Articles de revues : « Absolute gravity measurements »

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Zumberge, M. A., G. Sasagawa et M. Kappus. « Absolute gravity measurements in California ». Journal of Geophysical Research 91, B9 (1986) : 9135. http://dx.doi.org/10.1029/jb091ib09p09135.

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Ardyukov, D. G., E. N. Kalish, D. A. Nosov, I. S. Sizikov, M. G. Smirnov, Yu F. Stus, V. Yu Timofeev, R. G. Kulinich et M. G. Valitov. « Absolute gravity measurements at Shults Cape ». Giroskopiya i Navigatsiya 23, n^o 3 (2015) : 13–18. http://dx.doi.org/10.17285/0869-7035.2015.23.3.013-018.

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Ardyukov, D. G., E. N. Kalish, D. A. Nosov, I. S. Sizikov, M. G. Smirnov, Yu F. Stus, V. Yu Timofeev, R. G. Kulinich et M. G. Valitov. « Absolute gravity measurements at shults cape ». Gyroscopy and Navigation 6, n^o 4 (octobre 2015) : 260–64. http://dx.doi.org/10.1134/s2075108715040021.

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Goodacre, A. K., J. O. Liard, P. N. Courtier, R. V. Cooper, P. J. Winter et R. K. McConnell. « Absolute gravity measurements on the canadian gravity standardization network ». Bulletin Géodésique 65, n^o 3 (septembre 1991) : 170–78. http://dx.doi.org/10.1007/bf00806346.

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Krynski, Jan, Tomasz Olszak, Marcin Barlik et Przemyslaw Dykowski. « New gravity control in Poland – needs, the concept and the design ». Geodesy and Cartography 62, n^o 1 (1 juin 2013) : 3–21. http://dx.doi.org/10.2478/geocart-2013-0001.

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Abstract The existing Polish gravity control (POGK) established in the last few years of 20th century according to the international standards is spanned on 12 absolute gravity stations surveyed with four different types of absolute gravimeters. Relative measurements performed by various groups on nearly 350 points of POGK with the use of LaCoste&Romberg (LCR) gravimeters were linked to those 12 stations. The construction of the network, in particular the limited number of non homogeneously distributed absolute gravity stations with gravity determined with different instruments in different epochs is responsible for systematic errors in g on POGK stations. The estimate of those errors with the use of gravity measurements performed in 2007-2008 is given and their possible sources are discussed. The development of absolute gravity measurement technologies, in particular instruments for precise field absolute gravity measurements, provides an opportunity to establish new type of gravity control consisting of stations surveyed with absolute gravimeters. New gravity control planned to be established in 2012-2014 will consist of 28 fundamental points (surveyed with the FG5 - gravimeter), and 169 base points (surveyed with the A10 gravimeter). It will fulfill recent requirements of geodesy and geodynamics and it will provide good link to the existing POGK. A number of stations of the new gravity control with precisely determined position and height will form the national combined geodetic network. Methodology and measurement schemes for both absolute gravimeters as well as the technology for vertical gravity gradient determinations in the new gravity control were developed and tested. The way to assure proper gravity reference level with relation to ICAG and ECAG campaigns as well as local absolute gravimeter comparisons are described highlighting the role of metrology in the project. Integral part of the project are proposals of re-computation of old gravity data and their transformation to a new system (as 2nd order network) as well as a definition of gravity system as “zero-tide” system. Seasonal variability of gravity has been discussed indicating that the effects of environmental changes when establishing modern gravity control with absolute gravity survey cannot be totally neglected.

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Fukuda, Yoichi, Toshihiro Higashi, Shuzo Takemoto, Maiko Abe, Sjafra Dwipa, Dendi Surya Kusuma, Achmad Andan, Koichiro Doi, Yuichi Imanishi et Giuseppe Arduino. « The first absolute gravity measurements in Indonesia ». Journal of Geodynamics 38, n^o 3-5 (octobre 2004) : 489–501. http://dx.doi.org/10.1016/j.jog.2004.07.009.

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Williams, Simon D. P., Trevor F. Baker et Graham Jeffries. « Absolute gravity measurements at UK tide gauges ». Geophysical Research Letters 28, n^o 12 (15 juin 2001) : 2317–20. http://dx.doi.org/10.1029/2000gl012438.

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Sasagawa, Glenn, et Mark A. Zumberge. « Absolute gravity measurements in California, 1984–1989 ». Journal of Geophysical Research 96, B2 (1991) : 2501. http://dx.doi.org/10.1029/90jb02283.

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Kaczorowski, Marek, Tomasz Olszak, Janusz Walo et Marcin Barlik. « Research on absolute gravity variations in geodynamic laboratory in Książ in the period of 2007- 2011 ». Artificial Satellites 47, n^o 4 (1 décembre 2012) : 169–76. http://dx.doi.org/10.2478/v10018-012-0022-z.

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ABSTRACT In 2006 a gravimetric pavilion was installed inside the Geodynamic Laboratory (LG) in Książ. The pavilion was equipped with two pillars intended to serve relative and absolute gravimetric measurements. Installation of measurement platform for absolute gravity measurements inside gravimetric pavilion of LG made it possible to perform four sessions of absolute gravity measurements: two of them in 2007 (June 10-12 and Nov. 21-22), one in 2008 (Apr. 21-22) and one in 2011 (June 19-21). In 2007 the absolute measurements were performed using two FG5 ballistic gravimeters. In April 2007 the measurements were performed by Dr Makinen from Geodetic Institute of Finnish Academy of Science with application of FG5 No. 221 absolute gravimeter. In June 2007 and in the years 2008 and 2011 such gravimetric measurements were performed by the team from Department of Geodesy and Astronomical Geodesy of Warsaw University of Technology using FG5 No. 230 absolute gravimeter. Elaboration of observation sessions from both gravimeters was performed in the Department of Higher Geodesy following the procedures used in constituting of uniform gravimetric system of geodynamic polygons reference. This constituting of gravimetric system comprised inter alia application of identical models of lithospheric tides (global model by Wenzel, 1997) and ocean tides (Schwiderski, 1980) (reduction of absolute measurements with tidal signals). Observations performed during summer of 2007, autumn of 2007, and spring of 2008 and 2011 indicated existence of small changes of absolute gravity of the order of 1 Gal. Maxima of accelerations appear in the spring period, and minima in the autumn period. This effect is connected with the influence of global hydrological factors the annual amplitude of which is ca 1,5 Gal and achieve extreme values in the spring-autumn interval. Very small value of observed amplitude of gravity changes in the period of extreme variability suggests that the observed gravity changes in LG are caused only by global phenomenon. This proves high degree of „independence” of gravimetric measurement base in LG from the local environmental factors such as ground water level variations, ground humidity, impact of snow cover, etc. At this moment the instrumental environment of absolute measurements obtains particular value, especially in the case of the tiltmeters and relative the gravimeter Lacoste& Romberg (LR-648). The relative gravity measurements as performed simultaneously with absolute gravity measurements enable us to determine the local tidal ephemeredes which makes it possible to replace the global tidal modal with ocean tidal model with the more realistic, locally determined tidal parameters (the local tidal ephemeredes).

