Instability of an idealized tidal mixing front : symmetric instabilities and frictional effects
MetadataShow full item record
Finite amplitude instability of an idealized tidal mixing front is considered for cases where there is an active symmetric instability during the early stages of evolution. This can happen either when the initial front is sharp, or when a bottom stress leads to a well-mixed bottom boundary layer under the front. In either case, there is an initial phase, several days long, of slantwise convection, after which a much more energetic and spatially distributed baroclinic or barotropic instability dominates. The presence of an initial symmetrically unstable phase has no obvious effect on the subsequent eddy evolution. Bottom friction does lead to a slower growth rate for baroclinic instabilities, a lower eddy kinetic energy level, and (through stratified spindown) a tendency for flows to be more nearly surface intensified. The surface intensification means that the evolving eddy field cannot proceed toward a barotropic state, and so the horizontal eddy scale is also constrained. Thus, the finite-amplitude inverse cascade is strongly affected by the presence of a bottom stress. Scalings are derived for the frictionally corrected eddy kinetic energy and lateral mixing coefficient. The results, in terms of frictional effects on eddy structure and energy, appear to be valid beyond just the tidal mixing frontal problem.
Author Posting. © Sears Foundation for Marine Research, 2013. This article is posted here by permission of Sears Foundation for Marine Research for personal use, not for redistribution. The definitive version was published in Journal of Marine Research 71 (2013): 425-450, doi:10.1357/002224013812587582.
Showing items related by title, author, creator and subject.
Evaluation of an acoustic remote sensing method for frontal-zone studies using double-diffusive instability microstructure data and density interface data from intrusions Duda, Timothy F.; Lavery, Andone C.; Sellers, Cynthia J. (Elsevier, 2016-10-19)Understanding intrusive exchange at oceanic water mass fronts may depend on building data-constrained models of the processes, but obtaining the needed representative and comprehensive data is challenging. Acoustic imaging ...
High-angle wave instability and emergent shoreline shapes : 2. Wave climate analysis and comparisons to nature Ashton, Andrew D.; Murray, A. Brad (American Geophysical Union, 2006-12-15)Recent research has revealed that the plan view evolution of a coast due to gradients in alongshore sediment transport is highly dependant upon the angles at which waves approach the shore, giving rise to an instability ...
White, Brian L.; Nepf, Heidi M. (Cambridge University Press, 2007-11-23)Results are presented from an experimental study of shallow flow in a channel partially obstructed by an array of circular cylinders. The cylinder array is a model for emergent vegetation in an open channel, but also ...