GISTEMP uses GHCN-M 3, but does not use the GHCN-M 3 metadata. Instead, it uses its own metadata, plainly derived from the GHCN-M 3 metadata, by an unpublished program, and then apparently refined by hand.
1. There are the following changes, which look manual to me.
1.1. station name corrections:
14168902000 TRISTAN DA CU -> TRISTAN DA CUNHA
14361998000 PORT-AUX-FRAN -> PORT-AUX-FRANCE, KERGUELEN
21135700000 GUR'EV -> ATYRAU
30485585000 ISLA JUAN FER -> ISLA JUAN FERNANDEZ
30489056000 CENTRO
MET.AN -> CENTRO
MET.AN, Marsh
40371964000 WITHEHORSE, Y -> WHITEHORSE, Y
63826063000 ST.PETERBURG -> ST.PETERSBURG
64308160000 ZARAGOZA/AEROPUERTO -> ZARAGOZA/AEROPUERTO SPAIN
64502590000 VISBY FLYGPLA -> VISBY AIRPORT SWEDEN
70089055000 CMS"VICE.DO.M -> CMS_VICE.DO.Marambio
70089061000 PALMER STATIO -> PALMER STATION
70089066000 BASE SAN MART -> BASE SAN MARTIN
1.2. elevation entries, replacing 'missing data' markers of -999:
30188963000 13
70089009000 2835
70089055000 198
70089059001 10
70188968000 6
1.3. other metadata, replacing blank metadata entries. Some of this is evidently fake (indeed the TOPO and STVEG columns are all explicitly 'fake')
42500021514 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500026353 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500035512 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500091500 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500100803 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500101956 -9U 132fakeLA-9x-9COOL GRASS/SHRUBC
42500105685 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500106305 -9U 624fakeno-9A-9WARM DECIDUOUS C
42500116738 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500141867 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500147542 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500150381 -9S 12fakeno-9x-9WARM GRASS/SHRUBB
42500153762 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500170814 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500171628 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500180700 44S 15fakeCO 1x-9WATER B
42500185718 2690U 2342fakeno-9A 3WARM CROPS C
42500196783 25U 25fakeCO25x-9COOL FOR./FIELD C
42500198757 56U 50fakeCO25x-9COOL FOR./FIELD C
42500199316 56S 13fakeCO25x-9COOL FOR./FIELD C
42500210252 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500213303 -9S 11fakeno-9A-9WARM DECIDUOUS B
42500215175 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500244364 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500247318 -9S 12fakeno-9x-9WARM GRASS/SHRUBB
42500248569 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500258133 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500270706 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500288816 -9S 109fakeno-9x-9COOL FIELD/WOODSB
42500292608 -9S 12fakeno-9x-9WARM GRASS/SHRUBB
42500300023 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500302060 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500302129 -9S 11fakeno-9A-9WARM DECIDUOUS C
42500304996 -9S 12fakeno-9x-9WARM GRASS/SHRUBB
42500308737 -9S 12fakeno-9x-9WARM GRASS/SHRUBB
42500318694 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500321408 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500332098 -9S 12fakeno-9x-9WARM GRASS/SHRUBB
42500364896 -9S 12fakeno-9x-9WARM GRASS/SHRUBB
42500367029 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500416794 -9S 26fakeno-9x-9WARM CROPS C
42500422726 -9S 12fakeno-9x-9WARM GRASS/SHRUBB
42500425477 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500426135 -9S 12fakeno-9x-9WARM GRASS/SHRUBB
42500427559 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500427729 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500437607 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500437612 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500451630 -9S 12fakeno-9x-9WARM GRASS/SHRUBB
42500451939 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500453222 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500455224 -9S 12fakeno-9x-9WARM GRASS/SHRUBB
42500457267 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500466989 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500467029 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500469610 -9S 12fakeno-9x-9WARM GRASS/SHRUBB
42500475808 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500480552 -9R -9fakeno-9A-9WARM DECIDUOUS A
42500481840 -9S 12fakeno-9x-9WARM GRASS/SHRUBB
64308160000 288U 449HIxxno-9A10WARM GRASS/SHRUBA
2. There are two new integer columns at the end of every row. The first takes 134 different values from 0 up to 186. The second takes the two values 0 and 90. I suspect these are something to do with rural/urban classification, possibly using satellites. Note that in earlier versions of GISTEMP, there were two fields here, us_light and global_light, which were similarly GISS-specific.
--
Nick Barnes, Climate Code Foundation,
http://climatecode.org/