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Titre : Multi-scale gravity field modeling in space and time Type de document : Article/Communication Auteurs : Shuo (2) Wang, Auteur ; Isabelle Panet , Auteur ; Guillaume Ramillien, Auteur ; Frédéric Guilloux, Auteur Editeur : Munich [Allemagne] : European Geosciences Union EGU Année de publication : 2016 Collection : Geophysical Research Abstracts, ISSN 1607-7962 num. 18 Conférence : EGU 2016, General Assembly 17/04/2016 22/04/2016 Vienne Autriche OA Abstracts only Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] levé gravimétrique
[Termes IGN] ondelette d'Abel-Poisson
[Termes IGN] ondelette de HaarRésumé : (auteur) The Earth constantly deforms as it undergoes dynamic phenomena, such as earthquakes, post-glacial rebound and water displacement in its fluid envelopes. These processes have different spatial and temporal scales and are accompanied by mass displacements, which create temporal variations of the gravity field. Since 2002, the GRACE satellite missions provide an unprecedented view of the gravity field spatial and temporal variations. Gravity models built from these satellite data are essential to study the Earth’s dynamic processes (Tapley et al., 2004). Up to present, time variations of the gravity field are often modelled using spatial spherical harmonics functions averaged over a fixed period, as 10 days or 1 month. This approach is well suited for modeling global phenomena. To better estimate gravity related to local and/or transient processes, such as earthquakes or floods, and adapt the temporal resolution of the model to its spatial resolution, we propose to model the gravity field using localized functions in space and time. For that, we build a model of the gravity field in space and time with a four-dimensional wavelet basis, well localized in space and time. First we design the 4D basis, then, we study the inverse problem to model the gravity field from the potential differences between the twin GRACE satellites, and its regularization using prior knowledge on the water cycle. Our demonstration of surface water mass signals decomposition in time and space is based on the use of synthetic along-track gravitational potential data. We test the developed approach on one year of 4D gravity modeling and compare the reconstructed water heights to those of the input hydrological model. Perspectives of this work is to apply the approach on real GRACE data, addressing the challenge of a re?alistic noise, to better describe and understand physical processus with high temporal resolution/low spatial resolution or the contrary. Numéro de notice : C2016-069 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Poster DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99901 Documents numériques
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Multi-scale gravity field modeling ... - poster pdf auteurAdobe Acrobat PDF Error analysis of a new planar electrostatic gravity gradiometer for airborne surveys / Karim Douch in Journal of geodesy, vol 89 n° 12 (december 2015)
[article]
Titre : Error analysis of a new planar electrostatic gravity gradiometer for airborne surveys Type de document : Article/Communication Auteurs : Karim Douch , Auteur ; Isabelle Panet , Auteur ; Gwendoline Pajot-Métivier , Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 1217 - 1231 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] accélération de la pesanteur
[Termes IGN] accéléromètre
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] erreur systématique
[Termes IGN] gradiométrie
[Termes IGN] gravimètre
[Termes IGN] gravimétrie aérienne
[Termes IGN] gyroscope
[Termes IGN] lever aérienRésumé : (auteur) Moving-base gravity gradiometry has proven to be a convenient method to determine the Earth’s gravity field. The ESA mission GOCE (Gravity field and steady-state Ocean Circulation Explorer) has enabled to map the Earth gravity field and its gradients with a resolution of 80 km, leading to significant advances in physical oceanography and solid Earth physics. At smaller scales, airborne gravity gradiometry has been increasingly used during the past decade in mineral and hydrocarbon exploration. In both cases the sensitivity of gradiometers to the short wavelengths of the gravity field is of crucial interest. Here, we quantify and characterize the error on the gravity gradients estimated from measurements performed with a new instrument concept, called GREMLIT, for typical airborne conditions. GREMLIT is an ultra-sensitive planar gravitational gradiometer which consists in a planar acceleration gradiometer together with 3 gyroscopes. To conduct