Publications de l'équipe Géodésie de l'UMR IPGP
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Homogenizing GPS integrated water vapor time series: Benchmarking break detection methods on synthetic data sets / Roeland Van Malderen in Earth and space science, vol 7 n° 5 (May 2020)
[article]
Titre : Homogenizing GPS integrated water vapor time series: Benchmarking break detection methods on synthetic data sets Type de document : Article/Communication Auteurs : Roeland Van Malderen, Auteur ; Eric Pottiaux, Auteur ; Anna Klos, Auteur ; P. Domonkos, Auteur ; Michal Elias, Auteur ; Tong Ning, Auteur ; Olivier Bock , Auteur ; J. Guijarro, Auteur ; F. Alshawaf, Auteur ; M. Hoseini, Auteur ; Annarosa Quarello , Auteur ; et al., Auteur Année de publication : 2020 Projets : GNSS4SWEC / Article en page(s) : n° e2020EA001121 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] coordonnées GNSS
[Termes IGN] données hétérogènes
[Termes IGN] homogénéisation
[Termes IGN] jeu de données
[Termes IGN] prévision météorologique
[Termes IGN] série temporelle
[Termes IGN] station permanente
[Termes IGN] teneur intégrée en vapeur d'eauRésumé : (auteur) We assess the performance of different break detection methods on three sets of benchmark data sets, each consisting of 120 daily time series of integrated water vapor differences. These differences are generated from the Global Positioning System (GPS) measurements at 120 sites worldwide, and the numerical weather prediction reanalysis (ERA‐Interim) integrated water vapor output, which serves as the reference series here. The benchmark includes homogeneous and inhomogeneous sections with added nonclimatic shifts (breaks) in the latter. Three different variants of the benchmark time series are produced, with increasing complexity, by adding autoregressive noise of the first order to the white noise model and the periodic behavior and consecutively by adding gaps and allowing nonclimatic trends. The purpose of this “complex experiment” is to examine the performance of break detection methods in a more realistic case when the reference series are not homogeneous. We evaluate the performance of break detection methods with skill scores, centered root mean square errors (CRMSE), and trend differences relative to the trends of the homogeneous series. We found that most methods underestimate the number of breaks and have a significant number of false detections. Despite this, the degree of CRMSE reduction is significant (roughly between 40% and 80%) in the easy to moderate experiments, with the ratio of trend bias reduction is even exceeding the 90% of the raw data error. For the complex experiment, the improvement ranges between 15% and 35% with respect to the raw data, both in terms of RMSE and trend estimations. Numéro de notice : A2020-335 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : MATHEMATIQUE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1029/2020EA001121 Date de publication en ligne : 20/04/2020 En ligne : https://doi.org/10.1029/2020EA001121 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96837
in Earth and space science > vol 7 n° 5 (May 2020) . - n° e2020EA001121[article]Joint inversion of GPS and high-resolution GRACE gravity data for the 2012 Wharton basin earthquakes / Michel Diament in Journal of geodynamics, vol 136 (May 2020)
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Titre : Joint inversion of GPS and high-resolution GRACE gravity data for the 2012 Wharton basin earthquakes Type de document : Article/Communication Auteurs : Michel Diament , Auteur ; Valentin O. Mikhailov, Auteur ; Elena P. Timoshkina, Auteur Année de publication : 2020 Projets : TOSCA / Article en page(s) : n° 101722 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] coordonnées GPS
[Termes IGN] déformation de la croute terrestre
[Termes IGN] données GRACE
[Termes IGN] élasticité
[Termes IGN] Indien (océan)
[Termes IGN] séisme
[Termes IGN] viscositéRésumé : (auteur) The Wharton basin is situated in the north-eastern part of the Indian Ocean. In 2012 it hosted the largest intraplate strike-slip earthquakes ever recorded by geophysical networks. The Mw 8.6 earthquake of April 11, 2012, was preceded by a major foreshock (Mw 7.2) on January 10 and was followed two hours afterward by a Mw 8.2 event. These three large events occurred at the diffuse boundary between the Indian and Australian plates and were almost pure strike-slips on sub-vertical rupture surfaces. Using GRACE data, we first extracted the coseismic and postseismic gravity signals caused by these earthquakes. Then we fitted both GPS and the highest available spatial resolution of GRACE data using the geometry of the fault system suggested by Hill et al. (2015). We propose a regularization, which allows to solve for a linear problem in order to invert GPS and GRACE data under constraints on the rake angle. Our inversion yields a uniform displacement field on all elements of a given fault plane. Our solution shows that even the main displacement occurred on WNW trending faults, comparable displacement also occurred on a rupture striking NNE. Hence, we show that the deformation in this diffuse plate boundary region in 2012 was accommodated by displacements along both fault-systems. A viscoelastic relaxation of the asthenosphere with a Maxwell viscosity 1019 Pa∙s successfully explains the postseismic displacements at GPS sites and postseismic gravity signals. The limited postseismic aftershock activity suggests small postseismic slip in the area of the 2012 Wharton earthquakes contrary to what is often observed after large subduction event. Because a part of the observed signal could be related to afterslip, our obtained Maxwell viscosity value should be considered as a lower limit of the asthenospheric viscosity below the Wharton basin. Numéro de notice : A2020-876 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.jog.2020.101722 Date de publication en ligne : 20/03/2020 En ligne : https://doi.org/10.1016/j.jog.2020.101722 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99670
