...
General requirements
Encoding format
- Participating Centres are expected to produce output fields in GRIB2 data format and with consistent units. All data must be encoded following the below rules in the paragraph Encoding details. For more general information about GRIB2 format please refer to WMO Manual on Codes WMO GRIB2 data format.
Missing values
- Bitmaps shall be used to indicate missing values
...
- The fields have to be provided on a regular latitude‐longitude grid at the resolution that is best matching the native resolution of the direct model output.
- Grids are defined in GRIB2 using an accuracy of 1/1000000 (one millionth) of a degree.
- If several limited areas will be provided they should be merged into one larger area on a regular lat-lon grid, with a missing value indicator in the grid-points not covered.
GRIB2 encoding
All data must be encoded following the required rules described below to achieve fully compliant LC-WFV format from all centres.
Encoding software
ECMWF makes available a GRIB decoding library (ecCodes) for the benefit of the WMO community. ecCodes can be freely downloaded from here and the documentation can be found here. EcCodes provides a simplified access to GRIB2 headers through a set of virtual keys documented here
For more general information about GRIB2 format please refer to WMO Manual on Codes .
Encoding details
Parameters
...