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South China Sea internal tide/internal waves-impact on the temporal variability of horizontal array gain at 276 Hz

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dc.contributor.author Orr, Marshall H.
dc.contributor.author Pasewark, Bruce H.
dc.contributor.author Wolf, Stephen N.
dc.contributor.author Lynch, James F.
dc.contributor.author Schroeder, Theodore
dc.contributor.author Chiu, Ching-Sang
dc.date.accessioned 2006-03-16T20:25:50Z
dc.date.available 2006-03-16T20:25:50Z
dc.date.issued 2004-10
dc.identifier.citation IEEE Journal of Oceanic Engineering 29 (2004): 1292-1307 en
dc.identifier.uri http://hdl.handle.net/1912/675
dc.description Author Posting. © IEEE, 2004. This article is posted here by permission of IEEE for personal use, not for redistribution. The definitive version was published in IEEE Journal of Oceanic Engineering 29 (2004): 1292-1307, doi:10.1109/JOE.2004.836794. en
dc.description.abstract The temporal variability of the spatial coherence of an acoustic signal received on a bottomed horizontal array has been calculated for 276-Hz narrow-band signals. A conventional plane wave beamformer was applied to the received signals. The temporal variability of the array's omnipower, beam power, and array gain are related to variability in the sound-speed field. The spectral characteristics of array omnipower are nonstationary and changed as the spectral characteristics of the temperature field varied. The array omnipower and beam-power variability tracked each other in time and varied by as much as 15 dB over time intervals as short as 7 min. Array gain varied up to 5 dB and usually tracked the omnipower variability. A contiguous 24-h section of data is discussed in detail. This data section is from a time period during which the high-frequency fluid dynamic perturbation of the sound-speed field was of smaller amplitude than other sections of the 16-d data set. Consequently, this section of data sets an upper bound for the realizable array gain. The temporal variability of array gain and spatial coherence at times appears to be correlated with environmental perturbation of the sound-speed field, but are also correlated with changes in the signal-to-noise ratio. The data was acquired during the Office of Naval Research's South China Sea Asian Seas International Acoustics Experiment. The 465-m 32-channel horizontal array was placed on the bottom in 120 m of water at the South China Sea shelf break. The acoustic source was moored in 114 m of water /spl sim/19 km from the receiving array. en
dc.description.sponsorship This work was supported by the Office of Naval Research. en
dc.format.extent 1254863 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US en
dc.publisher IEEE en
dc.relation.uri http://dx.doi.org/10.1109/JOE.2004.836794
dc.subject Array signal gain en
dc.subject Coherence en
dc.subject Internal waves en
dc.subject Narrow-band conventional beamforming en
dc.subject Shallow-water arrays en
dc.title South China Sea internal tide/internal waves-impact on the temporal variability of horizontal array gain at 276 Hz en
dc.type Article en
dc.identifier.doi 10.1109/JOE.2004.836794


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