Centre dedocumentation
scientifique

Influence of aperiodic non-tidal atmospheric and oceanic loading deformations on the stochastic properties of global GNSS vertical land motion time series / Kevin Gobron in Journal of geophysical research : Solid Earth, vol 126 n° 9 (September 2021)  

Public [article]  inJournal of geophysical research : Solid Earth > vol 126 n° 9 (September 2021) . - n° e2021JB022370 Titre : Influence of aperiodic non-tidal atmospheric and oceanic loading deformations on the stochastic properties of global GNSS vertical land motion time series Type de document : Article/Communication Auteurs : Kevin Gobron, Auteur ; Paul Rebischung , Auteur ; Michel Van Camp, Auteur ; Alain Demoulin, Auteur ; Olivier de Viron, Auteur Année de publication : 2021 Projets : 2-Pas d'info accessible - article non ouvert / Article en page(s) : n° e2021JB022370 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] coordonnées GNSS [Termes IGN] déformation verticale de la croute terrestre [Termes IGN] erreur systématique [Termes IGN] résidu [Termes IGN] série temporelle [Termes IGN] station permanente [Termes IGN] surcharge atmosphérique [Termes IGN] surcharge océanique Résumé : (auteur) Monitoring vertical land motions (VLMs) at the level of 0.1 mm/yr remains one of the most challenging scientific applications of global navigation satellite systems (GNSS). Such small rates of change can result from climatic and tectonic phenomena, and their detection is important to many solid Earth-related studies, including the prediction of coastal sea-level change and the understanding of intraplate deformation. Reaching a level of precision allowing to detect such small signals requires a thorough understanding of the stochastic variability in GNSS VLM time series. This paper investigates how the aperiodic part of non-tidal atmospheric and oceanic loading (NTAOL) deformations influences the stochastic properties of VLM time series. Using the time series of over 10,000 stations, we describe the impact of correcting for NTAOL deformation on 5 complementary metrics, namely: the repeatability of position residuals, the power-spectrum of position residuals, the estimated time-correlation properties, the corresponding velocity uncertainties, and the spatial correlation of the residuals. We show that NTAOL deformations cause a latitude-dependent bias in white noise plus power-law model parameter estimates. This bias is significantly mitigated when correcting for NTAOL deformation, which reduces velocity uncertainties at high latitudes by 70%. Therefore, removing NTAOL deformation before the statistical analysis of VLM time series might help to detect subtle VLM signals in these areas. Our spatial correlation analysis also reveals a seasonality in the spatial correlation of the residuals, which is reduced after removing NTAOL deformation, confirming that NTAOL is a clear source of common-mode errors in GNSS VLM time series. Numéro de notice : A2021-783 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1029/2021JB022370 Date de publication en ligne : 01/09/2021 En ligne : https://doi.org/10.1029/2021JB022370 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98954 [article]

Vertical land motion in the Southwest and Central Pacific from available GNSS solutions and implications for relative sea levels / Valérie Ballu in Geophysical journal international, vol 218 n° 3 (September 2019)  

Public [article]  inGeophysical journal international > vol 218 n° 3 (September 2019) . - pp 1537 - 1551 Titre : Vertical land motion in the Southwest and Central Pacific from available GNSS solutions and implications for relative sea levels Type de document : Article/Communication Auteurs : Valérie Ballu, Auteur ; Médéric Gravelle, Auteur ; Guy Wöppelmann, Auteur ; Olivier de Viron, Auteur ; Paul Rebischung , Auteur ; Mélanie Becker, Auteur ; Pierre Sakic-Kieffer, Auteur Année de publication : 2019 Projets : STORISK / Duvat, Virginie, TOSCA / Duvat, Virginie Article en page(s) : pp 1537 - 1551 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] changement du niveau de la mer [Termes IGN] déformation verticale de la croute terrestre [Termes IGN] données GNSS [Termes IGN] incertitude géométrique [Termes IGN] Pacifique ouest [Termes IGN] Pacifique Sud [Termes IGN] série temporelle Résumé : (auteur) Coastal populations are impacted by relative sea level variations, which consist both of absolute sea level variations and of vertical land motions. This paper focuses on the Southwest and Central Pacific region, a recognized vulnerable region to sea level rise and where a large range of vertical land motion dynamics is observed. We analyse vertical displacement rates obtained from Global Navigation Satellite Systems (GNSS) by different analysis centres. We study the role played by modelled parameters, such as step discontinuities (due to equipment changes, earthquakes, etc.), in the position time-series analysis. We propose a new modelling approach based on a joint inversion of GNSS position time-series from different analysis centres. The final uncertainty on the vertical land motion rates is estimated as a combination of the uncertainty due to the GNSS data processing itself and the uncertainty due to the stability of the reference frame in which the GNSS data are expressed. We find that the dominant trend in the Southwest and Central Pacific is a moderate subsidence, with an average rate of −1.1 mm yr–1, but significant variations are observed, with displacement rates varying from an uplift of 1.6 ± 0.3 mm yr–1 to a subsidence of −5.4 ± 0.3 mm yr–1. Taking into account the geodynamic context, we assess, for each station, the relevance of current estimates of linear vertical displacement rate and uncertainty for forecasting future coastal sea levels. Numéro de notice : A2019-634 Affiliation des auteurs : Géodésie+Ext (mi2018-2019) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1093/gji/ggz247 Date de publication en ligne : 27/05/2019 En ligne : https://doi.org/10.1093/gji/ggz247 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95452 [article]

