Descripteur
Documents disponibles dans cette catégorie (1346)
![](./images/expand_all.gif)
![](./images/collapse_all.gif)
Etendre la recherche sur niveau(x) vers le bas
Multi-technique monitoring of ocean tide loading in Northern France / Muriel Llubes in Comptes rendus : Géoscience, vol 340 n° 6 (June 2010)
![]()
[article]
Titre : Multi-technique monitoring of ocean tide loading in Northern France Titre original : Campagne multi-technique d’étude de la charge océanique dans le Nord de la France Type de document : Article/Communication Auteurs : Muriel Llubes, Auteur ; Nicolas Florsch, Auteur ; Jean-Paul Boy, Auteur ; Martine Amalvict, Auteur ; Pascal Bonnefond, Auteur ; Marie-Noëlle Bouin , Auteur ; et al., Auteur
Année de publication : 2008 Article en page(s) : pp 379 - 389 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] données GPS
[Termes IGN] surcharge océaniqueRésumé : (auteur) We have organised afield study of ocean tide loading in the northwestern part of France, where tidal amplitudes are known to be among the highest in the world. GPS and gravimetric techniques have already proved their capability to measure such weak and high-frequency signals. In this study, these classical observations are complemented with less usual techniques, such as tiltmeter and Satellite Laser Ranging (SLR) measurements. We present here the preliminary results for a common period of observations spanning from 12–19 May 2004. Additional measurements from the French Transportable Laser Ranging Station (FTLRS) were available during September and October 2004. Observation residuals are computed as the difference between the observed and the predicted time signals. We obtain small RMS residuals for GPS measurements (2.5/3.1/4.5 mm for the eastward, northward and upward components), for absolute and relative gravimetry (9 nm/s2 and 13 nm/s2) and for tiltmeters (0.05 μrad for EW component). We also fit the amplitude of the main M2 tidal constituent to FTLRS observations and we find a value of 3.731 cm, which is comparable to the theoretical value. Numéro de notice : A2010-699 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.crte.2008.03.005 Date de publication en ligne : 15/06/2008 En ligne : https://doi.org/10.1016/j.crte.2008.03.005 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103435
in Comptes rendus : Géoscience > vol 340 n° 6 (June 2010) . - pp 379 - 389[article]GPS estimates of ocean tide loading in NW-France: Determination of ocean tide loading constituents and comparison with a recent ocean tide model / Mathilde Vergnolle in Geophysical journal international, vol 173 n° 2 (May 2008)
![]()
[article]
Titre : GPS estimates of ocean tide loading in NW-France: Determination of ocean tide loading constituents and comparison with a recent ocean tide model Type de document : Article/Communication Auteurs : Mathilde Vergnolle, Auteur ; Marie-Noëlle Bouin , Auteur ; Laurent Morel, Auteur ; F. Masson, Auteur ; S. Durand, Auteur ; J. Nicolas, Auteur ; Stavros A. Melachroinos, Auteur
Année de publication : 2008 Article en page(s) : pp 444 - 458 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] amplitude
[Termes IGN] analyse harmonique
[Termes IGN] effet de charge
[Termes IGN] France (administrative)
[Termes IGN] marée océanique
[Termes IGN] série temporelleRésumé : (auteur) Ocean loading effects cause 3-D displacements large enough to affect space geodesy measurements either at the subdiurnal periods or at longer time scales by the means of spurious signals. GPS measurements, in turn, could provide local improvements of the models in coastal areas if their ability to precisely monitor such rapid displacements is assessed. In this paper, we use 105 days of continuous GPS measurements collected in 2004 in the French Brittany and Cotentin region to investigate: (1) the precision achieved by the GPS analysis on measuring 3-D subdiurnal displacements and amplitude and phase of the tidal constituents, (2) the quality of the most recent ocean tide model FES2004 in such a complex coastal context. Indeed, in this area, tide amplitudes are among the largest in the world (up to 16 cm of loading displacements on the vertical component) and are believed to show strong shallow-water tides. From a state of the art GPS analysis using the scientific GAMIT software over 2-h sessions, we test two independent strategies for the realization of the reference frame. The position time series are then compared with the displacements predicted by the FES2004 model applied on an elastic Earth model. The two sets of results are consistent with each other at the same level of agreement than with the predicted displacements, namely 3-5 mm on the horizontal components, 10 mm on the vertical. This assesses the capability of this technique for measuring 3-D ocean tide loading deformation. We validate the FES2004 model in the Brittany area, even though it slightly (2-7 mm) underestimates the three components amplitudes. With a harmonic analysis of the observed position time series, we obtain nevertheless an agreement at a submillimetre level for the M2, N2, O1, Q1 tidal constituents and at a millimetre level for the K1 and S2 tidal constituents. Moreover, we can extract a significant M4 load signal at the 95 per cent confidence level from the GPS time series at the stations located in the Mont St Michel area. The detection of other shallow-water constituents would be helpful to understand the amplitude deficit between the FES2004 predicted and GPS observed displacements. Numéro de notice : A2008-616 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1365-246X.2008.03734.x Date de publication en ligne : 01/05/2008 En ligne : https://doi.org/10.1111/j.1365-246X.2008.03734.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102899
