References of "Francis, Olivier 50001803"
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See detailConcept and Status of the ECGN Project
Ihde, J.; Baker, T. F.; Bruyninx, C. et al

in Torres, João Agria; Hornik, Helmut (Eds.) EUREF Publication No. 13 (2004)

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See detailIndication of the uplift of the Ardenne in long-term gravity variations in Membach (Belgium)
Francis, Olivier UL; Van Camp, Michel; van Dam, Tonie UL et al

in Geophysical Journal International (2004), 158(1), 346-352

We report on the results of 7 yr of collocated gravity observations made with an FG5 abso- lute (AG) gravimeter and a GWR C-Series superconducting gravimeter (SG) located at the Membach Geophysical ... [more ▼]

We report on the results of 7 yr of collocated gravity observations made with an FG5 abso- lute (AG) gravimeter and a GWR C-Series superconducting gravimeter (SG) located at the Membach Geophysical Station in eastern Belgium. The SG gravity residuals track changes in gravity periodically observed by the AG, at the microgal level. Further, in the SG resid- ual signal we distinguish a quasi-seasonal term that can be mostly explained by variations in local water storage effects. In the AG time-series we observe a small trend in the gravity of −0.6 ± 0.1 μGal yr−1 perhaps indicating that the Membach Station is being displaced up- wards by about 3.0 mm yr−1. An uplift of the region is confirmed by Global Positioning System (GPS) measurements performed 3 km away. We are able to explain the features in the gravity time-series in terms of water storage variability, post-glacial rebound and tectonic activity. [less ▲]

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See detailProceedings of the Workshop: The Sate of GPS Vertical Positioning Precision: Separation of Earth Processes by Space Geodesy
van Dam, Tonie UL; Francis, Olivier UL

Book published by Centre Européen de Géodynamique et de Séismologie (2004)

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See detailProceedings of the Workshop: IMGC-2002 Instrumentation and Metrology in Gravimetry
Francis, Olivier UL; van Dam, Tonie UL

Book published by Centre Européen de Géodynamique et de Séismologie (2003)

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See detailGenèse et Futur d'un laboratoire de Gravimétrie à Walferdange (Luxembourg)
Melchior, Paul; Flick, Johny; Francis, Olivier UL

in Helmut Moritz's Fetschrift zum 70. Geburtstag (2003)

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See detailProcessing of the Absolute data of the ICAG01
Francis, Olivier UL; van Dam, Tonie UL

in Francis, Olivier; van Dam, Tonie (Eds.) Proceedings of the Workshop: IMG-2002 Instrumentation and Metrology in Gravimetry (2003)

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See detailUnified European Gravity Reference Network 2002 (UEGN2002), a Status Report
Kenyeres, A.; Boedecker, G.; Francis, Olivier UL

in Tziavos, Ilias N. (Ed.) Gravity and Geoid 2002 (2003)

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See detailRESEAU DE GRAVIMETRIE ABSOLUE ALGERIEN
Francis, Olivier UL

in Bulletin des Sciences Géographiques (2003), 09(Avril), 3-9

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See detailAnalysis of the Results of the Sixth International Comparison of Absolute Gravimeters ICAG-2001
Vistuhskin, Leonid; Jiang, Zhiheng; Becker, Matthias et al

in Tziavos, Ilias N. (Ed.) Gravity and Geoid 2002 (2003)

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See detailGGFC Special Bureau for Loading: Current status and plans
van Dam, Tonie UL; Plag, H. P.; Francis, Olivier UL et al

in Richter, Bernd; Schwegmann, Wolfgang; Dick, Wolfgang R. (Eds.) Proceedings of the IERS Workshop on Combination Research and Global Geophysical Fluids (2003)

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See detailSixth International Comparison of Absolute Gravimeters, ICAG-2001
Vitushkin, Leonid; Jiang, Zhiheng; Becker, Matthias et al

in Francis, Olivier; van Dam, Tonie (Eds.) Proceedings of the Workshop: IMG-2002 Instrumentation and Metrology in Gravimetry (2003)

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See detailComparison between modeled and Observed Gravity Tidal Parameters at Ny-Alesund, Svalbard
Sato, Tadahiro; Tamura, Y; Matsumoto, K et al

in Francis, Olivier; van Dam, Tonie (Eds.) Proceedings of the Workshop: IMG-2002 Instrumentation and Metrology in Gravimetry (2003)

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See detailThe New IERS Special Bureau for Loading (SBL)
van Dam, Tonie UL; Plag, Hans-Peter; Blewitt, Geoffrey et al

in International VLBI Service for Geodesy and Astrometry: General Meeting Proceedings (2002)

Currently, the establishment of the International Earth Rotation Service (IERS) Special Bureau for Loading (SBL) is in progress as part of the IERS Global Geophysical Fluids Center (GGFC). The main ... [more ▼]

Currently, the establishment of the International Earth Rotation Service (IERS) Special Bureau for Loading (SBL) is in progress as part of the IERS Global Geophysical Fluids Center (GGFC). The main purpose of the SBL is to provide reliable, consistent model predictions of loading signals that have been thoroughly tested and validated. The products will describe at least the surface deformation, gravity signal and geo-center variations due to the various surface loading processes in reference frames relevant for direct comparison with existing geodetic observing techniques. To achieve these goals, major scientific advances are required with respect to the Earth model, the theory and algorithms used to model deformations of the Earth as well as improvements in the observational data related to surface loading. [less ▲]

