Upward Shift of the Atmospheric General Circulation under Global Warming: Theory and Simulations

Many features of the general circulation of the atmosphere shift upward in response to warming in simulations of climate change with both general circulation models (GCMs) and cloud-system-resolving models. The importance of the upward shift is well known, but its physical basis and the extent to wh...

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Main Authors: Singh, Martin Simran, O'Gorman, Paul
Other Authors: Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Format: Article
Language:en_US
Published: American Meteorological Society 2013
Online Access:http://hdl.handle.net/1721.1/79635
https://orcid.org/0000-0003-1748-0816
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author Singh, Martin Simran
O'Gorman, Paul
author2 Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
author_facet Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Singh, Martin Simran
O'Gorman, Paul
author_sort Singh, Martin Simran
collection MIT
description Many features of the general circulation of the atmosphere shift upward in response to warming in simulations of climate change with both general circulation models (GCMs) and cloud-system-resolving models. The importance of the upward shift is well known, but its physical basis and the extent to which it occurs coherently across variables are not well understood. A transformation is derived here that shows how an upward shift of a solution to the moist primitive equations gives a new approximate solution with higher tropospheric temperatures. According to the transformation, all variables shift upward with warming but with an additional modification to the temperature and a general weakening of the pressure velocity. The applicability of the vertical-shift transformation is explored using a hierarchy of models from adiabatic parcel ascents to comprehensive GCMs. The transformation is found to capture many features of the response to climate change in simulations with an idealized GCM, including the mid- and upper-tropospheric changes in lapse rate, relative humidity, and meridional wind. The transformation is less accurate when applied to simulations with more realistic GCMs, but it nonetheless captures some important features. Deviations from the simulated response are primarily due to the surface boundary conditions, which do not necessarily conform to the transformation, especially in the case of the zonal winds. The results allow for a physical interpretation of the upward shift in terms of the governing equations and suggest that it may be thought of as a coherent response of the general circulation of the mid- and upper troposphere.
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spelling mit-1721.1/796352024-05-15T08:46:47Z Upward Shift of the Atmospheric General Circulation under Global Warming: Theory and Simulations Singh, Martin Simran O'Gorman, Paul Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Singh, Martin Simran O'Gorman, Paul Ambrose Many features of the general circulation of the atmosphere shift upward in response to warming in simulations of climate change with both general circulation models (GCMs) and cloud-system-resolving models. The importance of the upward shift is well known, but its physical basis and the extent to which it occurs coherently across variables are not well understood. A transformation is derived here that shows how an upward shift of a solution to the moist primitive equations gives a new approximate solution with higher tropospheric temperatures. According to the transformation, all variables shift upward with warming but with an additional modification to the temperature and a general weakening of the pressure velocity. The applicability of the vertical-shift transformation is explored using a hierarchy of models from adiabatic parcel ascents to comprehensive GCMs. The transformation is found to capture many features of the response to climate change in simulations with an idealized GCM, including the mid- and upper-tropospheric changes in lapse rate, relative humidity, and meridional wind. The transformation is less accurate when applied to simulations with more realistic GCMs, but it nonetheless captures some important features. Deviations from the simulated response are primarily due to the surface boundary conditions, which do not necessarily conform to the transformation, especially in the case of the zonal winds. The results allow for a physical interpretation of the upward shift in terms of the governing equations and suggest that it may be thought of as a coherent response of the general circulation of the mid- and upper troposphere. United States. Dept. of Energy. Office of Science National Science Foundation (U.S.) (Grant AGS-1148594) 2013-07-19T15:55:49Z 2013-07-19T15:55:49Z 2012-12 2012-11 Article http://purl.org/eprint/type/JournalArticle 0894-8755 1520-0442 http://hdl.handle.net/1721.1/79635 Singh, Martin S., Paul A. O’Gorman, 2012: Upward Shift of the Atmospheric General Circulation under Global Warming: Theory and Simulations. J. Climate, 25, 8259–8276. © 2012 American Meteorological Society https://orcid.org/0000-0003-1748-0816 en_US http://dx.doi.org/10.1175/jcli-d-11-00699.1 Journal of Climate Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Meteorological Society American Meteorological Society
spellingShingle Singh, Martin Simran
O'Gorman, Paul
Upward Shift of the Atmospheric General Circulation under Global Warming: Theory and Simulations
title Upward Shift of the Atmospheric General Circulation under Global Warming: Theory and Simulations
title_full Upward Shift of the Atmospheric General Circulation under Global Warming: Theory and Simulations
title_fullStr Upward Shift of the Atmospheric General Circulation under Global Warming: Theory and Simulations
title_full_unstemmed Upward Shift of the Atmospheric General Circulation under Global Warming: Theory and Simulations
title_short Upward Shift of the Atmospheric General Circulation under Global Warming: Theory and Simulations
title_sort upward shift of the atmospheric general circulation under global warming theory and simulations
url http://hdl.handle.net/1721.1/79635
https://orcid.org/0000-0003-1748-0816
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