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dc.contributor.authorFalder, Matthewen
dc.contributor.authorWhite, Nicholasen
dc.contributor.authorCaulfield, Colm-cilleen
dc.date.accessioned2016-03-07T12:58:44Z
dc.date.available2016-03-07T12:58:44Z
dc.date.issued2016-02-05en
dc.identifier.citationFalder et al. Journal of Physical Oceanography (2016). doi: 10.1175/JPO-D-15-0140.1en
dc.identifier.issn0022-3670
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/254202
dc.description.abstractBroadband measurements of the internal wavefield will help to unlock an understanding of the energy cascade within the oceanic realm. However, there are challenges in acquiring observations with sufficient spatial resolution, especially in horizontal dimensions. Seismic reflection profiling can achieve a horizontal and vertical resolution of order meters. It is suitable for imaging thermohaline fine structure on scales that range from tens of meters to hundreds of kilometers. This range straddles the transition from internal wave to turbulent regimes. Here, we analyze an 80 km long seismic image from the Falkland Plateau and calculate vertical displacement spectra of tracked reflections. First, we show that these spectra are consistent with the Garrett-Munk model at small horizontal wavenumbers (i.e. k_x ~< 3×10−3 cpm). There is a transition to stratified turbulence at larger wavenumbers (i.e. k_x ~> 2 × 10−1 cpm). This transition occurs at length scales that are significantly larger than the Ozmidov length scale above which stratification is expected to modify isotropic Kolmogorov turbulence. Secondly, we observe a rapid onset of this stratified turbulence over a narrow range of length scales. This onset is consistent with a characteristic energy injection scale of stratified turbulence with a forward cascade toward smaller scales through isotropic turbulence below the Ozmidov length scale culminating in microscale dissipation. Finally, we estimate the spatial pattern of diapycnal diffusivity and show that the existence of an injection scale can increase these estimates by a factor of two.
dc.description.sponsorshipM.F. is supported by the Department of Earth Sciences. Research activity of C.P.C. is supported by EPSRC Programme Grant EP/K034529/1 (“Mathematical Underpinnings of Stratified Turbulence”). We thank C. Bond, A. Dickinson, K. Gunn, S. Holbrook, J. Klymak, J. Moum and S. Thorpe for their help. We are very grateful to J. Klymak for generously making available his MATLAB toolbox for calculating Garrett-Munk spectra. Department of Earth Sciences contribution number esc.XXXX.
dc.languageEnglishen
dc.language.isoenen
dc.publisherAmerican Meteorological Society
dc.titleSeismic Imaging of Rapid Onset of Stratified Turbulence in the South Atlantic Oceanen
dc.typeArticle
dc.description.versionThis is the author accepted manuscript. The final version is available from the American Meteorological Society via http://dx.doi.org/10.1175/JPO-D-15-0140.1en
prism.publicationDate2016en
prism.publicationNameJournal of Physical Oceanographyen
dc.rioxxterms.funderEPSRC
dc.rioxxterms.projectidEP/K034529/1
dcterms.dateAccepted2016-01-05en
rioxxterms.versionofrecord10.1175/JPO-D-15-0140.1en
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2016-02-05en
dc.contributor.orcidCaulfield, Colm-cille [0000-0002-3170-9480]
dc.identifier.eissn1520-0485
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idEPSRC (EP/K034529/1)
rioxxterms.freetoread.startdate2016-08-05


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