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 of the suite you copied earlier:

cd ~/roses/<suite-id>/app/lfric_atm

See also

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

cd ~/roses/<suite-id>/app/lfric_atm

Warning

“Other” means your own machine, or a system run by another institution (see Choosing your platform). This step cannot be completed there without local equivalents of the Met Office services it depends on: a supported LFRic build environment, repository access, shared ancillary data, and an HPC batch queue. The commands below are given so you can follow along and adapt them to your site, not because they will work unchanged.

cd ~/roses/<suite-id>/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 7 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'

See also

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

Listing 8 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'

Note

“Other” means your own machine, or a system run by another institution. You provide the environment yourself. See Choosing your platform.

Listing 9 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!