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Weather-Layer Dynamics of Baroclinic Eddies and Multiple Jets in an Idealized General Circulation Model

O'Gorman, Paul A. and Schneider, Tapio (2008) Weather-Layer Dynamics of Baroclinic Eddies and Multiple Jets in an Idealized General Circulation Model. Journal of the Atmospheric Sciences, 65 (2). pp. 524-535. ISSN 0022-4928. https://resolver.caltech.edu/CaltechAUTHORS:OGOjas08

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Abstract

The general circulation and the behavior of multiple jets and baroclinic eddies are described for an atmosphere in which meridional potential temperature gradients and eddies are confined to a weather layer. The weather layer is separated from the frictional lower boundary by a statically stable barotropic layer with significant mass. Closure of the zonal momentum budget in the resulting circulation is achieved through ageostrophic meridional cells that extend to the lower boundary, at which momentum is dissipated. In a series of simulations with a multilevel primitive equation model, dynamic changes in the static stability of the weather layer are found to be critical in determining the scaling of the baroclinic eddies, an effect not captured in quasigeostrophic models. For simulations with a single jet in each hemisphere, the static stability of the weather layer adjusts so that a significant inverse energy cascade to scales larger than the Rossby deformation radius does not occur. The eddy length is found to scale with both the Rossby deformation radius and the Rhines scale. Simulations with larger planetary radii and low pole-to-equator temperature gradients exhibit multiple jets in each hemisphere. Eddy lengths and energies for the jet nearest the equator in each hemisphere have the same scaling as those in the single-jet simulations. Similar scalings are found for jets farther poleward but with different constants of proportionality that are consistent with more supercritical eddies. The local eddy length is found to have only a weak variation with latitude, and the local meridional jet spacing is found to scale with the local eddy length in all cases. Insights from the weather-layer simulations may be relevant to circulations in gas giant planets and the ocean.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1175/2007JAS2280.1DOIUNSPECIFIED
ORCID:
AuthorORCID
Schneider, Tapio0000-0001-5687-2287
Additional Information:© 2008 American Meteorological Society. (Manuscript received 24 August 2006, in final form 30 April 2007) We are grateful for support by an Alfred P. Sloan Research Fellowship and by the National Science Foundation (Grant ATM-0450059). The numerical simulations were performed on Caltech’s Division of Geological and Planetary Sciences Dell cluster.
Issue or Number:2
Record Number:CaltechAUTHORS:OGOjas08
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:OGOjas08
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9783
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:15 Mar 2008
Last Modified:03 Oct 2019 00:03

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