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Butler, Amy H., Thompson, David W. J. 
ORCID: https://orcid.org/0000-0002-5413-4376 and Birner, Thomas
(2011)
Isentropic slopes, downgradient eddy fluxes, and the extratropical atmospheric circulation response to tropical tropospheric heating.
Journal of the Atmospheric Sciences, 69 (10).
2292–2305.
ISSN 0022-4928
Abstract
Climate change experiments run on Intergovernmental Panel on Climate Change (IPCC)–class numerical models consistently suggest that increasing concentrations of greenhouse gases will lead to a poleward shift of the midlatitude jets and their associated eddy fluxes of heat and potential vorticity (PV). Experiments run on idealized models suggest that the poleward contraction of the jets can be traced to the effects of increased latent heating and thus locally enhanced warming in the tropical troposphere. Here the authors provide new insights into the dynamics of the circulation response to tropical tropospheric heating using transient experiments in an idealized general circulation model. It is argued that the response of the midlatitude jets to tropical heating is driven fundamentally by 1) the projection of the heating onto the meridional slope of the lower tropospheric isentropic surfaces, and 2) a diffusive model of the eddy fluxes of heat and PV. In the lower and middle troposphere, regions where the meridional slope of the isentropes (i.e., the baroclinicity) is increased are marked by anomalously poleward eddy fluxes of heat, and vice versa. Near the tropopause, regions where the meridional gradients in PV are increased are characterized by anomalously equatorward eddy fluxes of PV, and vice versa. The barotropic component of the response is shown to be closely approximated by the changes in the lower-level heat fluxes. As such, the changes in the eddy fluxes of momentum near the tropopause appear to be driven primarily by the changes in wave generation in the lower troposphere.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | atmospheric circulation,dynamics,potential vorticity,sdg 13 - climate action ,/dk/atira/pure/sustainabledevelopmentgoals/climate_action |
| Faculty \ School: | Faculty of Science > School of Environmental Sciences |
| UEA Research Groups: | Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences Faculty of Science > Research Groups > Climatic Research Unit |
| Related URLs: | |
| Depositing User: | LivePure Connector |
| Date Deposited: | 07 Jun 2022 13:30 |
| Last Modified: | 15 Jun 2023 04:32 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/85402 |
| DOI: | 10.1175/JAS-D-10-05025.1 |
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