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Comprehensive study on the tropospheric wet delay and horizontal gradients during a severe weather event / Victoria Graffigna in Remote sensing, vol 14 n° 4 (February-2 2022)  

Public [article]  inRemote sensing > vol 14 n° 4 (February-2 2022) . - n° 888 Titre : Comprehensive study on the tropospheric wet delay and horizontal gradients during a severe weather event Type de document : Article/Communication Auteurs : Victoria Graffigna, Auteur ; Manuel Hernández-Pajares, Auteur ; Francisco Azpilicueta, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 888 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] données météorologiques [Termes IGN] gradient de troposphère [Termes IGN] phénomène climatique extrême [Termes IGN] positionnement ponctuel précis [Termes IGN] retard troposphérique zénithal [Termes IGN] station GNSS [Termes IGN] surveillance météorologique [Termes IGN] tempête [Termes IGN] Texas (Etats-Unis) [Termes IGN] vapeur d'eau Résumé : (auteur) GNSS meteorology is today one of the most growing technologies to monitor severe weather events. In this paper, we present the usage of 160 GPS reference stations over the period of 14 days to monitor and track Hurricane Harvey, which struck Texas in August 2017. We estimate the Zenith Wet Delay (ZWD) and the tropospheric gradients with 30 s interval using TOMION v2 software and carry out the processing in Precise Point Positioning (PPP) mode. We study the relationship of these parameters with atmospheric variables extracted from Tropical Rainfall Measuring Mission (TRMM) satellite mission and climate reanalysis model ERA5. This research finds that the ZWD shows patterns related to the rainfall rate and to the location of the hurricane. We also find that the tropospheric gradients are correlated with water vapor gradients before and after the hurricane, and with the wind and the pressure gradients only after the hurricane. This study also shows a new finding regarding the spectral distribution of the gradients, with a clear diurnal period present, which is also found on the ZWD itself. This kind of study approaches the GNSS meteorology to the increasing requirements of meteorologist in terms of monitoring severe weather events. Numéro de notice : A2022-166 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.3390/rs14040888 Date de publication en ligne : 12/02/2022 En ligne : https://doi.org/10.3390/rs14040888 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99791 [article]

Remote Sensing / Andrew Hammond (2021)  

Public Titre : Remote Sensing Type de document : Monographie Auteurs : Andrew Hammond, Éditeur scientifique Editeur : London [UK] : IntechOpen Année de publication : 2021 Importance : 140 p. ISBN/ISSN/EAN : 978-1-83880-978-2 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Télédétection [Termes IGN] Amérique du sud [Termes IGN] analyse d'image orientée objet [Termes IGN] biomasse [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] données spatiotemporelles [Termes IGN] Enhanced vegetation index [Termes IGN] géostatistique [Termes IGN] image Sentinel-MSI [Termes IGN] image Terra-MODIS [Termes IGN] incendie de forêt [Termes IGN] Inde [Termes IGN] mésosphère [Termes IGN] précision stéréoscopique [Termes IGN] sciences naturelles [Termes IGN] segmentation d'image [Termes IGN] série temporelle [Termes IGN] stratosphère [Termes IGN] système d'information géographique [Termes IGN] température au sol [Termes IGN] troposphère Index. décimale : 35.00 Télédétection - généralités Résumé : (Editeur) This Edited Volume is a collection of reviewed and relevant research chapters, offering a comprehensive overview of recent developments in the field of Remote Sensing. The book comprises single chapters authored by various researchers and edited by an expert active in this research area. All chapters are complete in themselves but united under a common research study topic. This publication aims at providing a thorough overview of the latest research efforts by international authors on this field of study, and open new possible research paths for further novel developments. Note de contenu : 1. Lidar Observations in South America. Part I - Mesosphere and Stratosphere 2. Lidar Observations in South America. Part II - Troposphere 3. Application of Remote Sensing in Natural Sciences 4. Assessment of Ecological Disturbance Caused by Flood and Fire in Assam Forests, India, Using MODIS Time Series Data of 2001-2011 5. Delineation of Open-Pit Mining Boundaries on Multispectral Imagery 6. Stereoscopic Precision of the Large Format Digital Cameras 7. Remote Sensing Applications in Disease Mapping Numéro de notice : 26799 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Recueil / ouvrage collectif DOI : 10.5772/intechopen.87829 Date de publication en ligne : 08/12/2021 En ligne : https://doi.org/10.5772/intechopen.87829 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100066

Troposphere delay modeling with horizontal gradients for satellite laser ranging / Mateusz Drożdżewski in Journal of geodesy, vol 93 n°10 (October 2019)  

Public [article]  inJournal of geodesy > vol 93 n°10 (October 2019) Titre : Troposphere delay modeling with horizontal gradients for satellite laser ranging Type de document : Article/Communication Auteurs : Mateusz Drożdżewski, Auteur ; Krzysztof Sosnica, Auteur ; Florian Zus, Auteur ; Kyriakos Balidakis, Auteur Année de publication : 2019 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] angle vertical [Termes IGN] coordonnées polaires [Termes IGN] dissymétrie [Termes IGN] erreur systématique [Termes IGN] géocentre [Termes IGN] gradient de troposphère [Termes IGN] interférométrie à très grande base [Termes IGN] Lageos [Termes IGN] retard troposphérique [Termes IGN] Sentinel-3 [Termes IGN] station TLS (télémétrie) [Termes IGN] télémètre laser sur satellite Résumé : (auteur) Satellite laser ranging (SLR) constitutes a fundamental space geodetic technique providing global geodetic parameters, such as geocenter coordinates, Earth rotation parameters, and low-degree gravity field coefficients. The tropospheric delay correction is one of the crucial corrections that have to be taken into account when processing SLR data. Current conventional models of the troposphere delays assume a full symmetry of the atmosphere above SLR stations. Neglecting horizontal gradients in SLR solutions introduces a systematic error in SLR products, especially for the observations at low elevation angles, and leads to a deterioration of the consistency between SLR and other space geodetic techniques, such as global navigational satellite systems and very-long-baseline interferometry. We derive new mapping function coefficients, as well as first- and second-order horizontal gradients, all of which are based on numerical weather models, in order to properly consider the azimuthal asymmetry in SLR solutions. We test the enhanced mapping function and horizontal gradients on the solutions based on 11 years of SLR observations to LAGEOS-1/2 satellites and 1 year of SLR observations to Sentinel-3A. The consideration of azimuthal asymmetry of the atmosphere above the SLR stations has a systematic effect on SLR-derived products, such as station and geocenter coordinates and pole coordinates. Horizontal gradients in SLR solutions improve the consistency between SLR-derived pole coordinates and the combined IERS-C04 series by means of reducing the offset for the X and Y pole coordinates by 20 μas. The second-order horizontal gradients are negligible in SLR solutions; thus, including first-order gradients is sufficient for SLR solutions. Numéro de notice : A2019-607 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-019-01287-1 Date de publication en ligne : 22/08/2019 En ligne : https://doi.org/10.1007/s00190-019-01287-1 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94790 [article]

Sensitivity of GPS tropospheric estimates to mesoscale convective systems in West Africa / Samuel Nahmani in Atmospheric chemistry and physics, vol 19 n° 14 (July 2019)  

Public [article]  inAtmospheric chemistry and physics > vol 19 n° 14 (July 2019) . - pp 9541 - 9561 Titre : Sensitivity of GPS tropospheric estimates to mesoscale convective systems in West Africa Type de document : Article/Communication Auteurs : Samuel Nahmani , Auteur ; Olivier Bock , Auteur ; Françoise Guichard, Auteur Année de publication : 2019 Projets : VEGAN / Bock, Olivier, TOSCA / Bock, Olivier Article en page(s) : pp 9541 - 9561 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] Afrique occidentale [Termes IGN] analyse de sensibilité [Termes IGN] bande C [Termes IGN] convection [Termes IGN] données GPS [Termes IGN] GAMIT [Termes IGN] GIPSY-OASIS [Termes IGN] gradient de troposphère [Termes IGN] meso échelle [Termes IGN] modèle atmosphérique [Termes IGN] Niger [Termes IGN] propagation troposphérique [Termes IGN] résidu [Termes IGN] retard troposphérique zénithal [Termes IGN] signal GPS Résumé : (Auteur) This study analyzes the characteristics of GPS tropospheric estimates (zenith wet delays – ZWDs, gradients, and post-fit phase residuals) during the passage of mesoscale convective systems (MCSs) and evaluates their sensitivity to the research-level GPS data processing strategy implemented. Here, we focus on MCS events observed during the monsoon season of West Africa. This region is particularly well suited for the study of these events due to the high frequency of MCS occurrences in the contrasting climatic environments between the Guinean coast and the Sahel. This contrast is well sampled with data generated by six African Monsoon Multidisciplinary Analysis (AMMA) GPS stations. Tropospheric estimates for a 3-year period (2006–2008), processed with both the GAMIT and GIPSY-OASIS software packages, were analyzed and intercompared. First, the case of a MCS that passed over Niamey, Niger, on 11 August 2006 demonstrates a strong impact of the MCS on GPS estimates and post-fit residuals when the GPS signals propagate through the convective cells as detected on reflectivity maps from the MIT C-band Doppler radar. The estimates are also capable of detecting changes in the structure and dynamics of the MCS. However, the sensitivity is different depending on the tropospheric modeling approach adopted in the software. With GIPSY-OASIS, the high temporal sampling (5 min) of ZWDs and gradients is well suited for detecting the small-scale, short-lived, convective cells, while the post-fit residuals remain quite small. With GAMIT, the lower temporal sampling of the estimated parameters (hourly for ZWDs and daily for gradients) is not sufficient to capture the rapid delay variations associated with the passage of the MCS, but the post-fit phase residuals clearly reflect the presence of a strong refractivity anomaly. The results are generalized with a composite analysis of 414 MCS events observed over the 3-year period at the six GPS stations with the GIPSY-OASIS estimates. A systematic peak is found in the ZWDs coincident with the cold pool crossing time associated with the MCSs. The tropospheric gradients reflect the path of the MCS propagation (generally from east to west). This study concludes that ZWDs, gradients, and post-fit phase residuals provide relevant and complementary information on MCSs passing over or in the vicinity of a GPS station. Numéro de notice : A2019-572 Affiliation des auteurs : Géodésie+Ext (mi2018-2019) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/acp-19-9541-2019 Date de publication en ligne : 29/07/2019 En ligne : https://doi.org/10.5194/acp-19-9541-2019 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94444 [article]

