Descripteur
Documents disponibles dans cette catégorie (2140)
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
Comparisons of atmospheric mass variations derived from ECMWF reanalysis and operational fields, over 2003–2011 / E. Forootan in Journal of geodesy, vol 88 n° 5 (May 2014)
[article]
Titre : Comparisons of atmospheric mass variations derived from ECMWF reanalysis and operational fields, over 2003–2011 Type de document : Article/Communication Auteurs : E. Forootan, Auteur ; Olga Didova, Auteur ; M. Schumacher, Auteur ; J. Kusche, Auteur ; B. Elsaka, Auteur Année de publication : 2014 Article en page(s) : pp 503 - 514 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] analyse comparative
[Termes IGN] analyse diachronique
[Termes IGN] atmosphère terrestre
[Termes IGN] données GRACE
[Termes IGN] levé gravimétrique
[Termes IGN] masse d'air
[Termes IGN] variationRésumé : (Auteur) There are two spurious jumps in the atmospheric part of the Gravity Recovery and Climate Experiment-Atmosphere and Ocean De-aliasing level 1B (GRACE-AOD1B) products, which occurred in January-February of the years 2006 and 2010, as a result of the vertical level and horizontal resolution changes in the ECMWFop (European Centre for Medium-Range Weather Forecasts operational analysis). These jumps cause a systematic error in the estimation of mass changes from GRACE time-variable level 2 products, since GRACE-AOD1B mass variations are removed during the computation of GRACE level 2. In this short note, the potential impact of using an improved set of 6-hourly atmospheric de-aliasing products on the computations of linear trends as well as the amplitude of annual and semi-annual mass changes from GRACE is assessed. These improvements result from 1) employing a modified 3D integration approach (ITG3D), and 2) using long-term consistent atmospheric fields from the ECMWF reanalysis (ERA-Interim). The monthly averages of the new ITG3D-ERA-Interim de-aliasing products are then compared to the atmospheric part of GRACE-AOD1B, covering January 2003 to December 2010. These comparisons include the 33 world largest river basins along with Greenland and Antarctica ice sheets. The results indicate a considerable difference in total atmospheric mass derived from the two products over some of the mentioned regions. We suggest that future GRACE studies consider these through updating uncertainty budgets or by applying corrections to estimated trends and amplitudes/phases Numéro de notice : A2014-258 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0696-x Date de publication en ligne : 07/02/2014 En ligne : https://doi.org/10.1007/s00190-014-0696-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33161
in Journal of geodesy > vol 88 n° 5 (May 2014) . - pp 503 - 514[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2014051 SL Revue Centre de documentation Revues en salle Disponible Earth orientation parameters estimated from VLBI during the CONT11 campaign / Tobias Nilsson in Journal of geodesy, vol 88 n° 5 (May 2014)
[article]
Titre : Earth orientation parameters estimated from VLBI during the CONT11 campaign Type de document : Article/Communication Auteurs : Tobias Nilsson, Auteur ; Robert Heinkelmann, Auteur ; Maria Karbon, Auteur ; Virginia Raposo-Pulibo, Auteur ; Harald Schuh, Auteur Année de publication : 2014 Article en page(s) : pp 491 - 491 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] données ITGB
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] orientation de la Terre
[Termes IGN] positionnement par ITGB
[Termes IGN] série temporelleRésumé : (Auteur) In this paper, we investigate the accuracy of the earth orientation parameters (EOP) estimated from the continuous VLBI campaign CONT11. We first estimated EOP with daily resolution and compared these to EOP estimated from GNSS data. We find that the WRMS differences are about 31 u as for polar motion and 7 u s for length of day. This is about the precision we could expect, based on Monte Carlo simulations and the results of the previous CONT campaigns. We also estimated EOP with hourly resolution to study the sub-diurnal variations. The results confirm the results of previous studies, showing that the current IERS model for high-frequency EOP variations does not explain all the sub-diurnal variations seen in the estimated time series. We then compared our results to various empirical high-frequency EOP models. However, we did not find that any of these gave any unambiguous improvement. Several simulations testing the impact of various aspects of, e.g. the observing network were also made. For example, we made simulations assuming that all CONT11 stations were equipped with fast VLBI2010 antennas. We found that the WRMS error decreased by about a factor five compared to the current VLBI system. Furthermore, the simulations showed that it is very important to have a homogenous global distribution of the stations for achieving the highest precision for the EOP. Numéro de notice : A2014-257 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0700-5 Date de publication en ligne : 21/02/2014 En ligne : https://doi.org/10.1007/s00190-014-0700-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33160
