Chapter 9. Use Cases

Table of Contents
The basic example
Setting up a branch or hybrid run
Changing PE layout
Setting CAM output fields
Setting CAM forcings
Initializing the ocean model with a spun-up initial condition
Taking a run over from another user
Use of an Earth System Modeling Framework (ESMF) library and ESMF interfaces

The basic example

This specifies all the steps necessary to create, configure, build, and run a case. The following assumes that $CCSMROOT is /user/ccsmroot.

  1. Create a new case named b40.B2000 in the ~/cesm1 directory. Use a present-day control compset at 1-degree resolution on yellowstone.

> cd /user/ccsmroot
    > create_newcase -case ~/cesm1/b40.B2000 \
                     -compset B_2000 \
                     -res 0.9x1.25_gx1v6 \
                     -mach yellowstone 
  2. Go to the $CASEROOT directory. Edit env_mach_pes.xml if a different pe-layout is desired first. Then configure and build the case.

> cd ~/cesm1/b40.B2000
    > ./configure -case
  3. Create a production test. Go to the test directory. Build the test first, then run the test and check the TestStatus (the first word should be PASS).

> ./create_production_test
    > cd ../b40.B2000_ERT
    > bsub < b40.B2000_ERT.yellowstone.test
    > cat TestStatus 
  4. Go back to the case directory, set the job to run 12 model months, use an editor to change the time limit in the run file to accommodate a 12-month run, and submit the job.

> cd ../b40.B2000
    > xmlchange -file env_run.xml -id STOP_OPTION -val nmonths
    > xmlchange -file env_run.xml -id STOP_N -val 12
    > # use an editor to change "#BSUB -W 1:30" to "#BSUB -W 6:00"
    > bsub <
  5. Make sure the run succeeded.

> grep "SUCCESSFUL TERMINATION" poe.stdout.*
  6. Set it to resubmit itself 10 times so that it will run a total of 11 years (including the initial year), and resubmit the case. (Note that a resubmit will automatically change the run to be a continuation run).

> xmlchange -file env_run.xml -id RESUBMIT -val 10
    > bsub <