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Bower, D. R., et N. Courtier. « Precipitation effects on gravity measurements at the Canadian Absolute Gravity Site ». Physics of the Earth and Planetary Interiors 106, n^o 3-4 (avril 1998) : 353–69. http://dx.doi.org/10.1016/s0031-9201(97)00101-5.

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Koichiro, Doi, Hayakawa Hideaki, Kazama Takahito, Higashi Toshihiro, Osono Shingo, Fukuda Yoichi, Nishijima Jun, Aoyama Yuichi et Ueda Junichi. « Field measurements of absolute gravity in East Antarctica ». Advances in Polar Science 24, n^o 4 (2013) : 339. http://dx.doi.org/10.3724/sp.j.1085.2013.00339.

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Boulanger, Y. D. « The Second International Comparison of Absolute Gravity Measurements ». Bulletin Géodésique 61, n^o 1 (mars 1987) : 85–86. http://dx.doi.org/10.1007/bf02520418.

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Sugihara, Mituhiko, et Tsuneo Ishido. « Geothermal reservoir monitoring with a combination of absolute and relative gravimetry ». GEOPHYSICS 73, n^o 6 (novembre 2008) : WA37—WA47. http://dx.doi.org/10.1190/1.2991105.

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Microgravity monitoring is a valuable tool for mapping the redistribution of subsurface mass and for assessing changes in fluid recharge from reservoir boundaries associated with geothermal exploitation. To further the development of a high-precision absolute/relative hybrid gravity-measurement technique, we conducted measurements using an absolute gravimeter in two geothermal fields in Japan. The absolute gravity measurements were performed in the central production areas to directly measure gravity changes caused by fluid withdrawal. We succeeded in measuring long-term trends within an accuracy of a few microgals in the Okuaizu and Ogiri fields, which have been producing electricity for several years. Absolute measurements in the center of the field provide reliable and local reference datum anchor points for more widely distributed relative gravity measurements. In the Ogiri field, we carried out time-lapse hybrid measurements with this combination of absolute and relative gravimetry and delineated the spatial distributions of long- and short-term changes. The long-term changes are relatively small, considering the four-year observation interval. This suggests a near balance between the mass withdrawal rate from wells and mass recharge from peripheral regions. The apparent balance is reproduced fairly well by a preliminary numerical reservoir simulation study. The observed long- and short-term changes are thought to be useful constraints for planned history-matching studies based on refined reservoir models with greater spatial resolution that incorporate detailed well-by-well production histories.

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Cheng, Bing, Pei-Jun Chen, Yin Zhou, Kai-Nan Wang, Dong Zhu, Li Chu, Kan-Xing Weng et al. « Experiment on dynamic absolute gravity measurement based on cold atom gravimeter ». Acta Physica Sinica 71, n^o 2 (2022) : 026701. http://dx.doi.org/10.7498/aps.71.20211449.

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Dynamic gravity measurements can improve the survey efficiency of the gravity field, and can play an important role in implementing the basic geological surveys, resource exploration, and geophysical research. Based on cold atom gravimeter, inertial stabilization platform and the movable vehicle device, a system for dynamically measuring absolute gravity is built, and the dynamic measurement experiments are carried out. Firstly, the noise power spectra of the vertical vibration are measured at different moving velocities, and the influence of such a vibration on the measurement of absolute gravity is analyzed theoretically. Besides, the influence on the contrasts and offsets of the atomic interference fringes are evaluated from different moving velocities, then the effect of vibration compensation in the dynamic measurement environment is analyzed. When the maximum moving speed is 5.50 cm/s and the maximum vibration amplitude is 0.1 m/s2, the atomic interference fringes can still be rebuilt based on the technology of vibration compensation. On this basis, the atomic interference fringes are obtained at different values of T and different moving velocities, then the absolute gravity value in the dynamic measurement environment is evaluated. After the correction of the systematic system and subtraction by the initial value of absolute gravity, the final measured result is (–1.22 ± 2.42) mGal. Finally, the experiment on the static absolute gravity is conducted, and the two values are found to be not much different from each other through comparing the static measurement data with the dynamic measurement data. The experiment of dynamic absolute gravity measurement in this paper may provide the helpful reference data for the dynamic absolute gravity measurement with moving vehicles.

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Sasagawa, Glenn S., Mark A. Zumberge, J. Mark Stevenson, Ted Lautzenhiser, Jim Wirtz et Mark E. Ander. « The 1987 Southeastern Alaska Gravity Calibration Range : Absolute and relative gravity measurements ». Journal of Geophysical Research 94, B6 (1989) : 7661. http://dx.doi.org/10.1029/jb094ib06p07661.

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de Angelis, M., F. Greco, A. Pistorio, N. Poli, M. Prevedelli, G. Saccorotti, F. Sorrentino et G. M. Tino. « Measurement of absolute gravity acceleration in Firenze ». Solid Earth Discussions 3, n^o 1 (31 janvier 2011) : 43–64. http://dx.doi.org/10.5194/sed-3-43-2011.

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Abstract. This paper reports the results from the accurate measurement of the acceleration of gravity g taken at two separate premises in the Polo Scientifico of the University of Firenze (Italy). In these laboratories, two separate experiments aiming at measuring the Newtonian constant and testing the Newtonian law at short distances are in progress. Both experiments require an independent knowledge on the local value of g. The only available datum, pertaining to the italian zero-order gravity network, was taken more than 20 years ago at a distance of more than 60 km from the study site. Gravity measurements were conducted using an FG5 absolute gravimeter, and accompanied by seismic recordings for evaluating the noise condition at the site. The absolute accelerations of gravity at the two laboratories are (980 492 160.6 ± 4.0) μGal and (980 492 048.3 ± 3.0) μGal for the European Laboratory for Non-Linear Spectroscopy (LENS) and Dipartimento di Fisica e Astronomia, respectively. Other than for the two referenced experiments, the data here presented will serve as a benchmark for any future study requiring an accurate knowledge of the absolute value of the acceleration of gravity in the study region.

