Editing General circulation model (section)

==Computations==
[[File:Volume-Rendered Global Atmospheric Model.ogv|thumb|350px|This visualization shows early test renderings of a global computational model of Earth's atmosphere based on data from NASA's Goddard Earth Observing System Model, Version 5 (GEOS-5).]]Climate models use [[quantitative method]]s to simulate the interactions of the [[Earth's atmosphere|atmosphere]], oceans, [[land surface]] and [[cryosphere|ice]].

All climate models take account of incoming energy as short wave [[electromagnetic radiation]], chiefly [[Visible spectrum|visible]] and short-wave (near) [[infrared]], as well as outgoing energy as long wave (far) infrared electromagnetic radiation from the earth. Any imbalance results in a [[First law of thermodynamics|change in temperature]].

The most talked-about models of recent years relate temperature to [[exhaust gas|emission]]s of [[greenhouse gas]]es. These models project an upward trend in the [[surface temperature record]], as well as a more rapid increase in temperature at higher altitudes.<ref>Meehl ''et al.'', [http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch10.html Climate Change 2007 Chapter 10: Global Climate Projections] {{webarchive |url=https://web.archive.org/web/20160415020743/http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch10.html |date=15 April 2016 }},{{Page needed|date=December 2011}} in {{Citation 
| year   = 2007
| author = IPCC AR4 WG1
| author-link = IPCC
| title  = Climate Change 2007: The Physical Science Basis
| series = Contribution of Working Group I to the [[IPCC Fourth Assessment Report|Fourth Assessment Report]] of the Intergovernmental Panel on Climate Change
| editor = Solomon, S. |editor2=Qin, D. |editor3=Manning, M. |editor4=Chen, Z. |editor5=Marquis, M. |editor6=Averyt, K.B. |editor7=Tignor, M. |editor8=Miller, H.L.
| publisher = Cambridge University Press
| url  = http://www.ipcc.ch/publications_and_data/ar4/wg1/en/contents.html
| isbn = 978-0-521-88009-1 
}} (pb: {{ISBNT|978-0-521-70596-7}})
</ref>

Three (or more properly, four since time is also considered) dimensional GCM's discretise the equations for fluid motion and energy transfer and integrate these over time. They also contain parametrisations for processes such as convection that occur on scales too small to be resolved directly.

Atmospheric GCMs (AGCMs) model the atmosphere and impose sea surface temperatures as boundary conditions. Coupled atmosphere-ocean GCMs (AOGCMs, e.g. [[HadCM3]], [[EdGCM]], GFDL CM2.X, ARPEGE-Climat<ref>[http://www.cnrm.meteo.fr/gmapdoc/spip.php?article202 ARPEGE-Climat homepage, Version 5.1] {{webarchive |url=https://web.archive.org/web/20160104172118/http://www.cnrm.meteo.fr/gmapdoc/spip.php?article202 |date=4 January 2016 }}, 3 Sep 2009. Retrieved 1 October 2012. [http://www.cnrm.meteo.fr/gmgec/spip.php?article83 ARPEGE-Climat homepage] {{webarchive |url=https://web.archive.org/web/20140219004340/http://www.cnrm.meteo.fr/gmgec/spip.php?article83 |date=19 February 2014 }}, 6 August 2009. Retrieved 1 Oct 2012.</ref>) combine the two models.

Models range in complexity:

* A simple [[radiant heat]] transfer model treats the earth as a single point and averages outgoing energy
* This can be expanded vertically (radiative-convective models), or horizontally
* Finally, (coupled) atmosphere–ocean–sea ice global climate models discretise and solve the full equations for mass and energy transfer and radiant exchange.
* Box models treat flows across and within ocean basins.

Other submodels can be interlinked, such as [[land use]], allowing researchers to predict the interaction between climate and ecosystems.