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Termes IGN > sciences naturelles > physique > optique > optique physique > radiométrie > rayonnement électromagnétique > propagation troposphérique > retard troposphérique > retard troposphérique zénithal
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Titre : GNSS meteorology in spatially dense networks Type de document : Thèse/HDR Auteurs : Fabian Peter Hurter, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2014 Collection : Astronomisch-Geodätische Arbeiten in der Schweiz, ISSN 0025-6676 num. 91 Importance : 185 Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-37-6 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Bernese
[Termes IGN] données GNSS
[Termes IGN] météorologie
[Termes IGN] propagation du signal
[Termes IGN] retard troposphérique zénithal
[Termes IGN] signal GNSS
[Termes IGN] station GNSS
[Termes IGN] station météorologique
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] traitement du signalIndex. décimale : 30.84 Applications de géodésie spatiale à l'atmosphère Résumé : (auteur) Two basic products from GNSS meteorology have been investigated in detail: (a) the Zenith Total Delay (ZTD) and, (b) wet refractivity fields reconstructed from Zenith Wet Delays (ZWD).The thesis aims at quantifying the accuracies of GNSS-derived ZTDs and refractivities and at characterizing their temporal and spatial resolution. In a first study using operational radiosondes and Global Navigation Satellite System (GNSS) data from the Swiss meteorological station in Payerne, the following uncertainty figures are obtained: With respect to the radiosonde, the GNSS-derived ZTD has a 1–3mm dry bias. Annual systematic variations of the comparison are found to have an amplitude of 1–2 mm . Removal of most systematic effects from the GNSS minus radiosonde ZTD time series plus a thorough budget of the radiosonde uncertainties allows the derivation of the random GNSS uncertainties. In the winter half-year, the standard deviation is shown to be 2.5–3.5 mm , during the summer half-year we obtain 3.5–5.0 mm.
In a further study in the western part of Switzerland, wet refractivities have been derived on the basis of interpolated ZWDs from the Automatic GNSS Network for Switzerland (AGNES). The employed interpolation algorithm is termed least-squares collocation. It makes use of a deterministic function to describe the general parametric field and a correlation function describing the spatial and temporal correlations between the zenith wet delays. Corresponding wet refractivities show accuracies superior to results from tomographic reconstructions of a similar data set. Further inclusion of ground meteorological measurements of temperature and water vapour pressure im- prove the derived refractivities in the lowest 2 km of the troposphere. Radio occultations are added to the reconstruction. The data combination enables the extension of the radio occultation profiles down to the ground. It is also shown that the GNSS data largely contributes to the profile quality above the atmospheric boundary layer. Transformation of the wet refractivities to humidity values with temperature profiles from a radiometer in Payerne show accuracies of a similar order of mag nitude to those from numerical weather prediction analysis. Hence, application of the algorithm in nowcasting of rain or investigating boundary layer processes are envisaged.
The third part of the thesis investigates the results from a campaign network of 34 geodetic- grade receivers. They were deployed close to and around Zermatt (Switzerland) for one month in summer 2010. The stations were spaced at distances of a few kilometers from each other and at heights between 1600–3500 m above mean sea level. The mountainous region provides an excellent natural laboratory to investigate the influences affecting the accuracy of the ZTD. Additionally, the Alpine region is prone to small-scale fluctuations in the troposphere. Thus, the spatial and temporal variability of the ZTD has been investigated. The influences of satellite obstructions, antenna and receiver types and a number of processing strategies on the estimated ZTD are analysed and validated with measurements from radiosondes launched during the campaign. The analysis suggests that 1 hour temporal resolution should not be undercut for estimated ZTDs. A temporal resolution of 30 minutes introduces more noise without better following the tropospheric fluctuation. The horizontal variability observed in ZTDs indicates correlation scale lengths of a few kilometers. From comparison with radiosondes, the ZTD uncertainty is shown to have 4–6 mm standard deviation. Some stations show signs of systematic effects caused by multipath and low- quality antenna patterns. Through the GNSS-inherent negative correlation of height with zenith delay, both parameters are similarly affected by these systematic influences. The performance of the numerical weather prediction model COSMO-2 is characterized in terms of integrated atmospheric state. The analysis yields preliminary recommendations on the assimilation of zenith total path delays into weather models in regions of highly complex topography such as the Swiss Alps.Note de contenu : 1 Introduction
1.1 Review of GNSS meteorology
1.2 Potential synergies with other water vapour measurements . 1.3 Challenges in GNSS meteorology
1.4 Objectives and structure of the thesis
2 Theory
2.1 Refractivity and path delay in the atmosphere
2.2 Collocation with the software COMEDIE
2.3 Water vapour tomography software AWATOS2
3 Comparison of zenith path delays from GNSS and radiosonde measurements
3.1 Data description
3.2 Formal uncertainties of ZTD estimates from GNSS
3.3 Comparison of ZTDs
3.4 Influence of processing strategy on GNSS ZTDs
3.5 2nd and 3rd order ionospheric effects .