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Greco, Filippo, Federica Riguzzi et Giovanna Berrino. « Insights into Seismogenetic Areas in Central Italy from Combined Absolute Gravity and GNSS Measurements ». Remote Sensing 13, n^o 22 (18 novembre 2021) : 4649. http://dx.doi.org/10.3390/rs13224649.

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In this study we present and discuss gravity and ground deformation variations, at different time scales, observed in a wide mesh absolute gravity and GNSS network set up in central Italy. The network was installed in the area affected by the 2009 (L’Aquila; Mw 6.1) and 2016 (Amatrice-Norcia; Mw 6.0 and 6.5) seismic activity, in order to verify if gravity and ground deformation variations could be related to seismic effects. The new network includes 5 stations distributed between the Lazio, Umbria, and Abruzzo regions. From 2018 to 2020 three campaigns were carried out using the transportable Micro-g LaCoste FG5#238 and the portable Micro-g LaCoste A10#39 absolute gravimeters and completed with two simultaneous GNSS measurements. Topographic instruments, measurement and analysis techniques enabling accurate measurements in the positioning of the stations and to control their variations over time were applied. The high reliability and accuracy of the absolute gravity data gathered, after being corrected for known effects, showed a negative short-term (2018–2020) pattern throughout the area, up to −30 µGal. Since some stations of the new network coincided with benchmarks already measured in the past, an analysis of long-term gravity changes was carried out and a fair degree of stability was observed in two stations, while positive large variations, of approximately 70 and 157 µGal, were recorded in the other two stations in the time intervals 1954–2020 and 2005–2010, respectively. On the other hand, variations highlighted by GNSS height measurements were all below 3 cm. Here, the first long-lasting gravity measurements carried out with absolute gravimeters in a seismic area in Italy are presented, providing meaningful geophysical information. The obtained results, in terms of availability of a combined absolute gravity and GNSS network, definition of data acquisition and analysis procedures, as well as creation of a high quality data archive, lay the foundations for a multidisciplinary approach towards improving the knowledge of this seismogenetic area of Italy.

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Akdoğan, Yunus Aytaç, Hasan Yildiz et Gonca Okay Ahi. « Evaluation of global gravity models from absolute gravity and vertical gravity gradient measurements in Turkey ». Measurement Science and Technology 30, n^o 11 (4 septembre 2019) : 115009. http://dx.doi.org/10.1088/1361-6501/ab2f1c.

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Zhu, Xueliang, Fengming Nie, Bingcai Liu, Ruikun Liu et Ailing Tian. « Multiposition Rotation Interference Absolute Measurement Method for High-Precision Optical Component Surfaces ». International Journal of Optics 2021 (14 septembre 2021) : 1–8. http://dx.doi.org/10.1155/2021/6621939.

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Modern optical engineering requires increasingly sophisticated interferometry methods capable of conducting subnanometer scale measurements of the large aperture, high-precision optical component surfaces. However, the accuracy of interferometry measurement is limited to the accuracy with which the surface of the reference mirror employed in the interferometer system is known, and the influence of gravity-induced deformation cannot be ignored. This is addressed in the present work by proposing a three-flat testing method based on multiposition rotation interference absolute surface measurement technology that combines the basic theory of N-position rotation with the separability of surface wavefront functions into sums of even and odd functions. These functions provide the rotational symmetric components of the wavefront, which then enables the absolute surface to be reconstructed based on the N-position rotation measurements. In addition, we propose a mechanical clamping combined with computational method to compensate for the gravity-induced deformations of the flats in the multiposition rotation absolute measurements. The high precision of the proposed absolute surface measurement method is demonstrated via simulations. The results of laboratory experiments indicate that the combination compensation method provides the high-precision surface reconstruction outcomes. The present work provides an important contribution for supporting the interferometry measurement of large aperture, high-precision optical component surfaces.

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Timofeev, V. Ju, D. G. Ardyukov, A. V. Timofeev, M. G. Valitov, I. S. Sizikov, D. A. Nosov et Yu F. Stus. « Gravity observation at Shults cape polygon ». Vestnik SSUGT (Siberian State University of Geosystems and Technologies) 27, n^o 4 (2022) : 31–44. http://dx.doi.org/10.33764/2411-1759-2022-27-4-31-44.

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Gravity measurements with different kind of absolute gravimeters and spring gravimeters were started at the Marine Experimental Observatory Shults Cape of Il'ichev Oceanological Institute, Far East Branch of Russian Academy of Sciences from 2010 year. Simultaneously, on the polygone, located in the South of Primorie, started the geodetic measurements by GNSS methods for determination of the coordinates and study of gravimetric points’ displacements. Gravimetric measurements are used to solve structural and monitoring tasks. Planned and high-altitude geodetic measurements are necessary for the correct interpretation of gravimetric results and obtaining reduced gravity values. Complex measurements with absolute and relative gravimeters are used to test the metrological characteristics of relative gravimeters such as SCINTREX and GPhone. As a result of the analysis of tidal variations of gravity, corrections to the absolute data were obtained. Carrying out measurements at different altitudes using absolute gravimeters of the GABLM-M type made it possible to reduce the values of gravity and compare experimental and theoretical estimates. The results are used in structural geological studies in Primorie. The second task of the research was to determine the level of time variations of gravity, 3D displacements of the earth's surface and determine their nature. According to measure-ments in the period 2010–2020, the effects associated with the Japanese earthquake of 11.03.2011 with a magnitude of M = 9,0 were investigated. At a distance of 1000 km from the epicenter, the mag-nitude of post-seismic subsidence for the period 2012–2020 was 22 m, gravity increased by 6 microgal. According to the shape of the attenuation curve of vertical displacements, a model was selected and an estimate of Maxwell's time (T = 3 years) was obtained. Within the framework of a two-layer model, the viscosity of the earth's crust lower part – the asthenosphere on the edge of the continent – was determined.

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Liu, Jiandong, Erhu Wei, Shuanggen Jin et Jingnan Liu. « Absolute Navigation and Positioning of Mars Rover Using Gravity-Aided Odometry ». Journal of Navigation 71, n^o 3 (23 novembre 2017) : 530–46. http://dx.doi.org/10.1017/s0373463317000893.

