Experiment 1 - CO2 x 10#

In this experiment, you will increase the atmospheric CO2 concentration by a factor of 10 to observe its effect on the model climate.

Step 1: Navigate to the application directory#

Start by changing into the lfric_atm application directory:

cd app/lfric_atm

See also

For help choosing the correct Monsoon3 service and finding the official setup guidance, see Using Monsoon3.

cd app/lfric_atm

Step 2: Edit the configuration file#

  1. Open rose-app.conf in a text editor of your choice.

  2. Search for the co2_mix_ratio key (located under the [namelist:radiative_gases] section).

  3. Change the value from 5.6062e-04 (present-day CO2) to 5.6062e-03 (10x present-day CO2), as highlighted below.

Listing 5 trunk/app/lfric_atm/rose-app.conf#
[namelist:radiative_gases]
ch4_mix_ratio=9.8200e-07
ch4_rad_opt='constant'
!!co2_clim_fcg_levls=
!!co2_clim_fcg_nyears=
!!co2_clim_fcg_rates=
!!co2_clim_fcg_years=
co2_mix_ratio=5.6062e-04
co2_rad_opt='constant'
Listing 6 trunk/app/lfric_atm/rose-app.conf#
[namelist:radiative_gases]
ch4_mix_ratio=9.8200e-07
ch4_rad_opt='constant'
!!co2_clim_fcg_levls=
!!co2_clim_fcg_nyears=
!!co2_clim_fcg_rates=
!!co2_clim_fcg_years=
co2_mix_ratio=5.6062e-04
co2_rad_opt='constant'

Step 3: Run the model and check the output#

Now that you have increased the CO2 concentration, run the model using what you have learnt in the previous exercises. After the model has completed, check the output files to observe the impact of the increased CO2 on the model climate. You can use tools like ncdump, xconv, or python to inspect the contents of the output NetCDF files and verify the changes.

You should now have successfully completed the CO2 x 10 experiment!