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Study on the inter-annual hydrology-induced deformations in Europe using GRACE and hydrological models / Artur Lenczuk in Journal of applied geodesy, vol 14 n° 4 (October 2020)  

Public [article]  inJournal of applied geodesy > vol 14 n° 4 (October 2020) . - pp 393 – 403 Titre : Study on the inter-annual hydrology-induced deformations in Europe using GRACE and hydrological models Type de document : Article/Communication Auteurs : Artur Lenczuk, Auteur ; Grzegorz Leszczuk, Auteur ; Anna Klos, Auteur Année de publication : 2020 Article en page(s) : pp 393 – 403 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] amplitude [Termes descripteurs IGN] analyse de spectre singulier [Termes descripteurs IGN] bassin hydrographique [Termes descripteurs IGN] déformation de la croute terrestre [Termes descripteurs IGN] données GLDAS [Termes descripteurs IGN] données GRACE [Termes descripteurs IGN] Europe (géographie politique) [Termes descripteurs IGN] modèle hydrographique [Termes descripteurs IGN] surcharge hydrologique [Termes descripteurs IGN] variation saisonnière Résumé : (auteur) Earth’s crust deforms in various time and spatial resolutions. To estimate them, geodetic observations are widely employed and compared to geophysical models. In this research, we focus on the Earth’s crust deformations resulting from hydrology mass changes, as observed by GRACE (Gravity Recovery and Climate Experiment) gravity mission and modeled using WGHM (WaterGAP Global Hydrological Model) and GLDAS (Global Land Data Assimilation System), hydrological models. We use the newest release of GRACE Level-2 products, i. e. RL06, provided by the CSR (Center for Space Research, Austin) analysis center in the form of a mascon solution. The analysis is performed for the European area, divided into 29 river basins. For each basin, the average signal is estimated. Then, annual amplitudes and trends are calculated. We found that the eastern part of Europe is characterized by the largest annual amplitudes of hydrology-induced Earth’s crust deformations, which decrease with decreasing distance to the Atlantic coast. GLDAS largely overestimates annual amplitudes in comparison to GRACE and WGHM. Hydrology models underestimate trends, which are observed by GRACE. For the basin-related average signals, we also estimate the non-linear variations over time using the Singular Spectrum Analysis (SSA). For the river basins situated on the southern borderline of Europe and Asia, large inter-annual deformations between 2004 and 2009 reaching a few millimeters are found; they are related to high precipitation and unexpectedly large drying. They were observed by GRACE but mismodelled in the GLDAS and WGHM models. Few smaller inter-annual deformations were also observed by GRACE between 2002-2017 for central and eastern European river basins, but these have been also well-covered by the WGHM and GLDAS hydrological models. Numéro de notice : A2020-677 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1515/jag-2020-0017 date de publication en ligne : 27/10/2020 En ligne : https://doi.org/10.1515/jag-2020-0017 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96170 [article]

GRACE-FO precise orbit determination and gravity recovery / Z. Kang in Journal of geodesy, vol 94 n° 9 (September 2020)  

Public [article]  inJournal of geodesy > vol 94 n° 9 (September 2020) . - n° 85 Titre : GRACE-FO precise orbit determination and gravity recovery Type de document : Article/Communication Auteurs : Z. Kang, Auteur ; S. Bettadpur, Auteur ; P. Nagel, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : n° 85 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] bande K [Termes descripteurs IGN] champ de pesanteur terrestre [Termes descripteurs IGN] données GRACE [Termes descripteurs IGN] double différence [Termes descripteurs IGN] interféromètre au laser [Termes descripteurs IGN] orbite précise [Termes descripteurs IGN] orbitographie Résumé : (auteur) The gravity recovery and climate experiment follow-on (GRACE-FO) satellites, launched in May of 2018, are equipped with geodetic quality GPS receivers for precise orbit determination (POD) and gravity recovery. The primary objective of the GRACE-FO mission is to map the time-variable and mean gravity field of the Earth. To achieve this goal, both GRACE-FO satellites are additionally equipped with a K-band ranging (KBR) system, accelerometers and star trackers. Data processing strategies, data weighting approaches and impacts of observation types and rates are investigated in order to determine the most efficient approach for processing GRACE-FO multi-type data for precise orbit determination and gravity recovery. Two GPS observation types, un-differenced (UD) and double-differenced (DD) observations in general can be used for GPS-based POD and gravity recovery. The GRACE-FO KBR observations are mainly used for gravity recovery, but they can be also used for POD to improve the relative orbit accuracy. The main purpose of this paper is to study the impacts of the DD, UD and KBR observations on GRACE-FO POD and gravity recovery. The precise orbit accuracy is assessed using several tests, which include analysis of orbital fits, satellite laser ranging residuals, KBR range residuals and orbit comparisons. The gravity recovery is validated by comparing different gravity solutions through coefficient-wise comparison, degree difference variances and water height variations over the whole Earth and selected area and river basins. Numéro de notice : A2020-542 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01414-3 date de publication en ligne : 16/08/2020 En ligne : https://doi.org/10.1007/s00190-020-01414-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95744 [article]