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Positioning and Navigation (PN) of Martian rovers still faces challenges due to limited observations. In this paper, the PN feasibilities of Mars rovers based on a Gravity-aided Odometry (GO) system are proposed and investigated in terms of numeric simulations and a case study. Statistical features of the Mars gravity field are studied to evaluate the feature diversity of the background map. The Iterative Closest Point (ICP) algorithm is introduced to match gravity measurements with the gravitational map. The trajectories of Mars Exploration Rovers (MER) and Mars Gravity Map 2011 (MGM2011) are used to complete the experiments. Several key factors of GO including odometry errors, measurement uncertainties, and grid resolution of the map are investigated to evaluate their influences on the positioning ability of the system. Simulated experiments indicate that the GO method could provide an alternative positioning solution for Martian surface rovers.

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Pešková, Alena, et Martin Štroner. « Adjustment and testing comparison of absolute gravimeters in November 2013 ». Geoinformatics FCE CTU 16, n^o 1 (8 octobre 2017) : 79–90. http://dx.doi.org/10.14311/gi.16.1.5.

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This paper is focused on a comparison measurement processing of absolute gravimeters in 2013. The comparison deals with a number of various types of absolute gravimeters and includes also an absolute gravimeter from Geodetic observatory Pecný. Comparative measurements are performed to detect systematic errors of gravimeters. A result of processing is most likely value of a gravity and a systematic error of individual devices. Measured values are input to a adjustment with condition a sum of systematic errors is zero. A part of this process is also verification following output: (i) value of a posteriori standard deviation, (ii) size of corrections and (iii) statistical significance of systematic errors. The results of adjustment are 15 gravity values on the reference places and 25 systematic errors of measuring instruments. Result shows that the presence of systematic errors in measurements is not statistically provable because the systematic errors are similarly sized as their standard deviation.

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Timofeev, Vladimir Yu, Dmitriy G. Ardyukov, Anton V. Timofeev, Pavel Yu Gornov, Yurii F. Stus et Vladimir M. Semibalamut. « VOLUME DEFORMATION VARIATIONS AND WELL-AQUIFER RESPONSE, ITS CONNECTION WITH GRAVITY MEASUREMENTS ». Vestnik SSUGT (Siberian State University of Geosystems and Technologies) 26, n^o 5 (2021) : 40–51. http://dx.doi.org/10.33764/2411-1759-2021-26-5-40-51.

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Precise gravity measurements at g0·10 -9 level requires taking into account density change, caused by the Earth’s crust deformation and the movement and position of the fluid in the layer. The paper presents analysis of water level observation in three boreholes situated at Primorie, at Kamchatka and at Baikal region. Water-level fluctuations were influenced by earth tides, barometric pressure, co-seismic effects and season precipitations. Water tidal signal was analyzed for calculations of level-strain coefficients, its values changed from 0.1 mm/10-9 to 1.6 mm/10-9. Gravity corrections were developed by volume variation. For borehole drilled at monolithic rock we used the phaselag effect for tidal strain and crack-system orientation was studied in Pribaikalie mountain valley. Longterm gravity results were tested with water level data at Talaya station (Pribaikalie). Talaya gravity point situated at monolithic rock had no influence from water level variation. Level-correction was less than absolute gravity measurement error. Quick coseismic effects of earthquakes are well registered by level measuring, deformation graphical and absolute gravimetric methods.

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Reudink, Rene, Roland Klees, Bas Alberts et Pieter van Waarden. « Absolute vertical motion of the Amsterdam Ordnance Datum (NAP) ». Proceedings of the International Association of Hydrological Sciences 382 (22 avril 2020) : 161–65. http://dx.doi.org/10.5194/piahs-382-161-2020.

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Abstract. The backbone of the Amsterdam Ordnance Datum (NAP) is a network of about 400 primary subsurface markers. Relative movements between the primary subsurface markers are measured with spirit levelling once in 10–20 years. However, little is known about absolute vertical movements of the primary network. This information is indispensable for the interpretation of water level measurements at the tide gauges along the Dutch coast. It may be provided by gravity measurements. Here we present a time-series analysis of more than twenty years of gravity measurements at the stations Westerbork, Epen, Zundert, and Radio Kootwijk. It reveals that only station Epen shows a statistically significant movement of -0.252±0.066 µGal yr−1, which corresponds to an uplift of 1.3±0.5 mm yr−1. For the other stations, the trends are statistically not different from zero at a significance level of 0.05. Corrections for water table variations are found to be indispensable; peak-to-peak amplitudes range from 4 µGal (Westerbork) to 28 µGal (Radio Kootwijk). Depsite some fundamental objections, corrections for instrumental offsets reduce the data scatter. First experiments with 7 years of soil moisture data acquired at station Radio Kootwijk reveal that the gravity signal of soil moisture variations has a standard deviation of 2.2 µGal, which is comparable to the noise standard deviation of measured gravity.

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Lambert, Anthony, Nicholas Courtier, Glenn S. Sasagawa, Fred Klopping, Daniel Winester, Thomas S. James et Jacques O. Liard. « New constraints on Laurentide postglacial rebound from absolute gravity measurements ». Geophysical Research Letters 28, n^o 10 (15 mai 2001) : 2109–12. http://dx.doi.org/10.1029/2000gl012611.

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Greco, F., G. Currenti, G. D’Agostino, A. Germak, R. Napoli, A. Pistorio et C. Del Negro. « Combining relative and absolute gravity measurements to enhance volcano monitoring ». Bulletin of Volcanology 74, n^o 7 (16 juin 2012) : 1745–56. http://dx.doi.org/10.1007/s00445-012-0630-0.

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Ferguson, John F., F. J. Klopping, Tianyou Chen, John E. Seibert, Jennifer L. Hare et Jerry L. Brady. « The 4D microgravity method for waterflood surveillance : Part 3 — 4D absolute microgravity surveys at Prudhoe Bay, Alaska ». GEOPHYSICS 73, n^o 6 (novembre 2008) : WA163—WA171. http://dx.doi.org/10.1190/1.2992510.

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The 4D microgravity method is becoming a mature technology. A project to develop practical measurement and interpretation techniques was conducted at Prudhoe Bay, Alaska, from 1994 through 2002. Beginning in 2003 these techniques have been systematically applied to monitor a waterflood in the gas cap of the Prudhoe Bay reservoir. Approximately 300 stations in a [Formula: see text] area are reoccupied in each survey year with sub-[Formula: see text] precision absolute gravity and centimeter precision Global Positioning System (GPS) geodetic measurements. The 4D gravity measured over epochs 2005–2003, 2006–2003, and 2007–2003 has been successfully modeled to track the mass of water injected since late in 2002. A new and improved version of the A-10 field-portable absolute gravity meter was developed in conjunction with this project and has proven to be a key element in the success of the 4D methodology. The use of an absolute gravity meter in a field survey of this magnitude is unprecedented. There are substantial differences between a 4D absolute microgravity survey and a conventional gravity survey in terms of station occupation procedures, GPS techniques, and the 4D elevation correction. We estimate that the overall precision of the 4D gravity signal in each epoch is less than [Formula: see text].

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Ferguson, J. F., T. Chen, J. Brady, C. L. Aiken et J. Seibert. « The 4D microgravity method for waterflood surveillance : Part II — Gravity measurements for the Prudhoe Bay reservoir, Alaska ». GEOPHYSICS 72, n^o 2 (mars 2007) : I33—I43. http://dx.doi.org/10.1190/1.2435473.

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Between 1994 and 2002, a series of experiments was conducted at Prudhoe Bay, Alaska, aimed at the development of an effective 4D (or time-lapse) gravity technique. Theoretical investigations had pointed out the potential for monitoring water injection in the [Formula: see text]-deep reservoir, but it was not clear that gravity measurements of sufficient accuracy could be made in the arctic environment. During the course of these experiments, new techniques and instrumentation were introduced and perfected for both gravity and position measurements. Gravity stations are located using high-precision global positioning system (GPS) techniques without permanent monuments. Robust methods for meter drift control have improved noise resistance in relative gravimeter surveys. Absolute gravity measurements with a field-portable instrument maintain absolute gravity levels among surveys. A 4D gravity-difference noise of [Formula: see text] standard deviation has been established at Prudhoe Bay for GPS-controlled relative gravimeter surveys. The lessons learned are now being applied to full-scale waterflood monitoring at Prudhoe Bay. The basic technique is applicable to microgravity surveys and 4D microgravity surveys for any purpose.

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Schäfer, Florian, Philippe Jousset, Andreas Güntner, Kemal Erbas, Jacques Hinderer, Séverine Rosat, Christian Voigt, Tilo Schöne et Richard Warburton. « Performance of three iGrav superconducting gravity meters before and after transport to remote monitoring sites ». Geophysical Journal International 223, n^o 2 (28 juillet 2020) : 959–72. http://dx.doi.org/10.1093/gji/ggaa359.

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SUMMARY High spatial and temporal resolution of gravity observations allows quantifying and understanding mass changes in volcanoes, geothermal or other complex geosystems. For this purpose, accurate gravity meters are required. However, transport of the gravity meters to remote study areas may affect the instrument's performance. In this work, we analyse the continuous measurements of three iGrav superconducting gravity meters (iGrav006, iGrav015 and iGrav032), before and after transport between different monitoring sites. For 4 months, we performed comparison measurements in a gravimetric observatory (J9, Strasbourg) where the three iGravs were subjected to the same environmental conditions. Subsequently, we transported them to Þeistareykir, a remote geothermal field in North Iceland. We examine the stability of three instrumental parameters: the calibration factors, noise levels and drift behaviour. For determining the calibration factor of each instrument, we used three methods: First, we performed relative calibration using side-by-side measurements with an observatory gravity meter (iOSG023) at J9. Secondly, we performed absolute calibration by comparing iGrav data and absolute gravity measurements (FG5#206) at J9 and Þeistareykir. Thirdly, we also developed an alternative method, based on intercomparison between pairs of iGravs to check the stability of relative calibration before and after transport to Iceland. The results show that observed changes of the relative calibration factors by transport were less than or equal to 0.01 per cent. Instrumental noise levels were similar before and after transport, whereas periods of high environmental noise at the Icelandic site limited the stability of the absolute calibration measurements, with uncertainties above 0.64 per cent (6 nm s–2 V–1). The initial transient drift of the iGravs was monotonically decreasing and seemed to be unaffected by transport when the 4K operating temperatures were maintained. However, it turned out that this cold transport (at 4 K) or sensor preparation procedures before transport may cause a change in the long-term quasi-linear drift rates (e.g. iGrav015 and iGrav032) and they had to be determined again after transport by absolute gravity measurements.

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Szabó, Viktor, et Dorota Marjańska. « Accuracy Analysis of Gravity Field Changes from Grace RL06 and RL05 Data Compared to in Situ Gravimetric Measurements in the Context of Choosing Optimal Filtering Type ». Artificial Satellites 55, n^o 3 (1 septembre 2020) : 100–117. http://dx.doi.org/10.2478/arsa-2020-0008.

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AbstractGlobal satellite gravity measurements provide unique information regarding gravity field distribution and its variability on the Earth. The main cause of gravity changes is the mass transportation within the Earth, appearing as, e.g. dynamic fluctuations in hydrology, glaciology, oceanology, meteorology and the lithosphere. This phenomenon has become more comprehensible thanks to the dedicated gravimetric missions such as Gravity Recovery and Climate Experiment (GRACE), Challenging Minisatellite Payload (CHAMP) and Gravity Field and Steady-State Ocean Circulation Explorer (GOCE). From among these missions, GRACE seems to be the most dominating source of gravity data, sharing a unique set of observations from over 15 years. The results of this experiment are often of interest to geodesists and geophysicists due to its high compatibility with the other methods of gravity measurements, especially absolute gravimetry. Direct validation of gravity field solutions is crucial as it can provide conclusions concerning forecasts of subsurface water changes. The aim of this work is to present the issue of selection of filtration parameters for monthly gravity field solutions in RL06 and RL05 releases and then to compare them to a time series of absolute gravimetric data conducted in quasi-monthly measurements in Astro-Geodetic Observatory in Józefosław (Poland). The other purpose of this study is to estimate the accuracy of GRACE temporal solutions in comparison with absolute terrestrial gravimetry data and making an attempt to indicate the significance of differences between solutions using various types of filtration (DDK, Gaussian) from selected research centres.

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Berrino, Giovanna, et Giuseppe Ricciardi. « Repeated absolute gravity measurements on a dense network at Campi Flegrei – a reliable tool for volcano monitoring ». Advances in Geosciences 52 (25 août 2020) : 41–54. http://dx.doi.org/10.5194/adgeo-52-41-2020.

