The Finnish Geodetic Institute (FGI) collects and analyzes long time series of surface gravity change and crustal motion in Dronning Maud Land, East Antarctica. The absolute gravity (AG) station at the Finnish Antarctic Research Station Aboa has been occupied in five FINNARP expeditions starting with 1993/1994, latest in 2011/2012. This is one of the longest AG time series in Antarctica. Crustal motion is observed at the permanent GPS station established by FGI at Aboa in 2003. Its data is included in large international cooperation projects. In addition, FGI has performed AG measurements at Maitri (India), Novolazarevskaya (Russia), SANAE IV (South Africa), and Troll (Norway). To separate local and regional/continental influences in gravity, variation in glacier surface heights within a few km of the AG sites is observed using GPS profiles, and the gravity effect modelled.
Contemporary variation in ice load causes changes in height and gravity, as does past variation in ice load (Postglacial Rebound PGR). Joint interpretation of observed gravity change and crustal deformation measured by continuous GNSS observations helps to separate the two causes. PGR models are essential for e.g. determining the current ice mass balance of the Antarctic from satellite gravity observations. The AG stations are used by many international teams to provide reference values for large-scale airborne gravity surveys. In this way, too, the AG measurements have become an indispensable part of Antarctic scientific infrastructure.
- Absolute gravimetry in Antarctica: Status and prospects, J. Mäkinen, M. Amalvict, K. Shibuya, and Y. Fukuda, Journal of Geodynamics, Vol. 43, Iss. 3, 2007, pp. 339–357
- Widespread low rates of Antarctic glacial isostatic adjustment revealed by GPS observations. Thomas, I. D., M. A. King, M. J. Bentley, P. L. Whitehouse, N. T. Penna, S. D. P. Williams, R. E. M. Riva, D. A. Lavallee, P. J. Clarke, E. C. King, R. C. A. Hindmarsh, and H. Koivula (2011). Geophys. Res. Lett., doi:10.1029/2011GL049277.