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Hydrological excitation of polar motion by different variables from the GLDAS models / Malgorzata Winska in Journal of geodesy, vol 91 n° 12 (December 2017)
[article]
Titre : Hydrological excitation of polar motion by different variables from the GLDAS models Type de document : Article/Communication Auteurs : Malgorzata Winska, Auteur ; Jolanta Nastula, Auteur ; David A. Salstein, Auteur Année de publication : 2017 Article en page(s) : pp 1461 - 1473 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] données GRACE
[Termes IGN] moment cinétique
[Termes IGN] mouvement du pôle
[Termes IGN] surcharge hydrologiqueMots-clés libres : Global Land Data Assimilation System model GLDAS model Résumé : (Auteur) Continental hydrological loading by land water, snow and ice is a process that is important for the full understanding of the excitation of polar motion. In this study, we compute different estimations of hydrological excitation functions of polar motion (as hydrological angular momentum, HAM) using various variables from the Global Land Data Assimilation System (GLDAS) models of the land-based hydrosphere. The main aim of this study is to show the influence of variables from different hydrological processes including evapotranspiration, runoff, snowmelt and soil moisture, on polar motion excitations at annual and short-term timescales. Hydrological excitation functions of polar motion are determined using selected variables of these GLDAS realizations. Furthermore, we use time-variable gravity field solutions from the Gravity Recovery and Climate Experiment (GRACE) to determine the hydrological mass effects on polar motion excitation. We first conduct an intercomparison of the maps of variations of regional hydrological excitation functions, timing and phase diagrams of different regional and global HAMs. Next, we estimate the hydrological signal in geodetically observed polar motion excitation as a residual by subtracting the contributions of atmospheric angular momentum and oceanic angular momentum. Finally, the hydrological excitations are compared with those hydrological signals determined from residuals of the observed polar motion excitation series. The results will help us understand the relative importance of polar motion excitation within the individual hydrological processes, based on hydrological modeling. This method will allow us to estimate how well the polar motion excitation budget in the seasonal and inter-annual spectral ranges can be closed. Numéro de notice : A2017-708 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1036-8 En ligne : https://doi.org/10.1007/s00190-017-1036-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=88089
in Journal of geodesy > vol 91 n° 12 (December 2017) . - pp 1461 - 1473[article]Seasonal low-degree changes in terrestrial water mass load from global GNSS measurements / Thierry Meyrath in Journal of geodesy, vol 91 n° 11 (November 2017)
[article]
Titre : Seasonal low-degree changes in terrestrial water mass load from global GNSS measurements Type de document : Article/Communication Auteurs : Thierry Meyrath, Auteur ; Tonie M. van Dam, Auteur ; Xavier Collilieux , Auteur ; Paul Rebischung , Auteur Année de publication : 2017 Projets : 1-Pas de projet / Article en page(s) : pp 1 - 22 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] coordonnées GNSS
[Termes IGN] géocentre
[Termes IGN] masse d'eau
[Termes IGN] mouvement du géocentre
[Termes IGN] surcharge océanique
[Termes IGN] variation saisonnièreRésumé : (auteur) Large-scale mass redistribution in the terrestrial water storage (TWS) leads to changes in the low-degree spherical harmonic coefficients of the Earth’s surface mass density field. Studying these low-degree fluctuations is an important task that contributes to our understanding of continental hydrology. In this study, we use global GNSS measurements of vertical and horizontal crustal displacements that we correct for atmospheric and oceanic effects, and use a set of modified basis functions similar to Clarke et al. (Geophys J Int 171:1–10, 2007) to perform an inversion of the corrected measurements in order to recover changes in the coefficients of degree-0 (hydrological mass change), degree-1 (centre of mass shift) and degree-2 (flattening of the Earth) caused by variations in the TWS over the period January 2003–January 2015. We infer from the GNSS-derived degree-0 estimate an annual variation in total continental water mass with an amplitude of (3.49±0.19)×103 Gt and a phase of 70∘±3∘ (implying a peak in early March), in excellent agreement with corresponding values derived from the Global Land Data Assimilation System (GLDAS) water storage model that amount to (3.39±0.10)×103 Gt and 71∘±2∘, respectively. The degree-1 coefficients we recover from GNSS predict