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Auteur Isabelle Panet
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Wavelet‐based directional analysis of the gravity field : evidence for large‐scale undulations / M. Hayn in Geophysical journal international, vol 189 n° 3 (June 2012)
[article]
Titre : Wavelet‐based directional analysis of the gravity field : evidence for large‐scale undulations Type de document : Article/Communication Auteurs : M. Hayn, Auteur ; Isabelle Panet , Auteur ; Michel Diament , Auteur ; Matthias Holschneider, Auteur ; Mioara Mandea, Auteur ; Anne Davaille Année de publication : 2012 Article en page(s) : pp 1430 - 1456 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] anomalie de pesanteur
[Termes IGN] données GRACE
[Termes IGN] manteau terrestre
[Termes IGN] modèle de géopotentiel
[Termes IGN] ondelette d'Abel-Poisson
[Termes IGN] Pacifique (océan)
[Termes IGN] subduction
[Termes IGN] transformation en ondelettesRésumé : (Auteur) In the eighties, the analysis of satellite altimetry data leads to the major discovery of gravity lineations in the oceans, with wavelengths between 200 and 1400 km. While the existence of the 200 km scale undulations is widely accepted, undulations at scales larger than 400 km are still a matter of debate. In this paper, we revisit the topic of the large‐scale geoid undulations over the oceans in the light of the satellite gravity data provided by the GRACE mission, considerably more precise than the altimetry data at wavelengths larger than 400 km.
First, we develop a dedicated method of directional Poisson wavelet analysis on the sphere with significance testing, in order to detect and characterize directional structures in geophysical data on the sphere at different spatial scales. This method is particularly well suited for potential field analysis. We validate it on a series of synthetic tests, and then apply it to analyze recent gravity models, as well as a bathymetry data set independent from gravity. Our analysis confirms the existence of gravity undulations at large scale in the oceans, with characteristic scales between 600 and 2000 km. Their direction correlates well with present‐day plate motion over the Pacific ocean, where they are particularly clear, and associated with a conjugate direction at 1500 km scale. A major finding is that the 2000 km scale geoid undulations dominate and had never been so clearly observed previously. This is due to the great precision of GRACE data at those wavelengths. Given the large scale of these undulations, they are most likely related to mantle processes. Taking into account observations and models from other geophysical information, as seismological tomography, convection and geochemical models and electrical conductivity in the mantle, we conceive that all these inputs indicate a directional fabric of the mantle flows at depth, reflecting how the history of subduction influences the organization of lower mantle upwellings.Numéro de notice : A2012-742 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1365-246X.2012.05455.x Date de publication en ligne : 19/04/2012 En ligne : https://doi.org/10.1111/j.1365-246X.2012.05455.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91491
in Geophysical journal international > vol 189 n° 3 (June 2012) . - pp 1430 - 1456[article]Hydrological deformation induced by the West African Monsoon : Comparison of GPS, GRACE and loading models / Samuel Nahmani in Journal of geophysical research : Solid Earth, Vol 117 n° B5 (May 2012)
[article]
Titre : Hydrological deformation induced by the West African Monsoon : Comparison of GPS, GRACE and loading models Type de document : Article/Communication Auteurs : Samuel Nahmani , Auteur ; Olivier Bock , Auteur ; Marie-Noëlle Bouin , Auteur ; Alvaro Santamaria Gomez, Auteur ; Jean-Paul Boy, Auteur ; Xavier Collilieux , Auteur ; Laurent Métivier , Auteur ; Isabelle Panet , Auteur ; Pierre Genthon, Auteur ; Caroline de Linage, Auteur ; Guy Wöppelmann , Auteur Année de publication : 2012 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Afrique occidentale
[Termes IGN] coordonnées GPS
[Termes IGN] déformation de la croute terrestre
[Termes IGN] données GRACE
[Termes IGN] données météorologiques
[Termes IGN] effet de charge
[Termes IGN] Gao
[Termes IGN] mousson
[Termes IGN] Niamey (Niger)
[Termes IGN] oscillation
[Termes IGN] Ouagadougou
[Termes IGN] station permanente
[Termes IGN] Tombouctou
[Termes IGN] variation saisonnièreRésumé : (Auteur) Three‐dimensional ground deformation measured with permanent GPS stations in West Africa was used for investigating the hydrological loading deformation associated with Monsoon precipitation. The GPS data were processed within a global network for the 2003–2008 period. Weekly station positions were retrieved with a repeatability (including unmodeled loading effects) of 1–2 mm in the horizontal components and between 2.5 and 6 mm in the vertical component. The annual signal in the vertical component for sites located between 9.6°N and 16.7°N is in the range 10–15 mm. It is consistent at the 3 mm‐level with the annual regional‐scale loading deformations estimated from GRACE satellite products and modeled with a combination of hydrological, atmospheric, and nontidal oceanic models. An additional 6 month transient signal