dc.contributor.author | Chai, Junyi | |
dc.contributor.author | Vallis, Geoffrey K. | |
dc.date.accessioned | 2016-02-23T16:06:22Z | |
dc.date.issued | 2014-07 | |
dc.description.abstract | This paper discusses the sensitivity of the horizontal and vertical scales of extratropical eddies when criticality is varied in a dry, primitive-equation, general circulation model. Criticality is a measure of extratropical isentropic slope and when defined appropriately its value is often close to 1 for Earth's climate. The model is forced by a Newtonian relaxation of temperature to a prescribed temperature profile, and criticality is increased by increasing the thermal relaxation rate on the mean flow. When criticality varies near 1, it is shown that there exists a weakly nonlinear regime in which the eddy scale increases with criticality without involving an inverse cascade, while at the same time the Rossby radius may in fact decrease. The quasigeostrophic instability of the Charney problem is revisited. It is demonstrated that both the horizontal and vertical scales of the most unstable wave depend on criticality, and simple estimates for the two scales are obtained. The authors reconcile the opposite trends of the eddy scale and Rossby radius and obtain an estimate for the eddy scale in terms of the Rossby radius and criticality that is broadly consistent with simulations. | en_GB |
dc.description.sponsorship | NSF | en_GB |
dc.description.sponsorship | NOAA | en_GB |
dc.identifier.citation | Vol. 71, pp. 2300 - 2318 | en_GB |
dc.identifier.doi | 10.1175/JAS-D-13-0351.1 | |
dc.identifier.grantnumber | AGS-1144302 | en_GB |
dc.identifier.grantnumber | NA08OAR4320752 | en_GB |
dc.identifier.uri | http://hdl.handle.net/10871/20095 | |
dc.language.iso | en | en_GB |
dc.publisher | American Meteorological Society | en_GB |
dc.rights | © Copyright 2014 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act September 2010 Page 2 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC §108, as revised by P.L. 94-553) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a web site or in a searchable database, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. Additional details are provided in the AMS Copyright Policy, available on the AMS Web site located at (http://www.ametsoc.org/) or from the AMS at 617-227-2425 or copyrights@ametsoc.org. | en_GB |
dc.subject | Baroclinic flows | en_GB |
dc.subject | Eddies | en_GB |
dc.subject | Instability | en_GB |
dc.subject | Turbulence | en_GB |
dc.subject | Extratropical cyclones | en_GB |
dc.subject | General circulation models | en_GB |
dc.title | The role of criticality on the horizontal and vertical scales of extratropical eddies in a dry GCM | en_GB |
dc.type | Article | en_GB |
dc.date.available | 2016-02-23T16:06:22Z | |
dc.identifier.issn | 0022-4928 | |
dc.identifier.eissn | 1520-0469 | |
dc.identifier.journal | Journal of the Atmospheric Sciences | en_GB |