annual geocentre motion (i.e. the offset change between the centre of common mass and the centre of figure) caused by changes in TWS with amplitudes of 0.69±0.07 mm for GX, 1.31±0.08 mm for GY and 2.60±0.13 mm for GZ. These values agree with GLDAS and estimates obtained from the combination of GRACE and the output of an ocean model using the approach of Swenson et al. (J Geophys Res 113(B8), 2008) at the level of about 0.5, 0.3 and 0.9 mm for GX, GY and GZ, respectively. Corresponding degree-1 coefficients from SLR, however, generally show higher variability and predict larger amplitudes for GX and GZ. The results we obtain for the degree-2 coefficients from GNSS are slightly mixed, and the level of agreement with the other sources heavily depends on the individual coefficient being investigated. The best agreement is observed for TC20 and TS22, which contain the most prominent annual signals among the degree-2 coefficients, with amplitudes amounting to (5.47±0.44)×10−3 and (4.52±0.31)×10−3 m of equivalent water height (EWH), respectively, as inferred from GNSS. Corresponding agreement with values from SLR and GRACE is at the level of or better than 0.4×10−3 and 0.9×10−3 m of EWH for TC20 and TS22, respectively, while for both coefficients, GLDAS predicts smaller amplitudes. Somewhat lower agreement is obtained for the order-1 coefficients, TC21 and TS21, while our GNSS inversion seems unable to reliably recover TC22. For all the coefficients we consider, the GNSS-derived estimates from the modified inversion approach are more consistent with the solutions from the other sources than corresponding estimates obtained from an unconstrained standard inversion. Numéro de notice : A2017-311 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1028-8 Date de publication en ligne : 25/04/2017 En ligne : http://doi.org/10.1007/s00190-017-1028-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85361
in Journal of geodesy > vol 91 n° 11 (November 2017) . - pp 1 - 22[article]ITRF2014 plate motion model / Zuheir Altamimi in Geophysical journal international, vol 209 n° 3 (June 2017)
[article]
Titre : ITRF2014 plate motion model Type de document : Article/Communication Auteurs : Zuheir Altamimi , Auteur ; Laurent Métivier , Auteur ; Paul Rebischung , Auteur ; Hélène Rouby , Auteur ; Xavier Collilieux , Auteur Année de publication : 2017 Projets : 1-Pas de projet / Article en page(s) : pp 1906 - 1912 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] déformation de la croute terrestre
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] modèle de déformation tectonique
[Termes IGN] modèle de déplacement de plaque
[Termes IGN] pôle de rotation
[Termes IGN] rebond post-glaciaire
[Termes IGN] station permanente
[Termes IGN] vitesse
[Termes IGN] vitesse de déplacementRésumé : (Auteur) For various geodetic and geophysical applications, users need to have access to a plate motion model (PMM) that is consistent with the ITRF2014 frame. This paper describes the approach used for determining a PMM from the horizontal velocities of a subset of the ITRF2014 sites away from plate boundaries, Glacial Isostatic Adjustment regions and other deforming zones. In theory, it would be necessary to include in the inversion model a translational motion vector (called in this paper origin rate bias, ORB) that would represent the relative motion between the ITRF2014 origin (long-term averaged centre of mass of the Earth as sensed by SLR) and the centre of tectonic plate motion. We show that in practice, the magnitude of the estimated ORB is strongly dependent on the selection of ITRF2014 sites used for the PMM adjustment. Its Z-component can in particular range between 0 and more than 1 mm yr−1 depending on the station network used, preventing any geophysical interpretation of the estimated value. Relying on rigorous statistical criteria, the site selection finally adopted for the ITRF2014-PMM adjustment leads to a relatively small ORB (0.30 ± 0.18 mm yr−1 in the Z-component), which is statistically insignificant at the 2-sigma level, but also according to an F-ratio test. Therefore we opted for an ITRF2014-PMM without estimating the ORB, which in turn accommodates geodetic applications that require access to the ITRF2014 frame through pure plate rotation poles. Numéro de notice : A2017-403 Affiliation des auteurs : LASTIG LAREG (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1093/gji/ggx136 Date de publication en ligne : 30/03/2017 En ligne : https://doi.org/10.1093/gji/ggx136 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86077
in Geophysical journal international > vol 209 n° 3 (June 2017) . - pp 1906 - 1912[article]Inverting Glacial Isostatic Adjustment signal using Bayesian framework and two linearly relaxing rheologies / Lambert Caron in Geophysical journal international, vol 209 n° 2 (May 2017)
