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ITRF2020 station position kinematic model / Zuheir Altamimi (2022)  

Public Titre : ITRF2020 station position kinematic model Type de document : Article/Communication Auteurs : Zuheir Altamimi , Auteur ; Paul Rebischung , Auteur ; Xavier Collilieux , Auteur ; Laurent Métivier , Auteur ; Kristel Chanard , Auteur Editeur : Washington DC [Maryland - Etats-Unis] : American Geophysical Union AGU Année de publication : 2022 Conférence : AGU 2022, Fall meeting, American Geophysical Union Fall Meeting 12/12/2022 16/12/2022 Chicago Illinois - Etats-Unis Importance : n° G12A-05 Langues : Anglais (eng) Résumé : (auteur) To adequately describe the shape of the deforming Earth’s surface, the ITRF2020 is provided as an augmented reference frame where the temporal station positions are modeled by a piece-wise linear part, and parametric functions describing annual and semi-annual displacements, as well as Post-Seismic Deformation (PSD) for stations subject to major earthquakes. The paper outlines the ITRF2020 analysis strategy and combination model that integrate time series of station positions and Earth Orientation Parameters provided by the IAG technique services of the four space geodetic techniques (DORIS, GNSS, SLR, VLBI). After recalling and discussing the main ITRF2020 features, we deliver some recommendations on how to consistently use the ITRF2020 station position kinematic model that includes the PSD parametric functions, the station seasonal signals expressed in either the Earth Center of Mass (CM) or the Center of Figure (CF) frames, the corresponding geocenter motion, that is the motion of the Center of Mass with respect to the Center of Figure of the solid Earth’s surface. Numéro de notice : C2022-051 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComSansActesPubliés-Unpublished DOI : sans En ligne : https://agu.confex.com/agu/fm22/meetingapp.cgi/Paper/1055248 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103159

Monitoring and modeling of the Sacramento Valley aquifer (California) using geodetic and piezometric measurements / Stacy Larochelle (2022)  

Public Titre : Monitoring and modeling of the Sacramento Valley aquifer (California) using geodetic and piezometric measurements Type de document : Article/Communication Auteurs : Stacy Larochelle, Auteur ; Kristel Chanard , Auteur ; Manon Dalaison, Auteur ; Luce Fleitout, Auteur ; Jérôme Nicolas Fortin, Auteur ; Laurent Longuevergne, Auteur ; Donald F. Argus, Auteur ; Romain Jolivet, Auteur ; Jean-Philippe Avouac, Auteur Editeur : Washington DC [Maryland - Etats-Unis] : American Geophysical Union AGU Année de publication : 2022 Conférence : AGU 2022, Fall meeting, American Geophysical Union Fall Meeting 12/12/2022 16/12/2022 Chicago Illinois - Etats-Unis Importance : n° NS23A-06 Langues : Anglais (eng) Résumé : (auteur) Changes in groundwater levels associated with hydroclimatic variations and anthropogenic water extraction can deform the solid Earth, both elastically and inelastically. Satellite-based geodetic techniques which measure the Earth’s surface displacements can thus be used to track changing conditions in aquifer systems. However, accurately extracting groundwater-induced deformation signals still poses a challenge as geodetic techniques like GNSS and InSAR also record noise, systematic errors and other sources of deformation. In this study, we take advantage of the relatively dense in situ groundwater monitoring network of the Sacramento Valley aquifer in California to constrain its deformation and hydromechanical properties. We start by characterizing the main seasonal and multiannual fluctuations in groundwater levels with an Independent Component Analysis (ICA) and exploit the resulting temporal signature to extract the associated deformation field from GNSS and InSAR time series. We then develop a poroelastic model of the aquifer to invert for its elastic storage capacity and estimate the respective contributions of elastic and inelastic processes to long-term subsidence. Our modeling also suggests that depth-dependent elastic properties are necessary to explain the spatial distribution of horizontal poroelastic displacements measured by GNSS. This work has important implications for the sustainable management of heavily-stressed Californian aquifers but also serves as a calibration between in situ and remote sensing techniques, which is essential for the successful deployment of satellite-based groundwater monitoring in areas with sparse field-based instrumentation. Numéro de notice : C2022-053 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Nature : Communication nature-HAL : ComSansActesPubliés-Unpublished DOI : sans En ligne : https://agu.confex.com/agu/fm22/meetingapp.cgi/Paper/1093662 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103158

Earth and Space Science Open Archive ESSOAr / American Geophysical Union (2019)  

Public Titre : Earth and Space Science Open Archive ESSOAr Type de document : Site web Auteurs : American Geophysical Union, Auteur Editeur : Washington DC [Maryland - Etats-Unis] : American Geophysical Union AGU Année de publication : 2019 Langues : Anglais (eng) Résumé : (auteur) The Earth and Space Science Open Archive (ESSOAr) is a community server established to accelerate the open discovery and dissemination of earth, environmental, and space science research by archiving and sharing early research outputs, including preprints, presentations from major scientific meetings, and important documents of scholarly societies. Numéro de notice : 17645 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Site internet En ligne : https://www.essoar.org/ Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97631

