View source for Community Climate System Model

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>

==Submodels==

===Ocean model (docn6)===
The Climatological Data Ocean Model {{proper name|(docn)}} is recently{{when|date=May 2023}} at version{{nbsp}}6.0. It must be run within the framework of CCSM rather than standalone.<ref name="Oceanmodel" /> It takes two [[netCDF]] datasets as input and sends six outputs to the coupler, to be integrated with the output of the other submodels.<ref>{{cite web |url=http://www.ccsm.ucar.edu/models/ccsm3.0/docn6/ |title=docn6 User's Guide |author=NCAR |access-date= 2016-12-11}}</ref>

===Atmosphere model (CAM)===
The Community Atmosphere Model (CAM) can also be run as a standalone atmosphere model. Its most current version is 3.1, while 3.0 was the fifth generation. On May 17, 2002, its name was changed from the NCAR Community Climate Model to reflect its role in the new system.<ref>{{cite web|url=http://www.ccsm.ucar.edu/models/atm-cam/docs/usersguide/|archive-url=https://web.archive.org/web/20040811042943/http://www.ccsm.ucar.edu/models/atm-cam/docs/usersguide/|url-status=dead|archive-date=2004-08-11|title=CAM User's Guide|author=NCAR <!-- |access-date= March 2009 -->}} </ref> It shares the same horizontal grid as the land model of CCSM: a 256×128 regular longitude/latitude global horizontal grid (giving a 1.4 degree resolution). It has 26 levels in the vertical.<ref>{{cite web |url=http://www.ccsm.ucar.edu/models/ccsm3.0/ccsm3.0_faq.html|title=CCSM3.0 FAQs |author=NCAR |access-date= 2016-12-11}}</ref>

=== Sea Ice Model (CICE) ===
The polar component of ocean-atmosphere coupling includes sea ice [[geophysics]] using the formerly-known Los Alamos Sea Ice Model, [[CICE (sea ice model)|CICE]], now often referred to as the CICE Consortium model, to which NCAR has contributed code and physical improvements through the Polar Climate Working Group.<ref>{{Cite journal|last1=Bailey|first1=D. A.|last2=Holland|first2=M. M.|author-link2=Marika Holland|last3=DuVivier|first3=A. K.|date=2017-12-01|title=The Community Earth System Model-Polar Climate Working Group and the status of CESM2.|journal=AGU Fall Meeting Abstracts|volume=21|pages=C21B–1118|bibcode=2017AGUFM.C21B1118B}}</ref> CICE simulates the growth, movement, deformation and melt of [[sea ice]], critical for calculating energy and mass fluxes between the polar atmosphere and oceans in the [[Earth system science|earth system]].<ref>{{Citation|last=Untersteiner|first=Norbert|chapter=The Geophysics of Sea Ice: Overview|date=1986|pages=1–8|publisher=Springer US|isbn=9781489953544|doi=10.1007/978-1-4899-5352-0_1|title=The Geophysics of Sea Ice}}</ref><ref>{{Cite journal|last1=Holland|first1=Marika M.|last2=Finnis|first2=Joel|last3=Serreze|first3=Mark C.|date=2006|title=Simulated Arctic Ocean Freshwater Budgets in the Twentieth and Twenty-First Centuries|journal=Journal of Climate|volume=19|issue=23|pages=6221–6242|doi=10.1175/jcli3967.1|bibcode=2006JCli...19.6221H |issn=0894-8755|doi-access=free}}</ref><ref>{{Cite journal|last1=Holland|first1=Marika M.|last2=Bailey|first2=David A.|last3=Briegleb|first3=Bruce P.|last4=Light|first4=Bonnie|last5=Hunke|first5=Elizabeth|date=2012|title=Improved Sea Ice Shortwave Radiation Physics in CCSM4: The Impact of Melt Ponds and Aerosols on Arctic Sea Ice*|journal=Journal of Climate|volume=25|issue=5|pages=1413–1430|doi=10.1175/jcli-d-11-00078.1|bibcode=2012JCli...25.1413H |issn=0894-8755|doi-access=free}}</ref>

==Development==
The first version of CCSM was created in 1983 as the Community Climate Model (CCM). Over the next two decades it was steadily improved and was renamed CCSM after the [[Climate System Model]] (CSM) components were introduced in May 1996.<ref name="Hoffman" /> In June 2004 NCAR released the third version, which included new versions of all of the submodels. In 2007 this new version (commonly given the acronym CCSM3 or NCCCSM<ref>{{cite web |url=http://www.mad.zmaw.de/projects-at-md/ipcc-data/order-data-on-dvd/information/models/|archive-url=https://web.archive.org/web/20110719120016/http://www.mad.zmaw.de/projects-at-md/ipcc-data/order-data-on-dvd/information/models/|url-status=dead|archive-date=2011-07-19|title=Modelle & Daten model abbreviations |publisher=[[Max Planck Institute for Meteorology]] <!-- |accessdate=February 2009 -->}} </ref>) was used in the [[IPCC Fourth Assessment Report]],<ref>{{cite web |url=http://www.nar.ucar.edu/2006/science/understanding/understanding_priority4_1.php |title=NCAR 2006 Annual Report |author=NCAR |publisher=[[NCAR]] |year=2006 |access-date=2016-12-11 |archive-url=https://web.archive.org/web/20160303171413/http://www.nar.ucar.edu/2006/science/understanding/understanding_priority4_1.php |archive-date=2016-03-03 |url-status=dead }}</ref> alongside many others. In May 2010 NCAR released CCSM version{{nbsp}}4 (CCSM4). On June 25, 2010 NCAR released the successor to CCSM, called the [[Community Earth System Model]] (CESM), version{{nbsp}}1.0 (CESM1), as a unified code release that included CCSM4 as the code base for its atmospheric component.

==References==
{{reflist|30em}}

==External links==
* [http://www.cesm.ucar.edu/models/ccsm4.0/ CCSM4]
* [http://www.cesm.ucar.edu/models/ccsm3.0/ CCSM3]
* [http://www.cesm.ucar.edu/models/ccsm2.0/ CCSM2]
* [http://www.cesm.ucar.edu/models/ccsm1.0/ CCSM1]
* [http://www.cesm.ucar.edu/models/atm-cam/ Community Atmosphere Model (CAM)], atmospheric component of CCSM

{{Atmospheric, Oceanographic and Climate Models|state=expanded}}
{{Computer modeling}}

[[Category:Numerical climate and weather models]]