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Termes IGN > sciences naturelles > sciences de la Terre et de l'univers > géosciences > géophysique interne > géodésie > géodésie physique > pesanteur terrestre > champ de pesanteur terrestre
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Evaluation of terrestrial and airborne gravity data over Antarctica : a generic approach / Philipp Zingerle in Journal of geodetic science, vol 9 n° 1 (January 2019)
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Titre : Evaluation of terrestrial and airborne gravity data over Antarctica : a generic approach Type de document : Article/Communication Auteurs : Philipp Zingerle, Auteur ; Roland Pail, Auteur ; M. Scheinert, Auteur ; T. Schaller, Auteur Année de publication : 2019 Article en page(s) : pp 29 - 40 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] Antarctique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] données localisées 3D
[Termes IGN] levé gravimétrique
[Termes IGN] modèle de géopotentielRésumé : (auteur) The AntGrav project, funded by the German Research Foundation (DFG) has the main objective to homogenize and optimize Antarctic gravity field information. Within this project an evaluation procedure is needed to inspect all different kind of gravity field surveys available in Antarctica. In this paper a suitable methodology is proposed.
We present an approach for fast 3D gravity point data reduction in different spectral bands. This is achieved through pre-calculating a fine 3D mesh of synthesized gravity functionals over the entirety of the Antarctic continent, for which two different global models are used: the combined satellite model GOCO05s for the long-wavelength part, and the topographic model Earth2014 for the shorter wavelengths. To maximize the applicability separate meshes are calculated for different spectral bands in order to specifically reduce a certain band or a selected combination. All meshes are calculated for gravity anomalies as well as gravity disturbances. Utilizing these meshes, synthesized gravity data at arbitrary positions is computed by conventional 3D interpolation methods (e.g. linear, cubic or spline).
It is shown that the applied approach can reach a worst-case interpolation error of less than 1 mGal. Evaluation results are presented for the AntGG grid and exemplary for the in-situ measurements of the AGAP and BAS-LAND campaigns. While general properties, large-scale errors and systematic effects can usually be detected, small-scale errors (e.g. of single points) are mostly untraceable due to the uncertainties within the topographic model.Numéro de notice : A2019-408 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1515/jogs-2019-0004 Date de publication en ligne : 19/08/2019 En ligne : https://doi.org/10.1515/jogs-2019-0004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93526
in Journal of geodetic science > vol 9 n° 1 (January 2019) . - pp 29 - 40[article]Mass variation observing system by high low inter-satellite links (MOBILE) : a new concept for sustained observation of mass transport from space / Roland Pail in Journal of geodetic science, vol 9 n° 1 (January 2019)
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Titre : Mass variation observing system by high low inter-satellite links (MOBILE) : a new concept for sustained observation of mass transport from space Type de document : Article/Communication Auteurs : Roland Pail, Auteur ; Jonathan Bamber, Auteur ; Richard Biancale, Auteur ; Rory Bingham, Auteur ; Carla Braitenberg, Auteur ; Annette Eicker, Auteur ; Frank Flechtner, Auteur ; Thomas Gruber, Auteur ; Andreas Güntner, Auteur ; Gerhard Heinzel, Auteur ; Martin Horwath, Auteur ; Laurent Longuevergne, Auteur ; J. Muller, Auteur ; Isabelle Panet , Auteur ; Hubert Savenije, Auteur ; S. Seneviratne, Auteur ; Nico Sneeuw, Auteur ; Tonie M. van Dam, Auteur ; Bert Wouters, Auteur
Année de publication : 2019 Projets : 1-Pas de projet / Article en page(s) : pp 48 - 58 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] gravimétrie spatiale
[Termes IGN] harmonique sphérique
[Termes IGN] masseRésumé : (auteur) As changes in gravity are directly related to mass variability, satellite missions observing the Earth’s time varying gravity field are a unique tool for observing mass transport processes in the Earth system, such as the water cycle, rapid changes in the cryosphere, oceans, and solid Earth processes, on a global scale. The observation of Earth’s gravity field was successfully performed by the GRACE and GOCE satellite missions, and will be continued by the GRACE Follow-On mission. A comprehensive team of European scientists proposed the next-generation gravity field mission MOBILE in response to the European Space Agency (ESA) call for a Core Mission in the frame of Earth Explorer 10 (EE10). MOBILE is based on the innovative observational concept of a high-low tracking formation with micrometer ranging accuracy, complemented by new instrument concepts. Since a high-low tracking mission primarily observes the radial component of gravity-induced orbit perturbations, the error structure is close to isotropic. This geometry significantly reduces artefacts of previous along-track ranging low-low formations (GRACE, GRACE-Follow-On) such as the typical striping patterns. The minimum configuration consists of at least two medium-Earth orbiters (MEOs) at 10000 km altitude or higher, and one low-Earth orbiter (LEO) at 350-400 km. The main instrument is a laser-based distance or distance change measurement system, which is placed at the LEO. The MEOs are equipped either with passive reflectors or transponders. In a numerical closed-loop simulation, it was demonstrated that this minimum