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GNSSseg, a statistical method for the segmentation of daily GNSS IWV time series / Annarosa Quarello in Remote sensing, vol 14 n° 14 (July-2 2022)  

Public [article]  inRemote sensing > vol 14 n° 14 (July-2 2022) . - n° 3379 Titre : GNSSseg, a statistical method for the segmentation of daily GNSS IWV time series Type de document : Article/Communication Auteurs : Annarosa Quarello , Auteur ; Olivier Bock , Auteur ; Emilie Lebarbier, Auteur Année de publication : 2022 Projets : VEGAN / Bock, Olivier Article en page(s) : n° 3379 Note générale : bibliographie This work was developed in the framework of the VEGA Project and supported by the CNRS Program LEFE/INSU. The contribution of the third author has been conducted as part of the Project Labex MME-DII (ANR11-LBX-0023-01) and within the FP2M Federation (CNRS FR 2036). Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] coordonnées GPS [Termes IGN] données météorologiques [Termes IGN] erreur systématique [Termes IGN] programmation dynamique [Termes IGN] R (langage) [Termes IGN] segmentation [Termes IGN] série temporelle [Termes IGN] teneur intégrée en vapeur d'eau Résumé : (auteur) Homogenization is an important and crucial step to improve the usage of observational data for climate analysis. This work is motivated by the analysis of long series of GNSS Integrated Water Vapour (IWV) data, which have not yet been used in this context. This paper proposes a novel segmentation method called segfunc that integrates a periodic bias and a heterogeneous, monthly varying, variance. The method consists in estimating first the variance using a robust estimator and then estimating the segmentation and periodic bias iteratively. This strategy allows for the use of the dynamic programming algorithm, which is the most efficient exact algorithm to estimate the change point positions. The performance of the method is assessed through numerical simulation experiments. It is implemented in the R package GNSSseg, which is available on the CRAN. This paper presents the application of the method to a real data set from a global network of 120 GNSS stations. A hit rate of 32% is achieved with respect to available metadata. The final segmentation is made in a semi-automatic way, where the change points detected by three different penalty criteria are manually selected. In this case, the hit rate reaches 60% with respect to the metadata. Numéro de notice : A2022-575 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/rs14143379 Date de publication en ligne : 13/07/2022 En ligne : https://doi.org/10.3390/rs14143379 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101294 [article]

Mapping and characterizing animals’ places of interest in forest environment / Laurence Jolivet (2021)  

Public Titre : Mapping and characterizing animals’ places of interest in forest environment Type de document : Article/Communication Auteurs : Laurence Jolivet , Auteur ; Florian Masson, Auteur ; Sonia Saïd, Auteur Editeur : International Cartographic Association ICA - Association cartographique internationale ACI Année de publication : 2021 Collection : Proceedings of the ICA num. 4 Projets : 1-Pas de projet / Bock, Olivier Conférence : ICC 2021, 30th ICA international cartographic conference 14/12/2021 18/12/2021 Florence Italie Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie thématique [Termes IGN] Cervidae [Termes IGN] comportement [Termes IGN] coordonnées GPS [Termes IGN] forêt tempérée [Termes IGN] migration animale [Termes IGN] réserve naturelle [Termes IGN] Vosges, massif des Mots-clés libres : première heure de passage = first passage time  foraging place = lieu de nourriture  functional space = espace fonctionnel Résumé : (auteur) Fauna impacts its environment as well as spatial environment influences fauna space use. Forest management implies taking into account pressure from animals in fragile-balanced patches. Our goal is to propose maps that would benefit forest planning by reflecting individual movement and space use depending on the animal species and local spatiotemporal environment. The study case focuses on two species, roe deer and red deer, and on a forested site in the northeast of France. Movements of several individuals were analysed from collected GPS locations. Foraging places likely to correspond to intense research behaviour were computed using the First-Passage Time method. These places were assumed as being of interest and were characterized with landscape features and temporal information. Maps were produced to synthetize information about foraging places by defining adapted symbolizations. Then maps about functional space were proposed based on extrapolation of favourable or avoided areas from the characterized observed foraging places and space use. Landscape patches were mapped according to a gradient of potential interest by animals’ species, in order to highlight needs of specific planning actions in the forestry context. Map displays were driven by forestry end-use and designed so that to be compliant to a numeric geographical portal, giving access to different available on-line layers and computed created ones. Numéro de notice : C2021-060 Affiliation des auteurs : UGE-LASTIG+Ext (2020- ) Thématique : BIODIVERSITE/GEOMATIQUE Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.5194/ica-proc-4-51-2021 Date de publication en ligne : 03/12/2021 En ligne : https://doi.org/10.5194/ica-proc-4-51-2021 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99390

