Two steps are performed one after the other:

1. Run the interpolation program INT2LM
   Start the runscript (run int2lm). This interpolates initial and boundary conditions from the driving model to the rotated latitude-longitude grid of the CCLM.
   

2. Run the regional climate model program CCLM
   Start the runscript (run cclm)

Inside the chain directory cclm-sp/step_by_step, you will find a number of files and directories for two examples:

• gcm_to_cclm/
  Directory where you run a downscaling simulation with GCM data as forcing.
• cclm_to_cclm/
  Directory where you run a nested simulation with CCLM data as forcing.

For your own experiment you can create a new directory in cclm-sp/step_by_step/gcm_to_cclm/ or in cclm-sp/step_by_step/ccm_to_cclm/ by hand and copy the contents of gcm_to_cclm or cclm_to_cclm into that directory and change the experiment name in the scripts.

Downscaling simulation with GCM data (gcm_to_cclm)

Change into the gcm_to_cclm directory:

cd cclm-sp/step_by_step/gcm_to_cclm

You find the scripts run_int2lm and run_cclm in this directory. On Mistral add your project account in the line #SBATCH --account= in both scripts. First submit the run int2lm job:

sbatch run_int2lm

If the int2lm run is successful you can find the interpolated output data under the data directory cclm-sp/step_by_step/gcm_to_cclm/data/int2lm_output. After int2lm job completion you can submit the cclm job:

sbatch run_cclm

If the cclm simulation is successful you can find the output data under the directory cclm-sp/step_by_step/gcm_to_cclm/data/cclm_output.

Nested simulation (cclm_to_cclm)

CCLM driven by a CCLM on a coarser grid. To run a nested simulation the output of the gcm_to_cclm scripts is needed. Change into the cclm_to_cclm directory:

cd cclm-sp/step_by_step/cclm_to_cclm

You find the scripts run_int2lm and run_cclm in this directory. On Mistral add your project account in the line #SBATCH --account= in both scripts. First submit the run int2lm job:

sbatch run_int2lm

If the int2lm run is successful you can find the interpolated output data under the data directory cclm-sp/step_by_step/cclm_to_cclm/data/int2lm_output. After int2lm job completion you can submit the cclm job:

sbatch run_cclm

If the cclm simulation is successful you can find the output data under the directory cclm-sp/step_by_step/cclm_to_cclm/data/cclm_output.

 Before running a simulation on machines other than the DKRZ HLRE ”Mistral” and with other batch scripts; change the batch settings and execution call in the run_* scripts. You may also have to use another command than srun, e.g. qsub or llsubmit, to submit the job.