configuration is in agreement with the threshold science requirements of 5 mm equivalent water height (EWH) accuracy at 400 km wavelength, and 10 cm EWH at 200 km. MOBILE provides promising potential future perspectives by linking the concept to existing space infrastructure such as Galileo next-generation, as future element of the Copernicus/Sentinel programme, and holds the potential of miniaturization even up to swarm configurations. As such MOBILE can be considered as a precursor and role model for a sustained mass transport observing system from space. Numéro de notice : A2019-635 Affiliation des auteurs : Géodésie+Ext (mi2018-2019) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1515/jogs-2019-0006 Date de publication en ligne : 21/10/2019 En ligne : https://doi.org/10.1515/jogs-2019-0006 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95454
in Journal of geodetic science > vol 9 n° 1 (January 2019) . - pp 48 - 58[article]Reconciling upper mantle seismic velocity and density structure below ocean basins / Isabelle Panet (2019)
Titre : Reconciling upper mantle seismic velocity and density structure below ocean basins Type de document : Article/Communication Auteurs : Isabelle Panet , Auteur ; Barbara Romanowicz, Auteur ; Marianne Greff-Lefftz, Auteur
Editeur : Saint-Mandé : Institut national de l'information géographique et forestière - IGN (2012-) Année de publication : 2019 Projets : 1-Pas de projet / Conférence : AGU 2019 Fall Meeting 09/12/2019 13/12/2019 San Francisco Californie - Etats-Unis programme sans actes Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] déformation de la croute terrestre
[Termes IGN] données bathymétriques
[Termes IGN] données GRACE
[Termes IGN] fond marin
[Termes IGN] geoïde marin
[Termes IGN] géophysique interne
[Termes IGN] Indien (océan)
[Termes IGN] manteau terrestre
[Termes IGN] Pacifique (océan)
[Termes IGN] structure géologique
[Termes IGN] vitesse de déplacementRésumé : (auteur) Imaging the spatial pattern of mantle flows and constraining their mass is one of the keys to understand the character of mantle convection inside the Earth, and its interactions with plate motions. The horizontal planform of the flows, their heterogeneity and mass transport at depth, are reflected in variations of the gravity field and seismic velocities, as well as deformations of the Earth's surface. Over ocean basins, these observables show an elusive medium-scale structure. A 1500-2000 km wavelength directional fabric following the present-day absolute plate motion is present in the Pacific Ocean in GRACE satellite gravity data (Hayn et al., 2012), while 2000-km wavelength slow shear velocity anomalies sharing a similar orientation are found in seismic tomography at upper mantle depths below the oceans (SEMUM2, French et al., 2013). Today, the dynamic processes at the origin of these observations remain unresolved.
Here, we develop a joint analysis of satellite gravity and bathymetry data together with the SEMUM2 seismic tomography model, in order to advance our understanding of upper to mid-mantle flows below the oceans. First, we enhance and reconstruct the medium-scale gravity and seafloor topography signals aligned with the present-day plate motion from an analysis of the rates of gravity vector variations and seafloor slopes. Then, we compare the obtained signals with the spatial distribution of shear velocity anomalies at depth. We show that slow velocity anomalies coincide with geoid lows, depressions in the seafloor topography, and mass excess in the mantle, in the Pacific ocean and part of the Indian ocean. We first consider a purely thermal interpretation of the seismic velocity variations, associated with medium-scale convective rolls in the upper to mid-mantle, a process able to only explain the observed geometry of anomalies. Investigating whether the needed mass excess arises from lithospheric or deeper sources, such as at the level of the 660-km interface, we conclude that it lies more likely within the slow velocity anomalies themselves, suggesting hot and dense structures. We finally discuss the possible meaning and implications of these results.Numéro de notice : C2019-058 Affiliation des auteurs : Géodésie+Ext (mi2018-2019) Thématique : POSITIONNEMENT Nature : Poster nature-HAL : Poster-avec-CL DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96896
Titre de série : Relativistic geodesy, ch. 2 Titre : Chronometric geodesy: Methods and applications Type de document : Chapitre/Contribution Auteurs : Pacôme Delva, Auteur ; Heiner Denker, Auteur ; Guillaume Lion , Auteur
Editeur : Springer International Publishing Année de publication : 2019 Collection : Fundamental Theories of Physics num. 196 Projets : ITOC / , AdOC / , FIRST-TF / Importance : pp 25 - 85 Note générale : bibliographie
This research was supported by the European Metrology Research Programme (EMRP) within the Joint Research Project “International Timescales with Optical Clocks” (SIB55 ITOC), as well as the Deutsche Forschungsgemeinschaft (DFG) within the Collaborative Research Centre 1128 “Relativistic Geodesy and Gravimetry with Quantum Sensors (geo-Q)”, project C04. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union. We gratefully acknowledge financial support from Labex FIRST-TF and ERC AdOC (Grant No. 617553).Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] chronométrie
[Termes IGN] décalage d'horloge
[Termes IGN] échelle de temps
