Code Release & Tools

The Whole Atmosphere Community Climate Model, v. 6 (WACCM6) is a high-top version of the Community Atmosphere Model (CAM), which is a component of the Community Earth System Model, (CESM). WACCM6 was part of the public release of CESM2.0 in 2019, with several updates released subsequently. WACCM-X is available as an option to extend the top boundary of the atmosphere model to the upper thermosphere. WACCM6 is supported for use only as a component of CESM, and not for uncoupled standalone calculations.

Users who wish to publish science with CESM2(WACCM) are encouraged to use a scientifically validated configuration. For most users, this will mean using CESM2.0, which was used for all CESM runs done for CMIP6. Users should select the latest incremental update (i.e., CESM2.1.5) described in the CESM2.1 release notes. Users who use CESM2.2 should be advised that there are currently no scientifically validated configurations for that code base.  The purpose of the CESM2.2 releases is to make available to the CESM user community model functionality and infrastructure improvements. It is to be used as a code base for new model developments that require this new infrastructure. Users wishing to publish science using configurations that are not scientifically validated should  validate the climate by doing long control runs for each compset they wish to use, and comparing them to CESM2.1 runs using our standard diagnostics packages.

Users may acquire the CESM source code by going to the CESM 2.0 release page and clicking on "registration" under the section "Acquiring the Release Code". Once you have agreed to the terms of use, you will be sent an email containing the location of the Subversion repository along with a user name and password. The username/password can be used with Subversion client software, such as the command-line tool svn, to download the code. Detailed instructions for downloading the code are available in the User Guides for CESM 2.1. Before downloading, please check for the latest model version (i.e.. 2.1.5, rather than 2.1) and modify the download path accordingly.

WACCM6 is built by selecting an appropriate WACCM component set and building the CESM as described in the User Guides for CESM 2.0. Scripts included with the source code will automatically download the input data sets needed to run the model for the component set and horizontal grid selected by the user. WACCM may be run coupled to a full ocean (B-compsets, supported at the f09_g17 grid), or a data ocean (F-compsets, supported at the f09_f09 and f19_f19 grids). The CAM documentation for CESM1.0 include sections for WACCM in the CAM scientific description.

A quickstart guide for building and running WACCM on NCAR's derecho is now available for download.

Please check the WACCM Support Forum for known bugs, other software and run-time issues, science issues, and general announcements.

Post-processing Analysis Tools

Additional CAM diagnostic packages are described under CAM Post-Processing Utilities on the CAM documentation page. Diagnostic packages for all model components (atmosphere, land, ice, and ocean) can be found from the component post-processing utilities page.

Validating CESM/WACCM

Users may validate their implementation of CESM/WACCM by repeating experiments we have done at NCAR, and using the component post-processing utilities to compare the climate generated to output we have made available publicly on the Earth System Grid. Please visit our CESM 2.0 experiments and diagnostics page for an updated list of experiments with links to output data locations. Output from additional experiments will be made available on a timeline in accordance with the CMIP6 data policy.