Direct measurement of evapotranspiration from a forest using a superconducting gravimeter / Michel Van Camp in Geophysical research letters, vol 43 n° 19 (15 October 2016)    

Public [article]  inGeophysical research letters > vol 43 n° 19 (15 October 2016) . - pp 10225 - 10231 Titre : Direct measurement of evapotranspiration from a forest using a superconducting gravimeter Type de document : Article/Communication Auteurs : Michel Van Camp, Auteur ; Olivier de Viron, Auteur ; Gwendoline Pajot-Métivier , Auteur ; Fabien Casenave , Auteur ; Arnaud Watlet, Auteur ; Alain Dassargues, Auteur ; Marnik Vanclooster, Auteur Année de publication : 2016 Article en page(s) : pp 10225 - 10231 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] Belgique [Termes IGN] évapotranspiration [Termes IGN] feuillu [Termes IGN] forêt tempérée [Termes IGN] gravimètre supraconducteur [Termes IGN] humidité du sol [Termes IGN] levé gravimétrique [Termes IGN] variation diurne Résumé : (auteur) Evapotranspiration (ET) controls the flux between the land surface and the atmosphere. Assessing the ET ecosystems remains a key challenge in hydrology. We have found that the ET water mass loss can be directly inferred from continuous gravity measurements: as water evaporates and transpires from terrestrial ecosystems, the mass distribution of water decreases, changing the gravity field. Using continuous superconducting gravity measurements, we were able to identify daily gravity changes at the level of, or smaller than 10-9 nm.s-2 (or 10-10 g) per day. This corresponds to 1.7 mm of water over an area of 50 ha. The strength of this method is its ability to enable a direct, traceable and continuous monitoring of actual ET for years at the mesoscale with a high accuracy. Numéro de notice : A2016-684 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/2016GL070534 Date de publication en ligne : 07/10/2016 En ligne : http://dx.doi.org/10.1002/2016GL070534 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81973 [article]

Documents numériques

peut être téléchargé Direct measurement of evapotranspiration ... - pdf éditeur Adobe Acrobat PDF

Optimized strategy for the calibration of superconducting gravimeters at the one per mille level / Michel Van Camp in Journal of geodesy, vol 90 n° 1 (January 2016)  

Public [article]  inJournal of geodesy > vol 90 n° 1 (January 2016) . - pp 91- 99 Titre : Optimized strategy for the calibration of superconducting gravimeters at the one per mille level Type de document : Article/Communication Auteurs : Michel Van Camp, Auteur ; Bruno Meurers, Auteur ; Olivier de Viron, Auteur ; Thomas Forbriger, Auteur Année de publication : 2016 Article en page(s) : pp 91- 99 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] étalonnage d'instrument [Termes IGN] gravimètre absolu [Termes IGN] gravimètre supraconducteur [Termes IGN] marée terrestre Résumé : (auteur) This paper reports on different sources of errors that occur in the calibration process of a superconducting gravimeter (SG), determined by comparison with a ballistic absolute gravimeter (AG); some of them have never been discussed in the literature. We then provide methods to mitigate the impact of those errors, to achieve a robust calibration estimate at the http://static-content.springer.com/image/art%3A10.1007%2Fs00190-015-0856-7/MediaObjects/190_2015_856_IEq1_HTML.gif level. We demonstrate that a standard deviation at the level of http://static-content.springer.com/image/art%3A10.1007%2Fs00190-015-0856-7/MediaObjects/190_2015_856_IEq2_HTML.gif can be reached within 48 h by measuring at spring tides and by increasing the AG sampling rate. This is much shorter than what is classically reported in previous empirical studies. Measuring more than 5 days around a tidal extreme does not improve the precision in the calibration factor significantly, as the variation in the error as a function of 1/N−−√ does not apply, considering the decrease in signal amplitude due to the tidal modulation. However, we investigate the precision improvement up to 120 days, which can be useful if an AG is run continuously: at mid-latitude it would require 21 days to ensure a calibration factor at the http://static-content.springer.com/image/art%3A10.1007%2Fs00190-015-0856-7/MediaObjects/190_2015_856_IEq4_HTML.gif level with a 99.7 % confidence interval. We also show that restricting the AG measurement periods to tidal extrema can reduce instrument demand, while this does not affect the precision on the calibration factor significantly. Then, we quantify the effect of high microseismic noise causing aliasing in the AG time series. We eventually discuss the attenuation bias that might be induced by noisy time series of the SG. When experiments are performed at the http://static-content.springer.com/image/art%3A10.1007%2Fs00190-015-0856-7/MediaObjects/190_2015_856_IEq5_HTML.gif level, 7 are needed to ensure that the error in the calibration estimate will be at the 1 per mille level with a 99 % confidence. Numéro de notice : A2016-021 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0856-7 Date de publication en ligne : 25/09/2015 En ligne : https://doi.org/10.1007/s00190-015-0856-7 Format de la ressource électronique : Url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79469 [article]

