Specifies the packing method used in the target GRIB messages. 


Valid values for latitude/longitude output are simple packing (simple), second order (so) or, for GRIB2 gridded fields only, CCSDS (ccsds). Valid values for spectral fields are complex packing (co) or simple packing (simple).

The default packing types for gridded data 

Input field 

MARS output packing type 
(with keyword grid=... )

Dissemination output packing type 
(with keyword grid=... )

GRIB1/GRIB2 griddedinherited from inputinherited from input
GRIB1 SHsimplesimple

To preserve the packing of the archived data one would specify archived value (packing = av).