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Variations of precipitable water vapor using GNSS CORS in Thailand / Chokchai Trakolkul in Survey review, vol 53 n°376 (January 2021)  

Public [article]  inSurvey review > vol 53 n°376 (January 2021) . - pp 90 - 96 Titre : Variations of precipitable water vapor using GNSS CORS in Thailand Type de document : Article/Communication Auteurs : Chokchai Trakolkul, Auteur ; Chalermchon Satirapod, Auteur Année de publication : 2021 Article en page(s) : pp 90 - 96 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] amplitude [Termes IGN] analyse comparative [Termes IGN] données WVR [Termes IGN] précipitation [Termes IGN] série temporelle [Termes IGN] station de référence [Termes IGN] station GNSS [Termes IGN] Thaïlande [Termes IGN] vapeur d'eau [Termes IGN] variation saisonnière Résumé : (auteur) This research aims to analyze variation in a time series of Precipitable Water Vapor (PWV time series) using data at 11 widely-distributed Continuously Operating Reference Stations (CORS) in Thailand. In this paper, the PWV time series is estimated based on data from 2007 to 2015, used to monitor trends and seasonal variations. Significant annual variations of PWV are found at all GNSS stations, with amplitude from 6 to 19 kg/m2. The variations between the annual amplitudes of PWV in the South and near the ocean coasts are generally smaller than in the inland regions. The phase shift of annual PWV variation is about −0.43 (around July, rainy season). The comparison of PWV and 24-hour cumulative rainfall data showed that the rainy season (running from around mid-May to the end of October) exhibits the slightest swing, and the highest average amount of PWV. These results are consistent with the 24-hour cumulative rainfall data. Numéro de notice : A2021-070 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2020.1713611 Date de publication en ligne : 20/01/2020 En ligne : https://doi.org/10.1080/00396265.2020.1713611 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96791 [article]

Multi-technique comparison of troposphere zenith delays and gradients during CONT08 / Kamil Teke in Journal of geodesy, vol 85 n° 7 (July 2011)  

Public [article]  inJournal of geodesy > vol 85 n° 7 (July 2011) . - pp 395 - 413 Titre : Multi-technique comparison of troposphere zenith delays and gradients during CONT08 Type de document : Article/Communication Auteurs : Kamil Teke, Auteur ; Johannes Böhm , Auteur ; Tobias Nilsson, Auteur ; Harald Schuh, Auteur ; Peter Steigenberger, Auteur ; Rolf Dach, Auteur ; Robert Heinkelmann, Auteur ; Pascal Willis , Auteur ; et al., Auteur Année de publication : 2011 Article en page(s) : pp 395 - 413 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] analyse comparative [Termes IGN] données DORIS [Termes IGN] données GPS [Termes IGN] données ITGB [Termes IGN] données WVR [Termes IGN] gradient de troposphère [Termes IGN] retard troposphérique [Termes IGN] troposphère Résumé : (Auteur) CONT08 was a 15 days campaign of continuous Very Long Baseline Interferometry (VLBI) sessions during the second half of August 2008 carried out by the International VLBI Service for Geodesy and Astrometry (IVS). In this study, VLBI estimates of troposphere zenith total delays (ZTD) and gradients during CONT08 were compared with those derived from observations with the Global Positioning System (GPS), Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS), and water vapor radiometers (WVR) co-located with the VLBI radio telescopes. Similar geophysical models were used for the analysis of the space geodetic data, whereas the parameterization for the least-squares adjustment of the space geodetic techniques was optimized for each technique. In addition to space geodetic techniques and WVR, ZTD and gradients from numerical weather models (NWM) were used from the European Centre for Medium-Range Weather Forecasts (ECMWF) (all sites), the Japan Meteorological Agency (JMA) and Cloud Resolving Storm Simulator (CReSS) (Tsukuba), and the High Resolution Limited Area Model (HIRLAM) (European sites). Biases, standard deviations, and correlation coefficients were computed between the troposphere estimates of the various techniques for all eleven CONT08 co-located sites. ZTD from space geodetic techniques generally agree at the sub-centimetre level during CONT08, and—as expected—the best agreement is found for intra-technique comparisons: between the Vienna VLBI Software and the combined IVS solutions as well as between the Center for Orbit Determination (CODE) solution and an IGS PPP time series; both intra-technique comparisons are with standard deviations of about 3–6 mm. The best inter space geodetic technique agreement of ZTD during CONT08 is found between the combined IVS and the IGS solutions with a mean standard deviation of about 6 mm over all sites, whereas the agreement with numerical weather models is between 6 and 20 mm. The standard deviations are generally larger at low latitude sites because of higher humidity, and the latter is also the reason why the standard deviations are larger at northern hemisphere stations during CONT08 in comparison to CONT02 which was observed in October 2002. The assessment of the troposphere gradients from the different techniques is not as clear because of different time intervals, different estimation properties, or different observables. However, the best inter-technique agreement is found between the IVS combined gradients and the GPS solutions with standard deviations between 0.2 and 0.7 mm. Numéro de notice : A2011-331 Affiliation des auteurs : IGN+Ext (1940-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-010-0434-y Date de publication en ligne : 27/04/2011 En ligne : https://doi.org/10.1007/s00190-010-0434-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31110 [article]

