This lesson is still being designed and assembled (Pre-Alpha version)

CO2 experiment


Teaching: 0 min
Exercises: 0 min
  • How to quadruple CO2?

  • Learn to change CO2 concentration in a CESM experiment

The goal is to quadruple CO2 (EXPNAME=CO2).

Quadrupling CO2: how to update the input dataset?

Copy LBC file to your case directory:

On Saga:
export EXPNAME=CO2

cd $HOME/cases/F2000climo-f19_g17.$EXPNAME

cp /cluster/work/users/$USER/inputdata/atm/waccm/lb/ .

Use nco utilities to edit values on the file (

We will use a function called ncap2 – (netCDF Arithmetic Averager) single line command below

On Saga:
module load NCO/4.7.9-intel-2018b

ncap2 -O -s 'CO2_LBC=(CO2_LBC*4)' LBC_2000climo_CMIP6_0p5degLat_c180227_$

Apply this change and add it to user_nl_cam.

On Saga:
echo "flbc_file = './LBC_2000climo_CMIP6_0p5degLat_c180227_$'" >> user_nl_cam 	


grep flbc /cluster/work/users/$USER/cesm/F2000climo-f19_g17.$EXPNAME/run/atm_in

Copy the changed LBC data file into the run directory.

On Saga:
cp LBC_2000climo_CMIP6_0p5degLat_c180227_$ /cluster/work/users/$USER/cesm/F2000climo-f19_g17.$EXPNAME/run/.

Key Points

  • CO2