Centre de documentation
scientifique

Data-adaptive spatio-temporal filtering of GRACE data / Paoline Prevost in Geophysical journal international, vol 219 n° 3 (December 2019)  

Public [article]  inGeophysical journal international > vol 219 n° 3 (December 2019) . - pp 2034 - 2055 Titre : Data-adaptive spatio-temporal filtering of GRACE data Type de document : Article/Communication Auteurs : Paoline Prevost, Auteur ; Kristel Chanard , Auteur ; Luce Fleitout, Auteur ; Eric Calais, Auteur ; Damian Walwer, Auteur ; Tonie M. van Dam, Auteur ; Michael Ghil, Auteur Année de publication : 2019 Projets : 2-Pas d'info accessible - article non ouvert / Article en page(s) : pp 2034 - 2055 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal [Termes IGN] analyse de spectre singulier [Termes IGN] données géophysiques [Termes IGN] données GRACE [Termes IGN] filtrage spatiotemporel [Termes IGN] harmonique sphérique Résumé : (auteur) Measurements of the spatio-temporal variations of Earth’s gravity field from the Gravity Recovery and Climate Experiment (GRACE) mission have led to new insights into large spatial mass redistribution at secular, seasonal and subseasonal timescales. GRACE solutions from various processing centres, while adopting different processing strategies, result in rather coherent estimates. However, these solutions also exhibit random as well as systematic errors, with specific spatial patterns in the latter. In order to dampen the noise and enhance the geophysical signals in the GRACE data, we propose an approach based on a data-driven spatio-temporal filter, namely the Multichannel Singular Spectrum Analysis (M-SSA). M-SSA is a data-adaptive, multivariate, and non-parametric method that simultaneously exploits the spatial and temporal correlations of geophysical fields to extract common modes of variability. We perform an M-SSA analysis on 13 yr of GRACE spherical harmonics solutions from five different processing centres in a simultaneous setup. We show that the method allows us to extract common modes of variability between solutions, while removing solution-specific spatio-temporal errors that arise from the processing strategies. In particular, the method efficiently filters out the spurious north–south stripes, which are caused in all likelihood by aliasing, due to the imperfect geophysical correction models and low-frequency noise in measurements. Comparison of the M-SSA GRACE solution with mass concentration (mascons) solutions shows that, while the former remains noisier, it does retrieve geophysical signals masked by the mascons regularization procedure. Numéro de notice : A2019-276 Affiliation des auteurs : Géodésie+Ext (mi2018-2019) Thématique : MATHEMATIQUE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1093/gji/ggz409 Date de publication en ligne : 19/09/2019 En ligne : https://doi.org/10.1093/gji/ggz409 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95381 [article]

Toward a global horizontal and vertical elastic load deformation model derived from GRACE and GNSS station position time series / Kristel Chanard in Journal of geophysical research : Solid Earth, vol 123 n° 4 (April 2018)  

Public [article]  inJournal of geophysical research : Solid Earth > vol 123 n° 4 (April 2018) . - pp 3225 - 3237 Titre : Toward a global horizontal and vertical elastic load deformation model derived from GRACE and GNSS station position time series Type de document : Article/Communication Auteurs : Kristel Chanard , Auteur ; Luce Fleitout, Auteur ; Eric Calais, Auteur ; Paul Rebischung , Auteur ; Jean-Philippe Avouac, Auteur Année de publication : 2018 Projets : 3-projet - voir note / Article en page(s) : pp 3225 - 3237 Note générale : bibliographie The project was funded by NSF grant EAR 1345136, the Laboratoire de Recherche Commun “Yves Rocard” (ENS‐CEA‐CNRS), and CNRS/TOSCA grant 2925. Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] coordonnées GNSS [Termes IGN] déformation horizontale de la croute terrestre [Termes IGN] déformation verticale de la croute terrestre [Termes IGN] données GRACE [Termes IGN] Earth Gravity Model 2008 [Termes IGN] erreur systématique [Termes IGN] harmonique sphérique [Termes IGN] modèle de déformation tectonique [Termes IGN] mouvement du géocentre [Termes IGN] série temporelle Résumé : (Auteur) We model surface displacements induced by variations in continental water, atmospheric pressure, and non‐tidal oceanic loading, derived from the Gravity and Recovery Climate Experiment (GRACE) for spherical harmonic degrees two and higher. As they are not observable by GRACE, we use at first the degree‐1 spherical harmonic coefficients from (Swenson2008estimating). We compare the predicted displacements with the position time series of 689 globally distributed continuous Global Navigation Satellite System (GNSS) stations. While GNSS vertical displacements are well explained by the model at a global scale, horizontal displacements are systematically underpredicted and out‐of‐phase with GNSS station position time series. We then re‐estimate the degree‐1 deformation field from a comparison between our GRACE‐derived model, with no a priori degree‐1 loads, and the GNSS observations. We show that this approach reconciles GRACE‐derived loading displacements and GNSS station position time series at a global scale, particularly in the horizontal components. Assuming that they reflect surface loading deformation only, our degree‐1 estimates can be translated into geocenter motion time series. We also address and assess the impact of systematic errors in GNSS station position time series at the Global Positioning System (GPS) draconitic period and its harmonics on the comparison between GNSS and GRACE‐derived annual displacements. Our results confirm that surface mass redistributions observed by GRACE, combined with an elastic spherical and layered Earth model, can be used to provide first order corrections for loading deformation observed in both horizontal and vertical components of GNSS station position time series. Numéro de notice : A2018-055 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Autre URL associée : vers HAL Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/2017JB015245 Date de publication en ligne : 21/02/2018 En ligne : https://doi.org/10.1002/2017JB015245 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89382 [article]

