Centre de documentation
scientifique

The impact of terrestrial gravity data density on geoid accuracy: case study Bilogora in Croatia / Olga Bjelotomić Oršulić in Survey review, vol 52 n° 373 (July 2020)  

Public [article]  inSurvey review > vol 52 n° 373 (July 2020) . - pp 299 - 308 Titre : The impact of terrestrial gravity data density on geoid accuracy: case study Bilogora in Croatia Type de document : Article/Communication Auteurs : Olga Bjelotomić Oršulić, Auteur ; Danko Markovinović, Auteur ; Matej Varga, Auteur ; Tomislav Basic, Auteur Année de publication : 2020 Article en page(s) : pp 299 - 308 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] Croatie [Termes IGN] données CHAMP [Termes IGN] géoïde [Termes IGN] gravimétrie terrestre [Termes IGN] levé gravimétrique [Termes IGN] quasi-géoïde [Termes IGN] station d'observation Résumé : (auteur) One of the main challenges in physical geodesy today is achieving the 1-centimetre gravimetric quasi-geoid model, since a model of such accuracy could be used in the definition and realisation of the height reference frame. One of the main obstacles in this challenge is the lack of terrestrial gravity data or its uneven distribution. Therefore, the main question arises: what density of gravity points is necessary in order to obtain a gravimetric quasi-geoid model with an accuracy of 1 centimetre or even better? In this simulated study, the results show a trend of decreasing RMS related to the sparser dataset used in computation, leading to the conclusion that the determination of the sub-centimetre quasi-geoid model is no longer a theory, but can be achieved with the exact density of terrestrial gravity data: gravity observation stations have to be distributed no farther than 500 m from one another. When dealing with a very rough topography, the distance should be even shorter. Numéro de notice : A2020-456 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2018.1562747 Date de publication en ligne : 13/01/2020 En ligne : https://doi.org/10.1080/00396265.2018.1562747 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95555 [article]

On the assimilation of absolute geodetic dynamic topography in a global ocean model: impact on the deep ocean state / Alexey Androsov in Journal of geodesy, vol 93 n° 2 (February 2019)  

Public [article]  inJournal of geodesy > vol 93 n° 2 (February 2019) . - pp 141 - 157 Titre : On the assimilation of absolute geodetic dynamic topography in a global ocean model: impact on the deep ocean state Type de document : Article/Communication Auteurs : Alexey Androsov, Auteur ; Lars Nerger, Auteur ; Reiner Schnur, Auteur ; Alberta Albertella, Auteur ; Reiner Rummel, Auteur ; et al., Auteur Année de publication : 2019 Article en page(s) : pp 141 - 157 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] assimilation des données [Termes IGN] circulation océanique [Termes IGN] données altimétriques [Termes IGN] données CHAMP [Termes IGN] données GOCE [Termes IGN] données GRACE [Termes IGN] filtre de Kalman [Termes IGN] geoïde marin [Termes IGN] géoïde terrestre [Termes IGN] hauteurs de mer [Termes IGN] modèle de simulation [Termes IGN] modèle océanographique [Termes IGN] océanographie dynamique [Termes IGN] salinité [Termes IGN] température de surface de la mer Résumé : (auteur) General ocean circulation models are not perfect. Forced with observed atmospheric fluxes they gradually drift away from measured distributions of temperature and salinity. We suggest data assimilation of absolute dynamical ocean topography (DOT) observed from space geodetic missions as an option to reduce these differences. Sea surface information of DOT is transferred into the deep ocean by defining the analysed ocean state as a weighted average of an ensemble of fully consistent model solutions using an error-subspace ensemble Kalman filter technique. Success of the technique is demonstrated by assimilation into a global configuration of the ocean circulation model FESOM over 1 year. The dynamic ocean topography data are obtained from a combination of multi-satellite altimetry and geoid measurements. The assimilation result is assessed using independent temperature and salinity analysis derived from profiling buoys of the AGRO float data set. The largest impact of the assimilation occurs at the first few analysis steps where both the model ocean topography and the steric height (i.e. temperature and salinity) are improved. The continued data assimilation over 1 year further improves the model state gradually. Deep ocean fields quickly adjust in a sustained manner: A model forecast initialized from the model state estimated by the data assimilation after only 1 month shows that improvements induced by the data assimilation remain in the model state for a long time. Even after 11 months, the modelled ocean topography and temperature fields show smaller errors than the model forecast without any data assimilation. Numéro de notice : A2019-076 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1151-1 Date de publication en ligne : 12/05/2018 En ligne : https://doi.org/10.1007/s00190-018-1151-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92190 [article]

