The Role and Capability of Absolute Gravity Measurements in Determining the Temporal Variations in the Earth’s Gravity Field

1996 ◽  
pp. 20-29 ◽  
Author(s):  
A. Lambert ◽  
T. S. James ◽  
J. O. Liard ◽  
N. Courtier
Keyword(s):  
Gravity Field ◽  
Temporal Variations ◽  
Absolute Gravity ◽  
Earth’S Gravity Field ◽  
Gravity Measurements

scholarly journals An improved test of the general relativistic effect of frame-dragging using the LARES and LAGEOS satellites

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
Ignazio Ciufolini ◽  
Antonio Paolozzi ◽  
Erricos C. Pavlis ◽  
Giampiero Sindoni ◽  
John Ries ◽  
...  
Keyword(s):  
General Relativity ◽  
Gravity Field ◽  
Temporal Variations ◽  
Gravity Field Model ◽  
Earth’S Gravity Field ◽  
Frame Dragging ◽  
Earth Gravity ◽  
Gravity Field Determination ◽  
General Relativistic ◽  
Static Part

Abstract We report the improved test of frame-dragging, an intriguing phenomenon predicted by Einstein’s General Relativity, obtained using 7 years of Satellite Laser Ranging (SLR) data of the satellite LARES (ASI, 2012) and 26 years of SLR data of LAGEOS (NASA, 1976) and LAGEOS 2 (ASI and NASA, 1992). We used the static part and temporal variations of the Earth gravity field obtained by the space geodesy mission GRACE (NASA and DLR) and in particular the static Earth’s gravity field model GGM05S augmented by a model for the 7-day temporal variations of the lowest degree Earth spherical harmonics. We used the orbital estimator GEODYN (NASA). We measured frame-dragging to be equal to $$0.9910 \pm 0.02$$0.9910±0.02, where 1 is the theoretical prediction of General Relativity normalized to its frame-dragging value and $$\pm 0.02$$±0.02 is the estimated systematic error due to modelling errors in the orbital perturbations, mainly due to the errors in the Earth’s gravity field determination. Therefore, our measurement confirms the prediction of General Relativity for frame-dragging with a few percent uncertainty.

scholarly journals Lithospheric stress, strain and displacement changes from GRACE-FO time-variable gravity: case study for Sar-e-Pol Zahab Earthquake 2018

2020 ◽  
Vol 223 (1) ◽  
pp. 379-397
Author(s):  
Mehdi Eshagh ◽  
Farzam Fatolazadeh ◽  
Robert Tenzer
Keyword(s):  
Gravity Field ◽  
Elastic Shell ◽  
Lower Boundary ◽  
Stable Solution ◽  
Temporal Variations ◽  
Stress Strain ◽  
Satellite Gravity ◽  
Earth’S Gravity Field ◽  
Long Wavelength ◽  
Ill Posed

SUMMARY Temporal variations in the Earth's gravity field can be used for monitoring of lithospheric deformations. The network of continuously operating gravity stations is required for this purpose but a global coverage by such network is currently extremely sparse. Temporal variations in long-wavelength part of the Earth's gravity field have been, however, observed by two satellite missions, namely the Gravity Recovery And Climate Experiment (GRACE) and the GRACE Follow-On (GRACE-FO). These satellite gravity observations can be used to study long-wavelength deformations of the lithosphere. Consequently, considering the lithosphere as a spherical elastic shell and solving the partial differential equation of elasticity for it, the stress, strain and displacement inside the lithosphere can be estimated. The lower boundary of this shell is assumed to be stressed by mantle convection, which has a direct relation to the Earth's gravity field according to Runcorn's theory. Changes in gravity field lead to changes in the sublithospheric stress and the stress propagated throughout the lithosphere. In this study, we develop mathematical models in spherical coordinates for describing the stress propagation from the sublithosphere through the lithosphere. We then organize a system of observation equations for finding a special solution to the boundary-value problem of elasticity in the way that provides a stable solution. In contrast, models presented in previously published studies are ill-posed. Furthermore, we use constants of the solution determined from the boundary stresses to determine the strain and displacements leading to these stresses, while in previous studies only the stress has been considered according to rheological properties of the lithosphere. We demonstrate a practical applicability of this theoretical model to estimate the stress–strain redistribution caused by the Sar-e-Pol Zahab 2018 earthquake in Iran by using the GRACE-FO monthly solutions.

scholarly journals DIONYSOS SATELLITE OBSERVATORY AND HIGHER GEODESY LABORATORY: HISTORY AND PERSPECTIVES

2017 ◽  
Vol 50 (2) ◽  
pp. 1091
Author(s):  
A. Marinou ◽  
D. Anastasiou ◽  
X. Papanikolaou ◽  
D. Paradissis ◽  
V. Zacharis
Keyword(s):  
Gravity Field ◽  
Temporal Variations ◽  
Technological Advance ◽  
Satellite Geodesy ◽  
Research Needs ◽  
Reference Systems ◽  
Earth’S Gravity Field ◽  
Wide Range