Constraints on transient viscoelastic rheology of the asthenosphere from seasonal deformation / Kristel Chanard in Geophysical research letters, vol 45 n° 5 (15 March 2018)  

Public [article]  inGeophysical research letters > vol 45 n° 5 (15 March 2018) . - pp 2328 - 2338 Titre : Constraints on transient viscoelastic rheology of the asthenosphere from seasonal deformation Type de document : Article/Communication Auteurs : Kristel Chanard , Auteur ; Luce Fleitout, Auteur ; Eric Calais, Auteur ; Sylvain Barbot, Auteur ; Jean-Philippe Avouac, Auteur Année de publication : 2018 Projets : 3-projet - voir note / Article en page(s) : pp 2328 - 2338 Note générale : bibliographie This work was partially supported by NSF grant EAR-1345136, the Laboratorie de Recherche Commun “Yves Rocard” (ENS-CEA-CNRS), and CNRS/TOSCA grant 2925. Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] déformation de la croute terrestre [Termes IGN] données GNSS [Termes IGN] données GRACE [Termes IGN] fonction de Green [Termes IGN] rhéologie [Termes IGN] viscosité Résumé : (auteur) We discuss the constraints on short‐term asthenospheric viscosity provided by seasonal deformation of the Earth. We use data from 195 globally distributed continuous Global Navigation Satellite System stations. Surface loading is derived from the Gravity Recovery and Climate Experiment and used as an input to predict geodetic displacements. We compute Green's functions for surface displacements for a purely elastic spherical reference Earth model and for viscoelastic Earth models. We show that a range of transient viscoelastic rheologies derived to explain the early phase of postseismic deformation may induce a detectable effect on the phase and amplitude of horizontal displacements induced by seasonal loading at long wavelengths (1,300–4,000 km). By comparing predicted and observed seasonal horizontal motion, we conclude that transient asthenospheric viscosity cannot be lower than 5 × 1017 Pa.s, suggesting that low values of transient asthenospheric viscosities reported in some postseismic studies cannot hold for the seasonal deformation global average. Numéro de notice : A2018-654 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/2017GL076451 Date de publication en ligne : 12/02/2018 En ligne : https://doi.org/10.1002/2017GL076451 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93514 [article]

Hydrologically-driven crustal stresses and seismicity in the New Madrid seismic zone / Timothy J. Craig in Nature communications, vol 8 (2017)  

Public [article]  inNature communications > vol 8 (2017) . - art 2143 Titre : Hydrologically-driven crustal stresses and seismicity in the New Madrid seismic zone Type de document : Article/Communication Auteurs : Timothy J. Craig, Auteur ; Kristel Chanard , Auteur ; Eric Calais, Auteur Année de publication : 2017 Projets : SINAPS / Article en page(s) : art 2143 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] Amérique du nord [Termes IGN] analyse de spectre singulier [Termes IGN] déformation de la croute terrestre [Termes IGN] données GPS [Termes IGN] données GRACE [Termes IGN] eau de surface [Termes IGN] faille géologique [Termes IGN] levé gravimétrique [Termes IGN] séisme [Termes IGN] sismicité [Termes IGN] tectonique des plaques Résumé : (auteur) The degree to which short-term non-tectonic processes, either natural and anthropogenic, influence the occurrence of earthquakes in active tectonic settings or ‘stable’ plate interiors, remains a subject of debate. Recent work in plate-boundary regions demonstrates the capacity for long-wavelength changes in continental water storage to produce observable surface deformation, induce crustal stresses and modulate seismicity rates. Here we show that a significant variation in the rate of microearthquakes in the intraplate New Madrid Seismic Zone at annual and multi-annual timescales coincides with hydrological loading in the upper Mississippi embayment. We demonstrate that this loading, which results in geodetically observed surface deformation, induces stresses within the lithosphere that, although of small amplitude, modulate the ongoing seismicity of the New Madrid region. Correspondence between surface deformation, hydrological loading and seismicity rates at both annual and multi-annual timescales indicates that seismicity variations are the direct result of elastic stresses induced by the water load. Numéro de notice : A2017-864 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1038/s41467-017-01696-w Date de publication en ligne : 15/12/2017 En ligne : http://dx.doi.org/10.1038/s41467-017-01696-w Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89865 [article]

