Halving the rotation of the Earth#

In this experiment, you will halve the rotation rate of the Earth 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 omega key (located under the [namelist:planet] section).

  3. Change the value from 7.292116E-5 (Earth’s rotation rate) to 3.646058E-5 (half of Earth’s rotation rate), as highlighted below.

Listing 3 trunk/app/lfric_atm/rose-app.conf#
[namelist:planet]
cp=1005.0
gravity=9.80665
omega=3.646058E-5
p_zero=100000.0
radius=6371229.0
rd=287.05
scaling_factor=1.0
Listing 4 trunk/app/lfric_atm/rose-app.conf#
[namelist:planet]
cp=1005.0
gravity=9.80665
omega=3.646058E-5
p_zero=100000.0
radius=6371229.0
rd=287.05
scaling_factor=1.0

Step 3: Run the model and check the output#

Now that you have halved the rotation rate of the Earth, 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 halved rotation rate 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 halved Earth rotation experiment!