BCMT - Vincent LESUR






EOST Jean-François GIRARD


OSU responsible: IPGP Web site: Data distribution: All observatory magnetic data are freely available and currently distributed through: BCMT: ( INTERMAGNET Web site ( WDC for Geomagnetism in Edinburgh (, Boulder ( and Kyoto (; Summary: The Bureau Central de Magnétisme Terrestre (BCMT) is a French organisation founded in 1921 and attached to the Institut de Physique du Globe de Paris (Paris IPGP). The primary mission of the BCMT is to provide ground geomagnetic observations of the highest quality to the scientific community, in France and abroad. The recorded data allow studying, on time scales ranging from seconds to decades, all contributions to magnetic field measurements -- e.g. magnetic fields generated in the core, the ionosphere and the magnetosphere. The BCMT also serves industrial, military and societal users, provided their needs are aligned with scientific needs. Two French institutions are involved in BCMT operations, IPGP and Ecole et Observatoire des Sciences de la Terre (EOST) in Strasbourg. Several other institutions, including CNRS-INSU and the Institut Polaire Français (IPEV), provide financial and/or human support. An international scientific council, set up in 2009, meets every two years to review BCMT activities and to provide advices and recommendations to the BCMT. To achieve its mission, the BCMT operates a network of 17 magnetic observatories distributed on 6 continents, including the National Magnetic Observatory located in Chambon la Forêt, Loiret. It also operates repeat and variometer station networks in metropolitan France. The BCMT observatories are run under the INTERMAGNET quality standards, and currently five of its observatories are part of this international network. BCMT observatories contribute to filling geographical gaps in scientifically interesting locations. The BCMT develops its own line of dedicated instruments, taking advantage of the Chambon la Forêt site where unique testing and calibration facilities are available. Several data products are distributed by the BCMT: preliminary one-second or one-minute data in real time (less than 5 min, 9 observatories) or near real time (less than 24 h, all observatories); quasi-definitive data with a one-month delay and definitive data with a one-year delay; repeat station data products such as a declination map and finally geomagnetic indices. BCMT data are available on its webpage (, and through other databases as the INTERMAGNET’s webpage (

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Dernière validation de la BDD : lundi 5 février 2024