Introduction

This page describes the files typically found in an OpenIFS 43r3 experiment. Experiment files are provided by the OpenIFS team at ECMWF as gzipped tarfile. These files provide initial and boundary conditions and currently are provided on request to the user for download via ftp.ecmwf.int.

Note that the experiment ID forms part of the name for all binary ICM* GRIB files. The experiment ID is also stored inside each GRIB file. Grib tools can be used to modify the experiment ID if required. Users should not just copy the files to a new name.

Other Files in the Experiment Directory

The experiment directory contains the initial data files described above. Moreover, other files and symbolic links are created when the model is run for the first time.

How do I start the experiment?

If all the environment variables are set and the symbolic file path links exist and are valid, the experiment could in principle be started by executing the model binary master.exe with appropriate command line parameters, as it is done in the oifs_run script:

master.exe -r -e -n

In practice this method is not recommended.  It is far better to make use of the provided service script oifs_run which verifies all the settings and if necessary creates the missing links. It calls the executable by invoking the MPI environment (which may well be hardware dependent) and will initiate postprocessing of the experiment results by moving the Grib model output to a target directory and concatenates according to time step. oifs_run can be called with command line parameters which are passed on to the model executable. If no command line parameters are provided oifs_run will substitute with default values for experiment ID, grid resolution, number of tasks and threads, etc. which are likely to be of no use. Therefore the command line parameters need to be set. By calling oifs_run the model will run interactively in the login shell.

oifs_run -r -e -n

Passing on the appropriate command line parameters can further be simplified by writing a brief job script which itself calls oifs_run with the required parameters. This job script is either run.ccb or run.ws.  run.ccb is a batch script which can be submitted to the Cray PBS schedule using the qsub ./run.ccb command.  run.ws is a shell script which can be called interactively from the command line and simply calls oifs_run.