Impact of the North Atlantic oscillation on Southern Europe water distribution: insights from geodetic data / Pierre Valty in Earth Interactions, vol 19 n° 10 (September 2015)    

Public [article]  inEarth Interactions > vol 19 n° 10 (September 2015) . - pp 1 - 16 Titre : Impact of the North Atlantic oscillation on Southern Europe water distribution: insights from geodetic data Type de document : Article/Communication Auteurs : Pierre Valty , Auteur ; Olivier de Viron, Auteur ; Isabelle Panet , Auteur ; Xavier Collilieux , Auteur Année de publication : 2015 Article en page(s) : pp 1 - 16 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] analyse en composantes principales [Termes IGN] Atlantique Nord [Termes IGN] distribution spatiale [Termes IGN] Europe du sud [Termes IGN] masse d'eau [Termes IGN] Noire, mer [Termes IGN] oscillation Résumé : (auteur) From space gravity and station position data over southern Europe from 2002 to 2010, this study investigates the interannual mass redistributions using principal component analysis. The dominant mode, which appears both in gravity and positioning, results from the North Atlantic Oscillation (NAO). This analysis allows us to isolate and characterize the NAO impact on the mass distribution, which appears centered over the Black Sea and its two main catchment basins, the Danube and Dnieper. Numéro de notice : A2015--072 Affiliation des auteurs : IGN+Ext (2012-2019) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1175/EI-D-14-0028.1 Date de publication en ligne : 16/09/2015 En ligne : http://dx.doi.org/10.1175/EI-D-14-0028.1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83241 [article]

Documents numériques

en open access Impact of the North Atlantic oscillation ... - pdf éditeur Adobe Acrobat PDF

Les effets de l'oscillation Nord-Atlantique sur les transferts de masse, vus par géodésie / Pierre Valty in XYZ, n° 139 (juin - août 2014)

Permalink

The quest for a consistent signal in ground and GRACE gravity time-series / Michel Van Camp in Geophysical journal international, vol 197 n° 1 (April 2014)  

Permalink

Comparative study of temporal variations in the earth’s gravity field using GRACE gravity models in the regions of three recent giant earthquakes / V.O. Mikhailov in Izvestiya, Physics of the Solid Earth, vol 50 n° 2 (March 2014)  

Permalink

Evaluation of MODIS data for improved monitoring of the Caspian Sea / Ayoub Moradi in International Journal of Remote Sensing IJRS, vol 35 n° 16 (January 2014)  

Permalink

Multi sensor study of hydrological changes in Caspian Sea / Ayoub Moradi (sept 2014)

Permalink

Assessing the precision in loading estimates by geodetic techniques in Southern Europe / Pierre Valty in Geophysical journal international, vol 194 n° 3 (September 2013)    

Permalink

Numerical modelling of post-seismic rupture propagation after the Sumatra 26.12.2004 earthquake constrained by GRACE gravity data / V.O. Mikhailov in Geophysical journal international, vol 194 n° 2 (August 2013)  

Permalink

Apport de la géodésie à l’étude des transferts de masse d’origine climatique / Pierre Valty (2013) 

Permalink

Recent changes of the Earth’s core derived from satellite observations of magnetic and gravity fields / Mioara Mandea in Proceedings of the National Academy of Sciences of the United States of America PNAS, vol 109 n° 47 (November 2012)  

Permalink

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)  

Permalink