Global Earth structure recovery from state-of-the-art models of the Earth’s gravity field and additional geophysical Information / K. Hamayun (2014)  

Public Titre : Global Earth structure recovery from state-of-the-art models of the Earth’s gravity field and additional geophysical Information Type de document : Thèse/HDR Auteurs : K. Hamayun, Auteur Editeur : Delft : Netherlands Geodetic Commission NGC Année de publication : 2014 Collection : Netherlands Geodetic Commission Publications on Geodesy, ISSN 0165-1706 num. 85 Importance : 165 p. ISBN/ISSN/EAN : 978-94-6186-325-6 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] anomalie de pesanteur [Termes IGN] champ de pesanteur terrestre [Termes IGN] données CHAMP [Termes IGN] données géophysiques [Termes IGN] données GOCE [Termes IGN] données GRACE [Termes IGN] levé gravimétrique Résumé : (auteur) Currently, a tremendous improvement is observed in the accuracy and spatial resolution of global Earth’s gravity field models. This improvement is achieved due to using various new data, including those from satellite gravimetry missions (CHAMP, GRACE, and GOCE); terrestrial and airborne gravity data, as well as altimetry data. The new gravity field models can be applied, in particular, to improve our knowledge of the Earth’s interior structure. The aim of this study is to compile a global map of the Moho interface using a global gravity model and additional available information about the crust density structure. In our study, we use the gravity field model EIGEN-6C2 and the global crustal model CRUST1.0 derived from seismic data. In addition, we utilize seismic-based models of Moho as prior information: CRUST1.0 model, as well as the Crust07 model, which was derived by a fully non-linear inversion of fundamental mode surface waves. The observed gravity field contains nuisance signals from the topography and density heterogeneities related to bathymetry, ice, sediments, and other crustal components. Therefore, we model and sequentially subtract these signals by applying so-called stripping corrections. This results in crust-stripped gravity field quantities (gravity anomalies and gravity disturbances). In the course of research, we review different analytical, semi-analytical, and numerical forward modeling techniques to compute the gravitational attraction of a body. We also derive an analytical formula for the computation of gravitational potential generated by a polyhedral body having linearly varying density. We compute the correction to observed gravity field using the analytical methods in the vicinity of the body and using semi-analytical methods in the far zone. We demonstrate that the sequential correction of gravity disturbances and gravity anomalies for nuisance signals increases the correlation with the Moho depths. We use the corrected gravity field to find the global (mean) value for the crust-mantle density contrast using the Pearson’s correlation method. We use an empirical technique in which the absolute correlation between the Moho depth from CRUST 1.0 model and the updated crust stripped gravity disturbances/anomalies is minimized. The updated stripped gravity disturbances/anomalies are obtained by adding a contribution (attraction) related to the density contrast between the reference crust and the upper most mantle to stripped gravity disturbances/anomalies. [...] Numéro de notice : 14852 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère DOI : 10.4233/uuid:f8f6d8cd-9a6e-4ad1-8152-8d164c1055c9 En ligne : https://doi.org/10.4233/uuid:f8f6d8cd-9a6e-4ad1-8152-8d164c1055c9 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=75698

Recent changes of the Earth’s core derived from satellite observations of magnetic and gravity fields / Mioara Mandea in Proceedings of the National Academy of Sciences of the United States of America PNAS, vol 109 n° 47 (November 2012)  

