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dc.contributor.authorLi, Ming
dc.contributor.authorTrowbridge, John H.
dc.contributor.authorGeyer, W. Rockwell
dc.date.accessioned2010-11-02T12:51:06Z
dc.date.available2010-11-02T12:51:06Z
dc.date.issued2008-02
dc.identifier.citationJournal of Physical Oceanography 38 (2008): 418-434en_US
dc.identifier.urihttp://hdl.handle.net/1912/4032
dc.descriptionAuthor Posting. © American Meteorological Society, 2008. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 38 (2008): 418-434, doi:10.1175/2007JPO3372.1.en_US
dc.description.abstractStratification and turbulent mixing exhibit a flood–ebb tidal asymmetry in estuaries and continental shelf regions affected by horizontal density gradients. The authors use a large-eddy simulation (LES) model to investigate the penetration of a tidally driven bottom boundary layer into stratified water in the presence of a horizontal density gradient. Turbulence in the bottom boundary layer is driven by bottom stress during flood tides, with low-gradient (Ri) and flux (Rf) Richardson numbers, but by localized shear during ebb tides, with Ri = ¼ and Rf = 0.2 in the upper half of the boundary layer. If the water column is unstratified initially, the LES model reproduces periodic stratification associated with tidal straining. The model results show that the energetics criterion based on the competition between tidal straining and tidal stirring provides a good prediction for the onset of periodic stratification, but the tidally averaged horizontal Richardson number Rix has a threshold value of about 0.2, which is lower than the 3 suggested in a recent study. Although the tidal straining leads to negative buoyancy flux on flood tides, the authors find that for typical values of the horizontal density gradient and tidal currents in estuaries and shelf regions, buoyancy production is much smaller than shear production in generating turbulent kinetic energy.en_US
dc.description.sponsorshipThis work is supported by Grants OCE-0451699 and OCE-0451740 from the National Science Foundation.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherAmerican Meteorological Societyen_US
dc.relation.urihttps://doi.org/10.1175/2007JPO3372.1
dc.subjectTidesen_US
dc.subjectMixingen_US
dc.subjectLarge eddy simulationsen_US
dc.titleAsymmetric tidal mixing due to the horizontal density gradienten_US
dc.typeArticleen_US
dc.identifier.doi10.1175/2007JPO3372.1


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