A. The 'CY' refers to the model 'cycle'. The 'R' refers to the IFS model release. The 'v01' refers solely to OpenIFS and is the version of OpenIFS based on that IFS cycle and release. ECMWF and Meteo-France jointly develop the IFS model. A new cycle is formed when the two centres merge their code changes, typically about once a year. A model release is specific to ECMWF (the 'R' actually represents 'Reading,UK') and there are usually at most 2 or 3 releases of the model before a new cycle is produced from the next merge with Meteo-France. The version number refers just to OpenIFS. As OpenIFS model versions have a much longer lifetime than IFS versions, OpenIFS is periodically updated with: technical changes for new compiler versions, new hardware, bugfixes from more recent IFS releases, new functionality and so on. Changes to the version number will not alter the model's results. Only changes to the cycle and release number will alter the scientific results from the model. |