was detected in the vertical component of GPS estimates at most of the West African sites. It takes the form of an oscillation occurring between September and March, and reaching a maximum amplitude of 12–16 mm at Ouagadougou (12.5°N). The analysis of in situ hydro‐geological data revealed a strong coincidence between this transient signal and peak river discharge at three sites located along the Niger River (Timbuktu, Gao, and Niamey). At Ouagadougou, a similar coincidence was found with the seasonal variations of the water table depth. We propose a mechanism to account for this signal that involves a sequence of swelling/shrinking of clays combined with local loading effects associated with flooding of the Niger River. Numéro de notice : A2012-753 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1029/2011JB009102 Date de publication en ligne : 12/05/2012 En ligne : https://doi.org/10.1029/2011JB009102 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91470
in Journal of geophysical research : Solid Earth > Vol 117 n° B5 (May 2012)[article]
Titre : Auvergne dataset: Testing several geoid computation methods Type de document : Article/Communication Auteurs : Pierre Valty , Auteur ; Henri Duquenne (1948-2010) , Auteur ; Isabelle Panet , Auteur Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2012 Collection : International Association of Geodesy Symposia, ISSN 0939-9585 num. 136 Conférence : IAG 2009 Symposium, Geodesy for Planet Earth 31/08/2009 04/09/2009 Buenos Aires Argentine Proceedings Springer Importance : pp 465 - 472 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] altitude
[Termes IGN] analyse de données
[Termes IGN] anomalie de pesanteur
[Termes IGN] Auvergne
[Termes IGN] formule de Stokes
[Termes IGN] levé gravimétrique
[Termes IGN] quasi-géoïdeRésumé : (auteur) In 2004, the French Institut Géographique National (IGN), upon the request of the steering committee of the European Gravity and Geoid Project, prepared a dataset to test geoid computation methods. It consists of a set of about 240,000 gravity points, three digital terrestrial models (an accurate one, a low-resolution one and a filtered one) and 75 GPS/levelling points to evaluate the quality of the computed geoid models (Duquenne, A data set to test geoid computation methods. In: Dergisi H (eds.), Proceedings of the 1st international symposium of the international gravity field service “gravity field of the earth”, pp 61–65, 2006). In this paper, we compared the following geoid computation methods using the Auvergne dataset: the remove-compute-restore method using the unmodified Stokes’ kernel, the deterministic (Wong and Gore) and stochastic (KTH) modifications of Stokes’ kernel. For each method, we tested different choices of the parameters (radius of integration of Stokes’ anomalies, degree of modification of Stokes’ kernel, radius of integration of terrain effect, etc.). We analysed the results in order to find out which method performs the best and how the geoid modelling method impacts the results, considering the presence of errors in the dataset. The question that this work intends to answer is whether we should put our efforts rather on the theoretical investigations of geoid modelling methodologies, or on the acquisition of gravity measurements. Numéro de notice : C2009-032 Affiliation des auteurs : LAREG (1991-2011) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.1007/978-3-642-20338-1_56 Date de publication en ligne : 16/07/2011 En ligne : https://doi.org/10.1007/978-3-642-20338-1_56 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91509 Détermination du champ de pesanteur par gradiométrie spatiale [diaporama] / Gwendoline Pajot-Métivier (2012)
Titre : Détermination du champ de pesanteur par gradiométrie spatiale [diaporama] Type de document : Article/Communication Auteurs : Gwendoline Pajot-Métivier , Auteur ; Isabelle Panet , Auteur ; David Coulot , Auteur ; Florent Deleflie, Auteur ; Laurent Métivier , Auteur Editeur : Saint-Mandé : Institut national de l'information géographique et forestière - IGN (2012-) Année de publication : 2012 Conférence : Journées Recherche de l’IGN 2012, 21es Journées 08/03/2012 09/03/2012 Saint-Mandé France programme Format : 30 x 21 cm Langues : Français (fre) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur local
[Termes IGN] géoïde gravimétriqueRésumé : (Documentaliste) La problématique de la présentation est formulée ainsi " Comment utiliser les données du satellite GOCE pour améliorer les modèles régionaux de champ de pesanteur et géoïde ? " Numéro de notice : C2012-020 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComSansActesPubliés-Unpublished DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=64349 Documents numériques
en open access
14366_diaporama_jr2012-pajot.pdfAdobe Acrobat PDF Flexible dataset combination and modelling by domain decomposition approaches / Isabelle Panet (2012)
Titre : Flexible dataset combination and modelling by domain decomposition approaches Type de document : Article/Communication Auteurs : Isabelle Panet , Auteur ; Yuki Kuroishi, Auteur ; Matthias Holschneider, Auteur Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2012 Collection : International Association of Geodesy Symposia, ISSN 0939-9585 num. 137 Projets : 2-Pas d'info accessible - article non ouvert / Conférence : IAG 2009, 7th Hotine-Marussi Symposium on Mathematical Geodesy 06/06/2009 10/06/2009 Rome Italie Proceedings Springer Importance : pp 67 - 73 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] compensation par moindres carrés