in Geophysical journal international > vol 173 n° 2 (May 2008) . - pp 444 - 458[article]Length-of-day and space-geodetic determination of the Earth's variable gravity field / G. Bourda in Journal of geodesy, vol 82 n° 4-5 (April - May 2008)
![]()
[article]
Titre : Length-of-day and space-geodetic determination of the Earth's variable gravity field Type de document : Article/Communication Auteurs : G. Bourda, Auteur Année de publication : 2008 Article en page(s) : pp 295 - 305 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] analyse comparative
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] données GRACE
[Termes IGN] données TLS (télémétrie)
[Termes IGN] GRACE
[Termes IGN] télémétrie laser sur satellite
[Termes IGN] variationRésumé : (Auteur) The temporal variations of the Earth’s gravity field, nowadays routinely determined from satellite laser ranging (SLR) and GRACE (Gravity Recovery And Climate Experiment), are related to changes in the Earth’s rotation rate through the Earth’s inertia tensor. We study this connection from actual data by comparing the traditional length-of-day (LOD) measurements provided by the International Earth Rotation and Reference Systems Service (IERS) to the variations of the degree-2 and order-0 Stokes coefficient of the gravity field determined from fitting the orbits of the LAGEOS-1 and -2 satellites since 1985. The two series show a good correlation (0.62) and similar annual and semi-annual signals, indicating that the gravity-field-derived LOD is valuable. Our analysis also provides evidence for additional signals common to both series, especially at a period near 120 days, which could be due to hydrological effects. Copyright Springer Numéro de notice : A2008-171 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-007-0180-y En ligne : https://doi.org/10.1007/s00190-007-0180-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29166
in Journal of geodesy > vol 82 n° 4-5 (April - May 2008) . - pp 295 - 305[article]Réservation
Réserver ce documentExemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 266-08042 RAB Revue Centre de documentation En réserve L003 Disponible 266-08041 RAB Revue Centre de documentation En réserve L003 Disponible On the non-uniqueness of local quasi-geoids computed from terrestrial gravity anomalies / I. Prutkin in Journal of geodesy, vol 82 n° 3 (March 2008)
![]()
[article]
Titre : On the non-uniqueness of local quasi-geoids computed from terrestrial gravity anomalies Type de document : Article/Communication Auteurs : I. Prutkin, Auteur ; R. Klees, Auteur Année de publication : 2008 Article en page(s) : pp 147 - 156 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] anomalie de pesanteur
[Termes IGN] champ de pesanteur local
[Termes IGN] données GPS
[Termes IGN] géoïde local
[Termes IGN] nivellement par GPSRésumé : (Auteur) We consider the problem of local (quasi-)geoid modelling from terrestrial gravity anomalies. Whereas this problem is uniquely solvable (up to spherical harmonic degree one) if gravity anomalies are globally available, the problem is non-unique if gravity anomalies are only available within a local area, which is the typical situation in local/regional gravity field modelling. We derive a mathematical description of the kernel of the gravity anomaly operator. The non-uniqueness can be removed using external height anomaly information, e.g., provided by GPS-levelling. The corresponding problem is formulated as a Cauchy problem for the Laplace equation. The existence and uniqueness of the solution of the Cauchy problem is guaranteed by the Cauchy–Kowalevskaya theorem. We propose several numerical procedures to compute the solution of the Cauchy problem from given differences between gravimetric and geometric height anomalies. We apply the numerical techniques to real data over the Netherlands and Germany. We show that we can compute a unique quasi-geoid from observed gravimetric and geometric height anomalies, which agree with the data within the expected noise level. We conclude that observed differences between gravimetric height anomalies and geometric height anomalies derived from GPS and levelling cannot only be attributed to systematic errors in the data sets, but are also caused by the intrinsic non-uniqueness of the problem of local quasi-geoid modelling from gravity anomalies. Hence, GPS-levelling data are necessary to get a unique solution, which also implies that they should not be used to validate local quasi-geoid solutions computed on the basis of gravity anomalies. Copyright Springer Numéro de notice : A2008-166 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-007-0161-1 En ligne : https://doi.org/10.1007/s00190-007-0161-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29161
