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dc.contributor.authorBrekke, Asgeir
dc.contributor.authorOyama, S
dc.contributor.authorWatkins, B. J.
dc.contributor.authorMaeda, S.
dc.contributor.authorShinagawa, H.
dc.contributor.authorNozawa, S.
dc.contributor.authorOgawa, Y.
dc.contributor.authorLathuillere, C.
dc.contributor.authorKofman, W.
dc.date.accessioned2010-02-11T12:54:51Z
dc.date.available2010-02-11T12:54:51Z
dc.date.issued2008-06-11
dc.description.abstractLower-thermospheric winds at high latitudes during moderately-disturbed geomagnetic conditions were studied using data obtained with the European Incoherent Scatter (EISCAT) Kiruna-Sodankylä-Tromsø (KST) ultrahigh frequency (UHF) radar system on 9–10 September 2004. The antenna-beam configuration was newly designed to minimize the estimated measurement error of the vertical neutralwind speed in the lower thermosphere. This method was also available to estimate the meridional and zonal components. The vertical neutral-wind speed at 109 km, 114 km, and 120 km heights showed large upward motions in excess of 30ms<sup>−1</sup> in association with an ionospheric heating event. Large downward speeds in excess of −30ms<sup>−1</sup> were also observed before and after the heating event. The meridional neutral-wind speed suddenly changed its direction from equatorward to poleward when the heating event began, and then returned equatorward coinciding with a decrease in the heating event. The magnetometer data from northern Scandinavia suggested that the center of the heated region was located about 80 km equatorward of Tromsø. The pressure gradient caused the lower-thermospheric wind to accelerate obliquely upward over Tromsø in the poleward direction. Acceleration of the neutral wind flowing on a vertically tilted isobar produced vertical wind speeds larger by more than two orders of magnitude than previously predicted, but still an order of magnitude smaller than observed speeds.en
dc.descriptionThis is the publishers version/PDF (Published in Annales Geophysicae, An Open Access Journal of the European Geosciences Union)en
dc.format.extent2843460 bytes
dc.format.mimetypeapplication/pdf
dc.identifier.citationAnnales Geophysicae, 26, 1491–1505, 2008en
dc.identifier.issn0992-7689
dc.identifier.urihttps://hdl.handle.net/10037/2383
dc.identifier.urnURN:NBN:no-uit_munin_2133
dc.language.isoengen
dc.publisherCopernicus Publications on behalf of the European Geosciences Unionen
dc.rights.accessRightsopenAccess
dc.subjectVDP::Mathematics and natural science: 400::Physics: 430::Astrophysics, astronomy: 438en
dc.subjectIonosphereen
dc.subjectIonosphere-atmosphere interactionsen
dc.subjectPolar ionosphereen
dc.subjectMeteorology and atmospheric dynamicsen
dc.subjectThermospheric dynamicsen
dc.titleGeneration of the lower-thermospheric vertical wind estimated with the EISCAT KST radar at high latitudes during periods of moderate geomagnetic disturbanceen
dc.typeJournal articleen
dc.typeTidsskriftartikkelen
dc.typePeer revieweden


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