Contient

• Comparison of atmospheric mass density models using a new data source: COSMIC satellite ephemerides / Yang Yang (2020)  
• Are there detectable common aperiodic displacements at ITRF co-location sites? / Maylis Teyssendier de la Serve (2021)  
• Analysis of IGS repro3 station position time series [diaporama] / Paul Rebischung (2021)  

AGU 2015 Fall Meeting, San Francisco, 14 - 18 December 2015 / Anonyme (2015)  

Public Titre : AGU 2015 Fall Meeting, San Francisco, 14 - 18 December 2015 Type de document : Actes de congrès Auteurs : Anonyme, Auteur Editeur : Washington DC [Maryland - Etats-Unis] : American Geophysical Union AGU Année de publication : 2015 Conférence : AGU 2015 Fall Meeting 14/10/2015 18/12/2015 San Francisco Californie - Etats-Unis Langues : Anglais (eng) Numéro de notice : 17335 Affiliation des auteurs : non IGN Nature : Actes DOI : sans En ligne : https://agu.confex.com/agu/fm15/meetingapp.cgi/Home/0 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83299

Contient

• Tropical forest structure characterization using airborne lidar data: an individual tree level approach / António Ferraz (dec 2015)  

Tropical forest structure characterization using airborne lidar data: an individual tree level approach / António Ferraz (dec 2015)  

Public contenu dans AGU 2015 Fall Meeting, San Francisco, 14 - 18 December 2015 / Anonyme (2015)   Titre : Tropical forest structure characterization using airborne lidar data: an individual tree level approach Type de document : Article/Communication Auteurs : António Ferraz , Auteur ; Sassan Saatchi, Auteur ; Clément Mallet , Auteur ; Victoria Meyer, Auteur Editeur : Washington DC [Maryland - Etats-Unis] : American Geophysical Union AGU Année de publication : dec 2015 Conférence : AGU 2015 Fall Meeting 14/10/2015 18/12/2015 San Francisco Californie - Etats-Unis Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] arbre (flore) [Termes IGN] biomasse aérienne [Termes IGN] distribution spatiale [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] forêt tropicale [Termes IGN] hauteur des arbres [Termes IGN] houppier [Termes IGN] Panama [Termes IGN] segmentation [Termes IGN] semis de points [Termes IGN] structure d'un peuplement forestier Résumé : (auteur) Fine scale tropical forest structure characterization has been performed by means of field measurements techniques that record both the specie and the diameter at the breast height (dbh) for every tree within a given area. Due to dense and complex vegetation, additional important ecological variables (e.g. the tree height and crown size) are usually not measured because they are hardly recognized from the ground. The poor knowledge on the 3D tropical forest structure has been a major limitation for the understanding of different ecological issues such as the spatial distribution of carbon stocks, regeneration and competition dynamics and light penetration gradient assessments. Airborne laser scanning (ALS) is an active remote sensing technique that provides georeferenced distance measurements between the aircraft and the surface. It provides an unstructured 3D point cloud that is a high-resolution model of the forest. This study presents the first approach for tropical forest characterization at a fine scale using remote sensing data. The multi-modal lidar point cloud is decomposed into 3D clusters that correspond to single trees by means of a technique called Adaptive Mean Shift Segmentation (AMS3D). The ability of the corresponding individual tree metrics (tree height, crown area and crown volume) for the estimation of above ground biomass (agb) over the 50 ha CTFS plot in Barro Colorado Island is here assessed. We conclude that our approach is able to map the agb spatial distribution with an error of nearly 12% (RMSE=28 Mg ha-1) compared with field-based estimates over 1ha plots. Numéro de notice : C2015-033 Affiliation des auteurs : LASTIG MATIS+Ext (2012-2019) Thématique : FORET/IMAGERIE Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : sans En ligne : https://agu.confex.com/agu/fm15/meetingapp.cgi/Paper/75802 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83298

Gravity field modeling in space and time / Shuo (2) Wang (2014) 

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Journal of geophysical research, JGR [rouge] Solid Earth (Bulletin de Journal of geophysical research : Solid Earth) / American Geophysical Union

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Journal of geophysical research, JGR [rouge] Solid Earth (Bulletin de Journal of geophysical research : Solid Earth) / American Geophysical Union

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Journal of geophysical research, JGR [rouge] Solid Earth (Bulletin de Journal of geophysical research : Solid Earth) / American Geophysical Union

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Journal of geophysical research, JGR [rouge] Solid Earth (Bulletin de Journal of geophysical research : Solid Earth) / American Geophysical Union

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Journal of geophysical research, JGR [rouge] Solid Earth (Bulletin de Journal of geophysical research : Solid Earth) / American Geophysical Union

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Journal of geophysical research, JGR [rouge] Solid Earth (Bulletin de Journal of geophysical research : Solid Earth) / American Geophysical Union

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Journal of geophysical research, JGR [rouge] Solid Earth (Bulletin de Journal of geophysical research : Solid Earth) / American Geophysical Union

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Journal of geophysical research, JGR [rouge] Solid Earth (Bulletin de Journal of geophysical research : Solid Earth) / American Geophysical Union

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Journal of geophysical research, JGR [rouge] Solid Earth (Bulletin de Journal of geophysical research : Solid Earth) / American Geophysical Union

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