3.6 Comparison of ZWDs
3.7 Formal uncertainty of radiosonde-derived ZTDs
3.8 Derivation of random GNSS ZTD uncertainty
3.9 Correlation between GNSS heights and ZTDs
3.10 Discussion .
3.11 Conclusion .
4 Payerne profile study
4.1 Abstract
4.2 Introduction
4.3 Description of data sets
4.4 Processing
4.5 Results .
4.6 Discussion
4.7 Conclusions
5 Geodetic water vapor campaign in Zermatt
5.1 Data description and processing
5.2 Troposphere results
5.3 Conclusions
6 ConclusionsNuméro de notice : 12952 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère En ligne : http://www.sgc.ethz.ch/sgc-volumes/sgk-91.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76823 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 12952-01 30.84 Livre Centre de documentation Géodésie Disponible DORIS and GPS monitoring of the Gavdos calibration site in Crete / Pascal Willis in Advances in space research, vol 51 n° 8 (April 2013)
[article]
Titre : DORIS and GPS monitoring of the Gavdos calibration site in Crete Type de document : Article/Communication Auteurs : Pascal Willis , Auteur ; Stelios Mertikas, Auteur ; Donald F. Argus, Auteur ; Olivier Bock , Auteur Année de publication : 2013 Projets : Gavdos / Article en page(s) : pp 1438 - 1447 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] analyse comparative
[Termes IGN] analyse diachronique
[Termes IGN] correction troposphérique
[Termes IGN] Crète (île)
[Termes IGN] étalonnage des données
[Termes IGN] GAMIT
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] modèle météorologique
[Termes IGN] positionnement par DORIS
[Termes IGN] positionnement par GPS
[Termes IGN] retard troposphérique zénithal
[Termes IGN] série temporelleRésumé : (auteur) Due to its specific geographical location as well as its geodetic equipment (DORIS, GNSS, microwave transponder and tide gauges), the Gavdos station in Crete, Greece is one of the very few sites around the world used for satellite altimetry calibration. To investigate the quality of the Gavdos geodetic coordinates and velocities, we analyzed and compared here DORIS and GPS-derived results obtained during several years of observations. The DORIS solution is the latest ignwd11 solution at IGN, expressed in ITRF2008, while the GPS solution was obtained using the GAMIT software package. Current results show that 1–2 mm/yr agreement can be obtained for 3-D velocity, showing a good agreement with current geophysical models. In particular, the agreement obtained for the vertical velocity is around 0.3–0.4 mm/yr, depending on the terrestrial reference frame. As a by-product of these geodetic GPS and DORIS results, Zenith Tropospheric Delays (ZTDs) estimations were also compared in 2010 between these two techniques, and compared to ECMWF values, showing a 6.6 mm agreement in dispersion without any significant difference between GPS and DORIS (with a 97.6% correlation), but with a 13–14 mm agreement in dispersion when comparing to ECMWF model (with only about 90% correlation for both techniques). These tropospheric delay estimations could also provide an external calibration of the tropospheric correction used for the geophysical data of satellite altimetry missions. Numéro de notice : A2013-798 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2012.08.006 En ligne : http://dx.doi.org/10.1016/j.asr.2012.08.006 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80125
in Advances in space research > vol 51 n° 8 (April 2013) . - pp 1438 - 1447[article]E-GVAP, un proyecto europeo meteorológico con GNSS. Participación del IGN / Marcelino Valdés Pérez de Vargas in Topografia y cartografia, vol 28 n° 165 (2013)
[article]
