This page has been revised as of   to introduce the new naming convention for AIFS data available via dissemination.  

AIFS data is due to be released via dissemination in April 2024. 

Naming convention - IFS data 

The following dissemination filename convention is used for the transmission of ECMWF dissemination products:

 ccSMMDDHHIImmddhhiiE where:

  • cc is Dissemination stream name
  • S is dissemination data stream indicator
  • MMDDHHII is month, day, hour and minute on which the products are based
  • mmddhhii is month, day, hour and minute on which the products are valid at
    • ddhhii is set to “______” for Seasonal Forecasting System products
    • ii is set to 01 for high resolution forecast time step zero, type=fc, step=0
  • E is the Experiment Version Number’ (as EXPVER in MARS, normally 1)

Dissemination data stream indicator



Stream & Type (where applicable)

AHRES Weather Parameter products (10-day)stream=oper, type=wp
BENS Weather Parameter products (15-day)stream=enfo, type=wp
CTropical Cyclone high resolution trajectory forecast products (HRES) (10-day)stream=oper/scda, type=tf
DHigh resolution forecast products - atmospheric data (HRES) (10-day)stream=oper (also scda for 06/18 if requested)
EEnsemble forecast products- atmospheric data (ENS) (15-day)stream=enfo (00/06/12/18)
FExtended range forecast products - atmospheric data (ENS-extended) (46-day)stream=eefo (was enfo)
GEnsemble forecast products - high-frequency wave data (ENS-WAM) (15-day)stream=waef 
HExtended range re-forecast products - atmospheric data (ENS-extended) (46-day)stream=eefh/eehs (was enfh/efhs)
IEnsemble re-forecast products - atmospheric data (ENS) (15-day)stream=enfh/efhs (new)
JEnsemble re-forecast products - wave data (ENS) (15-day)stream=enwh/wehs (new)
LSeasonal forecasting system products - atmospheric data (SEAS)stream=mmsm/mmsf/mmsa
NSeasonal forecasting system products - wave data (SEAS-WAM) stream=wasf
PHigh resolution forecast - wave data (HRES-WAM) (10-day)stream=wave (00/12)
QHigh resolution forecast - high-frequency wave data (HRES-WAM) (10-day)stream=scwv (06/18)
SHigh resolution forecast - high-frequency atmospheric data (HRES) (10-day)stream=scda
TTropical Cyclone ensemble trajectory forecast products (ENS)stream=enfo, type=tf
UEnsemble forecast post-processed products - wave data (e.g. ensemble means, extreme forecast indices)stream=waef, type=em/efi/sot/ep
VExtended range forecast products - wave data (ENS-WAM-extended) (46-day)stream=weef (was waef)
WEnsemble forecast products - wave data (ENS-WAM) (15-day)stream=waef 
XEnsemble forecast products - high-frequency atmospheric data (ENS) (15-day)stream=enfo 
YEnsemble forecast post-processed products - atmospheric data (e.g. ensemble means, extreme forecast indices)stream=enfo, type=em/efi/sot/ep
ZExtended  range re-forecast products - wave datastream=weeh/wees (was enwh/wehs)

File format

Most products are encoded in WMO FM-92 GRIB edition 1, unless otherwise specified in our Catalogue of Real-time products

  • Product subset I-i-c (High Resolution Atmospheric model), III-i-c (Ensemble Atmospheric model): Model level parameters encoded in WMO FM-92 GRIB edition 2
  • Product subsets I-ii, III-iv (Time Series of Weather Parameters) and Products subsets I-iii, III-viii (Tropical Cyclones), encoded in WMO FM-94 BUFR



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Naming - AIFS via dissemination 

Taking into account user feedback, ECMWF has chosen to implement a new naming convention for the AIFS data via dissemination.  

This only applies to AIFS data via Dissemination.  Later, ECMWF may implement this for the IFS data also. We would welcome your feedback on this new naming convention.  

The composition of the file will be comprised of MARS standard information such as class, stream, type but combined with unique user identifiers such as Destination name and Feed name: 

  • User Destination name (i.e. ABC)
  • User Feed name (i.e. A1)
  • Class (e.g. ai) 
  • Stream (e.g. oper)
  • Type (e.g. fc or an)
  • Production date (YYYYMMDD)
  • Range/step
  • Valid date (YYYYMMDD)
  • Experiment version (usually 0001 for current operational cycle) 

Therefore, an example filename would be: