Random forcing of geostrophic motion in rotating stratified turbulence

dc.contributor.authorWaite, Michael L
dc.date.accessioned2021-10-19T19:06:39Z
dc.date.available2021-10-19T19:06:39Z
dc.date.issued2017-12-29
dc.descriptionThe following article appeared in (Waite, M. L. (2017). Random forcing of geostrophic motion in rotating stratified turbulence. Physics of Fluids, 29(12), 126602. https://doi.org/10.1063/1.5004986) and may be found at (https://doi.org/10.1063/1.5004986). This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.en
dc.description.abstractRandom forcing of geostrophic motion is a common approach in idealized simulations of rotating stratified turbulence. Such forcing represents the injection of energy into large-scale balanced motion, and the resulting breakdown of quasi-geostrophic turbulence into inertia–gravity waves and stratified turbulence can shed light on the turbulent cascade processes of the atmospheric mesoscale. White noise forcing is commonly employed, which excites all frequencies equally, including frequencies much higher than the natural frequencies of large-scale vortices. In this paper, the effects of these high frequencies in the forcing are investigated. Geostrophic motion is randomly forced with red noise over a range of decorrelation time scales τ, from a few time steps to twice the large-scale vortex time scale. It is found that short τ (i.e., nearly white noise) results in about 46% more gravity wave energy than longer τ, despite the fact that waves are not directly forced. We argue that this effect is due to wave–vortex interactions, through which the high frequencies in the forcing are able to excite waves at their natural frequencies. It is concluded that white noise forcing should be avoided, even if it is only applied to the geostrophic motion, when a careful investigation of spontaneous wave generation is neededen
dc.description.sponsorshipFinancial support from the Natural Sciences and Engineering Research Council of Canada (Grant No. RGPIN-386456-2015) is gratefully acknowledged.en
dc.identifier.urihttps://doi.org/10.1063/1.5004986
dc.identifier.urihttp://hdl.handle.net/10012/17649
dc.language.isoenen
dc.publisherAIPen
dc.relation.ispartofseriesPhysics of Fluids;
dc.titleRandom forcing of geostrophic motion in rotating stratified turbulenceen
dc.typeArticleen
dcterms.bibliographicCitationWaite, M. L. (2017). Random forcing of geostrophic motion in rotating stratified turbulence. Physics of Fluids, 29(12), 126602. https://doi.org/10.1063/1.5004986en
uws.contributor.affiliation1Faculty of Mathematicsen
uws.contributor.affiliation2Applied Mathematicsen
uws.peerReviewStatusRevieweden
uws.scholarLevelFacultyen
uws.typeOfResourceTexten

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