Observatory Monthly Means Database

The Geomagnetism team of the British Geological Survey (BGS) maintains a database of monthly mean values from geomagnetic observatories worldwide.

The monthly means are compiled from a combination of definitive hourly data records held in the World Data Centre for Geomagnetism (Edinburgh), and near-definitive minute data held by INTERMAGNET and Tromsø Geophysical Observatory.

The data have been converted to a standardised and unified format and joined into a single series for each observatory, with all recorded baseline changes applied and known anomalous data removed.

Data are provided in a file format designed after the IAGA2002 format. A full description of the data files can be found in the database.

Data Usage Rules

The data held in the database are for scientific/academic use only. For commercial applications of these data, please contact the relevant observatory operating institute directly. See the "List of Magnetic Observatories" maintained on behalf of IAGA Div V-OBS for the details of operating institutes.

Data Acknowledgement

If data are used in publications and presentations, the observatory operating institute, data supplier (WDC, INTERMAGNET, TGO), and the WDC for Geomagnetism (Edinburgh) should be acknowledged.

Data Access

The database can be accessed at ftp://ftp.nmh.ac.uk/geomag/OMM.