in Journal of geodynamics > vol 136 (May 2020) . - n° 101722[article]Accounting for spatiotemporal correlations of GNSS coordinate time series to estimate station velocities / Clément Benoist in Journal of geodynamics, vol 135 (April 2020)
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Titre : Accounting for spatiotemporal correlations of GNSS coordinate time series to estimate station velocities Type de document : Article/Communication Auteurs : Clément Benoist , Auteur ; Xavier Collilieux , Auteur ; Paul Rebischung , Auteur ; Zuheir Altamimi , Auteur ; Olivier Jamet , Auteur ; Laurent Métivier , Auteur ; Kristel Chanard , Auteur ; Liliane Bel, Auteur Année de publication : 2020 Projets : GEODESIE / Coulot, David, Université de Paris / Clerici, Christine Article en page(s) : n° 101693 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] corrélation
[Termes IGN] covariance
[Termes IGN] données spatiotemporelles
[Termes IGN] repère de référence terrestre conventionnel
[Termes IGN] série temporelle
[Termes IGN] vitesseRésumé : (auteur) It is well known that GNSS permanent station coordinate time series exhibit time-correlated noise. Spatial correlations between coordinate time series of nearby stations are also long-established and generally handled by means of spatial filtering techniques. Accounting for both the temporal and spatial correlations of the noise via a spatiotemporal covariance model is however not yet a common practice. We demonstrate in this paper the interest of using such a spatiotemporal covariance model of the stochastic variations in GNSS time series in order to estimate long-term station coordinates and especially velocities.
We provide a methodology to rigorously assess the covariances between horizontal coordinate variations and use it to derive a simple exponential spatiotemporal covariance model for the stochastic variations in the IGS repro2 station coordinate time series. We then use this model to estimate station velocities for two selected datasets of 10 time series in Europe and 11 time series in the USA. We show that coordinate prediction as well as velocity determination from short time series are improved when using this spatiotemporal model, as compared with the case where spatiotemporal correlations are ignored.Numéro de notice : A2020-460 Affiliation des auteurs : Géodésie+Ext (mi2018-2019) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.jog.2020.101693 Date de publication en ligne : 13/01/2020 En ligne : https://doi.org/10.1016/j.jog.2020.101693 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95385
in Journal of geodynamics > vol 135 (April 2020) . - n° 101693[article]Assessment of geocenter motion estimates from the IGS second reprocessing / Yifang Ma in GPS solutions, vol 24 n° 2 (April 2020)
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Titre : Assessment of geocenter motion estimates from the IGS second reprocessing Type de document : Article/Communication Auteurs : Yifang Ma , Auteur ; Paul Rebischung , Auteur ; Zuheir Altamimi , Auteur ; Weiping Jiang, Auteur Année de publication : 2020 Projets : 3-projet - voir note / Clerici, Christine Article en page(s) : n° 55 Note générale : bibliographie
This study is supported by the National Science Fund for Distinguished Young Scholars (No. 41525014) and the National Key R&D Program of China (No. 2018YFC15036).Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] analyse comparative
[Termes IGN] données TLS (télémétrie)
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] mouvement du géocentre
[Termes IGN] série temporelle
[Termes IGN] variation saisonnière
[Termes IGN] variation temporelleRésumé : (auteur) We investigate geocenter motion time series derived from the combined solutions and six individual analysis center (AC) solutions of the International GNSS Service (IGS) second reprocessing campaign using the network shift approach, in terms of noise content, long-term trends, periodic and aperiodic variations. We assess these GNSS geocenter motion estimates by comparison with independent estimates from satellite laser ranging (SLR). The GNSS geocenter time series exhibit correlated noise which is better represented by a white plus power–law noise model in the X and Y directions, and by a white plus first-order autoregressive (or generalized Gauss–Markov) noise model in the Z direction. The GNSS geocenter time series include expected seasonal variations, but also spurious draconitic signals, particularly in the Z direction. GNSS annual geocenter motion estimates are in reasonable agreement with SLR estimates in the X and Y directions. In the Z direction, however, the annual signals derived from the IGS solutions disagree with SLR estimates, except for three particular ACs. This suggests that the different orbit modeling strategies used by these ACs may constitute an improvement over the conventional strategy employed by the other ACs. The background noise in GNSS and SLR geocenter time series finally appears to be correlated, suggesting that it might partly reflect real, aperiodic geocenter motion. Numéro de notice : A2020-838 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-020-0968-2 Date de publication en ligne : 10/03/2020 En ligne : https://doi.org/10.1007/s10291-020-0968-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98264
