The B configuration is the fully coupled model with active atmosphere, ice, land and ocean components communicating through the flux coupler. This is the default configuration for CCSM2 and will require minimal changes to the scripts. To run CCSM2 off site, see section 3.6. If you are running the B configuration on the IBM at NCAR, the following lines will need to be changed in the batch system information at the top of the main setup script:
# @ wall_clock_limit = 3800 # @ class = csl_reg # @ account_no = 00000000
Modifications are also needed in the main driver script to set the directories for the source code, input data, and executables. The following is a list of the environment variables that will need to be changed by the user:
setenv CASE test.a1 # case name setenv CASESTR "fully coupled $GRID test" # short descriptive text string setenv CSMROOT /fs/cgd/home0/$LOGNAME/ccsm2 # root directory of source setenv CSMDATA /fs/cgd/csm/inputdata # base dir for input data setenv EXEROOT /ptmp/$LOGNAME/$CASE # run model here
$CASE should be an identifier for the run. It should be kept as short as possible, since it is used in the output file names. Fewer than 8-10 characters is desirable. $CSMROOT is the top directory of the source code. $LOGNAME is set at login and does not need to be set in the main script file. $CSMDATA points to the location of the input data sets. $EXEROOT is typically a large temporary disk where the executable files, input data sets will reside during execution. Information output by the model will also be written to $EXEROOT. The main script is called test.a1.run and is in the /scripts/test.a1 directory. To execute a startup run, simply submit test.a1.run.
The model output will be in subdirectories in the $EXEROOT directory. An ice.log file will be written in $EXEROOT/ice that contains a copy of the ice setup script, and information about the compilation and model run. A 150 year simulation with the fully coupled model on the T42_gx1v3 grid will take about one month on 144 processors.