Skip to content
BY-NC-ND 3.0 license Open Access Published by De Gruyter Open Access April 9, 2015

Observed secular gravity trend at Onsala station with the FG5 gravimeter from Hannover

L. Timmen , A. Engfeldt and H.-G. Scherneck


Annual absolute gravity measurements with a FG5 instrument were performed in Onsala Space Observatory by the Institute of Geodesy of the Leibniz Universität Hannover from 2003 to 2011 and have been continued with the upgraded meter FG5X in 2014. Lantmäteriet, Gävle, with their FG5 absolute gravimeter have visited Onsala since 2007. Because small systematic errors may be inherent in each absolute gravimeter, their measuring level and a resulting bias (offset) between the instruments must be controlled over time by means of inter-comparison. From 2007 to 2014, 8 direct comparisons took place well distributed over the time span. A complete re-processing of the absolute gravity observations with the Hannover instrument has been conducted to improve the reduction of unwanted gravity effects. A new tidal model is based on continuous time series recorded with the GWR superconducting gravimeter at Onsala since 2009. The loading effect of the Kattegat is described with a varying sea bottom pressure (water and air mass load) and has been validated with the continuous gravity measurements. For the land uplift,which is a result of the still ongoing glacial isostatic adjustment in Fennoscandia, a secular gravity trend of −0.22 μGal/yr was obtained with a standard deviation of 0.17 μGal/yr. That indicates a slight uplift but is still not significantly different from zero.


Ekman M., 1996, A consistent map of the postglacial uplift of Fennoscandia, Terra Nova, 8, 158–165.10.1111/j.1365-3121.1996.tb00739.xSearch in Google Scholar

Ekman M. and Mäkinen J., 1996, Recent postglacial rebound, gravity change and mantle flow in Fennoscandia, Geophys. J. Int., 126, 229–234.10.1111/j.1365-246X.1996.tb05281.xSearch in Google Scholar

Francis O., Baumann H., Volarik T., et al., 2013, The European Comparison of Absolute Gravimeters 2011 (ECAG-2011) inWalferdange, Luxembourg: results and recommendations, Metrologia, 50, 257– 268.Search in Google Scholar

Francis O. and van Dam T., 2006, Analysis of results of the International Comparison of Absolute Gravimeters in Walferdange (Luxembourg) of November 2003, Cahiers du Centre Européen de Géodynamique et de Séismologie, 26, 1–23.Search in Google Scholar

Francis O., van Dam T., Germak A., et al., 2010, Results of the European Comparison of Absolute Gravimeters inWalferdange (Luxembourg) of November 2007. In: S.P. Mertikas (Ed.), Gravity, Geoid and Earth Observations, IAG Symposia, 135, Springer, 31-35.10.1007/978-3-642-10634-7_5Search in Google Scholar

Gitlein O., 2010, Absolutgravimetrische Bestimmung der Fennoskandischen Landhebung mit dem FG5-220. Doctoral Thesis in Geodesy, Deut. Geod. Komm. Bayer. Akad. Wissensch., C, 643.Search in Google Scholar

Goodkind J. M., 1999, The superconducting Gravimeter, Rev. Sci. Instrum., 70, 11, 4131-4152.10.1063/1.1150092Search in Google Scholar

Hinderer J., Crossley D. and Warburton R. J., 2009, Gravimetric methods – superconducting gravity meters. In: T. Herring (Ed.), Treat. Geophys., 3, Geodesy, Elsevier, 65-122.10.1016/B978-044452748-6/00172-3Search in Google Scholar

Jiang Z., Pálinkás V., Arias F. E., Liard J., Merlet S., et al., 2012, The 8th International Comparison of Absolute Gravimeters 2009: the first Key Comparison (CCM.G-K1) in the field of absolute gravimetry, Metrologia, 49, 666–684.Search in Google Scholar

Lidberg M., Johansson J. M., Hans-Georg Scherneck H.-G. and Milne G. A., 2010, Recent results based on continuous GPS observations of the GIA process in Fennoscandia from BIFROST, J. Geodyn, 50, 8-18.10.1016/j.jog.2009.11.010Search in Google Scholar

Nakiboglu S. M. and Lambeck K., 1991, Secular sea-level change. In: R. Sabadini, K. Lambeck and E. Boschi (Eds.), Glacial Isostasy, Sea Level and Mantle Rheology, Kluwer Acad. Pub., 237–258.10.1007/978-94-011-3374-6_12Search in Google Scholar

Niebauer T. M., Sasagawa G. S., Faller J. E., Hilt R. and Klopping F., 1999, A new generation of absolute gravimeters, Metrologia, 32, 159-180.10.1088/0026-1394/32/3/004Search in Google Scholar

Niebauer T. M., Billson R., Schiel A., van Westrum D. and Klopping F., 2013, The self-attraction correction for the FG5X absolute gravity meter, Metrologia, 50, 1-8.10.1088/0026-1394/50/1/1Search in Google Scholar

Pettersen B. R., Bilker-Koivula M., Breili K., Engfeldt A., Falk R., Gitlein O., Gjevestad J. G. O., Hoppe W., Lysaker D. I., Mäkinen J., Omang O. C. D., Reinhold A. and Timmen L., 2010, An accuracy assessment of absolute gravimetric observations in Fennoscandia, Nordic J. Surv. Real Estate Res., 7:1, 7-14.Search in Google Scholar

Poutanen M., Knudsen P., Lilje M., Nørbech T., Plag H.-P. and Scherneck H.-G., 2005, NGOS – The Nordic Geodetic Observing System, Nordic J. Surv. Real Estate Res., 2:2, 77-98.Search in Google Scholar

Scherneck H.-G., 2015, Five years of gravity measurement at Onsala Space Observatory: the superconducting gravimeter, J. Geod. Sc., submitted.Search in Google Scholar

Scherneck H.-G., Engfeldt A.,Olsson P.-A., Timmen L., 2015, Five years of gravity measurement at Onsala Space Observatory: the absolute scale, J. Geod. Sc., submitted.Search in Google Scholar

Steffen H. andWu P., 2011, Glacial isostatic adjustment in Fennoscandia - a review of data and modeling, J. Geodyn., 52, 169-204.10.1016/j.jog.2011.03.002Search in Google Scholar

Timmen L., 2010, Absolute and relative gravimetry. In: Guochang Xu (Ed.), Sciences of Geodesy-I, Advances and Future Directions, Springer1-48.10.1007/978-3-642-11741-1_1Search in Google Scholar

Timmen L., GitleinO., Klemann V. andWolf D., 2012, Observing gravity change in the Fennoscandian uplift areawith the Hanover absolute gravimeter, Pure Appl. Geophys., 169, 1331-1342. 10.1007/s00024-011-0397-9Search in Google Scholar

Received: 2014-12-3
Accepted: 2015-2-6
Published Online: 2015-4-9

© 2015 L. Timmen et al.

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Downloaded on 6.12.2022 from
Scroll Up Arrow