CO2 experiment

Overview

Teaching: 0 min
Exercises: 0 min

Questions

• How to quadruple CO2?

Objectives

• 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:

export EXPNAME=CO2

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

cp /cluster/work/users/$USER/inputdata/atm/waccm/lb/LBC_2000climo_CMIP6_0p5degLat_c180227.nc .

Use nco utilities to edit values on the file (http://nco.sourgeforce.net)

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

module load NCO/4.7.9-intel-2018b

ncap2 -O -s 'CO2_LBC=(CO2_LBC*4)' LBC_2000climo_CMIP6_0p5degLat_c180227.nc LBC_2000climo_CMIP6_0p5degLat_c180227_$EXPNAME.nc

Apply this change and add it to user_nl_cam.

echo "flbc_file = './LBC_2000climo_CMIP6_0p5degLat_c180227_$EXPNAME.nc'" >> user_nl_cam 	

./preview_namelists

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

Copy the changed LBC data file into the run directory.

cp LBC_2000climo_CMIP6_0p5degLat_c180227_$EXPNAME.nc /cluster/work/users/$USER/cesm/F2000climo-f19_g17.$EXPNAME/run/.

Key Points

• CO2