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See detailResults of the Sixth International Comparison of Absolute Gravimeters, ICAG-2001
Vitushkin, L.; Becker, M.; Jiang, Z. et al

in Metrologia (2002), 39(5), 407-427

The Sixth International Comparison of Absolute Gravimeters was held from 5 June to 28 August 2001 at the Bureau International des Poids et Mesures (BIPM), Sevres. Seventeen absolute gravimeters were used ... [more ▼]

The Sixth International Comparison of Absolute Gravimeters was held from 5 June to 28 August 2001 at the Bureau International des Poids et Mesures (BIPM), Sevres. Seventeen absolute gravimeters were used to make measurements at five sites of the BIPM gravity network. The vertical gravity gradients at the sites and the ties between them were also measured using seventeen relative gravimeters. For the first time the ties were also measured using absolute gravimeters. Various methods of processing the absolute and relative data were tested to calculate the results. The final results of ICAG-2001 are presented. The acceleration due to gravity at a height of 0.90 m is given as (980925701.2 ± 5.5) Gal and (980928018.8 ± 5.5) Gal for sites A and B, respectively, calculated using a combined adjustment of the absolute and relative data. [less ▲]

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See detailComment on "Nature of the recent vertical ground movements inferred from high-precision leveling data in an intraplate setting: NE Ardenne, Belgium" by A. Demoulin and A. Collignon
Camelbeeck, Thierry; Van Camp, Michel; Jongmans, Denis et al

in Journal of Geophysical Research (2002), 107(B11), 2281-2281

Comment on ‘‘Nature of the recent vertical ground movements inferred from high-precision leveling data in an intraplate setting: NE Ardenne, Belgium’’ by A. Demoulin and A. Collignon

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See detailExperiment to evaluate crustal motions across the Ardenne and the Roer Graben (north-western Europe) using absolute gravity measurements
Van Camp, M.; Camelbeeck, Thierry; Francis, Olivier UL

in Metrologia (2002), 39(5), 503-508

Absolute gravity measurements using the FG5-202 gravimeter have been conducted twice a year since September 1999 along a 120 km long profile across the Belgian Ardenne and the Roer Graben. As in this ... [more ▼]

Absolute gravity measurements using the FG5-202 gravimeter have been conducted twice a year since September 1999 along a 120 km long profile across the Belgian Ardenne and the Roer Graben. As in this region there is a difference of an order of magnitude between the inferred vertical crustal movements deduced from the difference of levelling (about 1 mm/year) and geological information (0.1 mm/year), our goal is to better constrain the present-day deformation. The absolute gravity measurements are performed at Rochefort, Humain, Werpin, Manhay, Sprimont, Membach (Belgium) and Monschau, Julich and Bensberg (Germany). A complete description of the network is given, and specific difficulties at some stations are presented. The precision achieved, generally less than 2.0 Gal integrated over more than 24 h of observation, is quite satisfactory at all stations but Julich. The mining activities around Julich cause an increase in the noise up to 7 Gal integrated over more than 72 h. We also discuss possible causes of gravity variations in this region. At present, it is still not possible to detect any trend in the available data. However, after five years of observations, we should be able to detect or constrain any possible long-term trend with a limit of 2.5 mm/year, assuming that a height change of 1 mm causes a change in gravity of 0.2 Gal. To ensure that the absolute gravimeter is giving accurate results, it has been regularly compared with the superconducting gravimeter installed at the Membach reference station. [less ▲]

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See detailAbsolute gravity measurements in Belgium: a tool for geodynamic interpretation
Van Camp, Michel; Francis, Olivier UL; Camelbeeck, Thierry

in Degryse, Patrick; Sintubin, Manuel (Eds.) Contributions to the Geology of Belgium and Northwest Europe (2002)

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See detailEvaluation of the precision of using absolute gravimeters to calibrate superconducting gravimeters
Francis, Olivier UL; van Dam, Tonie UL

in Metrologia (2002), 39(5), 485-488

We present an experiment in which four different FG5 absolute gravimeters (AG) were operated simultaneously alongside a superconducting relative gravimeter (SG). We demonstrate that 0.1 % precision can be ... [more ▼]

We present an experiment in which four different FG5 absolute gravimeters (AG) were operated simultaneously alongside a superconducting relative gravimeter (SG). We demonstrate that 0.1 % precision can be achieved on the calibration factor of the SG by comparison with AG measurements, independently of the FG5 instrument used for the calibration and of the offsets among the FG5 absolute values. This experiment demonstrates the robustness of using any FG5 absolute gravimeter to calibrate any SG. This result is of value to geoscientists analysing data from (a) globally distributed SGs which most probably have been calibrated using different instruments; or (b) any individual SG calibrated with different FG5 absolute gravimeters. [less ▲]

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See detailBeyond Tides - Determination of Core Properties from Superconducting Gravimeter Observations
Smylie, Douglas E.; Francis, Olivier UL; Merriam, James B.

in Journal of the Geodetic Society of Japan (2001), 47(1), 364-372

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See detailGlobal Positioning System and Gravity Used to Study Greenland Ice
van Dam, Tonie UL; Larson, Kristine; Wahr, John et al

in Earth in Space (2001), 13(5), 1-16

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