[Termes IGN] horloge atomiqueRésumé : (auteur) The theory of general relativity was born more than one hundred years ago, and since the beginning has striking prediction success. The gravitational redshift effect discovered by Einstein must be taken into account when comparing the frequencies of distant clocks. However, instead of using our knowledge of the Earth’s gravitational field to predict frequency shifts between distant clocks, one can revert the problem and ask if the measurement of frequency shifts between distant clocks can improve our knowledge of the gravitational field. This is known as chronometric geodesy. Since the beginning of the atomic time era in 1955, the accuracy and stability of atomic clocks were constantly ameliorated, with around one order of magnitude gained every ten years. Now that the atomic clock accuracy reaches the low 10−18 in fractional frequency, and can be compared to this level over continental distances with optical fibres, the accuracy of chronometric geodesy reaches the cm level and begins to be competitive with classical geodetic techniques such as geometric levelling and GNSS/geoid levelling. Moreover, the building of global timescales requires now to take into account these effects to the best possible accuracy. In this chapter we explain how atomic clock comparisons and the building of timescales can benefit from the latest developments in physical geodesy for the modelization and realization of the geoid, as well as how classical geodesy could benefit from this new type of observable, which are clock comparisons that are directly linked to gravity potential differences. Numéro de notice : H2019-006 Affiliation des auteurs : Géodésie+Ext (mi2018-2019) Thématique : POSITIONNEMENT Nature : Chapître / contribution nature-HAL : ChOuvrScient DOI : 10.1007/978-3-030-11500-5_2 Date de publication en ligne : 10/02/2019 En ligne : https://doi.org/10.1007/978-3-030-11500-5_2 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95546 An analysis of gravitational gradients in rotated frames and their relation to oriented mass sources / Isabelle Panet in Journal of geophysical research : Solid Earth, vol 123 n° 12 (December 2018)
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Titre : An analysis of gravitational gradients in rotated frames and their relation to oriented mass sources Type de document : Article/Communication Auteurs : Isabelle Panet , Auteur
Année de publication : 2018 Projets : TOSCA / Article en page(s) : pp 11062 -11090 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] analyse de sensibilité
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] gradient de gravitation
[Termes IGN] levé gravimétrique
[Termes IGN] masse de la Terre
[Termes IGN] modèle de géopotentiel
[Termes IGN] repère de référenceRésumé : (auteur) Many mass sources within the Earth and its fluid envelopes show elongated geometries, aligning with the orientations of plate boundaries and plate motions, coastlines, rivers, and drainage basins for instance. To enhance their identification and separation in global or regional gravity observations and models, a dedicated method based on gravitational gradients analysis is presented here. This approach provides a detailed description of the geographic pattern of the gravity variations, which are accurately mapped thanks to the regular spatial coverage of high‐accuracy satellite data and arise from lateral density changes within the planet. First, gravity gradients are defined at different spatial scales in spherical frames, which are rotated along the radial axis according to the orientation of the source. The sensitivity of these gradients to the mass distribution inside a spherical Earth is described and analytical expressions relating the source to the observable are introduced. Then, the gravity gradients responses at different spatial scales to flat, elementary mass sources located at the surface and at increasing depth are studied. Specifically, the paper investigates how a source width and orientation can be determined, for localized and oscillatory mass anomalies with different width‐to‐length aspect ratios. This theoretical case study aims at providing a basis for the analysis of more complex mass structures, when applying the presented method to static or time‐varying satellite gravity field models. It may help deciphering the nature of the gravity sources by the detection of meaningful geometries and orientations in the gravity field. Numéro de notice : A2018-655 Affiliation des auteurs : Géodésie (mi2018-2019) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1029/2018JB016717 Date de publication en ligne : 05/12/2018 En ligne : https://doi.org/10.1029/2018JB016717 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93520
in Journal of geophysical research : Solid Earth > vol 123 n° 12 (December 2018) . - pp 11062 -11090[article]A Terrestrial Reference Frame realised on the observation level using a GPS-LEO satellite constellation / Daniel Koenig in Journal of geodesy, vol 92 n° 11 (November 2018)
PermalinkLeast-squares cross-wavelet analysis and its applications in geophysical time series / Ebrahim Ghaderpour in Journal of geodesy, vol 92 n° 10 (October 2018)
PermalinkMigrating pattern of deformation prior to the Tohoku-Oki earthquake revealed by GRACE data / Isabelle Panet in Nature geoscience, vol 11 n° 5 (May 2018)
PermalinkHigh performance clocks and gravity field determination / Jurgen Müller in Space Science Reviews, vol 214 n° 1 (February 2018)
PermalinkDétermination d’un modèle géopotentiel à haute résolution en zone littorale aidé par des mesures d’horloges atomiques / Hugo Lecomte (2018)
PermalinkPermalinkMulti-scale modeling of Earth's gravity field in space and time / Shuo (2) Wang in Journal of geodynamics, vol 106 (May 2017)
PermalinkPermalinkPermalinkLa gravimétrie mobile en champ proche : outil essentiel pour la haute résolution en géodésie physique et en géosciences / Jérome Verdun (2017)
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