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Abstract. Since 1981, relative gravity measurements have routinely carried out at the Campi Flegrei caldera, a densely populated area. The gravity network also includes two absolute stations periodically measured with a laboratory absolute gravimeter, which does not permit field measurements. At the end of 2014, the Osservatorio Vesuviano, Section of Napoli of the Istituto Nazionale di Geofisica e Vulcanologia (INGV-OV), acquired a portable absolute gravimeter that allows field operations on outdoor sites. Therefore, in 2015 a dense absolute gravity network was established in Campi Flegrei. This will permit an advanced approach for volcano monitoring. The net consists of 36 stations, 34 of which located inside the caldera and placed upon or very close to gravity stations belonging to the relative network. Five surveys were carried out on June 2015, on February and November 2017, on October 2018 and on October 2019. The comparison with height changes suggests that significant Δg are partly due to the uplift occurred over the same time intervals and mostly to shallow processes associated to the dynamic of the local hydrothermal system. The comparison with the gradients observed during the last large uplift (1982–1984) and the following subsidence (1985–2003) confirms this observation. These results suggest that the present activity may be due to a transient or pulsating phenomenon as the alternating recharge/discharge of fluids in the surface hydrothermal system. Gravity changes detected by absolute measurements are in good agreement with those obtained by relative ones, and confirms the feasibility of this methodology for volcano monitoring. Finally, they also encourage replacing the relative networks with absolute ones, with all the consequent advantages.

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Ni, Dongdong. « Understanding Saturn’s interior from the Cassini Grand Finale gravity measurements ». Astronomy & ; Astrophysics 639 (juillet 2020) : A10. http://dx.doi.org/10.1051/0004-6361/202038267.

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Context. Measurements of Saturn’s gravity field by Cassini Grand Finale have been acquired with high precision. It has been demonstrated that the even gravitational harmonics J6–J10 have larger absolute values than the predictions by typical rigid-body interior models. A four-layer structure model, proposed to interpret Juno’s gravity measurements for Jupiter, has been applied to Saturn, but great attention was paid to the depth of zonal flows in order to interpret the large absolute values of J6–J10. Aims. We aim to understand the internal structure and interior composition of Saturn with a similar model for Jupiter. The additional uncertainties in Saturn’s structure and composition are investigated in detail, such as rotation periods, atmospheric helium mass fractions, and flow-induced gravity corrections. Also, we investigate the effect of equations of state for hydrogen and helium on the predictions of the core mass and heavy element abundance. Methods. In the four-layer structure model, we adjusted the heavy element abundances in the outer two envelopes and the mass of the compact core in order to reproduce Saturn’s equatorial radius as well as the Cassini Grand Finale gravity measurements corrected by the flow-induced gravity signals. Different four-layer interior models are specified in terms of the rotation period, the atmospheric helium mass fraction, and the flow-induced gravity corrections. Two different ab initio equations of state for hydrogen and helium were used in interior structure calculations. Optimized calculations were then performed to explore Saturn’s internal structure and composition. Results. It is found that the absolute values of J6–J10 tend to increase with increasing deep rotation rate and depend on the equations of state adopted in interior calculations. Saturn’s deep rotation rate and atmospheric helium mass fraction are important to determine the distribution of helium and heavy elements in the outer envelopes. We also show that the core mass and heavy element abundance in Saturn are dependent upon the deep rotation rate, the atmospheric helium mass fraction, the flow-induced gravity corrections, and the equations of state for hydrogen and helium.

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Anthony, Robert E., Adam T. Ringler et Dave C. Wilson. « Improvements in Absolute Seismometer Sensitivity Calibration Using Local Earth Gravity Measurements ». Bulletin of the Seismological Society of America 108, n^o 1 (19 décembre 2017) : 503–10. http://dx.doi.org/10.1785/0120170218.

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Niebauer, T. M., Ryan Billson, Brian Ellis, Bryon Mason, Derek van Westrum et Fred Klopping. « Simultaneous gravity and gradient measurements from a recoil-compensated absolute gravimeter ». Metrologia 48, n^o 3 (30 mars 2011) : 154–63. http://dx.doi.org/10.1088/0026-1394/48/3/009.

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Hinderer, J., N. Florsch, J. Mäkinen, H. Legros et J. E. Faller. « On the calibration of a superconducting gravimeter using absolute gravity measurements ». Geophysical Journal International 106, n^o 2 (août 1991) : 491–97. http://dx.doi.org/10.1111/j.1365-246x.1991.tb03907.x.

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Jushkin, V. D., L. V. Zotov et O. A. Khrapenko. « Hydrogeology correction in the gravitational field from satellite data ». Geodesy and Cartography 931, n^o 1 (20 février 2018) : 2–7. http://dx.doi.org/10.22389/0016-7126-2018-931-1-2-7.

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The results of repeated measurements of the acceleration of gravity by the Russian absolute ballistic field gravimeter GABL-M on points of oil and gas deposits in the permafrost over a five year period are presented. The changes of gravity acceleration by the absolute gravimeter and GRACE satellite were compared. The results of comparisons of differences gravity acceleration by ballistic gravimeter GABL-M and relative Canadian gravimeters CG5 were [i]shown. The errors in determination of parameters of the gravitational field ballistic gravimeter GABL-M and CG5 gravimeters group were presented. The method of measurement with the gravimeter GABL-M and the method of determining the vertical gradients relative CG5 gravity meters was described. The necessity of introducing corrections of hydrogeology is caused by influence of hydro geological factors on the gravitational field in the permafrost. They are comparable with the values of the field change in the result of gas pumping.

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Wang, Helin, Kainan Wang, Yunpeng Xu, Yituo Tang, Bin Wu, Bing Cheng, Leyuan Wu et al. « A Truck-Borne System Based on Cold Atom Gravimeter for Measuring the Absolute Gravity in the Field ». Sensors 22, n^o 16 (18 août 2022) : 6172. http://dx.doi.org/10.3390/s22166172.

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The cold atom gravimeter (CAG) has proven to be a powerful quantum sensor for the high-precision measurement of gravity field, which can work stably for a long time in the laboratory. However, most CAGs cannot operate in the field due to their complex structure, large volume and poor environmental adaptability. In this paper, a home-made, miniaturized CAG is developed and a truck-borne system based on it is integrated to measure the absolute gravity in the field. The measurement performance of this system is evaluated by applying it to measurements of the gravity field around the Xianlin reservoir in Hangzhou City of China. The internal and external coincidence accuracies of this measurement system were demonstrated to be 35.4 μGal and 76.7 μGal, respectively. Furthermore, the theoretical values of the measured eight points are calculated by using a forward modeling of a local high-resolution digital elevation model, and the calculated values are found to be in good agreement with the measured values. The results of this paper show that this home-made, truck-borne CAG system is reliable, and it is expected to improve the efficiency of gravity surveying in the field.

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Ayhan, Mehmet Emin, Bandar Saleh Abdulkareem Al-Muslmani, Jeff Kanney et Othman Abdulmohsen Issa Al-Kherayef. « Absolute gravity measurements by using FG5 and A10 absolute gravimeters in the Kingdom of Saudi Arabia ». Arabian Journal of Geosciences 8, n^o 8 (27 août 2014) : 6199–209. http://dx.doi.org/10.1007/s12517-014-1593-6.

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PARASKEVAS, Melissinos, Demitris PARADISSIS, Konstantinos RAPTAKIS, Paraskevi NOMIKOU, Emilie HOOFT et Konstantina BEJELOU. « Gravity observations on Santorini island (Greece) : Historical and recent campaigns ». Contributions to Geophysics and Geodesy 51, n^o 1 (15 mars 2021) : 1–24. http://dx.doi.org/10.31577/congeo.2021.51.1.1.

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Santorini is located in the central part of the Hellenic Volcanic Arc (South Aegean Sea) and is well known for the Late-Bronze-Age “Minoan” eruption that may have been responsible for the decline of the great Minoan civilization on the island of Crete. To use gravity to probe the internal structure of the volcano and to determine whether there are temporal variations in gravity due to near surface changes, we construct two gravity maps. Dionysos Satellite Observatory (DSO) of the National Technical University of Athens (NTUA) carried out terrestrial gravity measurements in December 2012 and in September 2014 at selected locations on Thera, Nea Kameni, Palea Kameni, Therasia, Aspronisi and Christiana islands. Absolute gravity values were calculated using raw gravity data at every station for all datasets. The results were compared with gravity measurements performed in July 1976 by DSO/NTUA and absolute gravity values derived from the Hellenic Military Geographical Service (HMGS) and other sources. Marine gravity data that were collected during the PROTEUS project in November and December 2015 fill between the land gravity datasets. An appropriate Digital Elevation Model (DEM) with topographic and bathymetric data was also produced. Finally, based on the two combined datasets (one for 2012–2014 and one for the 1970s), Free air and complete Bouguer gravity anomaly maps were produced following the appropriate data corrections and reductions. The pattern of complete Bouguer gravity anomaly maps was consistent with seismological results within the caldera. Finally from the comparison of the measurements made at the same place, we found that, within the caldera, the inner process of the volcano is ongoing both before, and after, the unrest period of 2011–2012.

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Psiaki, Mark L. « Absolute Orbit and Gravity Determination Using Relative Position Measurements Between Two Satellites ». Journal of Guidance, Control, and Dynamics 34, n^o 5 (septembre 2011) : 1285–97. http://dx.doi.org/10.2514/1.47560.

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Canuteson, Eric, Mark Zumberge et Jeffrey Hanson. « An absolute method of vertical seismometer calibration by reference to a falling mass with application to the measurement of the gain ». Bulletin of the Seismological Society of America 87, n^o 2 (1 avril 1997) : 484–93. http://dx.doi.org/10.1785/bssa0870020484.

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Abstract We measure the gain of a vertical seismometer by simultaneously recording the output of the seismometer and repeatedly measuring the displacement between the seismometer and a free-falling mass in a vacuum. The falling object provides an inertial reference frame. By comparing the ground motion measured by the seismometer with the independent record of displacement between the seismometer and inertial space, we obtain the gain. It is an absolute measurement of the gain relative to the local Lorentz reference frame. Bootstrap error estimates show that a high precision in the estimate of the gain can be obtained with a small number of individual drops. The method derived can be extended to multi-parameter searches of the vertical response function. The technique is also shown to reduce noise in absolute gravity measurements due to ground noise. Finally, we discuss the potential for replacing vibration isolation schemes in absolute gravity systems with digital noise reduction.

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Ern, M., P. Preusse et C. D. Warner. « Some experimental constraints for spectral parameters used in the Warner and McIntyre gravity wave parameterization scheme ». Atmospheric Chemistry and Physics Discussions 6, n^o 3 (14 juin 2006) : 4755–94. http://dx.doi.org/10.5194/acpd-6-4755-2006.

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Abstract. In order to incorporate the effect of gravity waves (GWs) on the atmospheric circulation most global circulation models (GCMs) employ gravity wave parameterization schemes. To date, GW parameterization schemes in GCMs are used without experimental validation of the set of global parameters assumed for the GW launch spectrum. This paper focuses on the Warner and McIntyre GW parameterization scheme. Ranges of parameters compatible with absolute values of gravity wave momentum flux (GW-MF) derived from CRISTA-1 and CRISTA-2 satellite measurements are deduced for several of the parameters and the limitations of both model and measurements are discussed. The findings presented in this paper show that the initial guess of spectral parameters provided by Warner and McIntyre (2001) are some kind of compromise with respect to agreement of absolute values and agreement of the horizontal structures found in both measurements and model results. Better agreement can be achieved by using a vertical wavenumber launch spectrum with a wider saturated spectral range and reduced spectral power in the unsaturated part. Still, even global features of the measurements remain unmatched, and it is inevitable to provide a globally varying source distribution in future.

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Tushingham, A. M., A. Lambert, J. O. Liard et W. R. Peltier. « Secular gravity changes : measurements and predictions for selected Canadian sites ». Canadian Journal of Earth Sciences 28, n^o 4 (1 avril 1991) : 557–60. http://dx.doi.org/10.1139/e91-049.

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Secular variations in surface gravity (ġ) over Canada are dominated by the Late Wisconsin deglaciation signal. Theoretical modelling of this deglaciation shows that the maximum values for ġ are to be expected around Hudson Bay. Using the JILA-2 absolute gravity apparatus of the Geological Survey of Canada, it should be possible to determine ġ at three sites near Hudson Bay by about 1993 and at more sites soon afterward. Secular rates of the ongoing postglacial-adjustment process will soon be determined at inland sites where no contemporary rates have been available.

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WANG, Yong, Wei-Min ZHANG, Jin-Gang ZHAN, Xing-Hua HAO, Hu-Biao WANG et Hou-Ze XU. « Gravity Change Detected by Repeated Absolute Gravity Measurements in Western Yunnan and Lhasa, China and Its Implication ». Chinese Journal of Geophysics 47, n^o 1 (janvier 2004) : 110–16. http://dx.doi.org/10.1002/cjg2.460.

