{ "id": "1612.09009", "version": "v1", "published": "2016-12-28T23:46:23.000Z", "updated": "2016-12-28T23:46:23.000Z", "title": "An asymptotic model for the propagation of oceanic internal tides through quasi-geostrophic flow", "authors": [ "Gregory L. Wagner", "Gwenael Ferrando", "William R. Young" ], "categories": [ "physics.flu-dyn" ], "abstract": "Starting from the hydrostatic Boussinesq equations, we derive a time-averaged `hydrostatic wave equation' that describes the propagation of inertia-gravity internal waves through quasi-geostrophic flow. The derivation uses a multiple-time-scale asymptotic method to isolate wave field evolution over intervals much longer than a wave period, assumes that the wave field has a well-defined and non-inertial frequency such as that of the mid-latitude semi-diurnal lunar tide, neglects nonlinear wave-wave interactions and makes no restriction on either the background density stratification or the relative spatial scales between the wave field and quasi-geostrophic flow. As a result the hydrostatic wave equation is a reduced model applicable to the propagation of large scale internal tides through the inhomogeneous and moving ocean. A numerical comparison with the linearized and hydrostatic Boussinesq equations demonstrates the validity of the hydrostatic wave equation and illustrates the manners of model failure when the quasi-geostrophic flow is too strong and the wave frequency is too close to inertial.", "revisions": [ { "version": "v1", "updated": "2016-12-28T23:46:23.000Z" } ], "analyses": { "keywords": [ "quasi-geostrophic flow", "oceanic internal tides", "hydrostatic wave equation", "asymptotic model", "hydrostatic boussinesq equations" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }