Descripteur
Documents disponibles dans cette catégorie (796)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externes
Etendre la recherche sur niveau(x) vers le bas
Toward a global horizontal and vertical elastic load deformation model derived from GRACE and GNSS station position time series / Kristel Chanard in Journal of geophysical research : Solid Earth, vol 123 n° 4 (April 2018)
[article]
Titre : Toward a global horizontal and vertical elastic load deformation model derived from GRACE and GNSS station position time series Type de document : Article/Communication Auteurs : Kristel Chanard , Auteur ; Luce Fleitout, Auteur ; Eric Calais, Auteur ; Paul Rebischung , Auteur ; Jean-Philippe Avouac, Auteur Année de publication : 2018 Projets : 3-projet - voir note / Article en page(s) : pp 3225 - 3237 Note générale : bibliographie
The project was funded by NSF grant EAR 1345136, the Laboratoire de Recherche Commun “Yves Rocard” (ENS‐CEA‐CNRS), and CNRS/TOSCA grant 2925.Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] coordonnées GNSS
[Termes IGN] déformation horizontale de la croute terrestre
[Termes IGN] déformation verticale de la croute terrestre
[Termes IGN] données GRACE
[Termes IGN] Earth Gravity Model 2008
[Termes IGN] erreur systématique
[Termes IGN] harmonique sphérique
[Termes IGN] modèle de déformation tectonique
[Termes IGN] mouvement du géocentre
[Termes IGN] série temporelleRésumé : (Auteur) We model surface displacements induced by variations in continental water, atmospheric pressure, and non‐tidal oceanic loading, derived from the Gravity and Recovery Climate Experiment (GRACE) for spherical harmonic degrees two and higher. As they are not observable by GRACE, we use at first the degree‐1 spherical harmonic coefficients from (Swenson2008estimating). We compare the predicted displacements with the position time series of 689 globally distributed continuous Global Navigation Satellite System (GNSS) stations. While GNSS vertical displacements are well explained by the model at a global scale, horizontal displacements are systematically underpredicted and out‐of‐phase with GNSS station position time series. We then re‐estimate the degree‐1 deformation field from a comparison between our GRACE‐derived model, with no a priori degree‐1 loads, and the GNSS observations. We show that this approach reconciles GRACE‐derived loading displacements and GNSS station position time series at a global scale, particularly in the horizontal components. Assuming that they reflect surface loading deformation only, our degree‐1 estimates can be translated into geocenter motion time series. We also address and assess the impact of systematic errors in GNSS station position time series at the Global Positioning System (GPS) draconitic period and its harmonics on the comparison between GNSS and GRACE‐derived annual displacements. Our results confirm that surface mass redistributions observed by GRACE, combined with an elastic spherical and layered Earth model, can be used to provide first order corrections for loading deformation observed in both horizontal and vertical components of GNSS station position time series. Numéro de notice : A2018-055 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Autre URL associée : vers HAL Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/2017JB015245 Date de publication en ligne : 21/02/2018 En ligne : https://doi.org/10.1002/2017JB015245 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89382
in Journal of geophysical research : Solid Earth > vol 123 n° 4 (April 2018) . - pp 3225 - 3237[article]Kriging and moving window kriging on a sphere in geometric (GNSS/levelling) geoid modelling / M. Ligas in Survey review, vol 50 n° 359 (March 2018)
[article]
Titre : Kriging and moving window kriging on a sphere in geometric (GNSS/levelling) geoid modelling Type de document : Article/Communication Auteurs : M. Ligas, Auteur ; M. Kulczycki, Auteur Année de publication : 2018 Article en page(s) : pp 155 - 162 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] Earth Gravity Model 2008
[Termes IGN] Etats-Unis
[Termes IGN] géoïde local
[Termes IGN] krigeageRésumé : (auteur) A comparison of kriging and moving window kriging (MWK) on a sphere is performed on GNSS/levelling data. The study was to give the answer on whether there is a significant gain in prediction accuracy when we apply an MWK instead of ‘classical’ kriging and also to what extent the use of global geopotential model EGM2008 improves prediction. The quality of prediction for all kriging and data variants has been investigated on three regions (being on the territory of the conterminous USA) characterised with a different spatial extent and density of sampling. Numerical tests revealed that in case of high-sampling density there was no accuracy gain when using MWK instead of classical kriging (cK). In contrast, for less numerous datasets and a much larger spatial extent (low-sampling density) MWK adapts itself to data much better than cK. Incorporation of EGM2008-based undulations as a long-wavelength trend for both cases (classical and moving window) significantly improved prediction quality. Numéro de notice : A2018-181 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/00396265.2016.1247131 Date de publication en ligne : 09/11/2016 En ligne : https://doi.org/10.1080/00396265.2016.1247131 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89825