The 2018–2019 seismo-volcanic crisis east of Mayotte, Comoros islands: seismicity and ground deformation markers of an exceptional submarine eruption / Anne Lemoine in Geophysical journal international, vol 223 n° 1 (October 2020)  

Public [article]  inGeophysical journal international > vol 223 n° 1 (October 2020) . - pp 22 - 44 Titre : The 2018–2019 seismo-volcanic crisis east of Mayotte, Comoros islands: seismicity and ground deformation markers of an exceptional submarine eruption Type de document : Article/Communication Auteurs : Anne Lemoine, Auteur ; Pierre Briole, Auteur ; Didier Bertil, Auteur ; Agathe Roullé, Auteur ; Michael Foumelis, Auteur ; Isabelle Thinon, Auteur ; Daniel Raucoules, Auteur ; Marcello de Michele, Auteur ; Pierre Valty , Auteur ; Roser Hoste Colomer, Auteur Année de publication : 2020 Article en page(s) : pp 22 - 44 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] Comores (îles) [Termes IGN] coordonnées GPS [Termes IGN] éruption volcanique [Termes IGN] fond marin [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] Mayotte [Termes IGN] séisme Résumé : (auteur) On 10 May 2018, an unprecedented long and intense seismic crisis started offshore, east of Mayotte, the easternmost of the Comoros volcanic islands. The population felt hundreds of events. Over the course of 1 yr, 32 earthquakes with magnitude greater than 5 occurred, including the largest event ever recorded in the Comoros (Mw = 5.9 on 15 May 2018). Earthquakes are clustered in space and time. Unusual intense long lasting monochromatic very long period events were also registered. From early July 2018, Global Navigation Satellite System (GNSS) stations and Interferometric Synthetic Aperture Radar (InSAR) registered a large drift, testimony of a large offshore deflation. We describe the onset and the evolution of a large magmatic event thanks to the analysis of the seismicity from the initiation of the crisis through its first year, compared to the ground deformation observation (GNSS and InSAR) and modelling. We discriminate and characterize the initial fracturing phase, the phase of magma intrusion and dyke propagation from depth to the subsurface, and the eruptive phase that starts on 3 July 2018, around 50 d after the first seismic events. The eruption is not terminated 2 yr after its initiation, with the persistence of an unusual seismicity, whose pattern has been similar since summer 2018, including episodic very low frequency events presenting a harmonic oscillation with a period of ∼16 s. From July 2018, the whole Mayotte Island drifted eastward and downward at a slightly increasing rate until reaching a peak in late 2018. At the apex, the mean deformation rate was 224 mm yr−1 eastward and 186 mm yr−1 downward. During 2019, the deformation smoothly decreased and in January 2020, it was less than 20 per cent of its peak value. A deflation model of a magma reservoir buried in a homogenous half space fits well the data. The modelled reservoir is located 45 ± 5 km east of Mayotte, at a depth of 28 ± 3 km and the inferred magma extraction at the apex was ∼94 m3 s−1. The introduction of a small secondary source located beneath Mayotte Island at the same depth as the main one improves the fit by 20 per cent. While the rate of the main source drops by a factor of 5 during 2019, the rate of the secondary source remains stable. This might be a clue of the occurrence of relaxation at depth that may continue for some time after the end of the eruption. According to our model, the total volume extracted from the deep reservoir was ∼2.65 km3 in January 2020. This is the largest offshore volcanic event ever quantitatively documented. This seismo-volcanic crisis is consistent with the trans-tensional regime along Comoros archipelago. Numéro de notice : A2020-842 Affiliation des auteurs : IGN+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1093/gji/ggaa273 Date de publication en ligne : 03/06/2020 En ligne : https://doi.org/10.1093/gji/ggaa273 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98513 [article]

