Centre de documentation
scientifique

Attribution of greenhouse gas emissions, concentrations and radiative forcing / I.E. Enting (1998)

Public Titre : Attribution of greenhouse gas emissions, concentrations and radiative forcing Type de document : Monographie Auteurs : I.E. Enting, Auteur Editeur : Aspendale : CSIRO Atmospheric Research Année de publication : 1998 Collection : CSIRO Atmospheric research technical paper num. 38 Importance : 29 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-0-643-06344-0 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Atmosphère [Termes IGN] climatologie [Termes IGN] écologie [Termes IGN] gaz [Termes IGN] pollution atmosphérique [Termes IGN] radioactivité [Termes IGN] secteur secondaire Numéro de notice : 66784 Affiliation des auteurs : non IGN Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=61661

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
66784-01	47.50	Livre	Centre de documentation	En réserve M-103	Disponible

Geophysical distributions of occultations of GPS satellites viewed from a low Earth orbiting satellite / D.M. O'Brien (1998)

Public Titre : Geophysical distributions of occultations of GPS satellites viewed from a low Earth orbiting satellite Type de document : Monographie Auteurs : D.M. O'Brien, Auteur ; Paul Tregoning, Auteur Editeur : Aspendale : CSIRO Atmospheric Research Année de publication : 1998 Collection : CSIRO Atmospheric research technical paper num. 39 Importance : 31 p. Format : 21 x 29 cm ISBN/ISSN/EAN : 978-0-643-06345-7 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] affaiblissement géométrique de la précision [Termes IGN] antenne GPS [Termes IGN] atmosphère terrestre [Termes IGN] constellation GPS [Termes IGN] distribution spatiale [Termes IGN] météorologie [Termes IGN] orbite basse [Termes IGN] radiooccultation [Termes IGN] récepteur GPS [Termes IGN] satellite artificiel [Termes IGN] satellite GPS Index. décimale : 30.84 Applications de géodésie spatiale à l'atmosphère Résumé : (Auteur) The infrastructure of the Global Positioning System (GPS), with a minimum of twenty four satellites in precisely determined orbits, each transmitting on two radio frequencies of approximately 1.58 GHz and 1.23 GHz, opens new opportunities for meteorology through radio occultation. A small satellite in low earth orbit (LEO) carrying a GPS receiver will see the satellites of the GPS constellation rise and set behind the earth. From measurements of the Doppler shifts of the radio waves during occultations of the GPS satellites, it is possible to deduce the bending of the radio waves in the atmosphere of the Earth, and hence determine the density profile of the atmosphere. The method is unaffected by cloud, does not involve radiometric calibration like other remote sensing methods, and provides density soundings over the entire globe. This technical paper examines the spatial distributions of occultations for four different GPS antenna configurations on the LEO and for orbits of the LEO ranging from equatorial to polar. It is found that the most uniform spatial distribution of occultations occurs for orbits with inclinations near 60° and 120°. In addition, probability distributions are computed for the number of GPS satellites in view and the geometric dilution of precision, the latter being a measure of the accuracy with which the orbit of the LEO may be determined. Because underflight of a GPS satellites by the LEO offer an opportunity to determine the structure of the ionosphere along radial lines from the LEO to the GPS satellite, the paper also computes the frequency of underflights and their spatial distributions. Numéro de notice : 66783 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=61660

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
66783-01	30.84	Livre	Centre de documentation	Géodésie	Disponible