β -plane turbulence in a basin with no-slip boundaries

Krämer, Werner; Buren, Van; Clercx, Hjh Herman; Heijst, van Gjf Gert-Jan

doi:10.1063/1.2173285

Cited by 11 publications

(3 citation statements)

References 26 publications

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“…More recently, oceanic multiple alternating jets (sometimes referred to as "latent jets" or "striations") have been observed in satellite altimetry, float datasets, and eddy-resolving ocean general circulation models [Buckingham and Cornillon, 2013;Cravatte et al, 2012Cravatte et al, , 2017Maximenko et al, 2005;Nakano and Hasumi, 2005;Richards et al, 2006;Sokolov and Rintoul, 2007;Van Sebille et al, 2011]. There is a general agreement that at the leading order the oceanic jets can be explained by quasi-geostrophic (QG) dynamics with the β-effect [Kramer et al, 2006;Nadiga, 2006]. However, ambiguities remain about their generation mechanisms, the relative importance of the barotropic and baroclinic modes, and the interactions between the jets and eddies.…”

Section: Introductionmentioning

confidence: 99%

A mechanism for jet drift over topography

Khatri

Berloff

2018

J. Fluid Mech.

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The dynamics of multiple alternating oceanic jets has been studied in the presence of a simple bottom topography with constant slope in the zonal direction. A baroclinic quasi-geostrophic model forced with a horizontally uniform and vertically sheared background flow generates mesoscale eddies and jets that are tilted from the zonal direction and drift with constant speed. The governing dynamical equations are rewritten in a tilted frame of reference moving with the jets, and the cross-jet time-mean profiles of the linear and nonlinear stress terms are analysed. Here, the linear stress terms are present because of the zonally asymmetric topography. It is demonstrated that the linear dynamics controls the drift mechanism. Also, it is found that the drifting jets are directly forced by the imposed vertical shear, whereas the eddies oppose the jets, although this is limited to continuously forced dissipative systems. This role of the eddies is opposite to the one in the classical baroclinic model of stationary, zonally symmetric multiple jets. This is expected to be more generic in the ocean, which is zonally asymmetric nearly everywhere.

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Section: Introductionmentioning

confidence: 99%

A mechanism for jet drift over topography

Khatri

Berloff

2018

J. Fluid Mech.

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“…Finally, there are relatively few studies of multiple zonal jets in idealized closed basins (Berloff 2005;Kramer et al 2006;Nadiga 2006), and dynamical differences between the zonal-channel and closed-basin jets remain poorly understood.…”

Section: Introductionmentioning

confidence: 99%

A mechanism of formation of multiple zonal jets in the oceans

2009

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Multiple alternating zonal jets observed in the ocean are studied with an idealized quasigeostrophic model of flow in a zonal channel. The jets are maintained by the eddies generated by the imposed, supercritical background flow. The formation, nonlinear dynamics and equilibration of the jets are explained in terms of linear stability arguments and nonlinear self-interactions of the linear eigenmodes. In the proposed mechanism, energy of the background flow is released to the primary instability mode with long meridional and short zonal length scales. This mode undergoes secondary, transverse instability that sets the meridional scale of the emerging multiple zonal jets. This instability channels energy into several weakly damped zonal eigenmodes that amplify the jets. The emerging jets feed back on the instabilities through the partial meridional localization of the most unstable eigenmodes.

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“…For example, alternating jets are well-known from β-plane turbulence and are associated with a halting of the two-dimensional inverse energy cascade by Rossby wave dispersion (e.g., Rhines, 1975;Vallis and Maltrud, 1993). It is thus possible that the observed alternating jets in the oceans are a result of the anisotropic inverse cascade mechanism (Kramer et al, 2006;Nadiga, 2006). They may also result from nonlinear selfinteractions of linear eigenmodes (Berloff et al, 2009) or from from radiating instabilities of unstable eastern boundary currents (Hristova et al, 2008;Wang et al, 2012).…”

Section: Introductionmentioning

confidence: 99%