This refers to all the input files that the OpenIFS model needs to run:

• initial data to start a forecast (normally obtained from ECMWF);
• ifsdata and climate files (downloaded from the OpenIFS ftp site);
• model namelist (only parts of the OpenIFS namelist can be uploaded, see below)

These ancillary files are stored in a zipped format on the CPDN repository.

Experiment information is read from the initial files GRIB metadata upon upload to the OpenIFS@Home repository and used to set the experiment id, date/time of forecast etc.

Experiment namelist

It's not possible to upload a complete model namelist to the OpenIFS@Home website. This is because some restrictions are necessary in order for the model to work correctly and efficiently when running on a volunteer's computer.

At the time of writing, the only part of the model namelist allowed to be uploaded is the 'NAMFPC', or 'FullPos' namelist, which controls all the model's output.  Even this is vetted by CPDN first to ensure the model does not produce more output than can be reasonably handled by the volunteer's computer and network for transfer of the results back to the CPDN database.

Apart from the model's NAMFPC output control namelist, the rest of the namelist is selected as a 'template' when the experiment on OpenIFS@Home is configured. Namelist experiment templates exist for different resolutions and different classes of experiments; for example 10 day NWP forecasts, seasonal forecasts etc. For more details please see the OpenIFS@Home dashboard and documentation, or contact the CPDN team directly.