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

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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

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