Absolute gravity measurements at the Princess Elisabeth station in Antarctica
For the third time, Professor Olivier Francis from the University of Luxembourg is measuring gravity at the Belgian station Princess Elisabeth (PE) in Antarctica. He is the head of the Geophysics Laboratory of the University of Luxembourg which was recently chosen to be the «Designated Institute» for gravity by the Bureau Luxembourgeois de Métrologie (BLM/ILNAS).
The gravity measurements are performed in the framework of the Giant-Lissa project funded by BELSPO (Politique scientifique fédérale belge). The objective is to precisely measure crust deformations due to climate changes to provide information on the ice mass balance of the Antarctic Ice sheet in the vicinity of the station. Two permanent GPS stations are continuously operating on the bedrock at the PE station since 2011. Absolute gravity observations were already carried out in 2011 and 2013. The combination of these two kinds of measurements allows us to discriminate the present ice mass changes (melting or accumulation) from the long-term crust vertical displacement due to the Global Isostatic Adjustment (GIA). The GIA results from the visco-elastic deformation of the Earth crust compensating from the un-load of its surface caused by the ice melting since the last glacial maximum.
The gravity measurements are performed on a pier directly connected to the bedrock in this dedicated shelter. The results of the two previous expeditions showed a slight increase in gravity at PE that has been confirmed this year. It could be interpreted as ice mass accumulation around the PE.
Outside view of the scientific shelter dedicated to the absolute gravity measurements. The permanent GPS antenna is also visible on the top of the nunatak.
Some views of the absolute gravimeter FG5X-216 from the University of Luxembourg inside the scientific shelter where absolute gravity measurements are performed.