A probabilistic framework for improving reverse geocoding output / Zhengcong Yin in Transactions in GIS, Vol 24 n° 3 (June 2020)  

Public [article]  inTransactions in GIS > Vol 24 n° 3 (June 2020) . - pp 656 - 680 Titre : A probabilistic framework for improving reverse geocoding output Type de document : Article/Communication Auteurs : Zhengcong Yin, Auteur ; Daniel W. Goldberg, Auteur ; Tracy A. Hammond, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 656 - 680 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] coordonnées GPS [Termes IGN] géocodage inverse [Termes IGN] géolocalisation [Termes IGN] intégrité topologique [Termes IGN] modèle stochastique Résumé : (auteur) Reverse geocoding, which transforms machine‐readable GPS coordinates into human‐readable location information, is widely used in a variety of location‐based services and analysis. The output quality of reverse geocoding is critical because it can greatly impact these services provided to end‐users. We argue that the output of reverse geocoding should be spatially close to and topologically correct with respect to the input coordinates, contain multiple suggestions ranked by a uniform standard, and incorporate GPS uncertainties. However, existing reverse geocoding systems often fail to fulfill these aims. To further improve the reverse geocoding process, we propose a probabilistic framework that includes: (1) a new workflow that can adapt all existing address models and unitizes distance and topology relations among retrieved reference data for candidate selections; (2) an advanced scoring mechanism that quantifies characteristics of the entire workflow and orders candidates according to their likelihood of being the best candidate; and (3) a novel algorithm that derives statistical surfaces for input GPS uncertainties and propagates such uncertainties into final output lists. The efficiency of the proposed approaches is demonstrated through comparisons to the four commercial reverse geocoding systems and through human judgments. We envision that more advanced reverse geocoding output ranking algorithms specific to different application scenarios can be built upon this work. Numéro de notice : A2020-444 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12623 Date de publication en ligne : 08/05/2020 En ligne : https://doi.org/10.1111/tgis.12623 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95507 [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)  

Public [article]  inJournal of geodynamics > vol 136 (May 2020) . - n° 101722 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 / Bock, Olivier 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] viscosité Résumé : (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 [article]

IWV retrieval from ground and shipborne GPS receivers during NAWDEX [diaporama] / Pierre Bosser (2020)  

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On the application of Monte Carlo singular spectrum analysis to GPS position time series / Seyed Mohsen Khazraei in Journal of geodesy, vol 93 n° 9 (September 2019)  

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A new global grid model for the determination of atmospheric weighted mean temperature in GPS precipitable water vapor / Liangke Huang in Journal of geodesy, vol 93 n° 2 (February 2019)  

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Does long-term GPS in the Western Alps finally confirm earthquake mechanisms? / Andrea Walpersdorf in Tectonics, vol 37 n° 10 (October 2018)  

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Multi‐scale observations of atmospheric moisture variability in relation to heavy precipitating systems in the northwestern Mediterranean during HyMeX IOP12 / Samiro Khodayar in Quarterly Journal of the Royal Meteorological Society, vol 144 n° 717 (October 2018 Part B)  

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Revisit the calibration errors on experimental slant total electron content (TEC) determined with GPS / Wenfeng Nie in GPS solutions, vol 22 n° 3 (July 2018)  

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The impact of solid Earth-tide model error on tropospheric zenith delay estimates and GPS coordinate time series / Fei Li in Survey review, vol 50 n° 361 (July 2018)  

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Influences of environmental loading corrections on the nonlinear variations and velocity uncertainties for the reprocessed global positioning system height time series of the crustal movement observation network of China / Peng Yuan in Remote sensing, vol 10 n° 6 (June 2018)    

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Reduction of ZTD outliers through improved GNSS data processing and screening strategies [Interactive discussion] / Katarzyna Stępniak in Atmospheric measurement techniques, vol 11 n° 3 (March 2018)  

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An accurate Kriging-based regional ionospheric model using combined GPS/BeiDou observations / Mohamed Abdelazeem in Journal of applied geodesy, vol 12 n° 1 (January 2018)  

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