Overview#

There are a number of ways that the model can be modified via namelist settings. These values control the way the code is run.

The namelist variables include settings to control over output, tune the model for various quantities, and many other options. For instance, the output frequency in the different components can be controlled via the namelists.

The steps to modify the namelists are:

In $CASEROOT

  • edit the user_nl_xxx files.

  • generate the namelists by running ./preview_namelists.

This results in the creation of component namelists, the *_in files (i.e. atm_in, lnd_in, and so on).

The *_in files are located in $CASEROOT/CaseDocs/ and in $RUNDIR.

An overview of the CESM directories and the location of the namelist files is showed in Figure 1

CESM directories and namelists

Figure 1: Overview of the CESM directories and the namelist files.

The *_in files should not be directly edited. Any manual changes of the *_in files will be overwritten when you compile or submit the run.

Note that step ./preview_namelists is optional as the script preview_namelists is also called when you build the model.

Note that you cannot change the namelist variables:

  • after the run is submitted

  • or when CONTINUE_RUN=TRUE.

Complete documentation about the namelist variables can be found on the CESM webpage.