Namelist changes

Overview

Teaching: 0 min
Exercises: 0 min

Questions

• How do I make namelist configuration changes

Objectives

Not all changes are made in the env_*.xml files. Some are make in CASEROOT/user_nl_*. These changes are specific to each component.

To make a namelist change, add namelist_var=new_namelist_var to user_nl_* for the specific component you want to change.

When you add changes to the user_nl_* files, model uses this to create the namelists it will use when it runs. We can see what this means:

$ cd ~/cases/b.run2
$ ./preview_namelists
$ ./xmlquery RUNDIR
$ cd /glade/scratch/cstan/b.day1.0/run
$ more atm_in

How do I know what namelist options there are to change for each component? http://www.cesm.ucar.edu/models/cesm2/settings/current/

Configure your new experiment

Change the output frequency of your experiment to produce daily precipitation output along with default monthly output for the default set of variables.

In user_nl_atm, add the following lines:

fincl2='PRECC','PRECL' # higher frequency output for PRECC and PRECL (convective and large scale precipitation)

nhtfrq=0,-24 # h0 files will be monthly with default variables; h1 files will be daily with fincl2 variables

mfilt = 1,1 # h0 files will be once monthly, h1 files will be once daily

Check that everything is set properly wiht ./preview_namelists

Key Points