Détail de l'auteur
Auteur Aude Chambodut |
Documents disponibles écrits par cet auteur (4)
Ajouter le résultat dans votre panier Affiner la recherche Interroger des sources externesLocal multi-polar expansions in potential field modeling / B. Minchev in Earth, Planets and Space, vol 61 n° 10 (October 2009)
Titre : Local multi-polar expansions in potential field modeling Type de document : Article/Communication Auteurs : B. Minchev, Auteur ; Aude Chambodut, Auteur ; Matthias Holschneider, Auteur ; Isabelle Panet Année de publication : 2009 Projets : 1-Pas de projet / Article en page(s) : pp 1127 - 1141 Note générale : bibliographie
This work was supported by the Deutsche Forschungsgemeinschaft(DFG) within the framework of the projects BMBF/DFG “GEOTECHNOLOGIEN” and the DFG project KO 2870/3-1.Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] données CHAMP
[Termes IGN] données géophysiques
[Termes IGN] harmonique sphérique
[Termes IGN] problème inverseRésumé : (auteur) The satellite era brings new challenges in the development and the implementation of potential field models. Major aspects are, therefore, the exploitation of existing space- and ground-based gravity and magnetic data for the long-term. Moreover, a continuous and near real-time global monitoring of the Earth system, allows for a consistent integration and assimilation of these data into complex models of the Earth’s gravity and magnetic fields, which have to consider the constantly increasing amount of available data. In this paper we propose how to speed up the computation of the normal equation in potential filed modeling by using local multi-polar approximations of the modeling functions. The basic idea is to take advantage of the rather smooth behavior of the internal fields at the satellite altitude and to replace the full available gravity or magnetic data by a collection of local moments. We also investigate what are the optimal values for the free parameters of our method. Results from numerical experiments with spherical harmonic models based on both scalar gravity potential and magnetic vector data are presented and discussed. The new developed method clearly shows that very large datasets can be used in potential field modeling in a fast and more economic manner. Numéro de notice : A2009-605 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1186/BF03352965 Date de publication en ligne : 30/11/2009 En ligne : https://doi.org/10.1186/BF03352965 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95757
in Earth, Planets and Space > vol 61 n° 10 (October 2009) . - pp 1127 - 1141[article]
Titre : New insights on intraplate volcanism in French Polynesia from wavelet analysis of GRACE, CHAMP, and sea surface data Type de document : Article/Communication Auteurs : Isabelle Panet Année de publication : 2006 Article en page(s) : 17 p. 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] Cook (îles)
[Termes IGN] croute océanique
[Termes IGN] données CHAMP
[Termes IGN] données GRACE
[Termes IGN] fond marin
[Termes IGN] Marquises, îles
[Termes IGN] ondelette
[Termes IGN] Polynésie française
[Termes IGN] Société, archipel de la (Polynésie française)
[Termes IGN] surface de la mer
[Termes IGN] Tuamotu, îles
[Termes IGN] volcanRésumé : (auteur) In this paper, we discuss the origin of superswell volcanism on the basis of representation and analysis of recent gravity and magnetic satellite data with wavelets in spherical geometry. We computed a refined gravity field in the south central Pacific based on the GRACE satellite GGM02S global gravity field and the KMS02 altimetric grid, and a magnetic anomaly field based on CHAMP data. The magnetic anomalies are marked by the magnetic lineation of the seafloor spreading and by a strong anomaly in the Tuamotu region, which we interpret as evidence for crustal thickening. We interpret our gravity field through a continuous wavelet analysis that allows to get a first idea of the internal density distribution. We also compute the continuous wavelet analysis of the bathymetric contribution to discriminate between deep and superficial sources. According to the gravity signature of the different chains as revealed by our analysis, various processes are at the origin of the volcanism in French Polynesia. As evidence, we show a large-scale anomaly over the Society Islands that we interpret as the gravity signature of a deeply anchored mantle plume. The gravity signature of the Cook-Austral chain indicates a complex origin which may involve deep processes. Finally, we discuss the particular location of the Marquesas chain as suggesting that the origin of the volcanism may interfere with secondary convection rolls or may be controlled by lithospheric weakness due to the regional stress field, or else related to the presence of the nearby Tuamotu plateau. Numéro de notice : A2006-305 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : MATHEMATIQUE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1029/2005JB004141 Date de publication en ligne : 23/09/2006 En ligne : https://doi.org/10.1029/2005JB004141 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96656
in Journal of geophysical research : Solid Earth > vol 111 n° B9 (September 2006) . - 17 p.[article]
Titre : Wavelet frames:An alternative to spherical harmonic representation of potential fields Type de document : Article/Communication Auteurs : Aude Chambodut, Auteur ; Isabelle Panet Année de publication : 2005 Article en page(s) : pp 875 - 899 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] champ magnétique
[Termes IGN] harmonique sphérique
[Termes IGN] ondelette d'Abel-PoissonRésumé : (auteur) Potential fields are classically represented on the sphere using spherical harmonics. However,
this decomposition leads to numerical difficulties when data to be modelled are irregularly distributed or cover a regional zone. To overcome this drawback, we develop a new representation
of the magnetic and the gravity fields based on wavelet frames.
