Code and configuration
OpenIFS is a version of the full IFS (Integrated Forecast System) code. OpenIFS is based on Cycle 38R1, the current operational model as of December 2012.
IFS CY38R1 comprises approximately 1.3 million lines and 5200 files. OpenIFS comprises roughly 0.5 million lines in 2600 files. OpenIFS uses the FCM build software from the UK Met Office to configure and compile the model and 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 and converting the resolution of initial data (NCONF=1 and 927).
Scientific capability
OpenIFS essentially includes the forecasting capability of IFS but without any data assimilation. OpenIFS & IFS are the same for:
- Dynamical core with semi-Lagrangian advection; finite difference/element vertical scheme.
- ECMWF physics parametrization scheme.
- ECMWF land surface model.
- ECMWF wave model.
Unlike IFS, OpenIFS does not include:
- 4D-Var and any observation handling.
- Non-hydrostatic dynamics.
- Adjoint / tangent-linear versions.
- Ocean 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. 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.