GRIB data is archived in one of the following spatial coordinate systems : 

  • Spherical Harmonics (SH) - Upper air fields.
  • Gaussian Grid (GG) - Surface and some upper air fields.
  • Latitude/Longitude (LL) - ECMWF wave data and data from other Centres.

The correspondence between the three types of grid resolutions is here.

See also

All gaussian grids (PDF)

Forecast User > Introducing the octahedral reduced Gaussian grid > Gaussian grids