README.md

Climate Modelling Lab, MSc Meteorology S2025 (280351 VU)

Recipe for lecturer: generate a tarball with the icon model code for distribution to students

Work with VSC account avoigt_teach.

Get model code, use branch climmodlab_s2023:

git clone https://gitlab.phaidra.org/climate/icon-esm-univie.git
git checkout origin/climmodlab_s2023

Configure following the recipe for the students below. Then create a distribution tarball:

make dist

This leads to the file icon-2.6.0.tar.bz2, which can be distributed to the students.

VSC reservation info and usage

To check the reservation:

scontrol show reservation=p72044

To use the reservation on the command line:

--reservation=p72044

To use the reservation in a job script:
#SBATCH --reservation=p72044

Recipe for students: how to get, configure and compile ICON on VSC4

Reserve a node for interactive use, do not work on the login nodes. See VSC Wiki.

salloc -N 1 --qos=skylake_0096 --partition=skylake_0096 --reservation=p72044 --exclusive -t 2:00:00

The ssh into the reserved node. You can check the reserved node with

squeue -u $USER

Get and untar the tarball and enter the model code directory:

cp  /gpfs/data/fs72044/avoigt_teach/icon-2.6.0.tar.bz2 /gpfs/data/fs72044/iconXY
tar xfv icon-2.6.0.tar.bz2
mv icon-2.6.0 icon-esm-univie
cd icon-esm-univie/

Configure the model, using MPI parallel communication (this step typically takes several minutes):

config/vsc/vsc4.intel-intelmpi_spack --enable-mpi

You can check for a successful configure step by looking at the last line of the file config.log. This line should read configure: exit 0.

Load the libraries that are needed for compilation of the model:

spack load /xg435ds  # intel-oneapi-compilers@2022.2.1 linux-almalinux8-skylake_avx512 / gcc@9.5.0
spack load /p7jisxw  # intel-oneapi-mkl@2022.2.1 linux-almalinux8-skylake_avx512 / intel@2021.7.1
spack load /6a7vghr  # netcdf-fortran@4.6.0 linux-almalinux8-skylake_avx512 / intel@2021.7.1
spack load /kqslczm  # libxml2@2.10.1 linux-almalinux8-skylake_avx512 / intel@2021.7.1
spack load /tlvfj62  # eccodes@2.25.0 linux-almalinux8-skylake_avx512 / intel@2021.7.1

Compile the model, using 8 cores for faster compilation (this step typically takes several minutes):

make -j 8

A successful compilation should end with the following lines printed to screen

FCLD bin/icon

support/util_file.o: In function `util_tmpnam':

/home/fs72044/avoigt_teach/climlab_s2024/icon-esm-univie/support/util_file.c:63: warning: the use of tmpnam' is dangerous, better use mkstemp'

make[1]: Leaving directory '/home/fs72044/avoigt_teach/climlab_s2024/icon-esm-univie'

The compilation leads to the binary bin/icon.

Running an AMIP-like simulation

A runscript for an AMIP-like simulation is available in runs/amip/, the run script is exp.amip.run. The script is written for user avoigt_teach and needs to be adapted accordingly for others users (e.g., replacing avoigt_teach where needed and adapting some of the directory names.)

The simulation is AMIP-like because SSTs, sea ice etc. are prescribed as climatological averages and are the same for each year.

Examples for boundary data remapped to a regular 360x180 deg lon-lat grid

See the directory boundary-data-remapped.

Analysis

Example notebook for icon nextgems data is in analysis/icon-nextgems/.

Preparing ICON-ESM input data

On Teachinghub, see ~/LEHRE/msc-climmodlab-s2025/icon-r2b4-inputdata for how the icon R2B4 grid looks like and how the SST and sea ice files look like.

CDO might be helpful to remap from the Healpix grid to the R2B4 grid.