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Geodetic mobile solar spectrometer [GEMOSS] / Alexander Somieski (2005)  

Public Titre : Geodetic mobile solar spectrometer [GEMOSS] Type de document : Thèse/HDR Auteurs : Alexander Somieski, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2005 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 68 Projets : Gavdos / Importance : 205 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-11-6 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Rayonnement électromagnétique [Termes IGN] campagne d'expérimentation [Termes IGN] positionnement par GPS [Termes IGN] propagation troposphérique [Termes IGN] spectromètre [Termes IGN] spectroscopie [Termes IGN] teneur en vapeur d'eau [Termes IGN] troposphère Index. décimale : 24.30 Rayonnement électromagnétique Résumé : (Auteur) The goal of this work was to develop a portable prototype of a solar spectrometer for the determination of tropospheric water vapor with a high precision as needed for geodetic applications. It was realized in the construction of the "GEodetic MObile Solar Spectrometer" (GEMOSS), which allows the simultaneous measurement of numerous single vibrational-rotational absorption lines in the wide wavelength range between 728 nm and 915 nm. In order to achieve the wide wavelength range and the envisaged high measurement accuracy, a new optical layout of a high-resolution echelle spectrograph was applied. Furthermore, its instrumental characteristics were determined and considered in the analysis and simulation of the spectrum. Therefore, investigations were carried out concerning hardware requirements, appropriate spectral intervals, stabilization of the wavelength scale, determination of the apparatus function and stray light. In addition to the theoretical aspects of molecular absorption and emission in Earth's atmosphere, the meteorological model, ray tracing and the current state of molecular spectroscopie databases were examined. Furthermore, an algorithm for retrieving the integrated precipitable water vapor (PW) from GEMOSS spectra was developed. It is based on the "Differential Optical Absorption Spectroscopy" (DOAS) and includes the simulation of synthetic solar spectra. For the simulation the line strength parameters of H20 absorption lines were taken frorn the molecular spectroscopie database by the European Space Agency (ESA). Although the line strength parameters, which have a large impact on the accuracy of the simulated spectra and the retrieved PW, were improved during the last years, they still reveal significant errors. The wide spectral range of GEMOSS enables the accurate correction of those parameters using solar spectra measured at atmospheric conditions controlled by radiosonde soundings and a water vapor radiometer (WVR). For this purpose, a dedicated campaign was carried out at the meteorological station at Payerne (Switzerland) in May and June 2004. CEMOSS and a co-located WVR were deployed next to a Global Positioning Systern (GPS) receiver of the Automated GPS Network of Switzerland (AGNES). The acquired dataset was utilized to improve line strength parameters of 69 individual transitions of the H20 molecule between 732 mn and 906 nm. In order to validate the performance of GEMOSS, a long-term series of PW was acquired at ETH Hönggerberg where a permanent GPS station (AGNES) is operated. With the utilization of up to 40 selected H20 absorption lines measured at the same time, an accuracy of the PW of 0.5 kg/m can be achieved. The comparison between GEMOSS and GPS revealed that GPS over-estimated the PW during the summer 2003 by about 2-3 kg/m . The same discrepancies were observed at Payerne in 2004 by comparing the GPS results with GEMOSS, WVR and radiosondes. In the framework of the EU-project "GAVDOS", GEMOSS was operated under the track of the altimeter satellite Jason at Rethimnon (Crete, Greece) and at Fiskardo on the island of Kefalonia (Greece) in January and September in 2003. The highly precise PW measurements of GEMOSS were used to calibrate the on-board microwave radiometer of Jason (JMR). The integrated water vapor content which was simultaneously determined by GEMOSS and JMR agree at the 0.3-0.4 kg/m level. On the basis of these promising results GEMOSS can be considered as a novel portable tool for space-borne radiometer calibration and it will be deployed for further calibration of Jason in the future. Numéro de notice : 13265 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère DOI : 10.3929/ethz-a-004930678 En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-68.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54946

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
13265-01	24.30	Livre	Centre de documentation	Physique	Disponible
13265-02	24.30	Livre	Centre de documentation	Physique	Disponible

GPS Tomography and Remote Sensing Techniques for Water Vapor Determination in the ESCOMPTE Campaign / Beat Bürki (2004)

Public contenu dans Celebrating a decade of the International GPS Service, Workshop & Symposium 2004 / Michael Meindl (2004) Titre : GPS Tomography and Remote Sensing Techniques for Water Vapor Determination in the ESCOMPTE Campaign Type de document : Article/Communication Auteurs : Beat Bürki, Auteur ; Simon Lutz, Auteur ; Marc Troller, Auteur ; Alexander Somieski, Auteur ; Andrea Walpersdorf, Auteur ; Erik Doerflinger, Auteur ; Alain Geiger, Auteur ; Olivier Bock , Auteur ; et al., Auteur Editeur : Berne : Université de Berne Année de publication : 2004 Conférence : IGS 2004, international symposium, Celebrating a decade of the International GPS Service Symposium 01/03/2004 05/03/2004 Berne Suisse Format : 21 x 30 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] positionnement par GPS [Termes IGN] teneur en vapeur d'eau [Termes IGN] tomographie Résumé : (Auteur) The hierarchy of reference frames used in the IGS and the procedures and rationale for realizing them are reviewed. The Conventions of the IERS lag developments in the IGS in a number of important respects. Recommendations are offered for changes in the IERS Conventions to recognize geocenter motion (as already implemented by the IGS) and to enforce greater model consistency in order to achieve higher precision for combined reference frame products. Despite large improvements in the internal consistency of IGS product sets, defects remain which should be addressed in future developments. If the IGS is to remain a leader in this area, then a comprehensive, long-range strategy should be formulated and pursued to maintain and enhance the IGS reference frame, as well as to improve its delivery to users. Actions should include the official designation of a high-performance reference tracking network whose stations are expected to meet the highest standards possible. Numéro de notice : C2004-016 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=65027