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Monitoring the ionosphere with GPS: space weather / Anthea Coster in GPS world, vol 14 n° 5 (May 2003)

Public [article]  inGPS world > vol 14 n° 5 (May 2003) . - pp 42 - 49 Titre : Monitoring the ionosphere with GPS: space weather Type de document : Article/Communication Auteurs : Anthea Coster, Auteur ; J. Foster, Auteur ; P. Erickson, Auteur Année de publication : 2003 Article en page(s) : pp 42 - 49 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] données GPS [Termes IGN] ionosphère [Termes IGN] magnétosphère [Termes IGN] rayonnement ultraviolet [Termes IGN] surveillance météorologique [Termes IGN] tempête [Termes IGN] teneur totale en électrons Résumé : (Auteur) Here on Earth, high winds, heavy rains, deep snow, and other forms of severe weather can disrupt our daily lives. Conditions on the Sun and in the solar wind, magnetosphere, and the ionosphere can also affect our lives through the effects they have on satellites, communications, navigation, and power systems. Scientists are now studying space weather with a wide range of tools to try to learn more about the physical and chemical processes taking place in the upper atmosphere and beyond. One of these tools is GPS. The signals from the GPS satellites travel through the ionosphere on their way to receivers on or near Earth's surface. The free electrons populating this region of the atmosphere affect the propagation of the signals, changing their speed and direction of travel. By processing the data from a dual-frequency GPS receiver, it's actually possible to estimate just how many electrons were encountered by the signal along its travel path - the total electron content (TEC). TEC is the number of electrons in a column with a cross-sectional area of one square meter centered on the signal path. If a regional network of ground-based GPS receivers is used, then a map of TEC above the region can be constructed. The TEC normally varies smoothly from day to night as Earth's dayside atmosphere is ionized by the Sun's extreme ultraviolet radiation, while the nightside ionosphere electron content is reduced by chemical recombination. But the ionosphere can experience stormy weather just as the lower atmosphere does. Smooth variations in TEC are replaced by rapid fluctuations, and some regions experience significantly higher or lower TEC values than normal. In this month's column, we look at how GPS is being used to study such storms and how it is furthering our understanding of the Earth-Sun environment. Numéro de notice : A2003-421 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26501 [article]

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