COMMON CODE TABLE C-1: Identification of originating/generating centre
COMMON CODE TABLE C-12: Sub-Centres of Originating Centres
COMMON CODE TABLE C-13: Data sub categories of categories defined by entries in BUFR Table A
Table A: data categories
Apparently C-11 is the same as C-1, but C-11 is for GRIB and C-1 is for BUFR