Change search
ReferencesLink to record
Permanent link

Direct link
Wave and Jet Maintenance in Different Flow Regimes
Stockholm University, Faculty of Science, Department of Meteorology . Tel Aviv University, Israel.
Number of Authors: 2
2016 (English)In: Journal of Atmospheric Sciences, ISSN 0022-4928, E-ISSN 1520-0469, Vol. 73, no 6, 2465-2484 p.Article in journal (Refereed) Published
Abstract [en]

The wave spectrum and zonal-mean-flow maintenance in different flow regimes of the jet stream are studied using a two-layer modified quasigeostrophic (QG) model. As the wave energy is increased by varying the model parameters, the flow transitions from a subtropical jet regime to a merged jet regime and then to an eddy-driven jet regime. The subtropical jet is maintained at the Hadley cell edge by zonal-mean advection of momentum, while eddy heat flux and eddy momentum flux convergence (EMFC) are weak and concentrated far poleward. The merged jet is narrow and persistent and is maintained by EMFC from a narrow wave spectrum, dominated by zonal wavenumber 5. The eddy-driven jet is wide and fluctuating and is maintained by EMFC from a wide wave spectrum. The wave-mean flow feedback mechanisms that maintain each regime are explained qualitatively.The regime transitions are related to transitions in the wave spectrum. An analysis of the wave energy spectrum budget and a comparison with a quasi-linear version of the model show that the balance maintaining the spectrum in the merged and subtropical jet regimes is mainly a quasi-linear balance, whereas in the eddy-driven jet regime nonlinear inverse energy cascade takes place. The amplitude and wavenumber of the dominant wave mode in the merged and subtropical jet regimes are determined by the constraint that this mode would produce the wave fluxes necessary for maintaining a mean flow that is close to neutrality. In contrast, the equilibrated mean flow in the eddy-driven jet regime is weakly unstable.

Place, publisher, year, edition, pages
2016. Vol. 73, no 6, 2465-2484 p.
Keyword [en]
Circulation, Dynamics, Atmospheric circulation, Baroclinic flows, Dynamics, Feedback, Fluxes, Waves, atmospheric
National Category
Meteorology and Atmospheric Sciences
Identifiers
URN: urn:nbn:se:su:diva-132489DOI: 10.1175/JAS-D-15-0321.1ISI: 000378522600004OAI: oai:DiVA.org:su-132489DiVA: diva2:953237
Available from: 2016-08-17 Created: 2016-08-15 Last updated: 2016-08-17Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text
By organisation
Department of Meteorology
In the same journal
Journal of Atmospheric Sciences
Meteorology and Atmospheric Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 69 hits
ReferencesLink to record
Permanent link

Direct link