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dc.contributor.authorDickinson, Aen
dc.contributor.authorWhite, Nicholasen
dc.contributor.authorCaulfield, Colm-cilleen
dc.date.accessioned2018-02-06T15:06:47Z
dc.date.available2018-02-06T15:06:47Z
dc.date.issued2017-12-01en
dc.identifier.issn2169-9275
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/271734
dc.description.abstractBright reflections are observed within the upper 1000~m of the water column along a seismic reflection profile that traverses the northern margin of the Gulf of Mexico. Independent hydrographic calibration demonstrates that these reflections are primarily caused by temperature changes associated with different water masses that are entrained into the Gulf along the Loop Current. The internal wave field is analyzed by automatically tracking 1171 reflections, each of which is greater than 2~km in length. Power spectra of the horizontal gradient of isopycnal displacement, $\phi_{\xi_x}$, are calculated from these tracked reflections. At low horizontal wavenumbers ($k_x < 10^{-2}$ cpm), $\phi_{\xi_x} \propto k_x^{-0.2 \pm 0.6}$, in agreement with hydrographic observations of the internal wave field. The turbulent spectral subrange is rarely observed. Diapycnal diffusivity, $K$, is estimated from the observed internal wave spectral subrange of each tracked reflection using a fine-scale parametrization of turbulent mixing. Calculated values of $K$ vary between $10^{-8}$ and $10^{-4}$~m$^{2}$~s$^{-1}$ with a mean value of $K \sim 4 \times 10^{-6}$~m$^{2}$~s$^{-1}$. The spatial distribution of turbulent mixing shows that $K \sim 10^{-7}$~m$^{2}$~s$^{-1}$ away from the shelf edge in the upper 300~m where stratification is strong. Mixing is enhanced by up to four orders of magnitude adjacent to the shoaling bathymetry of the continental slope. This overall pattern matches that determined by analyzing nearby suites of CTD casts. However, the range of values recovered by spectral analysis of the seismic image is greater as a consequence of significantly better horizontal resolution.
dc.language.isoenen
dc.titleSpatial Variation of Diapycnal Diffusivity Estimated From Seismic Imaging of Internal Wave Field, Gulf of Mexicoen
dc.typeArticle
prism.endingPage9854
prism.issueIdentifier12en
prism.publicationDate2017en
prism.publicationNameJournal of Geophysical Research: Oceansen
prism.startingPage9827
prism.volume122en
dc.identifier.doi10.17863/CAM.18695
dcterms.dateAccepted2017-11-07en
rioxxterms.versionofrecord10.1002/2017JC013352en
rioxxterms.versionVoRen
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2017-12-01en
dc.contributor.orcidDickinson, A [0000-0001-7184-927X]
dc.contributor.orcidWhite, Nicholas [0000-0002-4460-299X]
dc.contributor.orcidCaulfield, Colm-cille [0000-0002-3170-9480]
dc.identifier.eissn2169-9291
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idNERC (1508938)
pubs.funder-project-idEPSRC (EP/K034529/1)
cam.orpheus.successThu Jan 30 13:04:25 GMT 2020 - The item has an open VoR version.*
rioxxterms.freetoread.startdate2100-01-01


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