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Observing magnetic fields: 100 years of data

Marking the centenary of the Lerwick Geophysical Observatory.

Variometer hut at the Lerwick Magnetic Observatory, designed in 1921
Variometer hut at the Lerwick Magnetic Observatory, designed in 1921. BGS © UKRI.

In scientific fields, a lot changes over the course of 100 years. From our understanding of how the world works to the tools that we use to measure data, very little stays the same. For that reason, it is important to celebrate things that have remained constant through that time and supported scientific learning and exploration for generations. One such thing is the Lerwick Geophysical Observatory, which recently celebrated its centenary — albeit one year late due to COVID-19 delays.

The Lerwick Geophysical Observatory in Shetland is a facility operated by the Met Office and some of the data collected there is processed and analysed by BGS. The observatory plays an important role in weather forecasting, the detection of the local magnetic field and seismic monitoring.

The high geomagnetic latitude of Shetland makes the Lerwick observatory an excellent site for measuring the Earth’s natural magnetic field variations and making aurora observations. In fact, the observatory was established when the Norwegian government lobbied the British to establish a meteorological observatory in the Shetland Islands after explorer Roald Amundsen expressed a desire to compare notes on the aurora borealis.

Black and white picture of a tall, triangular, metal framework next to a square building
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The geomagnetic observatory at Lerwick, Shetland, pictured in 1965. BGS © UKRI.

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Magnetic data has been recorded continuously since 1921, first in analogue form traced onto paper then, from the 1980s, as digital data. Today, modern magnetometers automatically transfer data every minute to the BGS office in Edinburgh for processing. BGS archives maintain a complete record of the natural magnetic field variations since 1921.

Guanren Wang from BGS’s geomagnetism team attended the observatory’s centenary celebration on 7 June 2022, where he gave a presentation about the history and current work of the observatory to an audience of local guests.

BGS geomagnetism team member Guanren Wang stands in front of a white hut
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BGS geomagnetic scientist Guanren Wang in front of the magnetometer hut, which is part of BGS’s equipment at Lerwick Met Observatory, taken on its 101st anniversary celebration. The white hut is a variometer hut designed in 1921. Its thick concrete walls are coated entirely in white paint to avoid heating in the sun; this is done so the internal room temperature is kept stable because magnetometer measurements are sensitive to changing temperatures. The whole hut is deliberately constructed from non-magnetic materials and is free of iron and steel. BGS © UKRI.

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Up-to-date magnetic field data is essential for a range of high-precision modern navigation techniques, which would have been unimaginable 100 years ago when the observatory was first established. This leads to the question — where will magnetic data take us in the next 100 years?

About the author

Eilidh Dunnet
Eilidh Dunnet

CSRF engagement and communications manager

BGS Edinburgh
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