in Survey review > vol 50 n° 359 (March 2018) . - pp 155 - 162[article]Regional geoid computation by least squares modified Hotine’s formula with additive corrections / Silja Märdla in Journal of geodesy, vol 92 n° 3 (March 2018)
[article]
Titre : Regional geoid computation by least squares modified Hotine’s formula with additive corrections Type de document : Article/Communication Auteurs : Silja Märdla, Auteur ; Artu Ellmann, Auteur ; Jonas Ågren, Auteur ; Lard Erik Sjöberg, Auteur Année de publication : 2018 Article en page(s) : pp 253 - 270 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] anomalie de pesanteur
[Termes IGN] formule de Stokes
[Termes IGN] géoïde local
[Termes IGN] méthode des moindres carrés
[Termes IGN] quasi-géoïdeRésumé : (Auteur) Geoid and quasigeoid modelling from gravity anomalies by the method of least squares modification of Stokes’s formula with additive corrections is adapted for the usage with gravity disturbances and Hotine’s formula. The biased, unbiased and optimum versions of least squares modification are considered. Equations are presented for the four additive corrections that account for the combined (direct plus indirect) effect of downward continuation (DWC), topographic, atmospheric and ellipsoidal corrections in geoid or quasigeoid modelling. The geoid or quasigeoid modelling scheme by the least squares modified Hotine formula is numerically verified, analysed and compared to the Stokes counterpart in a heterogeneous study area. The resulting geoid models and the additive corrections computed both for use with Stokes’s or Hotine’s formula differ most in high topography areas. Over the study area (reaching almost 2 km in altitude), the approximate geoid models (before the additive corrections) differ by 7 mm on average with a 3 mm standard deviation (SD) and a maximum of 1.3 cm. The additive corrections, out of which only the DWC correction has a numerically significant difference, improve the agreement between respective geoid or quasigeoid models to an average difference of 5 mm with a 1 mm SD and a maximum of 8 mm. Numéro de notice : A2018-060 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1061-7 Date de publication en ligne : 11/09/2017 En ligne : https://doi.org/10.1007/s00190-017-1061-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89393
in Journal of geodesy > vol 92 n° 3 (March 2018) . - pp 253 - 270[article]High performance clocks and gravity field determination / Jurgen Müller in Space Science Reviews, vol 214 n° 1 (February 2018)
[article]
Titre : High performance clocks and gravity field determination Type de document : Article/Communication Auteurs : Jurgen Müller, Auteur ; D. Dirkx, Auteur ; S. M. Kopeikin, Auteur ; Guillaume Lion , Auteur ; Isabelle Panet , Auteur ; Gérard Petit, Auteur ; Pieter N.A.M. Visser, Auteur Année de publication : 2018 Projets : 3-projet - voir note / , AdOC / Note générale : bibliographie
Jürgen Müller gratefully acknowledges support by the DFG Sonderforschungsbereich (SFB 1128: geo-Q) Relativistic Geodesy and Gravimetry with Quantum Sensors.Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] chronométrie
[Termes IGN] échelle de temps
[Termes IGN] gravimétrie spatiale
[Termes IGN] horloge atomique
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] potentiel de pesanteur terrestre
[Termes IGN] relativité généraleRésumé : (auteur) Time measured by an ideal clock crucially depends on the gravitational potential and velocity of the clock according to general relativity. Technological advances in manufacturing high-precision atomic clocks have rapidly improved their accuracy and stability over the last decade that approached the level of 10−18. This notable achievement along with the direct sensitivity of clocks to the strength of the gravitational field make them practically important for various geodetic applications that are addressed in the present paper. Based on a fully relativistic description of the background gravitational physics, we discuss the impact of those highly-precise clocks on the realization of reference frames and time scales used in geodesy. We discuss the current definitions of basic geodetic concepts and come to the conclusion that the advances in clocks and other metrological technologies will soon require the re-definition of time scales or, at least, clarification to ensure their continuity and consistent use in practice. The relative frequency shift between two clocks is directly related to the difference in the values of the gravity potential at the points of clock’s localization. According to general relativity the relative accuracy of clocks in 10−18 is equivalent to measuring the gravitational red shift effect between two clocks with