References of "Francis, Olivier 50001803"
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See detailDétermination de l'accélération de la pesanteur pour la balance du watt du LNE
Merlet, Sébastien; Gillot, Pierre; Farah, Tristan et al

in Revue Française de Métrologie (2014), 36(2014-4), 11-27

The “watt balance” project aims at linking the kilogram definition to the Planck constant. The weighing of the mass involved requires a determination of the acceleration g with an uncertainty better than ... [more ▼]

The “watt balance” project aims at linking the kilogram definition to the Planck constant. The weighing of the mass involved requires a determination of the acceleration g with an uncertainty better than 10-8. This work aims at determining g with an atomic gravimeter and a dedicated gravimetric site. [less ▲]

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See detailFuture and development of the European Combined Geodetic Network ECGN
Poutanen, Markku; Ihdes, Johannes; Bruyninx, Carine et al

in Rizos, C.; Willis, Pascal (Eds.) Earth on the Edge: Science for a Sustanaible Planet (2014)

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See detailReply to Comment on: ‘The quest for a consistent signal in ground and GRACE gravity time series’
Van Camp, Michel; de Viron, Olivier; Métivier, Laurent et al

in Geophysical Journal International (2014), 199(3), 1818-1822

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See detailHigh tilt susceptibility of the Scintrex CG-5 relative gravimeters
Reudink, R.; Klees, R.; Francis, Olivier UL et al

in Journal of Geodesy (2014), 88(6), 617-622

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See detailThe quest for a consistent signal in ground and GRACE gravity time series
Van Camp, Michel; de Viron, Olivier; Métivier, Laurent et al

in Geophysical Journal International (2014), 197

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See detailMeasurement of the speed-of-light perturbation of free-fall absolute gravimeters
Rothleitner, Christian UL; Niebauer, Tim; Francis, Olivier UL

in Metrologia (2014), 51(3), 9

We report on a direct measurement of the relativistic Doppler shift with a commercial free-fall absolute gravimeter of the type FG5X. The observed Doppler shift, which is commonly called speed-of-light ... [more ▼]

We report on a direct measurement of the relativistic Doppler shift with a commercial free-fall absolute gravimeter of the type FG5X. The observed Doppler shift, which is commonly called speed-of-light perturbation, can be well described by the relativistic Doppler formula, where the constant object velocity is replaced by a time-dependent velocity with constant acceleration. The observed speed-of-light perturbation stands in contrast to other publications, which predict a higher frequency shift. It has been measured with a relative uncertainty of 1.1 × 10 −3 . [less ▲]

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See detailStability comparison of two absolute gravimeters: optical versus atomic interferometers
Gillot, P.; Francis, Olivier UL; Landragin, A. et al

in Metrologia (2014), 51(5), 15-17

We report the direct comparison between the stabilities of two mobile absolute gravimeters of different technology: the LNE-SYRTE Cold Atom Gravimeter (CAG) and FG5X#216 of the Université du Luxembourg ... [more ▼]

We report the direct comparison between the stabilities of two mobile absolute gravimeters of different technology: the LNE-SYRTE Cold Atom Gravimeter (CAG) and FG5X#216 of the Université du Luxembourg. These instruments rely on two different principles of operation: atomic and optical interferometry. The comparison took place in the Walferdange Underground Laboratory for Geodynamics in Luxembourg, at the beginning of the last International Comparison of Absolute Gravimeters, ICAG-2013. We analyse a 2h10 duration common measurement, and find that the CAG shows better immunity with respect to changes in the level of vibration noise, as well as a slightly better short term stability. [less ▲]

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See detailThe European Comparison of Absolute Gravimeters 2011 (ECAG-2011) in Walferdange, Luxembourg: results and recommendations
Francis, Olivier UL; Baumann, Henri; Volarik, Tomas et al

in Metrologia (2013), 50(3), 257

We present the results of the third European Comparison of Absolute Gravimeters held in Walferdange, Grand Duchy of Luxembourg, in November 2011. Twenty-two gravimeters from both metrological and non ... [more ▼]

We present the results of the third European Comparison of Absolute Gravimeters held in Walferdange, Grand Duchy of Luxembourg, in November 2011. Twenty-two gravimeters from both metrological and non-metrological institutes are compared. For the first time, corrections for the laser beam diffraction and the self-attraction of the gravimeters are implemented. The gravity observations are also corrected for geophysical gravity changes that occurred during the comparison using the observations of a superconducting gravimeter. We show that these corrections improve the degree of equivalence between the gravimeters. We present the results for two different combinations of data. In the first one, we use only the observations from the metrological institutes. In the second solution, we include all the data from both metrological and non-metrological institutes. Those solutions are then compared with the official result of the comparison published previously and based on the observations of the metrological institutes and the gravity differences at the different sites as measured by non-metrological institutes. Overall, the absolute gravity meters agree with one another with a standard deviation of3.1 µ Gal. Finally, the results of this comparison are linked to previous ones. We conclude with some important recommendations for future comparisons. [less ▲]

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See detailConstraints on the upper crustal magma reservoir beneath Yellowstone Caldera inferred from lake-seiche induced strain observations
Luttrell, Karen; Mencin, David; Francis, Olivier UL et al

in Geophysical Research Letters (2013), 40(3), 501--506

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See detailOn the gravimetric contribution to watt balance experiments
Jiang, Z.; Pálinkáš, V.; Francis, Olivier UL et al

in Metrologia (2013), 50(5), 452

It has been recommended that the relative standard uncertainty of the numerical value of the Planck constant required for the redefinition of the kilogram should not exceed 2 × 10 −8 . To reach this goal ... [more ▼]

It has been recommended that the relative standard uncertainty of the numerical value of the Planck constant required for the redefinition of the kilogram should not exceed 2 × 10 −8 . To reach this goal using experiments based on a watt balance, the free-fall acceleration ( g ) traceable to the SI, at a given point and a given time, needs to be known with a sufficiently small uncertainty well below 2 × 10 −8 . Reducing the uncertainty in g allows the other uncertainties related to the watt balance to be increased. Instead of a simultaneous operation of an absolute gravimeter with a watt balance, we propose an alternative approach and demonstrate that a standard uncertainty below 5 µGal (relative uncertainty of 5 × 10 −9 ) is reachable under the conditions at BIPM. Further decreasing the uncertainty could significantly increase commitments in terms of personnel and equipment and would not significantly improve the uncertainty targeted for the BIPM watt balance experiment. A 5 µGal uncertainty might also satisfy the needs of other watt balance experiments underway or planned. In our approach we combine the following information: (1) the Key Comparison Reference Values obtained from the CCM.G-K1, a key comparison carried out in the frame of the International Comparison of Absolute Gravimeters in 2009 (ICAG2009); (2) the accurate gravity network established using the qualified absolute and relative gravimeters; (3) temporal gravity variations based on observed Earth-tide parameters and modelled effects of polar motion and atmospheric mass redistribution; (4) uncertainty estimates that account for non-modelled effects; (5) the option to carry out absolute gravity measurements once every one or two years with two or more gravimeters for monitoring the stability of the gravity field at the BIPM. [less ▲]

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See detailRelative Gravity Measurement Campaign during the 8th International Comparison of Absolute Gravimeters (2009)
Jiang, Z.; Pálinkáš, V.; Francis, Olivier UL et al

in Metrologia (2012), 49(1), 95

The 8th International Comparison of Absolute Gravimeters (ICAG-2009) and the associated Relative Gravity Campaign (RGC2009) took place at the Bureau International des Poids et Mesures (BIPM) between July ... [more ▼]

The 8th International Comparison of Absolute Gravimeters (ICAG-2009) and the associated Relative Gravity Campaign (RGC2009) took place at the Bureau International des Poids et Mesures (BIPM) between July and October 2009. Altogether 24 institutes with 22 absolute gravimeters and 9 relative gravimeters participated in the ICAG/RGC campaign. Accurate absolute and relative gravity measurements as well as precision levelling measurements were performed on the micro-gravity 3D-grid at the BIPM. The 2009 comparison was the first to be organized as a Comité International des Poids et Mesures (CIPM) metrological Key Comparison under the CIPM MRA (Mutual Recognition Arrangement), which means that the result will be officially recognized by the governmental organizations responsible. As a consequence, the relative gravimeters employed were carefully selected and the measurement schedules were rigorously enforced compared with earlier campaigns. Thus the quality of the RGC2009 and the determination of the BIPM local gravity network were improved. After 30 years and eight successive ICAGs, the BIPM has decided to transfer its role to the national metrological institutes, although the CIPM will continue to organize the key comparison as ICAGs. The background to the RGC2009, and the organization, data processing and final results of the gravity and vertical gravity gradients, are presented in this paper. This report is more detailed than previous final reports of the RGCs. [less ▲]

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See detailECAG-2011 期间 FG5/232 绝对重力仪观测及结果分析
Songbai, Xuan; Chongyang, Shen; Hongbo, Tan et al

in 大地测量与地球动力学 (2012), 32(4),

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See detailUpdating the Precise Gravity Network at the BIPM
Jiang, Z.; Arias, E. F.; Tisserand, L. et al

in Geodesy for Planet Earth (2012)

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See detailBedrock displacements in Greenland manifest ice mass variations, climate cycles and climate change
Bevis, Michael; Wahr, John; Khan, Shfaqat A. et al

in Proceedings of the National Academy of Sciences of the United States of America (2012), 109(30), 11944-11948

The Greenland GPS Network (GNET) uses the Global Positioning System (GPS) to measure the displacement of bedrock exposed near the margins of the Greenland ice sheet. The entire network is uplifting in ... [more ▼]

The Greenland GPS Network (GNET) uses the Global Positioning System (GPS) to measure the displacement of bedrock exposed near the margins of the Greenland ice sheet. The entire network is uplifting in response to past and present-day changes in ice mass. Crustal displacement is largely accounted for by an annual oscillation superimposed on a sustained trend. The oscillation is driven by earth’s elastic response to seasonal variations in ice mass and air mass (i.e., atmospheric pressure). Observed vertical velocities are higher and often much higher than predicted rates of postglacial rebound (PGR), implying that uplift is usually dominated by the solid earth’s instantaneous elastic response to contemporary losses in ice mass rather than PGR. Superimposed on longer-term trends, an anomalous ‘pulse’ of uplift accumulated at many GNET stations during an approximate six-month period in 2010. This anomalous uplift is spatially correlated with the 2010 melting day anomaly. [less ▲]

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See detailThe 8th International Comparison of Absolute Gravimeters 2009: the first Key Comparison (CCM.G-K1) in the field of absolute gravimetry
Jiang, Z.; Pálinkáš, V.; Arias, F. E. et al

in Metrologia (2012), 49(6), 666

The 8th International Comparison of Absolute Gravimeters (ICAG2009) took place at the headquarters of the International Bureau of Weights and Measures (BIPM) from September to October 2009. It was the ... [more ▼]

The 8th International Comparison of Absolute Gravimeters (ICAG2009) took place at the headquarters of the International Bureau of Weights and Measures (BIPM) from September to October 2009. It was the first ICAG organized as a key comparison in the framework of the CIPM Mutual Recognition Arrangement of the International Committee for Weights and Measures (CIPM MRA) (CIPM 1999). ICAG2009 was composed of a Key Comparison (KC) as defined by the CIPM MRA, organized by the Consultative Committee for Mass and Related Quantities (CCM) and designated as CCM.G-K1. Participating gravimeters and their operators came from national metrology institutes (NMIs) or their designated institutes (DIs) as defined by the CIPM MRA. A Pilot Study (PS) was run in parallel in order to include gravimeters and their operators from other institutes which, while not signatories of the CIPM MRA, nevertheless play important roles in international gravimetry measurements. The aim of the CIPM MRA is to have international acceptance of the measurement capabilities of the participating institutes in various fields of metrology. The results of CCM.G-K1 thus constitute an accurate and consistent gravity reference traceable to the SI (International System of Units), which can be used as the global basis for geodetic, geophysical and metrological observations of gravity. The measurements performed afterwards by the KC participants can be referred to the international metrological reference, i.e. they are SI-traceable. The ICAG2009 was complemented by a number of associated measurements: the Relative Gravity Campaign (RGC2009), high-precision levelling and an accurate gravity survey in support of the BIPM watt balance project. The major measurements took place at the BIPM between July and October 2009. Altogether 24 institutes with 22 absolute gravimeters (one of the 22 AGs was ultimately withdrawn) and nine relative gravimeters participated in the ICAG/RGC campaign. This paper is focused on the absolute gravity campaign. We review the history of the ICAGs and present the organization, data processing and the final results of the ICAG2009. After almost thirty years of hosting eight successive ICAGs, the CIPM decided to transfer the responsibility for piloting the future ICAGs to NMIs, although maintaining a supervisory role through its Consultative Committee for Mass and Related Quantities. [less ▲]

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