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This page describes the required steps to use OpenIFS/AC "v2ac-rc" on the ECMWF HPCF.

OpenIFS/AC compared to the standard OpenIFS model

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OpenIFS/AC consists of the standard OpenIFS model and the additional composition software package. Both components together are referred to as OpenIFS/AC (with AC standing for "atmospheric composition"). 

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Once the standard OpenIFS model code is unpacked, unpack package <package-name> into $OIFS_HOME, overwriting any pre-existing files from the standard model installation.

TO DO:  we need a separate code package for the OpenIFS/AC code that can be unpacked into the existing OpenIFS 43r3v2 source code distribution

Working with the git repository

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In order to build OpenIFS/AC one can use the standard environment settings for oifs43r3v2 can be used with the application of two changes:

• change OIFS_HOME to point to the installation of openifs-ac , (and not to the standard oifs43r3v2 distributionoifs43r3 installation)
• change OIFS_DATA_DIR to a bespoke path as the additional data packages will be added to the climate data files
• before compiling the model sources edit $OIFS_HOME/make/oifs.fcm to enable chemistry (which is by default disabled)

It is recommend for the first two changes to use a specific "soifsac" alias custom configuration script to set the environment variables.

Alternatively the settings can be enabled when running the prep scripts .Later, for that come with OpenIFS/AC:  For the t21 acceptance tests, the environment variables and paths are set within the oifs-config.<my_name>.sh which needs to be edited in the platform subdirectory. This is described below.

Obtaining additional data packages

• Download the additional data tarballs that are required for chemistry experiments:

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• Unpack the following files:  oifs-ac-43r3-chem.tgz and oifs-ac-43r3-xtra.tgz into $OIFS_DATA_DIR. This will result in the following directory structure:

The following files can be unpacked to a different any location (can be outside $OIFS_DATA_DIR):

• Unpack oifs-ac-43r3-initcond.tgz into a directory INITIAL-CONDITIONS. These files are initial data files for the model experiments.
• Unpack ICMCL-2010.tgz into a directory ICMCL. This directory contains monthly files with surface boundary conditions (e.g. SSTs, soil temps, albedos, LAI etc).

(Comment:  if we unpack these files into $OIFS_DATA_DIR there is no need for a 43r3 subdirectory.  Note the ifsdata, wam and rdata directories are missing and need to be copied over from a standard OIFS_DATA_DIR installation)

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Compile the model as usual using fcm:

(run first the configuration script that sets the environment)

cd $OIFS_HOME/make

fcm make -v -j 6 -f oifs.fcm

The code should compile without errors when using CCE compilers. Make sure the binaries will later not be accidentally overwritten by any future compiler runs; we save them in a custom directory:

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Run the acceptance tests

The model package offers various tests to check the basic functionality of the model and to verify that all paths to the data directories are correct and accessible.

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To check the model is working normally carry out the various acceptance tests in $OIFS_HOME/t21test and t21test_xios_t255ac.

This requires editing the wrapper scripts job.sh and setup-exp.sh by setting the path to the appropriate master.exe and by changing RUNCMD to to something appropriate for the platform.

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Now we can carry out the tests:

t21test:  

./job.sh -n 12 -t 2 -m ../make/cce-opt/oifs/bin/master.exe

If the oifs_run script (or the oiac_run script) is used without the --nomove option it produces an error at the end of the acceptance test, stating the ICMGGepc8+* files cannot be found. This refers to the copying of model output to output1 and the postprocessing and is therefore not relevant to the model functionality.

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