[article]
Titre : Inverting Glacial Isostatic Adjustment signal using Bayesian framework and two linearly relaxing rheologies Type de document : Article/Communication Auteurs : Lambert Caron, Auteur ; Laurent Métivier , Auteur ; Marianne Greff-Lefftz, Auteur ; Luce Fleitout, Auteur ; Hélène Rouby , Auteur Année de publication : 2017 Projets : TOSCA / Article en page(s) : pp 1126 - 1147 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] anomalie de pesanteur
[Termes IGN] calotte glaciaire
[Termes IGN] élasticité
[Termes IGN] gravimétrie spatiale
[Termes IGN] manteau terrestre
[Termes IGN] méthode de Monte-Carlo par chaînes de Markov
[Termes IGN] rebond post-glaciaire
[Termes IGN] rhéologieRésumé : (Auteur) Glacial Isostatic Adjustment (GIA) models commonly assume a mantle with a viscoelastic Maxwell rheology and a fixed ice history model. Here, we use a Bayesian Monte Carlo approach with a Markov chain formalism to invert the global GIA signal simultaneously for the mechanical properties of the mantle and the volumes of the ice sheets, using as starting ice models two previously published ice histories. Two stress relaxing rheologies are considered: Burgers and Maxwell linear viscoelasticities. A total of 5720 global palaeo sea level records are used, covering the last 35 kyr. Our goal is not only to seek the model best fitting this data set, but also to determine and display the range of possible solutions with their respective probability of explaining the data. In all cases, our a posteriori probability maps exhibit the classic character of solutions for GIA-determined mantle viscosity with two distinct peaks. What is new in our treatment is the presence of the bi-viscous Burgers rheology and the fact that we invert rheology jointly with ice history, in combination with the greatly expanded palaeo sea level records. The solutions tend to be characterized by an upper-mantle viscosity of around 5 × 1020 Pa s with one preferred lower-mantle viscosities at 3 × 1021 Pa s and the other more than 2 × 1022 Pa s, a rather classical pairing. Best-fitting models depend upon the starting ice history and the stress relaxing law. A first peak (P1) has the highest probability only in the case with a Maxwell rheology and ice history based on ICE-5G, while the second peak (P2) is favoured for ANU-based ice history or Burgers stress relaxation. The latter solution also may satisfy lower-mantle viscosity inferences from long-term geodynamics and gravity gradient anomalies over Laurentia. P2 is also consistent with large Laurentian and Fennoscandian ice-sheet volumes at the Last Glacial Maximum (LGM) and smaller LGM Antarctic ice volume than in either ICE-5G or ANU. Exploration of a bi-viscous linear relaxing rheology in GIA now seems logical due to a new set of requirements to satisfy observations of transient post-seismic flow seen so ubiquitously in space gravimetry and other global geodetic data. Numéro de notice : A2017-402 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1093/gji/ggx083 Date de publication en ligne : 27/02/2017 En ligne : https://doi.org/10.1093/gji/ggx083 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86108
in Geophysical journal international > vol 209 n° 2 (May 2017) . - pp 1126 - 1147[article]Assessment of second- and third-order ionospheric effects on regional networks : case study in China with longer CMONOC GPS coordinate time series / Liansheng Deng in Journal of geodesy, vol 91 n° 2 (February 2017)
[article]
Titre : Assessment of second- and third-order ionospheric effects on regional networks : case study in China with longer CMONOC GPS coordinate time series Type de document : Article/Communication Auteurs : Liansheng Deng, Auteur ; Weiping Jiang, Auteur ; Zhao Li, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 207 - 227 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] analyse diachronique
[Termes IGN] Chine
[Termes IGN] coordonnées GPS
[Termes IGN] correction ionosphérique
[Termes IGN] déformation de la croute terrestre
[Termes IGN] effet atmosphérique
[Termes IGN] propagation ionosphérique
[Termes IGN] réseau géodésique local
[Termes IGN] retard ionosphèrique
[Termes IGN] série temporelle
