Create forcings for the CCLM model with int2lm
Contents
Create forcings for the CCLM model with int2lm¶
The int2lm tool enables creating regional forcings for the Cosmo-CLM model from coarse global model data or reanalysis data. See https://www.cosmo-model.org/content/model/documentation/core/int2lm_2.08.pdf for more information and/or ask the CLM community.
Prerequisites¶
Set up a destiantion (e.g. on the HLRN in Göttingen) as described in First use.
Note that you might only clone and build the tools/I2LM component for this use case.
As a starting point you can take the example setup I2LM_example from the file SETUPS.example (or the corresponding example on your favorite target machine).
This example can be used to create CCLM forcings over the Eurocordex domain on an 0.22°x0.22° grid using the ERA-Interim reanalysis data. If you want to do something else, you have to make some adaptions in the setup.
Make your adaptions¶
Global settings¶
Once you set up your destination, go there and change to the input directory.
Here you find the file global_settings.py it has the same format as for other use cases.
How to set it up can be found in Setting up the global_settings.py.
Jobscript¶
Follow the steps described in Setting up your jobscript template.
Local settings¶
In the folder input/I2LM_Eurocordex the file local_settings.py can be found (note that the input folder might be renamed as I2LM_<your_domain> according to the domain you want to process).
Here you have to modify the database from where the coarse data is taken for the interpolation.
First, choose a file with the external fields for the CCLM run you want to perform.
In the example setup this looks like:
####################################################
# Local settings for the int2lm run #
####################################################
###################################
# Data base #
###################################
# name of the used climatology file
climatology_file = "climatology_cD3_0220.nc"
# path to the climatology file, if empty it is assumed relative to this directory
climatology_dir = ""
TODO: Explain where or how to get the climatology files.
Second, specify where to find coarse data that will be interpolated, e.g.
# path to the coarse grid data, if empty it is assumed relative to this directory
# in this directory the data should be in subdirectories called yearYYYY (e.g. year1980)
coarse_data_dir = "/scratch/usr/mviowmod/DATABASE/CCLM_FORCING/ERAI"
# prefix of the coarse data files, this might be either "cas" or "caf"
coarse_data_pref = "caf"
These so-called caf or cas files can be found at the DKRZ servers for a few global models and reanalysis data, see https://redc.clm-community.eu/projects/data/wiki/Initial_and_Boundary_Data and/or ask the CLM community.
Input of the int2lm tool¶
The main input of the int2lm tool is the file INPUT in input/I2LM_Eurocordex.
How to set it up correctly can be found in the original documentation https://www.cosmo-model.org/content/model/documentation/core/int2lm_2.08.pdf.
Importantly, variables that have the value *auto* in the example setup will be overwritten when the job is running and you do not have to set them manually.