Dionysos Satellite Observatory and Higher Geodesy Laboratory have been in operation since the 60s and their main objective is to fulfill academic and research needs, determined through the ongoing scientific and technological advance in the field of geodesy. They are involved in all scientific domains related to the determination of earth’s size and figure, as well as its temporal variations. Their field of expertise is Satellite Geodesy, (spanning a wide range of applications like reference systems, tectonic geodesy, etc.), as well as the study of the geoid and earth's gravity field.

scholarly journals ANALYSIS OF ISOSTATICALLY-BALANCED CORTICAL MODELS USING MODERN GLOBAL GEOPOTENTIAL MODELS

2017 ◽  
Vol 23 (4) ◽  
pp. 623-635
Author(s):  
Claudia Infante ◽  
Claudia Tocho ◽  
Daniel Del Cogliano
Keyword(s):  
Gravity Field ◽  
Temporal Variations ◽  
Geoid Height ◽  
Geological Structure ◽  
Earth’S Gravity Field ◽  
Isostatic Equilibrium ◽  
Geopotential Models ◽  
Show Evidence ◽  
Residual Geoid ◽  
Cortical Models

Abstract: The knowledge of the Earth's gravity field and its temporal variations is the main goal of the dedicated gravity field missions CHAMP, GRACE and GOCE. Since then, several global geopotential models (GGMs) have been released. This paper uses geoid heights derived from global geopotential models to analyze the cortical features of the Tandilia structure which is assumed to be in isostatic equilibrium. The geoid heights are suitably filtered so that the structure becomes apparent as a residual geoid height. Assuming that the geological structure is in isostatic equilibrium, the residual geoid height can be assimilated and compared to the isostatic geoid height generated from an isostatically compensated crust. The residual geoid height was obtained from the EGM2008 and the EIGEN-6C4 global geopotential models, respectively. The isostatic geoid was computed using the cortical parameters from the global crustal models GEMMA and CRUST 1.0 and from local parameters determined in the area under study. The obtained results make it clear that the isostatic geoid height might become appropriate to validate crustal models if the structures analyzed show evidence of being in isostatic equilibrium.

scholarly journals Gravity field modelling and gravimetry

2015 ◽  
Vol 64 (2) ◽  
pp. 177-200 ◽  
Author(s):  
Jan Krynski
Keyword(s):  
Gravity Field ◽  
Temporal Variations ◽  
Absolute Gravity ◽  
Satellite Gravity ◽  
Gravity Field Modelling ◽  
Field Modelling ◽  
Use Of Data ◽  
Research Activities ◽  
Geopotential Models

Abstract The summary of research activities concerning gravity field modelling and gravimetric works performed in Poland in the period of 2011-2014 is presented. It contains the results of research on geoid modelling in Poland and other countries, evaluation of global geopotential models, determination of temporal variations of the gravity field with the use of data from satellite gravity space missions, absolute gravity surveys for the maintenance and modernization of the gravity control in Poland and overseas, metrological aspects in gravimetry, maintenance of gravimetric calibration baselines, and investigations of the nontidal gravity changes. The bibliography of the related works is given in references.

scholarly journals Indoor height determination of the new absolute gravimetric station of L'Aquila

2020 ◽  
Vol 63 (Vol 63 (2020)) ◽  
Author(s):  
Marco Fortunato ◽  
Augusto Mazzoni ◽  
Giovanna Berrino ◽  
Filippo Greco ◽  
Federica Riguzzi ◽  
...  
Keyword(s):  
Gravity Field ◽  
Equipotential Surface ◽  
Absolute Gravity ◽  
Post Processing ◽  
Height Difference ◽  
Geoidal Undulation ◽  
Height Determination ◽  
Topographic Survey ◽  
Gravity Measurements

In this paper we describe all the field operations and the robust post-processing proceduresto determine the height of the new absolute gravimetric station purposely selected to belong to a new absolute gravimetric network and located in the Science Faculty of the L’Aquila University. This site has been realized indoor in the Geomagnetism laboratory, so that the height cannot be measured directly, but linking it to the GNSS antenna of AQUI benchmark located on the roof of the same building, by a classical topographic survey. After the topographic survey, the estimated height difference between AQUI and the absolute gravimetric site AQUIgis 14.9700.003 m. At the epoch of the 2018 gravimetric measures, the height of AQUI GNSS station was 712.9740.003 m, therefore the estimated ellipsoidalheight of the gravimetric site at the epoch of gravity measurements is 698.0040.005 m. Absolute gravity measurements are referred to the equipotential surface of gravity field, so that the knowledge of the geoidal undulation at AQUIg allows us to infer the orthometric height as 649.32 m.

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