Setting up a new domain

The following files are domain specific and have to be created for a new domain:

As an example the CORDEX South-East Asia domain is taken. You can see this example at the end of each step.  

Step 1
If you already have a netCDF file that holds the rotated coordinate information for your desired domain you can use this for your TARGET_GRID and proceed to step 2.
Choose the region with the interface WebPEP@DKRZ. There is no need to take account of extra grid boxes at the boundaries (e.g. for a sponge layer). Then click the "create grid" button. In a new window you will get the cfu command you can use to create your grid file. The cfu command is the one that is distributed with the SPICE scripts.
The grid file is your TARGET_GRID file.

Example

CORDEX South-East Asia domain SEA-44

Select the domain in WebPEP-go	Open
Shown after you click the "create grid" button	Open
Create the rotated grid file SEA-44_rotated.nc on your system	cfu create_rotgrid 89.15 -15.07 0.44 0.44 132 97 0 90 180 SEA-44_rotated.nc

You have now created your target grid file:

TARGET_GRID=SEA-44_rotated.nc

Step 2
If you already have the appropriate RxxByy values for your ICON simulation you can skip to step 3.
You can use the R and B finder tool to find the R and B values nearest to the grid mesh width you choose in step 1.

Example

CORDEX South-East Asia domain SEA-44

A grid width of 0.44 degrees gives 48.88884 km (=0.44*111.111)

Open

Step 3

In order to make it easier for you to create the ICON grid that covers your desired domain with the Zonda, you may use the cfu command

see SPICE documentation for an explanation of this command.
The input file is the grid file you created in step 1.

Step 4
The files for LAM_GRID, PARENT_GRID, EXTPAR will now be created by the Zonda. You can use the information you have got in steps 3 and 4 for this. 

Example

CORDEX South-East Asia domain SEA-44

Visit the Zonda and put in the numbers you got from the previous steps. For the parent grid you set R13B02 in our case, i.e. one number less in B.

Put in the R and B values for your grid and the name for the output files.	Open
Use the output of the cfu icon_domain command to fill out the domain values. The parent_id can be set to 0.	Open
Optionally you can select different datasets than the default for the external parameter file. it_cl_type option 2 ('old and coarse…') is recommended.	Open
Copy the json code, which is created below the input section by using the ‘Copy and submit request' button. Confirm your request by pressing ‘Open request’ - a GitHub account is required. Follow the instructions of the created GitHub issue.	Open

You will receive an email when the data are ready including a description how to download them. In this example case you will receive the following data files and folders:

SEA-44_DOM01.html SEA-44_DOM01.nc SEA-44_DOM01.parent.nc SEA-44_DOM01_external_parameter.nc logs/ namelists/

Step 5

In case the external data file is in netCDF4 format the data file may have to be transformed into netCDF3. This depends on the CDO version you use. CDO versions from 2.x onwards can read netCDF4. Check with

and transform with

Step 6

Copy the mandatory files into your grid description directory.

Step 7

Adjust the valid range of output variables to your domain and/or resolution for samovar checks. For certain regions adapted lists are already given, e.g. samovar_EUR-11.csv and samovar_ts_EUR-11.csv