Using quantum optical sensors for determining the Earth’s gravity field from space / Jurgen Müller in Journal of geodesy, vol 94 n° 8 (August 2020)  

Public [article]  inJournal of geodesy > vol 94 n° 8 (August 2020) . - n° 71 Titre : Using quantum optical sensors for determining the Earth’s gravity field from space Type de document : Article/Communication Auteurs : Jurgen Müller, Auteur ; Hu Wu, Auteur Année de publication : 2020 Article en page(s) : n° 71 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] capteur optique [Termes descripteurs IGN] champ de pesanteur terrestre [Termes descripteurs IGN] données GOCE [Termes descripteurs IGN] données GRACE [Termes descripteurs IGN] gradient [Termes descripteurs IGN] gradiomètre [Termes descripteurs IGN] gravimétrie spatiale [Termes descripteurs IGN] horloge du satellite [Termes descripteurs IGN] incertitude temporelle [Termes descripteurs IGN] longueur d'onde [Termes descripteurs IGN] onde myriamétrique [Termes descripteurs IGN] optique quantique Résumé : (auteur) Quantum optical technology provides an opportunity to develop new kinds of gravity sensors and to enable novel measurement concepts for gravimetry. Two candidates are considered in this study: the cold atom interferometry (CAI) gradiometer and optical clocks. Both sensors show a high sensitivity and long-term stability. They are assumed on board of a low-orbit satellite like gravity field and steady-state ocean circulation explorer (GOCE) and gravity recovery and climate experiment (GRACE) to determine the Earth’s gravity field. Their individual contributions were assessed through closed-loop simulations which rigorously mapped the sensors’ sensitivities to the gravity field coefficients. Clocks, which can directly obtain the gravity potential (differences) through frequency comparison, show a high sensitivity to the very long-wavelength gravity field. In the GRACE orbit, clocks with an uncertainty level of 1.0×10−18 are capable to retrieve temporal gravity signals below degree 12, while 1.0×10−17 clocks are useful for detecting the signals of degree 2 only. However, it poses challenges for clocks to achieve such uncertainties in a short time. In space, the CAI gradiometer is expected to have its ultimate sensitivity and a remarkable stability over a long time (measurements are precise down to very low frequencies). The three diagonal gravity gradients can properly be measured by CAI gradiometry with a same noise level of 5.0 mE/Hz−−−√. They can potentially lead to a 2–5 times better solution of the static gravity field than that of GOCE above degree and order 50, where the GOCE solution is mainly dominated by the gradient measurements. In the lower degree part, benefits from CAI gradiometry are still visible, but there, solutions from GRACE-like missions are superior. Numéro de notice : A2020-537 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01401-8 date de publication en ligne : 24/07/2020 En ligne : https://doi.org/10.1007/s00190-020-01401-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95730 [article]

Improved arctic ocean mass variability inferred from time-variable gravity with constraints and dual leakage correction / Dapeng Mu in Marine geodesy, Vol 43 n° 3 (May 2020)  

Public [article]  inMarine geodesy > Vol 43 n° 3 (May 2020) . - pp 269 - 284 Titre : Improved arctic ocean mass variability inferred from time-variable gravity with constraints and dual leakage correction Type de document : Article/Communication Auteurs : Dapeng Mu, Auteur ; Tianhe Xu, Auteur ; Guochang Xu, Auteur Année de publication : 2020 Article en page(s) : pp 269 - 284 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] Arctique, océan [Termes descripteurs IGN] données GRACE [Termes descripteurs IGN] harmonique sphérique [Termes descripteurs IGN] marée océanique Résumé : (Auteur) The ocean mass variability inferred from Gravity Recovery and Climate Experiment (GRACE) satellites mission is challenged by the stripes and the leakage across land-ocean boundary. The recently released GRACE mascons solutions are advanced by applying constraints that remove efficiently the stripes and dual leakage correction that restores the coastal ocean mass variability. Here we quantitatively evaluate the improvement in the Arctic Ocean mass variability by GRACE mascons. To do so, we compare the combination of GRACE solutions (including the mascons solutions and traditional spherical harmonic coefficients (SHCs) solutions) and the steric estimates against the altimeter observations. Our results suggest that mascons solutions produce stronger correlations compared to SHCs solutions, especially along the coastal zone, indicating the importance of the dual leakage correction. Stronger correlation is produced by the mascons over a small basin in the interior of the Arctic Ocean, suggesting that mascons solutions deliver better ocean mass variability than the SHCs solutions. Since the comparisons are carried out over two sub-basins, we conclude that mascons are able to provide better regional ocean mass variability that may have implications for regional sea level budget, in particular over the coastal zone. Numéro de notice : A2020-185 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01490419.2020.1711832 date de publication en ligne : 17/01/2020 En ligne : https://doi.org/10.1080/01490419.2020.1711832 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94975 [article]