in Journal of geodesy > vol 88 n° 5 (May 2014) . - pp 491 - 491[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2014051 SL Revue Centre de documentation Revues en salle Disponible Comparison among three harmonic analysis techniques on the sphere and the ellipsoid / Hussein Abd-Elmotaal in Journal of applied geodesy, vol 8 n° 1 (April 2014)
[article]
Titre : Comparison among three harmonic analysis techniques on the sphere and the ellipsoid Type de document : Article/Communication Auteurs : Hussein Abd-Elmotaal, Auteur ; Kurt Seitz, Auteur ; Mostafa Abd-Elbaky, Auteur ; Bernhard Heck, Auteur Année de publication : 2014 Article en page(s) : pp 1 - 19 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] analyse comparative
[Termes IGN] anomalie de pesanteur
[Termes IGN] Earth Gravity Model 2008
[Termes IGN] ellipsoïde (géodésie)
[Termes IGN] harmonique ellipsoïdale
[Termes IGN] harmonique sphérique
[Termes IGN] méthode des moindres carrés
[Termes IGN] transformation rapide de FourierRésumé : (Auteur) The paper presents a comparison among three different techniques for harmonic analysis on the sphere and the ellipsoid. The EGM2008 global geopotential model has been used up to degree and order 360 in order to create gravity anomaly fields on both the sphere and the ellipsoid as the function fields of the current investigation. Harmonic analysis has then been carried out to compute the dimensionless potential coeficients using the created function fields. Three different harmonic analysis techniques have been applied: the least-squares technique, the Fast Fourier Transform (FFT) technique and the Gauss-Legendre numerical integration technique. The computed coeficients in spherical harmonics have then been compared with EGM2008 (in the frequency domain) and the computed fields on the sphere and the ellipsoid have been compared with fields created by EGM2008 up to degree and order 360 (in the space domain) in order to estimate the accuracy of the three different harmonic analysis techniques used within the current investigation. The results proved that the least-squares technique gives the best accuracy both in frequency and space domain. The FFT technique provides quite good results in a very short cpu time. The Gauss-Legendre technique gives the worst results among the presented techniques, but still the residuals in the space domain are negligibly small. Numéro de notice : A2014-270 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2013-0008 En ligne : http://www.degruyter.com/view/j/jag.2014.8.issue-1/jag-2013-0008/jag-2013-0008.x [...] Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33173
in Journal of applied geodesy > vol 8 n° 1 (April 2014) . - pp 1 - 19[article]Evaluation of the third- and fourth-generation GOCE Earth gravity field models with Australian terrestrial gravity data in spherical harmonics / Moritz Rexer in Journal of geodesy, vol 88 n° 4 (April 2014)
[article]
Titre : Evaluation of the third- and fourth-generation GOCE Earth gravity field models with Australian terrestrial gravity data in spherical harmonics Type de document : Article/Communication Auteurs : Moritz Rexer, Auteur ; Christian Hirt, Auteur ; Roland Pail, Auteur ; Sten Claessens, Auteur Année de publication : 2014 Article en page(s) : pp 319 - 333 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] Australie
[Termes IGN] données géophysiques
[Termes IGN] données GOCE
[Termes IGN] évaluation des données
[Termes IGN] harmonique sphérique
[Termes IGN] levé gravimétriqueRésumé : (Auteur) In March 2013, the fourth generation of European Space Agency’s (ESA) global gravity field models, DIR4 (Bruinsma et al. in Proceedings of the ESA living planet symposium, 28 June–2 July, Bergen, ESA, Publication SP-686, 2010b) and TIM4 (Migliaccio et al. in Proceedings of the ESA living planet symposium, 28 June–2 July, Bergen, ESA, Publication SP-686, 2010), generated from the Gravity field and steady-state Ocean Circulation Explorer (GOCE) gravity observation satellite was released. We evaluate the models using an independent ground truth data set of gravity anomalies over Australia. Combined with Gravity Recovery and Climate Experiment (GRACE) satellite gravity, a new gravity model is obtained that is used to perform comparisons with GOCE models in spherical harmonics. Over Australia, the new gravity model proves to have significantly higher accuracy in the degrees below 120 as compared to EGM2008 and seems to be at least comparable to the accuracy of this model between degree 150 and degree 260. Comparisons in terms of residual quasi-geoid heights, gravity disturbances, and radial gravity gradients evaluated on the ellipsoid and at approximate GOCE mean satellite altitude ( h=250 km) show both fourth generation models to improve