ICON Training - Hands-on Session

Exercise 5: Programming ICON - Running ICON

../../../_images/ex05.png

ICON Training - Hands-on Session

Exercise 5: Programming ICON - Running ICON#

In this notebook, we will set up and submit an ICON job on Levante based on the setup from the previous Exercise 4: Running the ICON-LAM Setup. The output namelist will be amended by the new variable added to the code in Exercise 5: Programming ICON.

General preparations (from the previous exercise)#

Base directory for ICON sources and binary:

export SCRATCHDIR=/scratch/${USER::1}/$USER
export ICONDIR=$SCRATCHDIR/icon

Absolute path to directory with plenty of space:

export EXPDIR=$SCRATCHDIR/exercise_programming
if [ ! -d $EXPDIR ]; then
    mkdir -p $EXPDIR
fi

We start by preparing all the necessary data in the output directory. Note that the following block copies already prepared namelists icon_master.namelist, NAMELIST_ICON and a sbatch script into the output directory.

export SCRIPTDIR=$HOME/icon-training-scripts/exercise_programming
cp $SCRIPTDIR/prepared/icon_master.namelist $EXPDIR/
cp $SCRIPTDIR/prepared/NAMELIST_ICON $EXPDIR/
cp $SCRIPTDIR/prepared/icon-lam.sbatch $EXPDIR/

# directory with input grids and external data:
export GRIDDIR=/pool/data/ICON/ICON_training/exercise_lam/grids
# directory with initial data (takes reference data which is identical to the output of Ex. 4):
export DATADIR=/pool/data/ICON/ICON_training/exercise_lam/data_lam

cd ${EXPDIR}

# Link data needed for radiation
ln -sf ${ICONDIR}/externals/ecrad/data ecrad_data

# grid files: link to output directory
ln -sf ${GRIDDIR}/*.nc .
# data files
ln -sf ${DATADIR}/* .

# dictionaries for the mapping: DWD GRIB2 names <-> ICON internal names
ln -sf ${ICONDIR}/run/ana_varnames_map_file.txt .
ln -sf ${GRIDDIR}/../exercise_lam/map_file.latbc .

# For output: Dictionary for the mapping: names specified in the output nml <-> ICON internal names
ln -sf ${ICONDIR}/run/dict.output.dwd dict.output.dwd

Adding a new output namelist#

Exercise: Add the variable you have implemented into ICON to the following output namelist on regular lon/lat grid. 
cat >> $EXPDIR/NAMELIST_ICON << EOF
! output_nml: specifies an output stream --------------------------------------
&output_nml
 filetype                    = 4                     ! netcdf
 dom                         = 1
 output_bounds               = 0., 10000000., 3600.  ! start, end, increment
 steps_per_file              = 1
 mode                        = 1
 include_last                = .FALSE.
 steps_per_file_inclfirst    = .FALSE.
 output_filename             = 'Ex5_Diagnostic'
 filename_format             = '<output_filename>_DOM<physdom>_<datetime2>'
 output_grid                 = .FALSE.
 remap                       = 1                     ! 1: remap to lat-lon grid
 reg_lon_def                 = 0.8,0.1,17.2
 reg_lat_def                 = 43.9,0.1,57.7
 ml_varlist                  = ????????
/
EOF
Solution ml_varlist = 'process_id'

The ICON batch job#

Submit the job to the HPC cluster, using the Slurm command sbatch.

export ICONDIR=$ICONDIR
cd $EXPDIR && sbatch --account=$SLURM_JOB_ACCOUNT icon-lam.sbatch

Author info: Deutscher Wetterdienst (DWD) 2025 :: icon@dwd.de. For a full list of contributors, see CONTRIBUTING in the root directory. License info: see LICENSE file.

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