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<OAI-PMH schemaLocation=http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd> <responseDate>2018-01-15T15:42:42Z</responseDate> <request identifier=oai:HAL:insu-00347961v1 verb=GetRecord metadataPrefix=oai_dc>http://api.archives-ouvertes.fr/oai/hal/</request> <GetRecord> <record> <header> <identifier>oai:HAL:insu-00347961v1</identifier> <datestamp>2018-01-11</datestamp> <setSpec>type:ART</setSpec> <setSpec>subject:sdu</setSpec> <setSpec>collection:INSU</setSpec> <setSpec>collection:CNRS</setSpec> <setSpec>collection:UNIV-GRENOBLE1</setSpec> <setSpec>collection:UNIV-SAVOIE</setSpec> <setSpec>collection:GM</setSpec> <setSpec>collection:UPMC</setSpec> <setSpec>collection:OSUG</setSpec> <setSpec>collection:UGA</setSpec> <setSpec>collection:IFSTTAR</setSpec> <setSpec>collection:UVSQ</setSpec> <setSpec>collection:AGROPOLIS</setSpec> <setSpec>collection:UNIV-AG</setSpec> <setSpec>collection:ISTERRE</setSpec> <setSpec>collection:GIP-BE</setSpec> <setSpec>collection:B3ESTE</setSpec> <setSpec>collection:UNIV-MONTPELLIER</setSpec> <setSpec>collection:AERONOMIE</setSpec> </header> <metadata><dc> <publisher>HAL CCSD</publisher> <title lang=en>Assessment of GPS data for meteorological applications over Africa: Study of error sources and analysis of positioning accuracy</title> <creator>Walpersdorf, Andrea</creator> <creator>Bouin, M. N.</creator> <creator>Bock, O.</creator> <creator>Doerflinger, Erik</creator> <contributor>Laboratoire de Géophysique Interne et Tectonophysique (LGIT) ; Observatoire des Sciences de l'Univers de Grenoble (OSUG) ; Université Joseph Fourier - Grenoble 1 (UJF) - Institut national des sciences de l'Univers (INSU - CNRS) - Centre National de la Recherche Scientifique (CNRS) - Université Joseph Fourier - Grenoble 1 (UJF) - Institut national des sciences de l'Univers (INSU - CNRS) - Centre National de la Recherche Scientifique (CNRS) - Laboratoire Central des Ponts et Chaussées (LCPC) - Institut des Sciences de la Terre (ISTerre) ; Université Joseph Fourier - Grenoble 1 (UJF) - Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR) - Institut national des sciences de l'Univers (INSU - CNRS) - Institut de recherche pour le développement [IRD] : UR219 - PRES Université de Grenoble - Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]) - Centre National de la Recherche Scientifique (CNRS) - Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR) - Institut de recherche pour le développement [IRD] : UR219 - PRES Université de Grenoble - Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]) - Centre National de la Recherche Scientifique (CNRS)</contributor> <contributor>LAboratoire de Recherche en Géodésie [Champs-sur-Marne] (LAREG) ; Institut géographique national [IGN ]</contributor> <contributor>Service d'aéronomie (SA) ; Université de Versailles Saint-Quentin-en-Yvelines (UVSQ) - Université Pierre et Marie Curie - Paris 6 (UPMC) - Institut national des sciences de l'Univers (INSU - CNRS) - Centre National de la Recherche Scientifique (CNRS)</contributor> <contributor>Géosciences Montpellier ; Université des Antilles et de la Guyane (UAG) - Institut national des sciences de l'Univers (INSU - CNRS) - Université de Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS)</contributor> <description>International audience</description> <source>ISSN: 1364-6826</source> <source>Journal of Atmospheric and Solar-Terrestrial Physics</source> <publisher>Elsevier</publisher> <identifier>insu-00347961</identifier> <identifier>https://hal-insu.archives-ouvertes.fr/insu-00347961</identifier> <source>https://hal-insu.archives-ouvertes.fr/insu-00347961</source> <source>Journal of Atmospheric and Solar-Terrestrial Physics, Elsevier, 2007, 69 (12), pp.1312 à 1330. 〈10.1016/j.jastp.2007.04.008〉</source> <identifier>DOI : 10.1016/j.jastp.2007.04.008</identifier> <relation>info:eu-repo/semantics/altIdentifier/doi/10.1016/j.jastp.2007.04.008</relation> <language>en</language> <subject lang=en>International GNSS Service for Geodynamics (IGS)</subject> <subject lang=en>Precipitable water vapour</subject> <subject lang=en>African Monsoon Multidisciplinary Analysis (AMMA)</subject> <subject lang=en>GPS meteorology</subject> <subject lang=en>Zenith total delay</subject> <subject>[SDU.STU.ME] Sciences of the Universe [physics]/Earth Sciences/Meteorology</subject> <type>info:eu-repo/semantics/article</type> <type>Journal articles</type> <description lang=en>The aim of this study is to assess the availability and quality of data from the International GNSS Service (IGS) Global Positioning System (GPS) network in Africa, especially for retrieving zenith tropospheric delay (ZTD), from which precipitable water vapour (PWV) can be derived, in view of application to the African Monsoon Multidisciplinary Analysis (AMMA) project. Three major error sources for the GPS data analysis evaluating PWV in Africa are the accuracy of the satellite orbits, the correction for the radio delay induced by the ionosphere and the vertical site displacements due to ocean loading. The first part of this study examines these error sources and the validity of GPS data for meteorological applications in Africa in dedicated analyses spanning the year 2001. These analyses were performed using the IGS precise orbits. Weak degradation of baseline precision with increasing baseline lengths suggests that the average orbital error is not limiting the GPS analysis in Africa. The impact of the ionosphere has been evaluated during a maximum of solar activity in 2001. The loss of L2 data has actually been observed. It amounts to 2% on average for 2001, with maxima of 8% during magnetic storm events. A slight decrease in formal accuracy of ZTD seems to be related to the loss of L2 data at the end of the day. This indicates that scintillation effects are present in the GPS observations but however are not a major limitation. The impact of ocean loading is found to be significant on ZTD estimates (up to ±2 mm in equivalent PWV). The use of a proper ocean loading model eliminates this effect. The second aspect of this study concerns the IGS analysis quality for the African stations. The accuracy has been assessed through position dispersion between individual solutions and the most recent version of the IGS combined solution IGb00, and residuals from the transformation of the IGS combined solution into the International Terrestrial Reference Frame 2005. The positioning performance of the IGS analysis is consistent with an accuracy in ZTD of ±6 mm (±1 mm in PWV), as requested for meteorological applications such as planned in AMMA.</description> <date>2007</date> </dc> </metadata> </record> </GetRecord> </OAI-PMH>