Variational treatment of inertia-gravity waves interacting with a quasi-geostrophic mean flow

TitleVariational treatment of inertia-gravity waves interacting with a quasi-geostrophic mean flow
Publication TypeJournal Article
Year of Publication2016
AuthorsSalmon R
JournalJournal of Fluid Mechanics
Volume809
Pagination502-529
Date Published2016/12
Type of ArticleArticle
ISBN Number0022-1120
Accession NumberWOS:000388867800020
Keywordsinternal waves; Potential vorticity; quasi-geostrophic flows; variational methods
Abstract

The equations for three-dimensional hydrostatic Boussinesq dynamics are equivalent to a variational principle that is closely analogous to the variational principle for classical electrodynamics. Inertia gravity waves are analogous to electromagnetic waves, and available potential vorticity (i.e. the amount by which the potential vorticity exceeds the potential vorticity of the rest state) is analogous to electric charge. The Lagrangian can he expressed as the sum of three parts. The first part corresponds to quasi-geostrophic dynamics in the absence of inertia gravity waves. The second part corresponds to inertia gravity waves in the absence of quasi-geostrophic flow. The third part represents a coupling between the inertia gravity waves and quasi-geostrophic motion. This formulation provides the basis for a general theory of inertia gravity waves interacting with a quasi-geostrophic mean flow.

DOI10.1017/jfm.2016.693
Short TitleJ. Fluid Mech.
Student Publication: 
No
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