the height difference amounting to 1 cm. This makes the clocks an indispensable tool in high-precision geodesy in addition to laser ranging and space geodetic techniques. We show how clock measurements can provide geopotential numbers for the realization of gravity-field-related height systems and can resolve discrepancies in classically-determined height systems as well as between national height systems. Another application of clocks is the direct use of observed potential differences for the improved recovery of regional gravity field solutions. Finally, clock measurements for space-borne gravimetry are analyzed along with closely-related deficiencies of this method like an extra-ordinary knowledge of the spacecraft velocity, etc. For all these applications besides the near-future prospects, we also discuss the challenges that are related to using those novel clock data in geodesy. Numéro de notice : A2018-197 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s11214-017-0431-z Date de publication en ligne : 30/11/2017 En ligne : https://doi.org/10.1007/s11214-017-0431-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89864
in Space Science Reviews > vol 214 n° 1 (February 2018)[article]Applying the GOCE-based GGMs for the quasi-geoid modelling of Finland / Timo Saari in Journal of applied geodesy, vol 12 n° 1 (January 2018)
[article]
Titre : Applying the GOCE-based GGMs for the quasi-geoid modelling of Finland Type de document : Article/Communication Auteurs : Timo Saari, Auteur ; Mirjam Bilker-Koivula, Auteur Année de publication : 2018 Article en page(s) : pp - 15 - 28 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] données GOCE
[Termes IGN] Finlande
[Termes IGN] géoïde local
[Termes IGN] levé gravimétrique
[Termes IGN] nivellement par GPS
[Termes IGN] pesanteur terrestre
[Termes IGN] quasi-géoïdeMots-clés libres : GOCE Quasi-geoid GPS-levelling Gravity EIGEN-6C4 NKG2015 Résumé : (auteur) The gravity satellite mission GOCE made its final observations in the fall of 2013. Since the reentry to the Earth’s atmosphere, the full cycle of the GOCE data has been published by ESA. At first, we evaluated all the GOCE-based global geoid models over Finland using terrestrial gravity and GNSS-levelling data. The most suitable model was selected as a global background model for the Finnish quasi-geoid calculations. Next, we combined the chosen model with terrestrial gravity data of Finland and surrounding areas. Quasi-geoid models with different modifications were calculated using the GOCE DIR5 model up to spherical harmonic degree and order (d/o) 240 and 300, and the high resolution EIGEN-6C4 (includes the complete GOCE data) model up to degree and order 1000 and 2190. The calculated quasi-geoid models were validated to the measurements on site with two independent GPS-levelling datasets. The best quasi-geoid models with GOCE gave standard deviations of 2.6 cm (FIN_DIR5 d/o 240) and 2.3 cm (FIN_DIR5 d/o 300) in Finland. For the high resolution model FIN_EIGEN-6C4, the results were 1.8 cm (d/o 1000) and 1.7 cm (d/o 2190). In addition, the results were compared with the latest geoid models available in Finland (FIN2005N00, NKG2004, NKG2015, EGG2008). The sub-2-centimetre (and near 2 cm, when using the GOCE-based models) accuracy is an improvement over the previous and current Finnish geoid models. Numéro de notice : A2018-014 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2017-0020 En ligne : https://doi.org/10.1515/jag-2017-0020 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89093
in Journal of applied geodesy > vol 12 n° 1 (January 2018) . - pp - 15 - 28[article]Assessing the quality of GEOID12B model through field surveys / Ahmed F. Elaksher in Journal of applied geodesy, vol 12 n° 1 (January 2018)PermalinkDétermination du géopotentiel à haute résolution spatiale : apport des horloges atomiques et des algorithmes génétiques / Guillaume Lion (2018)PermalinkDétermination d’un modèle géopotentiel à haute résolution en zone littorale aidé par des mesures d’horloges atomiques / Hugo Lecomte (2018)PermalinkPermalinkHeight biases of SRTM DEM related to EGM96: from a global perspective to regional practice / A. Üstün in Survey review, vol 50 n° 358 (January 2018)PermalinkNumerical solution to the oblique derivative boundary value problem on non-uniform grids above the Earth topography / Matej Medl’a in Journal of geodesy, vol 92 n° 1 (January 2018)PermalinkA numerical test of the topographic bias / Lars E. Sjöberg in Journal of geodetic science, vol 8 n° 1 (January 2018)PermalinkMICROSCOPE mission: First results of a space test of the equivalence principle / Pierre Touboul in Physical Review Letters, vol 119 n° 3 (December 2017)PermalinkOn the estimation of physical height changes using GRACE satellite mission data – A case study of Central Europe / Walyeldeen Godah in Geodesy and cartography, vol 66 n° 2 (December 2017)PermalinkExperiences with the QDaedalus system for astrogeodetic determination of deflections of the vertical / Markus Hauk in Survey review, vol 49 n° 355 (October 2017)Permalink