Code and configuration
OpenIFS is based on ECMWF's IFS (Integrated Forecast System) code. The first version of OpenIFS is based on Cycle 38R1, the operational model introduced in June 2012 (it has since been superceded for operations)
IFS CY38R1 comprises approximately 1.3 million lines and 5200 files. OpenIFS comprises roughly 0.5 million lines in 2600 files. OpenIFS is designed to be easy to install on external computer systems.
Although the IFS can be run in a number of configurations, OpenIFS only supports forecast mode (NCONF=1) and interpolation mode (NCONF=927).
Scientific capability
OpenIFS includes all the same forecasting capability of IFS but without any data assimilation. OpenIFS & IFS are the same with respect to:
- Hydrostatic dynamical core.
- ECMWF physics parametrization scheme.
- ECMWF land surface model.
Unlike IFS, OpenIFS does not include:
- 4D-Var and any observation handling.
- Non-hydrostatic dynamics.
- Adjoint / tangent-linear versions.
- Ocean model.
- Wave model.
- Ability to output Arpege file formats, only GRIB output is supported.
Support
Only operational configurations of IFS at ECMWF will be supported and for which documentation is available. Although we may endeavour to provide help on non-standard or untested configurations we cannot provide direct support for them.
Acknowledgements
The dynamical core IPR is shared with MeteoFrance and collaborators. The IPR of the 'fullpos' and 'ddh' packages in OpenIFS are acknowledged as held by MeteoFrance and we thank our colleagues for permission to include it in OpenIFS.