[Termes IGN] surcharge atmosphériqueRésumé : (Auteur) Higher-order ionospheric (HOI) delays are one of the principal technique-specific error sources in precise global positioning system analysis and have been proposed to become a standard part of precise GPS data processing. In this research, we apply HOI delay corrections to the Crustal Movement Observation Network of China’s (CMONOC) data processing (from January 2000 to December 2013) and furnish quantitative results for the effects of HOI on CMONOC coordinate time series. The results for both a regional reference frame and global reference frame are analyzed and compared to clarify the HOI effects on the CMONOC network. We find that HOI corrections can effectively reduce the semi-annual signals in the northern and vertical components. For sites with lower semi-annual amplitudes, the average decrease in magnitude can reach 30 and 10 % for the northern and vertical components, respectively. The noise amplitudes with HOI corrections and those without HOI corrections are not significantly different. Generally, the HOI effects on CMONOC networks in a global reference frame are less obvious than the results in the regional reference frame, probably because the HOI-induced errors are smaller in comparison to the higher noise levels seen when using a global reference frame. Furthermore, we investigate the combined contributions of environmental loading and HOI effects on the CMONOC stations. The largest loading effects on the vertical displacement are found in the mid- to high-latitude areas. The weighted root mean square differences between the corrected and original weekly GPS height time series of the loading model indicate that the mass loading adequately reduced the scatter on the CMONOC height time series, whereas the results in the global reference frame showed better agreements between the GPS coordinate time series and the environmental loading. When combining the effects of environmental loading and HOI corrections, the results with the HOI corrections reduced the scatter on the observed GPS height coordinates better than the height when estimated without HOI corrections, and the combined solutions in the regional reference frame indicate more preferred improvements. Therefore, regional reference frames are recommended to investigate the HOI effects on regional networks. Numéro de notice : A2017-064 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0957-y En ligne : http://dx.doi.org/10.1007/s00190-016-0957-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84278
in Journal of geodesy > vol 91 n° 2 (February 2017) . - pp 207 - 227[article]Assessment of continental hydrosphere loading using GNSS measurements / Michał Zygmunt in Reports on geodesy and geoinformatics, vol 101 (June 2016)PermalinkMarine terraces and rates of vertical tectonic motion: The importance of glacio-isostatic adjustment along the Pacific coast of central North America / Alexander R. Simms in GSA bulletin, vol 128 n° 1-2 ([01/01/2016])PermalinkObserved changes in the Earth’s dynamic oblateness from GRACE data and geophysical models / Y. Sun in Journal of geodesy, vol 90 n° 1 (January 2016)PermalinkQuality evaluation of the weekly vertical loading effects induced from continental water storage models / Z. Li (2016)PermalinkRevisiting the pole tide for and from satellite altimetry / Shailen Desai in Journal of geodesy, vol 89 n° 12 (december 2015)PermalinkImpact of ocean tides loading on precise point positioning based on FES2004 model / J.Z. Kalita in Artificial satellites, vol 50 n° 2 (June 2015)PermalinkNon-linear motions of Australian geodetic stations induced by non-tidal ocean loading and the passage of tropical cyclones / A. Mémin in Journal of geodesy, vol 88 n° 10 (October 2014)PermalinkContinental hydrology loading observed by VLBI measurements / David Eriksson in Journal of geodesy, vol 88 n° 7 (July 2014)PermalinkSurcharges océaniques dans les signaux GPS : la quète de l'extrêmement petit / Christine Heimlich in XYZ, n° 139 (juin - août 2014)PermalinkEtude de l'impact d'un modèle de surcharges sur les résultats obtenus par télémétrie laser sur satellites / Goulven Tallec (2014)PermalinkAssessing the precision in loading estimates by geodetic techniques in Southern Europe / Pierre Valty in Geophysical journal international, vol 194 n° 3 (September 2013)PermalinkImpact of loading displacements on SLR-derived parameters and on the consistency between GNSS and SLR results / Krzysztof Sosnica in Journal of geodesy, vol 87 n° 8 (August 2013)PermalinkPermalinkÉtude comparative des précisions d’approximation de l’ITRF et application à la redéfinition des systèmes géodésiques utilisés au sein du groupe Total / Simon Olivé (2013)PermalinkSciences of geodesy, vol 2. Innovations and future developments / Guochang Xu (2013)PermalinkNontidal ocean loading: amplitudes and potential effects in GPS height time series / Tonie M. van Dam in Journal of geodesy, vol 86 n° 11 (November 2012)PermalinkThe effect of using inconsistent ocean tidal loading models on GPS coordinate solutions / Y. Fu in Journal of geodesy, vol 86 n° 6 (June 2012)PermalinkHydrological 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)PermalinkITRF2008 contribution to glacial isostatic adjustment and recent ice melting assessment / Laurent Métivier in Geophysical research letters, vol 39 n° 1 (January 2012)PermalinkModèles de mouvement des plaques tectoniques : Le cas de l’ITRF2008 [diaporama] / Zuheir Altamimi (2012)Permalink