Make use of YAC's metadata channel
YAC 3 now has a way to add metadata to each fields at definition. For reguar output coupling some of these metadata (the NetCDF part) is already provided in ICON (cf. src/coupling/mo_output_coupling.f90
). This needs to be extended by the relevant GRIB metadata (for the parameter, horizontal grid, and vertical levels). Also, for coupling output_nml results, the metadata side from ICON needs to be added.