A new velocity field for Africa from combined GPS and DORIS space geodetic solutions : Contribution to the definition of the African Reference Frame (AFREF) / E. Saria in Journal of geophysical research : Solid Earth, vol 118 n° 4 (April 2013)  

Public [article]  inJournal of geophysical research : Solid Earth > vol 118 n° 4 (April 2013) . - pp 1677 - 1697 Titre : A new velocity field for Africa from combined GPS and DORIS space geodetic solutions : Contribution to the definition of the African Reference Frame (AFREF) Type de document : Article/Communication Auteurs : E. Saria, Auteur ; Eric Calais, Auteur ; Zuheir Altamimi , Auteur ; Pascal Willis , Auteur ; H. Farah, Auteur Année de publication : 2013 Article en page(s) : pp 1677 - 1697 Note générale : bibliographie Langues : Anglais (eng) Résumé : (auteur) We analyzed 16 years of GPS and 17 years of Doppler orbitography and radiopositioning integrated by satellite (DORIS) data at continuously operating geodetic sites in Africa and surroundings to describe the present-day kinematics of the Nubian and Somalian plates and constrain relative motions across the East African Rift. The resulting velocity field describes horizontal and vertical motion at 133 GPS sites and 9 DORIS sites. Horizontal velocities at sites located on stable Nubia fit a single plate model with a weighted root mean square residual of 0.6 mm/yr (maximum residual 1 mm/yr), an upper bound for plate-wide motions and for regional-scale deformation in the seismically active southern Africa and Cameroon volcanic line. We confirm significant southward motion ( ∼ 1.5 mm/yr) in Morocco with respect to Nubia, consistent with earlier findings. We propose an updated angular velocity for the divergence between Nubia and Somalia, which provides the kinematic boundary conditions to rifting in East Africa. We update a plate motion model for the East African Rift and revise the counterclockwise rotation of the Victoria plate and clockwise rotation of the Rovuma plate with respect to Nubia. Vertical velocities range from − 2 to +2 mm/yr, close to their uncertainties, with no clear geographic pattern. This study provides the first continent-wide position/velocity solution for Africa, expressed in International Terrestrial Reference Frame (ITRF2008), a contribution to the upcoming African Reference Frame (AFREF). Except for a few regions, the African continent remains largely under-sampled by continuous space geodetic data. Efforts are needed to augment the geodetic infrastructure and openly share existing data sets so that the objectives of AFREF can be fully reached. Numéro de notice : A2013-796 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article DOI : 10.1002/jgrb.50137 Date de publication en ligne : 04/03/2013 En ligne : http://dx.doi.org/10.1002/jgrb.50137 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80072 [article]

Geodetic measurements of crustal deformation in the Western Mediterranean and Europe / Jean-Mathieu Nocquet in Pure and applied geophysics, vol 161 n° 3 (March 2004)  

Permalink

Crustal velocity field of western Europe from permanent GPS array solutions, 1996–2001 / Jean-Mathieu Nocquet in Geophysical journal international, vol 154 n° 1 (July 2003)  

Permalink

Reference frame activity: combination of national (RGP) and regional (regal) permanent networks solutions with euref-epn and ITRF 2000 / Jean-Mathieu Nocquet (2003)

Permalink

Current strain regime in the Western Alps from continuous Global Positioning System measurements, 1996–2001 / Eric Calais in Geology, vol 30 n° 7 (July 2002)  

Permalink

Mesure de la déformation crustale en Europe occidentale par géodésie spatiale / Jean-Mathieu Nocquet (2002)

Permalink

Intraplate deformation in western Europe deduced from an analysis of the International Terrestrial Reference Frame 1997 / Jean-Mathieu Nocquet in Journal of geophysical research : Solid Earth, vol 106 n° 6 (June 2001)  

Permalink

Regal, réseau GPS permanent dans les Alpes occidentales : configuration et premiers résultats / Eric Calais in Comptes rendus de l'Académie des sciences. Série 2, Sciences de la Terre et des planètes, tome 331 n° 7 (1 octobre 2000)  

Permalink

Des nouveaux outils au service de la mesure géophysique / Eric Calais in Géomètre, vol 2000 n° 3 (mars 2000)

Permalink

Le projet Régal : un réseau GPS permanent dans les Alpes / Eric Calais in XYZ, n° 77 (septembre - novembre 1998)

Permalink