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Dumont d'Urville Permanent Absolute Gravity Observatory Site

History and Details of Dumont d'Urville site:

After 1950, the first magnetic measurements in the region of Terre Adelie (Antarctica) were made in Port Martin, a base set up by the French polar expeditions (Missions Paul-Emile Victor) in January 1950. The Port Martin magnetic observatory, operated until February 1952 when the Port Martin base was destroyed in a fire. In the austral summer 1956, the permanent Dumont d'Urville base was created on the occasion of IGY and the magnetic observatory installed.

Large local magnetic anomalies were brought to light, on the all surface of the Petrel Island and especially around the absolute huts. These anomalies are due to veins of magnetite visible superficially. Therefore, right from the creation of this observatory in April 1957, it was known that the mean level of the magnetic field measured in this region was not representative of the regional magnetic field. However, the variations in mean field values could be considered as being the correct indicators of the secular variation.

In 1973 a VFO31 triaxial fluxgate variometer (X,Y and Z) was installed at Dumont d'Urville. For logistic reasons a new absolute hut was established in 1973 and the observatory references have been modified. Since 1981 the EOPG portable magnetometer with fluxgate sensor for Earth's magnetic field component measurements has used to made direct measurements of the intensity of horizontal components X and Y and of the vertical component Z. The measurements of total field F are made from the reference pier with a free proton magnetometer (Elsec) or of an Overhauser magnetometer SM90R (since 1992).

66° 39' 54"S
140° 0' 25.2" W

The absolute gravity hut at Dumont d'Urville. Photograph courtesy of Martine Amalvict, University of Strasbourg, 2000.

eopg.u-strasbg.fr/obsmag/En/observ/drv_obs.html