CMAQ Developers’ Guidance Kenneth Schere U.S. EPA – ORD Research Triangle Park, NC CMAS Users Forum October14, 2010 Chapel Hill, NC

CMAQ model code will be frozen as beta version six months in advance of intended new release date, and made available from EPA. Contact Atmospheric Model Development Branch (AMDB) of EPA (mathur.rohit@epa.gov) if you intend to make a contribution to the upcoming model release; you will be provided access to the beta code. Use consistency in coding practices naming conventions, inline documentation, and specification of compile-time vs. run-time parameters

Prior to submission of code to EPA, check that the code is consistent with the beta model version from which it was built especially in the use of “include” files and run-time parameter settings Document the computational performance used for the testing; include type and speed of the processor(s), the compiler brand and version, and CPU usage code testing and documentation of test results using more than one platform-compiler combination, if available, are desirable.

Provide a benchmark case for the revised CMAQ code so that users may attempt to run the code and reproduce the test case results Test case should include input data, output reference data, run scripts Work with EPA/AMDB technical staff for integration of beta codes into the final CMAQ public release. All contributed code should be in the form of subroutines or modules that can be turned on/off (modular) within CMAQ Frequent discussions are encouraged between the code contributor and EPA/AMDB staff during the integration period.

Adequately document or otherwise provide references to peer-reviewed literature supporting new science algorithms. Include model evaluation results for new science algorithms Length of simulations used for model evaluations should be sufficient to demonstrate the impacts of the model changes

Provide continued support for technical guidance on the use of the new code Support the implementation, interpretation, and user-support/troubleshooting of model applications. Maintain codes at the current state-of-science and consistent with the CMAQ code structure for incorporation into future CMAQ releases. In the absence of these steps by code contributors, the contributed codes may be removed by EPA from subsequent CMAQ releases.

Depending upon the resources available, EPA/AMDB will make every effort to work with the code contributor to include the contribution in the scheduled CMAQ model release. In the event that the above steps cannot be achieved by the model release deadline, EPA will continue working with the contributor to satisfy all requirements, and consider including the contributed code in a subsequent interim model release. Anticipated Schedule: Beta Code Freeze of CMAQv5.0 March 2011 Public Release of CMAQv5.0 Sept/Oct 2011