Deep water towed array measurements at close range

TitleDeep water towed array measurements at close range
Publication TypeJournal Article
Year of Publication2013
AuthorsHeaney K.D, Campbell R.L, Murray J.J, Baggeroer A.B, Scheer E.K, Stephen R.A, D'Spain G.L, Mercer J.A
JournalJournal of the Acoustical Society of America
Date Published2013/10
Type of ArticleArticle
ISBN Number0001-4966
Accession NumberWOS:000330119700073

During the North Pacific Acoustic Laboratory Philippine Sea 2009 experiment, towed array receptions were made from a towed source as the two ships transited from a separation of several Convergence Zones through a Closest Point of Approach at 3 km. A combination of narrowband tones and broadband pulses were transmitted covering the frequency band 79-535 Hz. The received energy arrives from two general paths-direct path and bottom bounce. Bearing-time records of the narrowband arrivals at times show a 35 degrees spread in the angle of arrival of the bottom bounce energy. Doppler processing of the tones shows significant frequency spread of the bottom bounce energy. Two-dimensional modeling using measured bathymetry, a geoacoustic parameterization based upon the geological record, and measured sound-speed field was performed. Inclusion of the effects of seafloor roughness and surface waves shows that in-plane scattering from rough interfaces can explain much of the observed spread in the arrivals. Evidence of out-of-plane scattering does exist, however, at short ranges. The amount of out-of-plane scattering is best observed in the broadband impulse-beam response analysis, which in-plane surface roughness modeling cannot explain. (C) 2013 Acoustical Society of America.

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