This page has been revised as of   to detail the AIFS file naming convention following operational implementation of AIFS Single v1 on 25 February 2025. These changes will take effect from the 06 UTC run.

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

S

Description

Stream & Type (where applicable)

AHigh resolution forecast Weather Parameter products (15-day)stream=oper, type=wp
BEnsemble forecast Weather Parameter products (15-day)stream=enfo, type=wp
CTropical Cyclone high resolution trajectory forecast products (HRES) (15-day)stream=oper/scda, type=tf
DHigh resolution forecast products - atmospheric data (HRES) (15-day)stream=oper (also scda for 06/18 if requested)
EEnsemble forecast products- atmospheric data (ENS) (15-day)stream=enfo (00/06/12/18)
FSubseasonal 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 
HSubseasonal re-forecast products - atmospheric data (ENS-extended) (46-day)stream=eefh/eehs (was enfh/efhs)
I

Ensemble reforecast products - atmospheric data (ENS) (15-day)

stream=enfh/efhs (new)

JEnsemble reforecast products - wave data (ENS) (15-day)stream=enwh/wehs (new)
LSeasonal forecasting system products - atmospheric data (SEAS)stream=mmsm/mmsf/mmsa
MHigh resolution post-processed forecast products for 'Thermofeel' parameters (15-day)stream=oper, type=fc (selected parameters only)
NSeasonal forecasting system products - wave data (SEAS-WAM) stream=wasf
OEnsemble forecast post-processed forecast products for 'Thermofeel' parameters (15-day)stream=enfo, type=pf/cf (selected parameters only)
PHigh resolution forecast - wave data (HRES-WAM) (15-day)stream=wave (00/12)
QHigh resolution forecast - high-frequency wave data (HRES-WAM) (15-day)stream=scwv (06/18)
SHigh resolution forecast - high-frequency atmospheric data (HRES) (15-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
VSubseasonal 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) (15-day)stream=enfo, type=em/efi/sot/ep
ZSubseasonal reforecast products - wave data (46-day)stream=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 in addition to a new MARS keyword ("model"), which identifies the AI model that produced the forecast. These MARS keys are combined with unique user identifiers such as Destination name and Feed name: 

  • User Destination name (i.e. ABC)
  • User Feed name (i.e. A1)
  • Model (e.g. aifs-single)
  • Class (e.g. ai) 
  • Stream (e.g. oper)
  • Type (e.g. fc or an)
  • Production date (YYYYMMDD)
  • Range/step
  • Valid date (YYYYMMDD)

Therefore, an example filename would be: 

Destination_Feed_Model_Class_Stream_Type_ProdDate_ValidDate_Step.grb
 
ABC_A1_aifs-single_ai_oper_fc_20250219T060000Z_20250219T060000Z_0h.grb