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dc.contributor.authorLavery, Andone C.
dc.contributor.authorChu, Dezhang
dc.contributor.authorMoum, James N.
dc.date.accessioned2011-01-07T17:14:11Z
dc.date.available2011-01-07T17:14:11Z
dc.date.issued2010-11-30
dc.identifier.citationIEEE Journal of Oceanic Engineering 35 (2010): 695-709en_US
dc.identifier.urihttp://hdl.handle.net/1912/4295
dc.descriptionAuthor Posting. © IEEE, 2010. 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 35 (2010): 695-709, doi:10.1109/JOE.2010.2047814.en_US
dc.description.abstractIn this paper, measurements of high-frequency broadband (160-590 kHz) acoustic backscattering from surface trapped nonlinear internal waves of depression are presented. These waves are ideal for assessing the contribution from oceanic microstructure to scattering as they are intensely turbulent. Almost coincident direct microstructure measurements were performed and zooplankton community structure was characterized using depth-resolved net sampling techniques. The contribution to scattering from microstructure can be difficult to distinguish from the contribution to scattering from zooplankton using a single narrowband frequency as microstructure and zooplankton are often colocated and can have similar scattering levels over a range of frequencies. Yet their spectra are distinct over a sufficiently broad frequency range, allowing broadband backscattering measurements to reduce the ambiguities typically associated with the interpretation of narrowband measurements. In addition, pulse compression signal processing techniques result in very high-resolution images, allowing physical processes that are otherwise hard to resolve to be imaged, such as Kelvin-Helmholtz shear instabilities. In this study, high-resolution acoustic observations of multiple nonlinear internal waves are presented and regions with distinct scattering spectra are identified. Spectra that decrease in level across the available frequency band were highly correlated to regions of intense turbulence and high stratification, and to Kevin-Helmholtz shear instabilities in particular. Spectra that increase in level across the available frequency band were consistent with scattering dominated by small zooplankton. Simple inversions for relevant microstructure parameters are presented. Limitations of, and improvements to, the broadband system and techniques utilized in this study are discussed.en_US
dc.description.sponsorshipThis work was supported in part by the Woods Hole Oceanographic Institution and the U.S. Office of Naval Research under Grant N000140210359.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherIEEEen_US
dc.relation.urihttps://doi.org/10.1109/JOE.2010.2047814
dc.subjectAcoustic scatteringen_US
dc.subjectBroadbanden_US
dc.subjectNonlinear internal wavesen_US
dc.subjectTurbulent oceanic microstructureen_US
dc.subjectZooplanktonen_US
dc.titleObservations of broadband acoustic backscattering from nonlinear internal waves : assessing the contribution from microstructureen_US
dc.typeArticleen_US
dc.identifier.doi10.1109/JOE.2010.2047814


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