this error analysis, a simulation of a realistic airborne survey with GREMLIT is carried out. We first simulate realistic GREMLIT synthetic data, taking into account the acceleration gradiometer and gyroscope noises and biases and the variation of orientation of the measurement reference frame. Then, we estimate the gravity gradients from these data. Special attention is paid to the processing of the gyroscopes measurements whose accuracy is not commensurate with the ultra-sensitive gradiometer. We propose a method to calibrate the gyroscopes biases with a precision of the order 10−8 rad/s. In order to transform the tensor from the measurement frame to the local geodetic frame, we estimate the error induced when replacing the non-measured elements of the gravity gradient tensor by an a priori model. With the appropriate smoothing, we show that it is possible to achieve a precision better than 2E for an along-track spatial resolution of 2 km. Numéro de notice : A2015-887 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0847-8 Date de publication en ligne : 07/08/2015 En ligne : https://doi.org/10.1007/s00190-015-0847-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79435
in Journal of geodesy > vol 89 n° 12 (december 2015) . - pp 1217 - 1231[article]Gravity field modelling and gravimetry / Jan Krynski in Geodesy and cartography, vol 64 n° 2 (December 2015)
[article]
Titre : Gravity field modelling and gravimetry Type de document : Article/Communication Auteurs : Jan Krynski, Auteur Année de publication : 2015 Article en page(s) : pp 177 - 200 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] géoïde local
[Termes IGN] levé gravimétrique
[Termes IGN] modèle de géopotentiel local
[Termes IGN] PologneRésumé : (auteur) The summary of research activities concerning gravity field modelling and gravimetric works performed in Poland in the period of 2011-2014 is presented. It contains the results of research on geoid modelling in Poland and other countries, evaluation of global geopotential models, determination of temporal variations of the gravity field with the use of data from satellite gravity space missions, absolute gravity surveys for the maintenance and modernization of the gravity control in Poland and overseas, metrological aspects in gravimetry, maintenance of gravimetric calibration baselines, and investigations of the nontidal gravity changes. The bibliography of the related works is given in references. Numéro de notice : A2015--017 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/geocart-2015-0012 En ligne : http://dx.doi.org/10.1515/geocart-2015-0012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80813
in Geodesy and cartography > vol 64 n° 2 (December 2015) . - pp 177 - 200[article]Science and user needs for observing global mass transport to understand global change and to benefit society / Roland Pail in Surveys in Geophysics, vol 36 n° 6 (November 2015)
[article]
Titre : Science and user needs for observing global mass transport to understand global change and to benefit society Type de document : Article/Communication Auteurs : Roland Pail, Auteur ; Rory Bingham, Auteur ; Carla Braitenberg, Auteur ; Henryk Dobslaw, Auteur ; Annette Eicker, Auteur ; Andreas Güntner, Auteur ; Martin Horwath, Auteur ; Eric Ivins, Auteur ; Laurent Longuevergne, Auteur ; Isabelle Panet , Auteur ; Bert Wouters, Auteur ; IUGG Expert Panel, Auteur Année de publication : 2015 Article en page(s) : pp 743 - 772 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Atmosphère
[Termes IGN] changement climatique
[Termes IGN] gravimétrie spatialeRésumé : (auteur) Satellite gravimetry is a unique measurement technique for observing mass transport processes in the Earth system on a global scale, providing essential indicators of both subtle and dramatic global change. Although past and current satellite gravity missions have achieved spectacular science results, due to their limited spatial and temporal resolution as well as limited length of the available time series numerous important questions are still unresolved. Therefore, it is important to move from current demonstration capabilities to sustained observation of the Earth’s gravity field. In an international initiative performed under the umbrella of the International Union of Geodesy and Geophysics, consensus on the science and user needs for a future satellite gravity observing system has been derived by an international panel of scientists representing the main fields of application, i.e., continental hydrology, cryosphere, ocean, atmosphere and solid Earth. In this paper the main results and findings of this initiative are