Early Access to GRIB edition 2 data

Users can now request model level data in GRIB edition 2 from the dissemination system.

• Dissemination of model level data in GRIB edition 2 is fully supported operationally.
• GRIB edition 1 and GRIB edition 2 can be mixed in the same dissemination file. Please contact Data and Services should you require to set up test dissemination streams.
• To request model level data in GRIB edition 2 from the dissemination system, the dissemination request should specify the keyword FORMAT=GRIB2
• Only model level data (LEVTYPE=ML) for streams OPER, ENFO, SCDA and ENFH can be requested in GRIB edition 2. The dissemination system will refuse GRIB edition 2 requests for other level types.
• The second order packing (PACKING=SO) is currently not available in GRIB edition 2.

• To decode and encode GRIB edition 2 data please download freely the grib_api library:

  http://www.ecmwf.int/products/data/software/download/grib_api.html

  All users of the ECMWF GRIBEX software are urged to migrate to using the ECMWF grib_api software. The recommended version is 1.8.0 or higher. Users of earlier grib_api versions are invited to upgrade their installation. Users of other GRIB decoding software need to make sure that they can decode the Centre’s GRIB edition 2 data.

  Please note that ECMWF is following the WMO recommendations for encoding data in GRIB edition 2, and does not use any specific local parameter tables. However, the current GRIB standard does not allow all of our parameters to be described and, for those parameters, we use experimental codes. These experimental codes have been submitted to the WMO for formal approval. Users of the grib_api library can use the shortName, name, units or paramId keys to access parameter information. This information is guaranteed to remain unchanged even if the GRIB codes for these parameters should change.

• To transform from GRIB edition 1 to GRIB edition 2 for model levels only, please make use of the grib1to2 tool which is available on all of the computing systems at ECMWF:

  usage:  grib1to2   in.grib1   out.grib2

  at this stage the tool is working only with ECMWF model level data (mars.levtype=ml, typeOfLevel='hybrid'). If data with type of level different from "hybrid" are processed the conversion tool fails printing an error message.