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  • The K-index scale summarises geomagnetic activity at an observatory by assigning a code, an integer in the range 0 to 9 (0 being the least active field and 9 the most active field) to each 3-hour Universal Time (UT) interval. K-Indices are available for Lerwick, Eskdalemuir, Greenwich, Abinger and Hartland Magnetic Observatories. From 1954-90 the values are hand scaled, from 1991 to the present day they are automatically scaled. The data not only aids scientific research into rates of change of the magnetic field and increases the accuracy of the BGS Global Geomagnetic Model, but also provides data to exploration geophysicists engaged in current and future oil exploration.

  • Offprints of articles relating to Geomagnetism from 1822 to 1981. Offprints collected by Kew Observatory, Meteorological Office, Edinburgh and Greenwich Observatory (Herstmonceux castle). The first page of each offprint has been digitised to produce a finding aid.

  • The aa index is a simple global geomagnetic activity index, with units of 1 nT (nanotesla), which is produced from the K indices from two approximately antipodal observatories. At present these are Hartland observatory in the UK and Canberra observatory in Australia. The main advantage in using aa indices for research purposes is that the time series spans further back (to 1868) than any of the other planetary indices time series.Also, up to date values are produced and made available weekly, giving nearer to real time availability than any other planetary index. In between the weekly updates, BGS calculates estimated aa indices, providing real time "nowcasts" which are updated on an hourly basis. These estimates are clearly marked with the letters "Est". Although calculated by the same method, the aa indices available on this service are not the definitive values. These are published by the International Service for Geomagnetic Indices, CRPE/CNET - CNRS, 4 Avenue de Neptune, F-94107 Saint Maur, Cedex, France.

  • Annual means of the geomagnetic field vector components from observatories around the world, from 1840 to the present day. At present there are about 160 observatories. These data are useful for tracking changes in the magnetic field generated inside the Earth. Data are produced by a number of organisations around the world, including BGS. Data are available in plain text from www.geomag.bgs.ac.uk. This data is connected to other geomagnetic data sets, but can be used without reference to them.

  • High frequency (100 Hz) data from two horizontal induction coils measuring the Earth's magnetic field at the Eskdalemuir Observatory in the United Kingdom. The data covers the period from January 2017 to September 2017. Also included are examples of Matlab code and the frequency calibration files to convert to the raw data to SI units. Thumbnail spectrograms and metadata about the setup and equipment is also supplied.

  • High frequency (100 Hz) data from two horizontal induction coils measuring the Earth's magnetic field at the Eskdalemuir Observatory in the United Kingdom. The data covers the period from January 2015 to December 2015. Also included are examples of Matlab code and the frequency calibration files to convert to the raw data to SI units. Thumbnail spectrograms and metadata about the setup and equipment is also supplied.

  • High frequency (100 Hz) data from two horizontal induction coils measuring the Earth's magnetic field at the Eskdalemuir Observatory in the United Kingdom. The data covers the period from January 2016 to December 2016. Also included are examples of Matlab code and the frequency calibration files to convert to the raw data to SI units. Thumbnail spectrograms and metadata are also supplied.

  • High frequency (100 Hz) data from two horizontal induction coils measuring the Earth's magnetic field at the Eskdalemuir Observatory in the United Kingdom. The data covers the period from January 2013 to December 2013. Also included are examples of Matlab code and the frequency calibration files to convert to the raw data to SI units. Thumbnail spectrograms and metadata about the setup and equipment is also supplied.

  • Hourly and minute means of the geomagnetic field vector components from observatories around the world from, respectively, 1883 and 1969, to the present day. At present there are about 160 observatories. These data are useful for tracking changes in the magnetic field generated inside and outside the Earth. Data are produced by a number of organisations around the world, including BGS. Data are available in plain text from www.wdc.bgs.ac.uk.

  • Magnetic time-series from the BGS SWIGS differential magnetometer method (DMM) systems. Funded by NERC, grant number: NE/P017231/1 "Space Weather Impact on Ground-based Systems (SWIGS)". These data consist of measurements of the Earth’s natural magnetic These data consist of measurements of the Earth’s natural magnetic field at the Abbey St. Bathans remote site (ASBR) and the natural magnetic field plus the field created by GIC at the Abbey St. Bathans underline site (ASBU). The database will include .xyz files with the DMM data and one document with metadata. See Hübert et al (2020) for further details.