in GPS solutions > vol 24 n° 2 (April 2020) . - n° 55[article]Comparative analysis of different atmospheric surface pressure models and their impacts on daily ITRF2014 GNSS residual time series / Zhao Li in Journal of geodesy, vol 94 n°4 (April 2020)
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Titre : Comparative analysis of different atmospheric surface pressure models and their impacts on daily ITRF2014 GNSS residual time series Type de document : Article/Communication Auteurs : Zhao Li, Auteur ; Chen Wu, Auteur ; Tonie M. van Dam, Auteur ; Paul Rebischung , Auteur ; Zuheir Altamimi , Auteur Année de publication : 2020 Projets : 3-projet - voir note / Clerici, Christine Article en page(s) : n° 42 Note générale : bibliographie
This research is supported by the National Key Research and Development Program of China (Project 2016YFB0502101), the European Commission/Research Grants Council (RGC) Collaboration Scheme sponsored by the Research Grants Council of Hong Kong Special Administrative Region, China (Project No. E-PolyU 501/16), and the National Science Foundation for Distinguished Young Scholars of China (Grant No. 41525014).Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] analyse comparative
[Termes IGN] coefficient de corrélation
[Termes IGN] données GNSS
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] MERRA
[Termes IGN] modèle atmosphérique
[Termes IGN] pression atmosphérique
[Termes IGN] radar JPL
[Termes IGN] résidu
[Termes IGN] série temporelle
[Termes IGN] station GNSSRésumé : (auteur) To remove atmospheric pressure loading (ATML) effect from GNSS coordinate time series, surface pressure (SP) models are required to predict the displacements. In this paper, we modeled the 3D ATML surface displacements using the latest MERRA-2 SP grids, together with four other products (NCEP-R-1, NCEP-R-2, ERA-Interim and MERRA) for 596 globally distributed GNSS stations, and compared them with ITRF2014 residual time series. The five sets of ATML displacements are highly consistent with each other, particularly for those stations far away from coasts, of which the lowest correlations in the Up component for all the four models w.r.t MERRA-2 become larger than 0.91. ERA-Interim-derived ATML displacement performs best in reducing scatter of the GNSS height for 90.3% of the stations (89.3% for NCEP-R-1, 89.1% for NCEP-R-2, 86.4% for MERRA and 85.1% for MERRA-2). We think that this may be possibly due to the 4D variational data assimilation method applied. Considering inland stations only, more than 96% exhibit WRMS reduction in the Up direction for all five models, with an average improvement of 3–4% compared with the original ITRF2014 residual time series before ATML correction. Most stations (> 67%) also exhibit horizontal WRMS reductions based on the five models, but of small magnitudes, with most improvements (> 76%) less than 5%. In particular, most stations in South America, South Africa, Oceania and the Southern Oceans show larger WRMS reductions with MERRA-2, while all other four SP datasets lead to larger WRMS reduction for the Up component than MERRA-2 in Europe. Through comparison of the daily pressure variation from the five SP models, we conclude that the bigger model differences in the SP-induced surface displacements and their impacts on the ITRF2014 residuals for coastal/island stations are mainly due to the IB correction based on the different land–sea masks. A unique high spatial resolution land–sea mask should be applied in the future, so that model differences would come from only SP grids. Further research is also required to compare the ATML effect in ice-covered and high mountainous regions, for example the Qinghai–Tibet Plateau in China, the Andes in South America, etc., where larger pressure differences between models tend to occur. Numéro de notice : A2020-159 Affiliation des auteurs : Géodésie+Ext (mi2018-2019) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01370-y Date de publication en ligne : 20/03/2020 En ligne : https://doi.org/10.1007/s00190-020-01370-y Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94813
in Journal of geodesy > vol 94 n°4 (April 2020) . - n° 42[article]A line integral approach for the computation of the potential harmonic coefficients of a constant density polyhedron / Olivier Jamet in Journal of geodesy, Vol 94 n°3 (March 2020)PermalinkA breakpoint detection in the mean model with heterogeneous variance on fixed time-intervals / Olivier Bock in Statistics and Computing, vol 29 n° 1 (February 2020)PermalinkITRF2014, Earth figure changes, and geocenter velocity: Implications for GIA and recent ice melting / Laurent Métivier in Journal of geophysical research : Solid Earth, vol 125 n° 2 (February 2020)PermalinkA warning against over-interpretation of seasonal signals measured by the Global Navigation Satellite System / Kristel Chanard in Nature communications, vol 11 (2020)PermalinkAdvanced GNSS tropospheric products for monitoring severe weather events and climate, ch. 5. Use of GNSS Tropospheric Products for Climate Monitoring (Working Group 3) / Olivier Bock (2020)PermalinkAdvanced GNSS tropospheric products for monitoring severe weather events and climate / Jonathan Jones (2020)PermalinkPermalinkDescription and evaluation of DTRF2014, JTRF2014 and ITRF2014, ch. 3. ITRS Center evaluation of DTRF2014 and JTRF2014 with respect to ITRF2014 / Zuheir Altamimi (2020)PermalinkDevelopment of new homogenisation methods for GNSS atmospheric data. Application to the analysis of climate trends and variability / Annarosa Quarello (2020)PermalinkIGS International GNSS Service technical report 2019. Reference frame working group technical report 2019 / Paul Rebischung (2020)Permalink