Titre : E-GVAP, un proyecto europeo meteorológico con GNSS. Participación del IGN Type de document : Article/Communication Auteurs : Marcelino Valdés Pérez de Vargas, Auteur ; Miguel Ángel Cano Villaverde, Auteur ; José Antonio Sanchez Sobrino, Auteur Année de publication : 2013 Conférence : TOPCART 2012, 10 congreso iberoamericano de geomatica y ciencias de la tierra 16/10/2012 19/10/2012 Madrid Espagne open access proceedings Article en page(s) : pp 26 - 36 Note générale : bibliographie Langues : Espagnol (spa) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] données GNSS
[Termes IGN] données météorologiques
[Termes IGN] Espagne
[Termes IGN] modèle météorologique
[Termes IGN] positionnement par GNSS
[Termes IGN] retard troposphérique zénithal
[Termes IGN] station permanente
[Termes IGN] teneur en vapeur d'eauRésumé : (auteur) The Global Navigation Satellite Systems (GNSS) permanent stations that until now were just used for geodetic positioning have found a new application in the field of meteorology. The knowledge of the stations coordinates allow to solve the zenith total delay (ZTD) at each location, and by appropriate model to deduce the content of water vapour of the atmosphere. If we can get that this information reaches at the maximum speed to the numerical weather prediction models they improve substantially. Instituto Geografico Nacional (IGN) at the request of Agencia Estatal de Meteorología (AEMET) participates since 2008 in the project of EUMETNET EIG GNSS water vapour programme E-GVAP as a processing expert institution achieving to process more than 300 stations every hour in our geographic area. Numéro de notice : A2012-722 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueNat DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84935
in Topografia y cartografia > vol 28 n° 165 (2013) . - pp 26 - 36[article]Documents numériques
en open access
E-GVAP, un proyecto europeo meteorológico con GNSSAdobe Acrobat PDF Study of seasonal-scale atmospheric water cycle with ground-based GPS receivers, radiosondes and NWP models over Morocco / Achraf Koulali in Atmospheric Research, vol 104 - 105 (February 2012)
[article]
Titre : Study of seasonal-scale atmospheric water cycle with ground-based GPS receivers, radiosondes and NWP models over Morocco Type de document : Article/Communication Auteurs : Achraf Koulali, Auteur ; Driss Ouazar, Auteur ; Olivier Bock , Auteur ; Abdelali Fadil, Auteur Année de publication : 2012 Article en page(s) : pp 273 - 291 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Canaries
[Termes IGN] circulation atmosphérique
[Termes IGN] données GPS
[Termes IGN] données météorologiques
[Termes IGN] Maroc
[Termes IGN] précipitation
[Termes IGN] radiosondage
[Termes IGN] récepteur GPS
[Termes IGN] retard troposphérique zénithal
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] variation saisonnièreRésumé : (Auteur) This study investigates the seasonal variation of precipitable water vapor, moisture transport and precipitation over Morocco and the Canary Islands using data from ground-based GPS receivers, radiosondes, GPCP and NCEP reanalysis II. In a first part, the datasets are inter-compared. Humidity biases are evidenced in both radiosonde observations (dry) and NCEP reanalysis (dry and wet) compared to GPS. Moisture transport and precipitation from the reanalysis and observations show a good agreement. Precipitable water shows a maximum in late summer whereas precipitation is peaking in winter and spring over Morocco. Moisture transport occurs preferentially in two layers, below and above 850 hPa. The monthly mean precipitable water variation over Morocco is controlled by the upper layer zonal and meridional moisture flux. Precipitation is rather controlled by the lower layer moisture flux and the upper layer meridional flux. The GPS tropospheric gradients show also a consistent seasonal evolution, which is explained by gradients both in the thickness of the troposphere and in the precipitable water vapor. Tropospheric gradients are correlated with moisture fluxes, mostly in the upper layer, and may therefore provide valuable information for meteorology and climatology. Numéro de notice : A2012-737 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.atmosres.2011.11.002 Date de publication en ligne : 13/11/2011 En ligne : https://doi.org/10.1016/j.atmosres.2011.11.002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91460