significantly w.r.t. their predecessors. Relatively, we find a root-mean-square improvement of 39 % for the DIR4 and 23 % for TIM4 over the respective third release models at a spatial scale of 100 km (degree 200). In terms of absolute errors, TIM4 is found to perform slightly better in the bands from degree 120 up to degree 160 and DIR4 is found to perform slightly better than TIM4 from degree 170 up to degree 250. Our analyses cannot confirm the DIR4 formal error of 1 cm geoid height (0.35 mGal in terms of gravity) at degree 200. The formal errors of TIM4, with 3.2 cm geoid height (0.9 mGal in terms of gravity) at degree 200, seem to be realistic. Due to combination with GRACE and SLR data, the DIR models, at satellite altitude, clearly show lower RMS values compared to TIM models in the long wavelength part of the spectrum (below degree and order 120). Our study shows different spectral sensitivity of different functionals at ground level and at GOCE satellite altitude and establishes the link among these findings and the Meissl scheme (Rummel and van Gelderen in Manusrcipta Geodaetica 20:379–385, 1995). Numéro de notice : A2014-158 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0680-x Date de publication en ligne : 14/12/2013 En ligne : https://doi.org/10.1007/s00190-013-0680-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33063
in Journal of geodesy > vol 88 n° 4 (April 2014) . - pp 319 - 333[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2014041 SL Revue Centre de documentation Revues en salle Disponible The quest for a consistent signal in ground and GRACE gravity time-series / Michel Van Camp in Geophysical journal international, vol 197 n° 1 (April 2014)
[article]
Titre : The quest for a consistent signal in ground and GRACE gravity time-series Type de document : Article/Communication Auteurs : Michel Van Camp, Auteur ; Olivier de Viron, Auteur ; Laurent Métivier , Auteur ; Bruno Meurers, Auteur Année de publication : 2014 Article en page(s) : pp 192 - 201 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] données GRACE
[Termes IGN] Europe centrale
[Termes IGN] gravimètre supraconducteur
[Termes IGN] levé gravimétrique
[Termes IGN] série temporelle
[Termes IGN] variation saisonnièreRésumé : (auteur) Recent studies show that terrestrial and space-based observations of gravity agree over Europe. In this paper, we compare time-series of terrestrial gravity (including the contribution due to surface displacement) as measured by superconducting gravimeters (SGs), space-based observations from Gravity Recovery and Climate Experiment (GRACE) and predicted changes in gravity derived from two global hydrological models at 10 SG stations in central Europe. Despite the fact that all observations and models observe a maximum in the same season due to water storage changes, there is little agreement between the SG time-series even when they are separated by distances smaller than the spatial resolution of GRACE. We also demonstrate that GRACE and the SG observations and the water storage models do not display significant correlation at seasonal periods nor at interannual periods. These findings are consistent with the fact that the SGs are sensitive primarily to mass changes in the few hundred metres surrounding the station. Numéro de notice : A2014-784 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Autre URL associée : URL article Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1093/gji/ggt524 Date de publication en ligne : 29/01/2014 En ligne : https://hal.science/hal-01087241/ Format de la ressource électronique : URL article HAL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78598
in Geophysical journal international > vol 197 n° 1 (April 2014) . - pp 192 - 201[article]GOCE: Probing Earth's interior / Isabelle Panet in Horizon 2020 Projects : Portal, n° 2 (March 2014)PermalinkThe impact of the dynamic sea surface topography on the quasi-geoid in shallow coastal waters / D.C. Slobbe in Journal of geodesy, vol 88 n° 3 (March 2014)PermalinkUsing models of the ocean's mean dynamic topography to identify errors in coastal geodetic levelling / M. S. Filmer in Marine geodesy, vol 37 n° 1 (March - May 2014)PermalinkGDQM-PL13 – the new gravimetric quasigeoid model for Poland / Malgorzata Szelachowska in Geoinformation issues, vol 6 n° 1 (2014)PermalinkMapping the mass distribution of Earth's mantle using satellite-derived gravity gradients / Isabelle Panet in Nature geoscience, vol 7 n° 2 (February 2014)PermalinkPermalinkPermalinkA collinearity diagnosis of the GNSS geocenter determination / Paul Rebischung in Journal of geodesy, vol 88 n° 1 (January 2014)PermalinkComparing seven candidate mission configurations for temporal gravity field retrieval through full-scale numerical simulation / Basem Elsaka in Journal of geodesy, vol 88 n° 1 (January 2014)PermalinkDéveloppement d'un accéléromètre atomique compact pour la gravimétrie de terrain et la navigation inertielle / Jean Lautier-Blisson (2014)Permalink