GNSS ionospheric TEC and positioning accuracy during intense space and terrestrial weather events in B&H / Randa Natraš in Geodetski vestnik, vol 63 n° 1 (March - May 2019)  

Public [article]  inGeodetski vestnik > vol 63 n° 1 (March - May 2019) . - pp 73 - 91 Titre : GNSS ionospheric TEC and positioning accuracy during intense space and terrestrial weather events in B&H Type de document : Article/Communication Auteurs : Randa Natraš, Auteur ; Dževad Krdžalić, Auteur ; Džana Horozović, Auteur ; et al., Auteur Année de publication : 2019 Article en page(s) : pp 73 - 91 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] Bosnie-Herzégovine [Termes IGN] ionosphère [Termes IGN] neige [Termes IGN] positionnement par GNSS [Termes IGN] positionnement ponctuel précis [Termes IGN] positionnement statique [Termes IGN] précision du positionnement [Termes IGN] tempête magnétique [Termes IGN] teneur totale en électrons [Termes IGN] troposphère Résumé : (Auteur) To achieve the high accuracy in GNSS positioning, the various atmospheric effects on GNSS signals need to be mitigated, where the major part present the ionised atmosphere (ionosphere) and the neutral atmosphere (troposphere). Additional signal scattering can occur from heavy precipitation and from snow accumulation on the antenna and on its surroundings. In this study, irregularities in the ionosphere induced by space weather were analysed, as well as sudden snowfall with its impact on meteorological conditions in the troposphere. State in the ionosphere was characterised by total electron content (TEC) derived from GNSS observation of EUREF Permanent Network (EPN) station SRJV in Bosnia and Herzegovina (B&H). Their impacts on the accuracy of GNSS positioning of the EPN station SRJV were examined by applying post-processing static PPP and network solutions using several software (the open-source and commercial). The study period was March 2015, when the strongest geomagnetic storm of solar cycle 24 (St. Patrick’s Day, March 17) and sudden intense snowfall (beginning of the month) occurred. Ionospheric TEC deviated for more than 20 TECU from the regular values during St. Patrick´s Day. Ionosphere-free combination in applied positioning techniques successfully eliminated most of the ionospheric terms. The highest deviations in Up component (to 7 cm) were observed during sudden snowfall characterised by changes in temperature, atmospheric pressure and humidity in the troposphere. Numéro de notice : A2019-167 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.15292/geodetski-vestnik.2019.01.73-91 Date de publication en ligne : 17/01/2019 En ligne : http://dx.doi.org/10.15292/geodetski-vestnik.2019.01.73-91 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92576 [article]

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Impact of GPS antenna phase center models on zenith wet delay and tropospheric gradients / Yohannes Getachew Ejigu in GPS solutions, vol 23 n° 1 (January 2019)  

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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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A two-stage tropospheric correction model combining data from GNSS and numerical weather model / Jan Douša in GPS solutions, vol 22 n° 3 (July 2018)  

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Amélioration des calculs GNSS à façon du SGN / Mathilde Kremp (2018) 

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Improving the modeling of the atmospheric delay in the data analysis of the Intensive VLBI sessions and the impact on the UT1 estimates / Tobias Nilsson in Journal of geodesy, vol 91 n° 7 (July 2017)  

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Using a regional numerical weather prediction model for GNSS positioning over Brazil / Daniele Barroca Marra Alves in GPS solutions, vol 20 n° 4 (October 2016)  

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A geometry-free and ionosphere-free multipath mitigation method for BDS three-frequency ambiguity resolution / Dezhong Chen in Journal of geodesy, vol 90 n° 8 (August 2016)  

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A new computerized ionosphere tomography model using the mapping function and an application to the study of seismic-ionosphere disturbance / Jian Kong in Journal of geodesy, vol 90 n° 8 (August 2016)  

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Optimal GPS/GALILEO GBAS methodologies with an application to troposphere / Alize Guilbert (2016)  

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A fast and accurate algorithm for high-frequency trans-ionospheric path length determination / Dudy D Wijaya in Journal of geodesy, vol 89 n° 12 (december 2015)  

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