Editing Community Climate System Model (section)

The '''Community Climate System Model''' ('''CCSM''') is a coupled [[general circulation model]] (GCM) developed by the [[University Corporation for Atmospheric Research]] (UCAR) with funding from the [[National Science Foundation]] (NSF), the [[United States Department of Energy|Department of Energy]] (DoE), and the [[National Aeronautics and Space Administration]] (NASA).<ref name="Hoffman">{{cite web |url=http://www.iop.org/EJ/article/1742-6596/46/1/051/jpconf6_46_051.pdf|title=Terrestrial biogeochemistry in the community climate system model (CCSM) |author=Forrest Hoffman |publisher=[[Institute of Physics Publishing]] |year=2006 |access-date=2016-12-11}}</ref>  The coupled components include an atmospheric model (Community Atmosphere Model), a land-surface model (Community Land Model), an ocean model ([[Parallel Ocean Program]]), and a sea ice model (Community Sea Ice Model, [[CICE (sea ice model)|CICE]]).<ref>{{cite web |url=http://www.ccsm.ucar.edu/about/|title=Overview of CCSM |author=UCAR |publisher=[[University Corporation for Atmospheric Research|UCAR]] |access-date= 2016-12-11}}</ref> CCSM is maintained by the [[National Center for Atmospheric Research]] (NCAR).

Its software design assumes a physical/dynamical component of the [[climate system]] and, as a freely available community model, is designed to work on a variety of [[Technical architecture|machine architectures]] powerful enough to run the model.<ref>{{cite journal |doi=10.1177/1094342005056094 |title=Overview of the Software Design of the Community Climate System Model |author=John B. Drake |journal=International Journal of High Performance Computing Applications |volume=19 |pages=177–186 |year=2005 |issue=3|citeseerx=10.1.1.77.6157|s2cid=1846204 }}</ref>  The CESM codebase is mostly [[public domain]] with some segregable components issued under [[Free software license|open source]] and other licenses.<ref name="cesm4-copyright-notice">
{{cite web
 | title = CESM: Copyright Notice and Disclaimer
 | url = http://www.cesm.ucar.edu/models/ccsm4.0/copyright.html
 | access-date = 2016-12-11
}}
</ref>  The offline chemical transport model has been described as "very efficient".<ref>{{cite web |url=http://www.sciencestorm.com/award/0405451.html|archive-url=https://web.archive.org/web/20110716015254/http://www.sciencestorm.com/award/0405451.html|url-status=dead|archive-date=2011-07-16|title=SGER: Evaluation of Community Climate System Model (CCSM) Constituent Transport Variability |author=Bruno Sanso <!-- |access-date= December 2008 -->}} </ref>

The model includes four submodels (land, sea-ice, ocean and atmosphere) connected by a coupler that exchanges information with the submodels. NCAR suggested that because of this, CCSM cannot be considered a single climate model, but rather a framework for building and testing various climate models.<ref name="Oceanmodel">{{cite web |url=http://www.ccsm.ucar.edu/models/ccsm3.0/docn6/|title=CCSM3 Ocean Model Overview |author=NCAR |access-date= 2016-12-11}}</ref>