Workflow of a CCSM4 run

Basic approach, startup run:

1. Create a new case using the script under ~/CCSM4/scripts, following the template: PATH, compset, resolution and machine file. Compset B is the fully coupled mode.

    ./create_newcase -case ~/ccsm4/$casename \
                           -compset B_2000 \
                           -res 0.9x1.25_gx1v6 \
                           -mach bluefire 
   

2. Go to the $CASEROOT directory, ~/ccsm4/$case, modify the processor layout (env_mach_pes.xml) or env_conf.xml files, then configure and build the model:

    ./configure -case
    ./$casename.$mach.build  
   

3. Create Production test (Optional): This will clone the current case and create a parallel folder ../$casename_ERT.x$mach. Go to the folder, and execute following commands:

    ./$casename_ERT.$mach.build
    bsub < $casename_ERT.$mach.test
    cat TestStatus
   

4. Once pass the test run, go back to the $CASEROOT, modify the env_run.xml as well as %casename.$mach.run. Using the given xmlchange script is recommended. The %casename.$mach.run is the batch submit script. Depending on the machines, it could be executed through bsub or qsub. In the env_run.xml file, one can edit items such as STOP_N, STOP_OPTION and RESUBMIT, to adjust the simulation length, as well as the resubmit frequencies. This modifications don’t require rebuilding executables.

A branch or hybrid run:

1. Follow Step 1 in the previous example to create a new case $casename2.

2. Edit env_conf.xml:

    xmlchange -file env_conf.xml -id RUN_TYPE    -val branch
    xmlchange -file env_conf.xml -id RUN_REFCASE -val $casename1
    xmlchange -file env_conf.xml -id RUN_REFDATE -val 0001-02-01
   

3. For a hybrid run, set RUN_TYPE to hybrid instead.

4. Configure and build the case executable.

    ./configure -case
    ./$casename.$mach.build   
   

5. Copy the necessary restart/initial data into $RUNROOT, a path similar to .../exe/$casename2/run

6. Repeat Step 4 in the previous example.

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File locking explained:

Locking variables is a feature of CCSM that prevents users from changing variables after they have been resolved (used) in other parts of the scripts system. The variables in env_case are locked when create_newcase is called. The env_conf and env_mach_pes variables are locked when configure is called. The env_build variables are locked when CCSM is built, and the env_run variables are never locked and can be changed anytime. In addition, the Macros file is locked as part of the build step. The $CASEROOT/LockedFiles directory saves copies of the xml files to facilitate the locking feature.

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More advanced use cases can be found in Chapter 9 of the CCSM4 user guide