Exemplaires(1)

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266-2011071	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Multi-technique comparison of tropospheric zenith delays derived during the CONT02 campaign / Pascal Willis in Journal of geodesy, vol 79 n° 10-11 (February 2006)  

Public [article]  inJournal of geodesy > vol 79 n° 10-11 (February 2006) . - pp 613 - 623 Titre : Multi-technique comparison of tropospheric zenith delays derived during the CONT02 campaign Type de document : Article/Communication Auteurs : Pascal Willis , Auteur ; K. Snajdrova, Auteur ; Johannes Böhm , Auteur ; Rüdiger Haas, Auteur Année de publication : 2006 Article en page(s) : pp 613 - 623 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] analyse comparative [Termes IGN] distance zénithale [Termes IGN] données WVR [Termes IGN] écart type [Termes IGN] erreur systématique [Termes IGN] météorologie [Termes IGN] positionnement par DORIS [Termes IGN] positionnement par GPS [Termes IGN] prévision météorologique [Termes IGN] propagation troposphérique [Termes IGN] traitement du signal [Termes IGN] troposphère Résumé : (Auteur) In October 2002, 15 continuous days of Very Long Baseline Interferometry (VLBI) data were observed in the Continuous VLBI 2002 (CONT02) campaign. All eight radio telescopes involved in CONT02 were co-located with at least one other space-geodetic technique, and three of them also with a Water Vapor Radiometer (WVR). The goal of this paper is to compare the tropospheric zenith delays observed during CONT02 by VLBI, Global Positioning System (GPS), Doppler Orbitography Radiopositioning Integrated by Satellite (DORIS) and WVR and te, compare them also with operational pressure level data from the European Centre for Medium-Range Weather Forecasts (ECMWF). We show that the tropospheric zenith delays from VLBI and GPS are in good agreement at the 3-7 mm level. However, while only small biases can be found for most of the stations, at Kokee Park (Hawaii, USA) and Westford (Massachusetts, USA) the zenith delays derived by GPS are larger by more than 5 mm than those from VLBI. At three of the four DORIS stations, there is also a fairly good agreement with GPS and VLBI (about 10 mm), but at Kokee Park the agreement is only at about 30 mm standard deviation, probably due to the much older installation and type of DORIS equipment. This comparison also allows testing of different DORIS analysis strategies with respect to their real impact on the precision of the derived tropospheric parameters. Ground truth information about the zenith delays can also be obtained from the ECMWF numerical weather model and at three sites using WVR measurements, allowing for comparisons with results from the space-geodetic techniques. While there is a good agreement (with some problems mentioned above about DORIS) among the space-geodetic techniques, the comparison with WVR and ECMWF is at a lower accuracy level. The complete CONT02 data set is sufficient to derive a good estimate of the actual precision and accuracy of each geodetic technique for applications in meteorology. Numéro de notice : A2006-088 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-005-0010-z En ligne : https://doi.org/10.1007/s00190-005-0010-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27815 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-06012	RAB	Revue	Centre de documentation	En réserve L003	Disponible
266-06011	RAB	Revue	Centre de documentation	En réserve L003	Disponible