summarized. The required target performance in terms of equivalent water height has been identified as 5 cm for monthly fields and 0.5 cm/year for long-term trends at a spatial resolution of 150 km. The benefits to meet the main scientific and societal objectives are investigated, and the added value is demonstrated for selected case studies covering the main fields of application. The resulting consolidated view on the required performance of a future sustained satellite gravity observing system represents a solid basis for the definition of technological and mission requirements, and is a prerequisite for mission design studies of future mission concepts and constellations. Numéro de notice : A2015--060 Affiliation des auteurs : IGN+Ext (2012-2019) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10712-015-9348-9 Date de publication en ligne : 27/10/2015 En ligne : http://dx.doi.org/10.1007/s10712-015-9348-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83282
in Surveys in Geophysics > vol 36 n° 6 (November 2015) . - pp 743 - 772[article]Sequential estimation of surface water mass changes from daily satellite gravimetry data / Guillaume L. Ramilien in Journal of geodesy, vol 89 n° 3 (March 2015)
[article]
Titre : Sequential estimation of surface water mass changes from daily satellite gravimetry data Type de document : Article/Communication Auteurs : Guillaume L. Ramilien, Auteur ; Frédéric Frappart, Auteur ; S. Gratton, Auteur Année de publication : 2015 Article en page(s) : pp 259 - 282 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Amazone (fleuve)
[Termes IGN] Amérique du sud
[Termes IGN] analyse diachronique
[Termes IGN] bande K
[Termes IGN] carte thématique
[Termes IGN] données GRACE
[Termes IGN] estimation statistique
[Termes IGN] filtre de Kalman
[Termes IGN] levé gravimétrique
[Termes IGN] masse d'eau
[Termes IGN] océanographie spatiale
[Termes IGN] variation temporelleRésumé : (auteur) We propose a recursive Kalman filtering approach to map regional spatio-temporal variations of terrestrial water mass over large continental areas, such as South America. Instead of correcting hydrology model outputs by the GRACE observations using a Kalman filter estimation strategy, regional 2-by-2 degree water mass solutions are constructed by integration of daily potential differences deduced from GRACE K-band range rate (KBRR) measurements. Recovery of regional water mass anomaly averages obtained by accumulation of information of daily noise-free simulated GRACE data shows that convergence is relatively fast and yields accurate solutions. In the case of cumulating real GRACE KBRR data contaminated by observational noise, the sequential method of step-by-step integration provides estimates of water mass variation for the period 2004–2011 by considering a set of suitable a priori error uncertainty parameters to stabilize the inversion. Spatial and temporal averages of the Kalman filter solutions over river basin surfaces are consistent with the ones computed using global monthly/10-day GRACE solutions from official providers CSR, GFZ and JPL. They are also highly correlated to in situ records of river discharges (70–95 %), especially for the Obidos station where the total outflow of the Amazon River is measured. The sparse daily coverage of the GRACE satellite tracks limits the time resolution of the regional Kalman filter solutions, and thus the detection of short-term hydrological events. Numéro de notice : A2015-338 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0772-2 Date de publication en ligne : 05/11/2014 En ligne : https://doi.org/10.1007/s00190-014-0772-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76707
in Journal of geodesy > vol 89 n° 3 (March 2015) . - pp 259 - 282[article]Determination of precise gravity field for the CLIC feasibility studies / Sébastien Guillaume (2015)PermalinkPermalinkPermalinkGravité de la Terre : des mesures aux modèles, une image de la dynamique interne / Isabelle Panet (2015)PermalinkPermalinkAssessment of observing time-variable gravity from GOCE GPS and accelerometer observations / Pieter N.A.M. Visser in Journal of geodesy, vol 88 n° 11 (November 2014)PermalinkUltra-sensitive electrostatic planar acceleration gradiometer for airborne geophysical surveys / Karim Douch in Measurement Science and Technology, vol 25 n° 10 (October 2014)PermalinkLes effets de l'oscillation Nord-Atlantique sur les transferts de masse, vus par géodésie / Pierre Valty in XYZ, n° 139 (juin - août 2014)PermalinkComparisons 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)PermalinkEvaluation 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)Permalink