In this paper, we first describe how to build wavelet frames on the sphere. The chosen frames
are based on the Poisson multipole wavelets, which are of special interest for geophysical
modelling, since their scaling parameter is linked to the multipole depth (Holschneider et al.).
The implementation of wavelet frames results from a discretization of the continuous wavelet
transform in space and scale. We also build different frames using two kinds of spherical meshes
and various scale sequences. We then validate the mathematical method through simple fits of
scalar functions on the sphere, named ‘scalar models’. Moreover, we propose magnetic and
gravity models, referred to as ‘vectorial models’, taking into account geophysical constraints.
We then discuss the representation of the Earth’s magnetic and gravity fields from data regularly
or irregularly distributed. Comparisons of the obtained wavelet models with the initial spherical
harmonic models point out the advantages of wavelet modelling when the used magnetic or
gravity data are sparsely distributed or cover just a very local zone.Numéro de notice : A2005-615 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1365-246X.2005.02754.x Date de publication en ligne : 01/12/2005 En ligne : https://doi.org/10.1111/j.1365-246X.2005.02754.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102897
in Geophysical journal international > vol 163 n° 3 (December 2005) . - pp 875 - 899[article]
contenu dans Gravity, geoid and space missions GGSM 2004, IAG international symposium, Porto, Portugal, August 30 - September 3, 2004 / Christopher Jekeli (2005)
Titre : Modelling the Earth’s gravity field using wavelet frames Type de document : Article/Communication Auteurs : Isabelle Panet Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2005 Collection : International Association of Geodesy Symposia, ISSN 0939-9585 num. 129 Conférence : IAG 2004, GGSM international symposium Gravity, geoid and space missions 30/08/2004 03/09/2004 Porto Portugal Importance : pp 48 - 53 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] collocation par moindres carrés
[Termes IGN] Earth Gravity Model 1996
[Termes IGN] modèle numérique
[Termes IGN] ondelette
[Termes IGN] ondelette d'Abel-Poisson
[Termes IGN] transformation en ondelettesRésumé : (auteur) Present and forthcoming satellite gravity missions provide us with new and unique datasets in order to model the Earth's gravity field at 100 km resolution. These new models will bring significant advances in our understanding of the Earth's structure and dynamics. However, it will be necessary to combine satellite data with surface and airborne measurements in order to improve the short wavelength components of the gravity field. The derived regional models with an increased spatial resolution will be used to carry out geodynamic studies at lithospheric or crustal scale. Whereas the classical spherical harmonics decomposition leads to strong numerical difficulties when dealing with local features, wavelet-based representations can handle the local scales as well as the global ones; they should thus be extremely useful to derive local models taking into account data of different origins. Here we describe the construction of wavelet frames on the sphere based on the Poisson multipole wavelet. Those wavelets are of special interest for field modelling since their shape is linked to the potential of multipole sources, and their scaling parameter to the multipole depth (Holschneider et al., 2003). We also compute a local wavelet decomposition of the gravity field at high resolution from evenly and unevenly distributed data using least squares collocation. Our first results show the efficiency of such a representation. Numéro de notice : C2004-028 Affiliation des auteurs : LAREG+Ext (1991-2011) Autre URL associée : vers HAL Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.1007/3-540-26932-0_9 En ligne : https://doi.org/10.1007/3-540-26932-0_9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96659
