MercoPress. South Atlantic News Agency

Magnetic observatory in South Georgia to track the “South Atlantic Anomaly”

A view of Grytviken a hub of scientific research

A magnetic observatory is being re-established on South Georgia to provide vital data on the 'South Atlantic Anomaly' as scientists monitor a possible reversal of the earth's magnetic field. This field, generated deep within the planet, shields against particle radiation from space.

South Georgia sits within an area where this shield is weaker due to the weaker spot in the earth's magnetic field known as the 'South Atlantic Anomaly' (SAA). In this area, radiation from space penetrates deeper into the atmosphere, which can be a hazard to satellites, spacecraft and high-altitude aircraft.

The SAA is growing and spreading westwards from South Africa as the Earth’s internal magnetic field rapidly weakens in this region. Scientists believe this may be evidence of a coming reversal in the direction of the Earth’s internal magnetic field. They do not know precisely what occurs during such reversals or how long it takes for a reversal to complete.

According to geomagneticists at the British Geological Survey: “The earth’s magnetic field has had many highs, lows and reversals in its past. The last reversal was around 800,000 years ago. So the Earth is known to be able to re-generate its field and has done so during human pre-history. Understanding the development of the SAA may therefore be significant in understanding the reversal process and its impact on life and the natural environment.”

There is a global network of magnetic observatories, and the new station being built at King Edward Point will allow better monitoring of the South Atlantic Anomaly and of changes occurring deep within the Earth. Due to the lack of land in the mid-Atlantic area only Ascension Island, Tristan da Cunha and St Helena observatories currently provide monitoring of the magnetic field and its changes in this important area.

“We need to better relate observations of the SAA made separately on the land masses of Africa and South America. The South Georgia observatory will therefore be a key addition to this small network of observatories”.

Construction of the new observatory started a year ago and members of the BGS return in February to complete building the observatory and installing the monitoring equipment. There was previously a magnetic observatory on the site until 1982. (South Georgia January newsletter)