Using real polar ground gravimetry data to solve the GOCE polar gap problem in satellite-only gravity field recovery / Biao Lu in Journal of geodesy, Vol 94 n°3 (March 2020)  

Public [article]  inJournal of geodesy > Vol 94 n°3 (March 2020) Titre : Using real polar ground gravimetry data to solve the GOCE polar gap problem in satellite-only gravity field recovery Type de document : Article/Communication Auteurs : Biao Lu, Auteur ; Christoph Förste, Auteur ; Franz Barthelmes, Auteur ; et al., Auteur Année de publication : 2020 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] anomalie de pesanteur [Termes descripteurs IGN] Antarctique [Termes descripteurs IGN] Arctique [Termes descripteurs IGN] champ de gravitation [Termes descripteurs IGN] données GOCE [Termes descripteurs IGN] données GRACE [Termes descripteurs IGN] Earth Gravity Model 2008 [Termes descripteurs IGN] filtrage d'information [Termes descripteurs IGN] levé gravimétrique [Termes descripteurs IGN] modèle de géopotentiel [Termes descripteurs IGN] zone polaire Résumé : (auteur) With the successful completion of European Space Agency (ESA)’s PolarGAP campaign, ground gravity data are now available for both polar regions. Therefore, it is now possible to solve the GOCE polar gap problem in satellite-only gravity field recovery by using additional polar ground gravity data instead of some regularization methods. However, ground gravimetry data need to be filtered to remove the short-wavelength information beyond a certain harmonic degree to avoid spectral leakage when inferring satellite-only gravity field models. For the Arctic, the ArcGP data set was successfully applied when inferring the high-resolution gravity field model EGM2008 which could be used for this filtering there. For Antarctica, a combination of latest airborne gravimetry data from ESA’s PolarGap campaign and some previous gravity data was recently published which was irregularly distributed in space and still had some small gaps within the GOCE south polar gap. Therefore, we proposed a point mass modeling method for this filtering which was similar to the way using EGM2008 for such filtering to the ground gravity data in the Arctic. Furthermore, a variance component estimation was applied to combine the normal equations from the different sources to build a global gravity field model called IGGT_R1C. Then, this model’s accuracy was evaluated by comparison with other gravity field models in terms of difference degree amplitudes, gravity anomaly differences as well as external checking by obit adjustment and gravity data in the GOCE polar gap areas. This gravity field model performed well globally according to these checking results; especially, the RMS of the residuals between the filtered gravity data and that calculated from IGGT_R1C was the smallest (2.6 mGal in the Arctic and 5.4 mGal in Antarctica) compared with that of the relevant satellite-only gravity field models, e.g., GOCO05s. Therefore, the disturbing impact of the GOCE polar data gap problem could be solved by adding the polar ground gravity data. Numéro de notice : A2020-155 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01361-z date de publication en ligne : 25/02/2020 En ligne : https://doi.org/10.1007/s00190-020-01361-z Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94805 [article]

Caractérisation de la contribution des charges hydrologiques, atmosphériques et océaniques aux séries temporelles de position GNSS : analyse comparée des modèles de charge et de mouvement du géocentre / Elie-Alban Lescout (2020) 

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

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Combination of GRACE monthly gravity fields on the normal equation level / Ulrich Meyer in Journal of geodesy, vol 93 n° 9 (September 2019)  

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Monitoring of extreme land hydrology events in central Poland using GRACE, land surface models and absolute gravity data / Joanna Kuczynska-Siehien in Journal of applied geodesy, vol 13 n° 3 (July 2019)  

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On the assimilation of absolute geodetic dynamic topography in a global ocean model: impact on the deep ocean state / Alexey Androsov in Journal of geodesy, vol 93 n° 2 (February 2019)  

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Satellite altimetry for earth sciences / Frédéric Frappart (2019)  

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A Terrestrial Reference Frame realised on the observation level using a GPS-LEO satellite constellation / Daniel Koenig in Journal of geodesy, vol 92 n° 11 (November 2018)  

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Migrating pattern of deformation prior to the Tohoku-Oki earthquake revealed by GRACE data / Isabelle Panet in Nature geoscience, vol 11 n° 5 (May 2018)  

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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)  

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

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