Welcome Our mission is to provide ground-based geomagnetic observations and data products of the highest quality.

the BCMT operates the French National Magnetic Observatory, located in Chambon-la-ForĂȘt (Loiret, France), a network of 18 overseas observatories and a network of 11 repeat stations in metropolitan France.
You will find on this site all the data collected (raw magnetic measurements as well as various data products derived from these measurements).

DOI for definitive data It is now possible to refer to BCMT variation and definitive data using Digital Object Identifiers:
doi:10.18715/BCMT.MAG.VAR (variation data),
doi:10.18715/BCMT.MAG.DEF (definitive data).
It provides a persistent way to access and cite magnetic BCMT datasets.

Franco-Chinese Observatory closure A light-train line opened in the city of Lanzhou, china, in April 2019. LZH magnetic observatory is now closed. Recordings will resume after the construction of new buildings 120Km away.