in Atmospheric Research > vol 104 - 105 (February 2012) . - pp 273 - 291[article]Comparison of regional and global GNSS positions, velocities and residual time series / Juliette Legrand (2012)
Titre : Comparison of regional and global GNSS positions, velocities and residual time series Type de document : Article/Communication Auteurs : Juliette Legrand, Auteur ; Nicolas Bergeot, Auteur ; Carine Bruyninx, Auteur ; Guy Wöppelmann , Auteur ; Alvaro Santamaria Gomez, Auteur ; Marie-Noëlle Bouin , Auteur ; Zuheir Altamimi , Auteur Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2012 Collection : International Association of Geodesy Symposia, ISSN 0939-9585 num. 136 Conférence : IAG 2009 Symposium, Geodesy for Planet Earth 31/08/2009 04/09/2009 Buenos Aires Argentine Proceedings Springer Importance : pp 95 - 103 Format : 16 x 24 cm Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] European Terrestrial Reference Frame
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] résidu
[Termes IGN] retard troposphérique zénithal
[Termes IGN] série temporelleRésumé : (auteur) More than 10 years (1996–2008) of weekly GPS solutions of 299 globally distributed stations have been used to quantify the impact of the reference frame definition and especially the size of the network on the estimated station positions, velocities, and residual position time series. For that purpose, weekly regional solutions (covering the European region) and global solutions have been respectively stacked to obtain regional and global station positions, velocities, and residual position time series. In both cases, the estimated long-term solutions have been tied to the ITRF2005 under minimal constraints using a selected set of reference stations. This study shows that: (1) regional position and velocity solutions can present biases with respect to each other and to global solutions, while in comparison, global solutions are much more stable; (2) the obtained residual position time series are affected by the size of the network with significantly reduced periodic signals in the regional networks, e.g. a 27% reduction of the annual signals in the height component. Numéro de notice : C2009-063 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.1007/978-3-642-20338-1_12 Date de publication en ligne : 26/07/2011 En ligne : https://doi.org/10.1007/978-3-642-20338-1_12 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102021 PermalinkPermalinkA first look at the effects of ionospheric signal bending on a globally processed GPS network / E. Petrie in Journal of geodesy, vol 84 n° 8 (August 2010)PermalinkEtude du cycle de l’eau à partir de modèles numériques de prévision météorologique et d’observations sur l’Afrique du Nord / Maïté Lacarra (2009)PermalinkL'allongement troposphérique / Samuel Nahmani (2008)PermalinkAssessment of GPS data for meteorological applications over Africa: Study of error sources and analysis of positioning accuracy / Andrea Walpersdorf in Journal of Atmospheric and Solar-Terrestrial Physics, vol 69 n° 12 (August 2007)PermalinkAn Improved mean-gravity model for GPS hydrostatic delay calibration / Pierre Bosser in IEEE Geoscience and Remote Sensing Letters, vol 4 n° 1 (2007)PermalinkPotentiel de la mesure GPS sol pour l’étude des pluies intenses méditerranéennes / Hugues Brenot (2006)PermalinkAtmospheric modeling in GPS data analysis for high accuracy positioning / Olivier Bock in Physics and chemistry of the Earth, Part A: Solid Earth and Geodesy, vol 26 n° 6-8 (2001)PermalinkEffect of small-scale atmospheric inhomogeneity on positioning accuracy with GPS / Olivier Bock in Geophysical research letters, vol 28 n° 11 (1 June 2001)Permalink