The Contribution of GGP Superconducting Gravimeters to GGOS

The network of more than 24 superconduct- ing gravimeters (SGs) of the Global Geodynamics Project (GGP) is available as a set of reference stations for studies related to time-varying gravimetry. The inherent stability of the SG allows it to detect signals from a sampling time of 1 s up to periods of several years with a time-domain accuracy of 0.1 μGal or better. SGs within the GGP network comprise a valuable set of stations for geodetic and geophysical studies that involve Earth's surface gravity field. Experience has shown that SGs can be calibrated to an accuracy of 0.01-0.1 %, and that most instruments have a low, but well-modeled, drift of a few μGal/yr. For most purposes except the determination of an absolute gravity reference level, the SG is the best observation-style instrument we have today. SG data is now freely available, much of it going back to the early 1990's, from the GGP database at ICET (International Centre of Earth Tides, in Brussels, Belgium) and GFZ (Potsdam, Germany). Frequently it is combined with other datasets such as atmospheric pressure and hydrology for studies of ground defor- mation and tectonics. One of the most interesting new ideas within GGOS (Global Geodetic Observing System) is the determination of the geocenter using a combination of satellite and ground-based gravimetry. The GGP network can provide a unique contribution through continuous data at the stations where absolute gravimeters (AGs) will be deployed. The combination

[1]  Jeffrey P. Walker,et al.  THE GLOBAL LAND DATA ASSIMILATION SYSTEM , 2004 .

[2]  David Crossley,et al.  Report of GGP Activities to Commission 3, Completing 10 Years for the Worldwide Network of Superconducting Gravimeters , 2009 .

[3]  Jacques Hinderer,et al.  Network of superconducting gravimeters benefits a number of disciplines , 1999 .

[4]  O. Francis,et al.  Uncertainty of absolute gravity measurements , 2005 .

[5]  J. Boy,et al.  Study of the seasonal gravity signal in superconducting gravimeter data , 2006 .

[6]  Michael B. Heflin,et al.  Seasonal and interannual global surface mass variations from multisatellite geodetic data , 2006 .

[7]  J. Hinderer,et al.  Scientific achievements from the first phase (1997–2003) of the Global Geodynamics Project using a worldwide network of superconducting gravimeters , 2004 .

[8]  R. Falk,et al.  Rigorous Combination of Superconducting and Absolute Gravity Measurements with Respect to Instrumental Properties , 2006 .

[9]  O. Francis,et al.  Evaluation of the precision of using absolute gravimeters to calibrate superconducting gravimeters , 2002 .

[10]  M. Camp,et al.  Correcting superconducting gravity time-series using rainfall modelling at the Vienna and Membach stations and application to Earth tide analysis , 2007 .

[11]  J. Hinderer,et al.  Crustal vertical motion along a profile crossing the Rhine graben from the Vosges to the Black Forest Mountains: Results from absolute gravity, GPS and levelling observations , 2006 .

[12]  A. Reinhold,et al.  Observing Fennoscandian Gravity Change by Absolute Gravimetry , 2006 .

[13]  T. Jahr,et al.  Hydrological experiments around the superconducting gravimeter at Moxa Observatory , 2006 .

[14]  O. Francis,et al.  Analysis of results of the International Comparison of Absolute Gravimeters in Walferdange (Luxembourg) of November 2003 , 2005 .

[15]  P. Milly,et al.  Global Modeling of Land Water and Energy Balances. Part I: The Land Dynamics (LaD) Model , 2002 .

[16]  Y. Imanishi,et al.  Verifying the precision of a new generation absolute gravimeter FG5—Comparison with superconducting gravimeters and detection of oceanic loading tide , 1997 .

[17]  J. Wahr,et al.  Predictions of vertical uplift caused by changing polar ice volumes on a viscoelastic earth , 1995 .

[18]  The Global Geodetic Observing System , 2007 .

[19]  Y. Fukuda,et al.  Calibration of the superconducting gravimeter T011 by parallel observation with the absolute gravimeter FG5 #210—a Bayesian approach , 2002 .