Magnetograms are records of variations in the strength and direction of the Earth’s magnetic field. Historically these magnetograms were recorded on paper using photographic techniques. In the UK, measurements were made at eight long-running observatories; Abinger, Eskdalemuir, Falmouth, Greenwich, Hartland, Kew, Lerwick, and Stonyhurst. BGS also hold magnetogram records from the Cape Evans observatory that ran continuously at Robert Falcon Scott’s Antarctic base camp during the British Antarctic Expedition 1910–13. The magnetogram collection, one of the longest running geomagnetic series in the world, provides a continuous record of more than 160 years of UK measurements. These magnetograms start in the 1840s and end in 1986 at which time digital recording of the magnetic field took over and magnetograms can be produced by computer graphic. The plots show variation in the Earth's magnetic field, typically over a 24-hour period. The collection is a valuable, partly untapped data resource for studying geomagnetic storms, space weather and the evolution of the Earth’s magnetic field. The magnetograms provide insight into: • the Earth’s outer core: long-term change (years to centuries) in the dynamo that sustains our magnetic field • space weather: short-term changes (seconds to days) in near-Earth space and on the ground • space climate: long-term change (decades to centuries) in solar activity and consequences for Earth’s environment All the above have an impact on human activities. For example, bad space weather affects technologies that we increasingly rely on, such as electrical power and GPS networks. In response to the threat of loss from degradation due to age and a desire to preserve and exploit old data, BGS undertook a programme of work to digitally photograph, archive and preserve the analogue paper records of magnetic field variation in the United Kingdom. Between 2009 and 2013, high-quality digital images of every available magnetogram were taken. These images are available to search online. Scientists and the general public around the world can now gain easy access to this historical dataset.
Stonyhurst Magnetic Observatory magnetograms