Public [article]  inProceedings of the National Academy of Sciences of the United States of America PNAS > vol 109 n° 47 (November 2012) Titre : Recent changes of the Earth’s core derived from satellite observations of magnetic and gravity fields Type de document : Article/Communication Auteurs : Mioara Mandea, Auteur ; Isabelle Panet , Auteur ; Vincent Lesur, Auteur ; Olivier de Viron, Auteur ; Michel Diament , Auteur ; Jean-Louis Le Mouël, Auteur Année de publication : 2012 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] champ de pesanteur terrestre [Termes IGN] champ géomagnétique [Termes IGN] données CHAMP [Termes IGN] données GRACE [Termes IGN] géocentre [Termes IGN] variation temporelle Résumé : (Auteur) To understand the dynamics of the Earth’s fluid, iron-rich outer core, only indirect observations are available. The Earth’s magnetic field, originating mainly within the core, and its temporal variations can be used to infer the fluid motion at the top of the core, on a decadal and subdecadal time-scale. Gravity variations resulting from changes in the mass distribution within the Earth may also occur on the same time-scales. Such variations include the signature of the flow inside the core, though they are largely dominated by the water cycle contributions. Our study is based on 8 y of high-resolution, high-accuracy magnetic and gravity satellite data, provided by the CHAMP and GRACE missions. From the newly derived geomagnetic models we have computed the core magnetic field, its temporal variations, and the core flow evolution. From the GRACE CNES/GRGS series of time variable geoid models, we have obtained interannual gravity models by using specifically designed postprocessing techniques. A correlation analysis between the magnetic and gravity series has demonstrated that the interannual changes in the second time derivative of the core magnetic field under a region from the Atlantic to Indian Ocean coincide in phase with changes in the gravity field. The order of magnitude of these changes and proposed correlation are plausible, compatible with a core origin; however, a complete theoretical model remains to be built. Our new results and their broad geophysical significance could be considered when planning new Earth observation space missions and devising more sophisticated Earth’s interior models. Numéro de notice : A2012-735 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1073/pnas.1207346109 Date de publication en ligne : 10/09/2012 En ligne : https://doi.org/10.1073/pnas.1207346109 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91455 [article]

Choix d'un modèle géopotentiel global pour la détermination du géoïde en Algérie / N. Rabehi in Bulletin des sciences géographiques, n° 27 (juin 2012)

Public [article]  inBulletin des sciences géographiques > n° 27 (juin 2012) . - pp 33 - 39 Titre : Choix d'un modèle géopotentiel global pour la détermination du géoïde en Algérie Type de document : Article/Communication Auteurs : N. Rabehi, Auteur ; M. Kreri, Auteur ; M. Touabet, Auteur ; M. Terbeche, Auteur Année de publication : 2012 Article en page(s) : pp 33 - 39 Note générale : Bibliographie Langues : Anglais (eng) Français (fre) Arabe (ara) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] Algérie [Termes IGN] champ de pesanteur terrestre [Termes IGN] données CHAMP [Termes IGN] données GRACE [Termes IGN] géoïde local Résumé : (Auteur) La connaissance de nouveaux modèles de champ de pesanteur a été améliorée durant les dernières années à partir des nouvelles missions spatiales (CHAMP et GRACE) dédiées à la détermination précise de haute résolution du champ de pesanteur terrestre. Le problème du choix d'un modèle géopotentiel qui ajuste au mieux les données gravimétriques reste posé et demeure sujet à débat. Dans ce travail, nous apportons une contribution à l'étude du géoïde en Algérie en utilisant une méthode de filtrage des coefficients des modèles géopotentiels. Cette technique va nous conduire à connaître l'apport des nouveaux coefficients des modèles géopotentiels sur la détermination du géoïde en Algérie, en combinant les informations provenant du modèle géopotentiel choisi par la méthode de filtrage, des données gravimétriques terrestres (EOL) et éventuellement du modèle numérique du terrain (GTOPO30). Numéro de notice : A2012-499 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31945 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
253-2012011	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Validation of international reference ionosphere models using in situ measurements from GRACE K-band ranging system and CHAMP planar Langmuir probe / C. Lee in Journal of geodesy, vol 85 n° 12 (December 2011)  

Permalink

Global gravity field determination using the GPS measurements made onboard the low Earth orbiting satellite CHAMP / Lars Prange (2010)  

Permalink

Local multi-polar expansions in potential field modeling / B. Minchev in Earth, Planets and Space, vol 61 n° 10 (October 2009)  

Permalink

Magnetic satellite missions: where have we been and where are we going? / Mioara Mandea in Comptes rendus : Géoscience, vol 338 n° 14-15 (November 2006)

Permalink

New insights on intraplate volcanism in French Polynesia from wavelet analysis of GRACE, CHAMP, and sea surface data / Isabelle Panet in Journal of geophysical research : Solid Earth, vol 111 n° B9 (September 2006)  

Permalink

13th international workshop on laser ranging / Ron Noomen (2003)  

Permalink