CESM Support Policy

November 2013


This policy relates to support of CESM. By CESM we refer to the entire CESM system and each component that it comprises. Support of this system consists of updates as needed of bug fixes, script changes, and/or code to address the requirements of the time evolution of supported machines. Support by the CESM Software Engineering Group (CSEG) will also entail responding to questions on the CESM Bulletin Board during the support period. Major releases of CESM are to be supported for five years after the date of release or for two years after the next major release, whichever period is longer. More details are provided below.

Code and Scripts

CESM releases may incorporate different types of model enhancements as specified in the model release strategy. Releases are identified by a numbering system CESMx.y.z where "x" refers to a major release, "y" refers to substantive changes in functionality, and "z" denotes implementation changes which are not climate changing or which involve bug fixes. Individual model enhancements may fall into different categories and as such, the characterization of the entire CESM system (and the appropriate numbering) is somewhat subjective. Note however, that a "major release" will include a number of different supported configurations (or component sets - "compsets") and numerous years of simulation output.

Given the different types of model releases, and their expected use, a different level of support is provided. For a major model release, we expect that the community will require a stable code base to perform experiments that may require several years to complete. As such, CESM code and scripts in this category are supported for five years after the date of a major release or for two years after the next major release, whichever period is longer. Non-major releases do not have an effect on this time period. Released code, scripts and associated input datasets for major as well as non-major releases will be available on the web for that period. This policy may be modified at the discretion of the SSC in order to extend the support time.

Based on this policy:

  • Support for CSM1 has expired.
  • Support for CCSM2.0 and CCSM2.0.1 has expired.
  • Support for CCSM3.0 has expired.
  • Support for CCSM4.0 and CESM1.0 will continue until at least 2015.


Support will consist of updates as needed of bug fixes, script changes, and/or code to allow the addition of new machines. These will be provided to supported major model releases for the duration of the major release support period. These will not have undergone the extensive testing associated with formal releases but will be provided for the benefit of the user community.

Input data files will accompany model source code and documentation for each release and correspond to the default data required by various component sets that are supported under the release.

CESM will ensure the availability of code/scripts and associated input datasets on the CESM release Subversion repository.

Code and Scripts

Category 1: Fully Supported Machines


Category 2: All other machines that are not user defined. User defined machines are specified with a designation of "USERDEFINED" in the machines page.

  • The support person identified with these machines will answer questions as their availability permits


Category 3: USERDEFINED machines

  • Users should post questions to the CESM bulletin board


The addition of new machines to, or removal of old systems from, the Category 1 class will be based upon the availability of future CESM production capability. Priority will be given to super-computers at NCAR, NSF, and DOE centers.

How Support is Provided

The CESM Software Engineering Group (CSEG) and CISL are continuing to support a CESM bulletin board for addressing issues such as porting to USERDEFINED machines, data inquiries and bug reports. A new bulletin board is being implemented that will address many of the shortcomings that have occurred with the original bulletin board. We plan to have this in place by early 2013.