Remove Tödi from install instructions

docs/models/icon/usage.md

@@ -69,21 +69,27 @@ srun -N 1 -c 12 --mem-per-cpu=20G spack install -v -j 12
 ```
 
 
-### Todi
+### Säntis
 
-!!! construction "Under construction - last update: 2024-09-20"
+!!! construction "Under construction - last update: 2024-12-18"
 
     Information on this section is not yet complete nor final. It will be updated following the progress of the Alps system deployment at CSCS and C2SM's adaptation to this new system. Please use the [C2SM support forum :material-open-in-new:](https://github.com/C2SM/Tasks-Support/discussions){:target="_blank"} in case of questions regarding building ICON on Alps.
 
-On Todi, Spack is also used to build ICON. However, there is no suitable `spack.yaml` file present for the Spack environment. Therefore, create a `spack.yaml` file and use the software stack upstream provided by the user environment.
+Currently, the same ICON user environment used on `todi` is being used. Since the environment is still linked to `todi`, you need to export the `CLUSTER_NAME` to `todi` for now:
+
+```bash
+export CLUSTER_NAME=todi
+```
+
+Next, follow the instructions to build ICON using Spack below.
 
 **1. Create a `spack.yaml` file**
 
 Create the following files from the ICON build folder (different to the ICON root folder in case of a out-of-source build).
 
 For CPU compilation:
 
-=== "config/cscs/spack/v0.21.1.3/todi_cpu_nvhpc/spack.yaml"
+=== "config/cscs/spack/v0.21.1.3/santis_cpu_nvhpc/spack.yaml"
 
   ```yaml
   spack:
@@ -101,7 +107,7 @@ For CPU compilation:
 
 For GPU compilation:
 
-=== "config/cscs/spack/v0.21.1.3/todi_gpu_nvhpc/spack.yaml"
+=== "config/cscs/spack/v0.21.1.3/santis_gpu_nvhpc/spack.yaml"
 
   ```yaml
   spack:
@@ -131,18 +137,11 @@ git clone --depth 1 --recurse-submodules --shallow-submodules -b ${SPACK_TAG} ht
 
 # Build ICON
 cd /path/to/icon-build-folder
-spack env activate -d config/cscs/spack/${SPACK_TAG}/todi_gpu_nvhpc
+spack env activate -d config/cscs/spack/${SPACK_TAG}/santis_gpu_nvhpc
 spack install
 ```
 
 
-### Santis
-Please follow the instructions for Todi, but run the following before loading the ICON user-environment:
-
-```bash
-export CLUSTER_NAME=todi
-```
-
 ## Run test case
 In the *run* folder, you find many prepared test cases, which you can convert into run scripts. To generate the runscript of one of the experiment files, e.g. *mch_ch_lowres*, you can use the `make_runscripts` function.