTOM, DEPTH FINDING, REFLECTION, SUPERLOW FREQUENCY, PHASED ARRAYS, HYDROPHONES, ACOUSTIC RANGES, MAGNETIC RECORDING SYSTEMS, MAGNETIC TAPE, COMPUTER PROGRAMS, AMPLITUDE MODULATION, ATTENUATION.

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE