High precision gravity measurements with the dual sphere superconducting gravimeter in Sutherland (South Africa)

2006 ◽  
Vol 109 (4) ◽  
pp. 515-520 ◽  
Author(s):  
J. Neumeyer ◽  
F. Barthelmes ◽  
O. Dierks ◽  
H. Pflug ◽  
P. Fourie
Keyword(s):  
South Africa ◽  
High Precision ◽  
Superconducting Gravimeter ◽  
Gravity Measurements

scholarly journals Three years of high precision gravity measurements at the gravimetric station of Brasimone - Italy

1998 ◽  
Vol 41 (2) ◽  
Author(s):  
G. Casula
Keyword(s):  
Gravity Field ◽  
High Precision ◽  
Nuclear Power ◽  
Meteorological Data ◽  
Normal Modes ◽  
Superconducting Gravimeter ◽  
Mass System ◽  
Global Geodynamics ◽  
Local Gravity ◽  
Italian Apennines

From August 1995 up to now, at the Enea Research Center of Brasimone, in the Italian Apennines between Bologna and Florence (Italy: 44º07'N, 11º.07'E, 890 m height), the superconducting gravimeter GWR model TT70 number T015 has been continuously recording the variation of the local gravity field, in the frame of the Global Geodynamics Project. The gravimetric laboratory, being a room of the disused nuclear power plant of Brasimone, is a very stable site, free from noise due to human activities. Data blocks of several months of continuous gravity records have been collected over a time span of three years, together with the meteorological data. The gravimeter has been calibrated at relative accuracy better than 0.3% with the aid of a mobile mass system, by imposed perturbations of the local gravity field and recording the gravimeter response. The results of this calibration technique were checked by two comparison experiments with absolute gravimeters performed during this period: the first, in May 1994 with the aid of the symmetrical rise and fall gravimeter of the Institute of Metrology Colonnetti of Turin, and the second in October 1997 involving an FG5 absolute gravimeter of the Institute de Physique du Globe of Strasbourg. The gravimeter signal was analysed to compute a high precision tidal model for Brasimone site. Starting from a set of gravimetric and atmospheric pressure data of high quality, relative to 46 months of observation, we performed the tidal analysis using Eterna 3.2 software to compute amplitudes, gravimetric factors and phases of the main waves of the Tamura catalogue. Finally a comparison experiment between two of the STS-1/VBB broadband seismometers of the MedNet project network and the gravity records relative to the Balleny Islands earthquake (March 25, 1998) were analysed to look for evidence of normal modes due to the free oscillations of the Earth.

scholarly journals Gravity reference at the Argentinean–German Geodetic Observatory (AGGO) by co-location of superconducting and absolute gravity measurements

2020 ◽  
Vol 94 (9) ◽  
Author(s):  
Ezequiel D. Antokoletz ◽  
Hartmut Wziontek ◽  
Claudia N. Tocho ◽  
Reinhard Falk
Keyword(s):  
Gravity Data ◽  
Total Error ◽  
International Comparisons ◽  
Superconducting Gravimeter ◽  
Calibration Factor ◽  
Absolute Gravity ◽  
Absolute Level ◽  
Gravity Measurements ◽  
Instrumental Drift

AbstractThe Argentinean–German Geodetic Observatory (AGGO) is a fundamental geodetic observatory located close to the city of La Plata, Argentina. Two high-precision gravity meters are installed at AGGO: the superconducting gravimeter SG038, which is in operation since December 2015, and the absolute gravimeter FG5-227, which has provided absolute gravity measurements since January 2018. By co-location of gravity observations from both meters between January 2018 and March 2019, calibration factor and instrumental drift of the SG038 were determined. The calibration factor of the SG038 was estimated by different strategies: from tidal models, dedicated absolute gravity measurements over several days and a joint approach (including the determination of the instrumental drift) using all available absolute gravity data. The final calibration factor differs from the determination at the previous station, the transportable integrated geodetic observatory, in Concepcion, Chile, by only 0.7‰, which does not imply a significant change. From the combined approach also the mean absolute level of the SG was determined, allowing to predict absolute gravity values from the SG at any time based on a repeatability of $$12\,\hbox {nm}/\hbox {s}^{2}$$ 12 nm / s 2 for the FG5-227 at AGGO. Such a continuous gravity reference function provides the basis for a comparison site for absolute gravimeters in the frame of the international gravity reference frame for South America and the Caribbean. However, it requires the assessment of the total error budget of the FG5-227, including the link to the international comparisons, which will be subject of future efforts.

Monitoring aquifer recharge using repeated high-precision gravity measurements: A pilot study in South Weber, Utah

Geophysics ◽  
2008 ◽  
Vol 73 (6) ◽  
pp. WA83-WA93 ◽  
Author(s):  
D. S. Chapman ◽  
E. Sahm ◽  
P. Gettings
Keyword(s):  
High Precision ◽  
Gravity Anomalies ◽  
Pilot Project ◽  
Alluvial Fan ◽  
Aquifer Recharge ◽  
Aquifer System ◽  
Aquifer Storage ◽  
Gravity Measurements ◽  
Groundwater Mound ◽  
Gravity Signal

Repeated high-precision gravity surveys were conducted over two infiltration cycles on an alluvial-fan aquifer system at the mouth of Weber Canyon in northern Utah as part of the Weber River Basin Aquifer Storage and Recovery Pilot Project (WRBASR). Gravity measurements collected before, during, and after infiltration events indicate that a perched groundwater mound formed during infiltration events and decayed smoothly following infiltration. Data also suggest the groundwater mound migrated gradually south-southwest from the surface infiltration site. Maximum measured gravity changes associated with the infiltration were [Formula: see text] during the first event (2004) and a net [Formula: see text] increase during the second event (2005). Gaussian in-tegration of the spatial gravity anomaly yields an anomalouscausative mass within 10% of the [Formula: see text] [Formula: see text] of infiltrated water measured in 2004. The spatial gravity field is consistent with a groundwater mound at the end of the infiltration cycle approximately equivalent to a cylindrical disc of height [Formula: see text] and a radius between [Formula: see text]. After infiltration ceased, gravity anomalies decreased to approximately 50% of their original amplitude over a characteristic time of three to four months. The reduction of the gravity signal is simulated by analytical solutions for the decay of a groundwater mound through a saturated porous media. This comparison places relatively tight bounds on the hydraulic conductivity of the alluvial-fan material below the infiltration site with a preferred value of [Formula: see text] on a length scale of a few hundred meters.

High-precision gravity measurements using atom interferometry

Metrologia ◽  
2001 ◽  
Vol 38 (1) ◽  
pp. 25-61 ◽  
Author(s):  
A Peters ◽  
K Y Chung ◽  
S Chu
Keyword(s):  
High Precision ◽  
Atom Interferometry ◽  
Gravity Measurements

Impact of high precision gravimetry in the context of a future new SI

2014 ◽  
Vol 30 ◽  
pp. 1460270
Author(s):  
Henri Baumann ◽  
Ali L. Eichenberger
Keyword(s):  
High Precision ◽  
Laser Interferometer ◽  
Mass Unit ◽  
Research Areas ◽  
Gravity Measurements ◽  
Definition Of ◽  
New Research ◽  
New Si ◽  
The Doors

In the early eighties, the development of ballistic absolute gravimeters based on laser interferometer opened the doors to new research areas in various scientific domains such as geodesy, geophysics or metrology. After a brief overview of the most used technique for gravity measurements, the implication of gravity in the context of an improved SI, especially for a new definition of the mass unit kg, will be presented.

A Compound Recoil-Compensated Chamber Design for Free-Fall Absolute Gravimeters

2020 ◽  
Author(s):  
Yi Wen ◽  
Kang Wu ◽  
Meiying Guo ◽  
Lijun Wang
Keyword(s):  
High Precision ◽  
Free Fall ◽  
Test Mass ◽  
Precision Measurements ◽  
Gravity Measurement ◽  
Absolute Gravity ◽  
Systematic Bias ◽  
Chamber Design ◽  
Measurement Results ◽  
Gravity Measurements

Abstract The ballistic free-fall absolute gravimeters are most commonly-used instruments for high-precision absolute gravity measurements in many fields, such as scientific research, resource survey, geophysics and so on. The instrumental recoil vibrations generated by the release of the test mass can cause troublesome systematic bias, because these vibrations are highly reproducible from drop to drop with coherent phase. A compound counterbalanced design of chamber using both belt-driven mechanism and cam-driven structure is proposed in this paper. This structure is designed to achieve excellent recoil compensation as well as long freefall length for high precision measurements. Simulation results show that the recoil vibration amplitude of the compound recoil-compensated structure during the drop is about 1/4 of that with only belt-driven counterbalanced structure. This confirms the feasibility and superiority of the new design. And it is believed that the absolute gravimeter based on this newly proposed chamber design is expected to obtain more precise gravity measurement results in the future.

Gravity terrain corrections calculated using digital elevation models

Geophysics ◽  
1990 ◽  
Vol 55 (1) ◽  
pp. 102-106 ◽  
Author(s):  
Allen H. Cogbill
Keyword(s):  
High Precision ◽  
The Other ◽  
Mountainous Areas ◽  
Data Set ◽  
Gravity Station ◽  
Digital Terrain ◽  
Terrain Effects ◽  
Digital Elevation ◽  
Gravity Measurements ◽  
Terrain Corrections

Corrections for terrain effects are required for virtually all gravity measurements acquired in mountainous areas, as well as for high‐precision surveys, even in areas of low relief. Terrain corrections are normally divided into two parts, one part being the correction for terrain relatively close to the gravity station (the “inner‐zone” correction) and the other part being the correction for more distant, say, >2 km, terrain. The latter correction is normally calculated using a machine procedure that accesses a digital‐terrain data set. The corrections for terrain very close to the gravity station are done manually using Hammer’s (1939) procedures or a similar method, are guessed in the field, or simply are neglected. Occasionally, special correction procedures are used for the inner‐zone terrain corrections (e.g., LaFehr et al., 1988); but such instances are uncommon.

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