The WDC is providing access to the PCN index calculated from DTU Space's geomagnetic data from Qaanaaq geomagnetic observatory in northern Greenland. Note that in August 2013, the International Association of Geomagnetism and Aeronomy (IAGA) has endorsed the PC index as proposed by AARI and DTU Space. This endorsed index is currently being implemented on the WDC websites and will be fully accessible in the near future. Until then, the WDC has an ftp-server to distribute the traditional (i.e. not IAGA-endorsed version of the) Northern PC index (description) derived from the geomagnetic observatory Qaanaaq (THL) and the Kp-index data products derived at the geomagnetic observatory Niemegk (NGK).
The WDC is also holding extensive archives of magnetograms and other geomagnetic observatory data products that predate the introduction of digital data recording. The material is in analogue form such as film or microfiche.
Catalogues (pdf) of the WDC Copenhagen analogue data archive
The WDC Copenhagen was established for the International Geophysical Year in 1957 at the Danish Meteorological Institute. The Geomagnetic Data Master Catalogue of hourly and 1-minute means of the geomagnetic observatories was developed at WDC Copenhagen and moved to WDC Edinburgh at BGS in 2007.
The WDC Copenhagen is maintained by DTU Space from 2010 onwards. The WDC Copenagen is accredited by ICSU World Data System (ICSU-WDS).