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Ern, M., P. Preusse et C. D. Warner. « Some experimental constraints for spectral parameters used in the Warner and McIntyre gravity wave parameterization scheme ». Atmospheric Chemistry and Physics 6, n^o 12 (27 septembre 2006) : 4361–81. http://dx.doi.org/10.5194/acp-6-4361-2006.

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Abstract. In order to incorporate the effect of gravity waves (GWs) on the atmospheric circulation most global circulation models (GCMs) employ gravity wave parameterization schemes. To date, GW parameterization schemes in GCMs are used without experimental validation of the set of global parameters assumed for the GW launch spectrum. This paper focuses on the Warner and McIntyre GW parameterization scheme. Ranges of parameters compatible with absolute values of gravity wave momentum flux (GW-MF) derived from CRISTA-1 and CRISTA-2 satellite measurements are deduced for several of the parameters and the limitations of both model and measurements are discussed. The findings presented in this paper show that the initial guess of spectral parameters provided by by Warner and McIntyre (2001) are some kind of compromise with respect to agreement of absolute values and agreement of the horizontal structures found in both measurements and model results. Better agreement can be achieved by using a vertical wavenumber launch spectrum with a wider saturated spectral range and reduced spectral power in the unsaturated part. However, even with this optimized set of global launch parameters not all features of the measurements are matched. This indicates that for further improvement spatial and seasonal variations of the launch parameters should be included in GW parameterization schemes.

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Kloppinga, Fred, Jaakko Mäkinen, Alexander Lothhammer, Herbert Wilmes, Erik Roland et Knut Røthing. « Absolute gravity measurements at Nordic geodetic laboratories in Fennoscandia and Spitsbergen 1991–1993 ». Journal of Applied Geophysics 34, n^o 2 (décembre 1995) : 145–46. http://dx.doi.org/10.1016/0926-9851(96)80877-9.

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Xing, Lelin, Hui Li, Jiancheng Li et Zhitang He. « Comparison of absolute gravity measurements obtained with FG5/232 and FG5/214 instruments ». Geo-spatial Information Science 12, n^o 4 (janvier 2009) : 307–10. http://dx.doi.org/10.1007/s11806-009-0085-4.

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Esparza, Alfredo, Jorge Arzate, Ludger Timmen, Jason Silliker et Manuel Schilling. « High precision measurements of Absolute Gravity in México : the Jalisco Block changes in gravity triggered by distant earthquakes ». Geofísica Internacional 59, n^o 3 (1 juillet 2020) : 155–68. http://dx.doi.org/10.22201/igeof.00167169p.2020.59.3.2091.

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En este trabajo se reportan los resultados de 16 mediciones de gravedad absoluta (GA) utilizando dos gravímetros de caída libre, el FG5X-220 de la Universidad Leibniz de Hannover (LUH) y el FG5X-252 del Centro Nacional de Metrología (CENAM). Previo al establecimiento de nuevas estaciones gravimétricas de primer orden y a las campañas de adquisición en el Bloque de Jalisco (BJ), se llevó a cabo la certificación del gravímetro FG5X-252 a partir de dos comparaciones instrumentales; la primera con el FG5X-220 de LUH, el cual es un instrumento certificado de larga estabilidad y repetibilidad debajo de los 2 µGal, y la segunda a través de una comparación internacional con otros 13 instrumentos en las instalaciones de la NOAA en Table Mountain, Colorado, USA. Las campañas de medición en el BJ se realizaron durante la estación seca (Feb/Mar) los años 2016 y 2018, e incluyó las estaciones de Chamela (CHA), Guadalajara (UGG), Manzanillo (MAN), Puerto Vallarta (UGP) y Tepic (TEP), ésta última establecida como nueva referencia en el norte del bloque. Los resultados obtenidos de estas dos campañas en el BJ fueron comparados con los valores medidos en 1996 por la NOAA en esta misma región del oeste de México. Los desplazamientos verticales observados en el lapso de dos años en las estaciones CHA (+22.7 cm), UGG (+44.3 cm) y MAN (+54.6 cm) supera sustancialmente el promedio anual (2.8 cm, 4.2 cm y 3.6 cm respectivamente) con respecto a las mediciones de GA de 1996. En el mismo periodo, la estación UGP subsidió 8.5 cm mientras que TEP permaneció muy estable (-0.25 cm). En septiembre de 2017 ocurrieron dos grandes sísmos de magnitudes 8.2 y 7.1, con epicentros en la costa de Chiapas (07/sep/2017) y en el Estado de Puebla (19/sep/2017), que fueron registrados en algunas de las estaciones GPS de la red UNAVCO en los sitios MAN, UGG y CHA a pesar de que la fuente sísmica más cercana se localiza a más de 500 km de distancia. El análisis de los datos adquiridos y otros datos geofísicos disponibles apoyan la hipótesis de que el sísmo con epicentro en Puebla disparó la subducción asísmica de una porción de la placa de Rivera (PR), lo que a su vez produjo el levantamiento en dichas estaciones. Concluimos que la subducción asísmica en la zona ocurre debido a la subducción de una corteza oceánica hidratada que arrastra un importante espesor de sedimentos marinos, lo que genera una interfaz lubricada.

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Baumann, Henri, et Ali L. Eichenberger. « Impact of high precision gravimetry in the context of a future new SI ». International Journal of Modern Physics : Conference Series 30 (janvier 2014) : 1460270. http://dx.doi.org/10.1142/s2010194514602701.

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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.

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Mikolaj, Michal, et Branislav Hábel. « The first tidal analysis based on the CG-5 Autograv gravity measurements at Modra station ». Contributions to Geophysics and Geodesy 43, n^o 1 (1 mars 2013) : 59–72. http://dx.doi.org/10.2478/congeo-2013-0004.

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Abstract We present the tidal parameters estimated for the absolute gravity site in Modra (Slovakia). This is the first tidal analysis based on gravity measurements for this location. Relative gravity variations observed by Scintrex CG-5 Autograv gravimeter were used for the tidal analysis. We observed large and non-linear instrumental drift which cannot be effectively eliminated by polynomial approximation. Drift was eliminated by a filtering. New set of tidal parameters was estimated and analyzed with the focus on diurnal and semi-diurnal tidal waves. Time and frequency domain comparison between new parameters and those obtained from the superconducting gravimeter located in Vienna was performed. A maximum amplitude factor difference of 0.2% was found between main tidal waves corrected for ocean tides and non-hydrostatic body tide model. New estimated tidal parameters can serve for the correction of local relative gravity measurements

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