Scott's South Pole scientific legacy | Observing the Earth's magnetic field

This year, 2012, commemorates 100 years since Scott's ill-fated journey to the South Pole. During the journey south and at the base camp at Cape Evans, scientific observations were of paramount importance to Scott and his team.

The BGS archive holds some unique records from this expedition concerning measurements of the strength and direction of the Earth's magnetic field and of atmospheric electricity.

One of Scott's 'notebooks'. Book title from Terra Nova, Magnetic Observations, Rough Book V.

Terrestrial magnetism and Antarctica

Scott's South Pole party. <br />
					    (© BAS/NERC)

Theories of terrestrial magnetism inspired many Antarctic expeditions during the 19th and 20th centuries. At this time the magnetic field was poorly mapped in the southern hemisphere and this hampered efforts to understand how it was generated.

At the Newcastle meeting of the British Association for the Advancement of Science in August 1838, it was resolved that the coverage of magnetic measurement in the southern hemisphere had to be improved; this meeting instigated the so-called Magnetic Crusade.

The two Antarctic expeditions led by Robert Falcon Scott both made extensive magnetic field observations. The first was the National Antarctic Expedition 1901–04 in the ship Discovery and the second was the British Antarctic Expedition 191013 in the Terra Nova. Both expeditions approached Antarctica from New Zealand and had their base camps at about 166° east of Greenwich and at 78° south.

During both expeditions extensive journeys were made into the interior of Antarctica to collect scientific data. During these journeys magnetic field observations were made and are now part of the digital data holdings of the BGS. The observations from the first expedition helped determine the location of the south magnetic pole.

The race to the Pole

Scott, Oates, Evans, Bowers and Wilson at South Pole 17 January 1912. (Image: Scott Polar Research Institute)

The most famous journey is that to the South Pole made by Scott and four companions (Oates, Bowers, Wilson and Evans) in the austral summer of 1911–12.

They arrived at the Pole on 17 January 1912 to discover that a Norwegian team led by Amundsen had beaten them by about a month.

Scott's team all perished on the return journey, with the last three, including Scott, thought to have died between 29–31 March within 11 miles of a depot containing fresh supplies.

Their three bodies were found on 12 November 1912 and their letters, diaries and scientific data were recovered before the tent was collapsed and a commemorative snow cairn built over.

The story of Scott's expedition stemming from these diaries has fascinated people ever since.

The scientific legacy

Locations of declination observations made by Scott's South Pole party.

Simpson entering the magnetic hut at Cape Evans. The entrance to the cave where the magnetograph was installed is in the background  (Image: Scott Polar Research Institute)

During the long and arduous journey to the Pole observations of compass variation, i.e. declination, were made. The exact locations and dates of these observations are shown in the map.

True bearings were determined by astronomical means and magnetic bearings were taken by a compass needle attached to the theodolite.

Back at the Cape Evans base camp continuous observations of the magnetic field were made from February 1911 to November 1912. The observations comprise continuous 3-component recordings of magnetic variations on photographic paper and approximately weekly absolute measurements of declination, horizontal intensity and magnetic dip.

There were several term hours during this time. Term hours are when magnetic observatories around the world have agreed to make intensive measurements of the magnetic field in order to capture more accurately the short period variations. During the operation of Cape Evans observatory there were about 36 such term hours.

Subsequently about 24 observatories were able to provide copies of their rapid-run magnetograph records. When these term hours coincided with magnetic activity more could be learned about the nature of magnetic storms and the aurora than from the normal-run magnetograph records.

Detailed analyses were also done to better understand daily variations. For details see Chree, C.  1921.  British (Terra Nova) Antarctic Expedition 1910–13  Terrestrial Magnetism 54 MB pdf.

BGS archives

Scott's notes in the BGS archive

Original magnetograph traces and notebooks from both of Scott's expeditions are held by the British Geological Survey.

Geomagnetic observatory operations by the Royal Greenwich Observatory and the Meteorological Office were transferred to the Institute of Geological Sciences in the 1960s; the IGS became the BGS in 1984.

Contact

Contact Susan Macmillan for further information