[Termes IGN] erreur systématique
[Termes IGN] filtrage du bruit
[Termes IGN] Japon
[Termes IGN] modèle de géopotentiel
[Termes IGN] modèle de géopotentiel local
[Termes IGN] ondelette
[Termes IGN] ondelette d'Abel-Poisson
[Termes IGN] transformation en ondelettesRésumé : (auteur) For geodetic and geophysical purposes, such as geoid determination or the study of the Earth’s structure, heterogeneous gravity datasets of various origins need to be combined over an area of interest, in order to derive a local gravity model at the highest possible resolution. The quality of the obtained gravity model strongly depends on the use of appropriate noise models for the different datasets in the combination process. In addition to random errors, those datasets are indeed often affected by systematic biases and correlated errors. Here we show how wavelets can be used to realize such combination in a flexible and economic way, and how the use of domain decomposition approaches allows to recalibrate the noise models in different wavebands and for different areas. We represent the gravity potential as a linear combination of Poisson multipole wavelets (Holschneider et al. 2003). We compute the wavelet model of the gravity field by regularized least-squares adjustment of the datasets. To solve the normal system, we apply the Schwarz iterative algorithms, based on a domain decomposition of the models space. Hierarchical scale subdomains are defined as subsets of wavelets at different scales, and for each scale, block subdomains are defined based on spatial splittings of the area. In the computation process, the data weights can be refined for each subdomain, allowing to take into account the effect of correlated noises in a simple way. Similarly, the weight of the regularization can be recalibrated for each subdomain, introducing non-stationarity in the a priori assumption of smoothness of the gravity field. We show and discuss examples of application of this method for regional gravity field modelling over a test area in Japan. Numéro de notice : C2009-035 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.1007/978-3-642-22078-4_10 Date de publication en ligne : 18/11/2011 En ligne : https://doi.org/10.1007/978-3-642-22078-4_10 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91642 Pacific geoid anomalies revisited in light of thermochemical oscillating domes in the lower mantle / Cécilia Cadio in Earth and planetary science letters, vol 306 n° 1-2 (June 2011)PermalinkPermalinkEtude géodésique du changement climatique en Méditerranée : première approche / Pierre Valty in Bulletin d'information scientifique et technique de l'IGN, n° 77 (avril 2011)PermalinkReprésentations en ondelettes du champ de pesanteur / Isabelle Panet in Bulletin d'information scientifique et technique de l'IGN, n° 77 (avril 2011)PermalinkSignature des séismes dans le champ de pesanteur / Isabelle Panet in Bulletin d'information scientifique et technique de l'IGN, n° 77 (avril 2011)PermalinkWavelet modelling of the gravity field by domain decomposition methods: an example over Japan / Isabelle Panet in Geophysical journal international, vol 184 n° 1 (January 2011)PermalinkUpper mantle rheology from GRACE and GPS postseismic deformation after the 2004 Sumatra‐Andaman earthquake / Isabelle Panet in Geochemistry, Geophysics, Geosystems, vol 11 n° 6 (June 2010)PermalinkWavelet modeling of the gravity field over Japan / Isabelle Panet in Bulletin of the Geographical survey institute, vol 57 (December 2009)PermalinkLocal multi-polar expansions in potential field modeling / B. Minchev in Earth, Planets and Space, vol 61 n° 10 (October 2009)PermalinkRetrieving earthquake signature in GRACE gravity solutions / Olivier de Viron in Geophysical journal international, vol 174 n° 1 (July 2008)PermalinkCoseismic and post-seismic signatures of the Sumatra 2004 December and 2005 March earthquakes in GRACE satellite gravity / Isabelle Panet in Geophysical journal international, vol 171 n° 1 (Octobre 2007)PermalinkNew 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)PermalinkExtracting low frequency climate signal from GRACE data / Olivier de Viron in eEarth, vol 1 n° 1 (2006)PermalinkReprésentation du champ de pesanteur sur des repères d'ondelettes sphériques / Isabelle Panet in Bulletin d'information scientifique et technique de l'IGN, n° 75 (mars 2006)PermalinkWavelet frames:An alternative to spherical harmonic representation of potential fields / Aude Chambodut in Geophysical journal international, vol 163 n° 3 (December 2005)PermalinkPermalinkPermalinkCan tectonic processes be recovered from new gravity satellite data? / Valentin O. Mikhailov in Earth and planetary science letters, vol 228 n° 3-4 (15 December 2004)PermalinkComparaison de trois familles d'ondelettes pour la représentation du champ de pesanteur terrestre / Isabelle Panet (2003)PermalinkLe SIG, outil de l'aménagement urbain, [Colloque organisé par les élèves IG de la promotion 2000], le jeudi 3 mai 2001 à l'ENSG / Jean-Christophe Barreteau (2001)Permalink
Head of the Gravity Field research team