in Journal of geodesy > vol 82 n° 3 (March 2008) . - pp 147 - 156[article]Réservation
Réserver ce documentExemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 266-08031 RAB Revue Centre de documentation En réserve L003 Disponible 266-08032 RAB Revue Centre de documentation En réserve L003 Disponible Effects of topographic-isostatic masses on gravitational functionals at the Earth's surface and at airborne and satellite altitudes / A. Makhloof in Journal of geodesy, vol 82 n° 2 (February 2008)
![]()
[article]
Titre : Effects of topographic-isostatic masses on gravitational functionals at the Earth's surface and at airborne and satellite altitudes Type de document : Article/Communication Auteurs : A. Makhloof, Auteur ; K.H. Ilk, Auteur Année de publication : 2008 Article en page(s) : pp 93 - 111 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur local
[Termes IGN] force de gravitation
[Termes IGN] gravimétrie aérienne
[Termes IGN] gravimétrie spatiale
[Termes IGN] isostasie
[Termes IGN] pesanteur terrestre
[Termes IGN] reliefRésumé : (Auteur) Topographic–isostatic masses represent an important source of gravity field information, especially in the high-frequency band, even if the detailed mass-density distribution inside the topographic masses is unknown. If this information is used within a remove-restore procedure, then the instability problems in downward continuation of gravity observations from aircraft or satellite altitudes can be reduced. In this article, integral formulae are derived for determination of gravitational effects of topographic–isostatic masses on the first- and second-order derivatives of the gravitational potential for three topographic–isostatic models. The application of these formulas is useful for airborne gravimetry/gradiometry and satellite gravity gradiometry. The formulas are presented in spherical approximation by separating the 3D integration in an analytical integration in the radial direction and 2D integration over the mean sphere. Therefore, spherical volume elements can be considered as being approximated by mass-lines located at the centre of the discretization compartments (the mass of the tesseroid is condensed mathematically along its vertical axis). The errors of this approximation are investigated for the second-order derivatives of the topographic–isostatic gravitational potential in the vicinity of the Earth’s surface. The formulas are then applied to various scenarios of airborne gravimetry/gradiometry and satellite gradiometry. The components of the gravitational vector at aircraft altitudes of 4 and 10 km have been determined, as well as the gravitational tensor components at a satellite altitude of 250 km envisaged for the forthcoming GOCE (gravity field and steady-state ocean-circulation explorer) mission. The numerical computations are based on digital elevation models with a 5-arc-minute resolution for satellite gravity gradiometry and 1-arc-minute resolution for airborne gravity/gradiometry. Copyright Springer Numéro de notice : A2008-044 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-007-0159-8 En ligne : https://doi.org/10.1007/s00190-007-0159-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29039
in Journal of geodesy > vol 82 n° 2 (February 2008) . - pp 93 - 111[article]Réservation
Réserver ce documentExemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 266-08022 RAB Revue Centre de documentation En réserve L003 Disponible 266-08021 RAB Revue Centre de documentation En réserve L003 Disponible PermalinkLe Quasi-géoïde libanais (QGL06) et la référence d'altitude du NGL (RAL 06) / Mohamed Allouche in XYZ, n° 113 (décembre 2007 - février 2008)
PermalinkQuasigeoid evaluation with improved levelled height data for Norway / D.I. Lysaker in Journal of geodesy, vol 81 n° 9 (September 2007)
PermalinkGeocentric sea-level trend estimates from GPS analyses at relevant tide gauges world-wide / Guy Wöppelmann in Global and Planetary Change, vol 57 n° 3-4 (June 2007)
PermalinkPractical geodesy: part 3 The geoid / Huibert-Jan Lekkerkerk in Geoinformatics, vol 10 n° 4 (01/06/2007)
PermalinkThe topographic bias by analytical continuation in physical geodesy / Lard Erik Sjöberg in Journal of geodesy, vol 81 n° 5 (May 2007)
PermalinkAirborne LaCoste & Romberg gravimetry: a space domain approach / M. Abbasi in Journal of geodesy, vol 81 n° 4 (April 2007)
Permalinkn° 143 - 2007 (Bulletin de Bulletin international des marées terrestres) / Association internationale de géodésie
PermalinkDetermination of the free core nutation period from tidal gravity observations of the GGP superconducting gravimeter network / B. Ducarme in Journal of geodesy, vol 81 n° 3 (March 2007)
PermalinkOfficial geoid undulations model: substitute for nationwide orthometric control network / G. Steinberg in GIM international, vol 21 n° 2 (February 2007)
Permalink