Generation of the lower-thermospheric vertical wind estimated with the EISCAT KST radar at high latitudes during periods of moderate geomagnetic disturbance
This is the publishers version/PDF (Published in Annales Geophysicae, An Open Access Journal of the European Geosciences Union) Lower-thermospheric winds at high latitudes during moderately-disturbed geomagnetic conditions were studied using data obtained with the European Incoherent Scatter (EISCAT...
Main Authors: | , , , , , , , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications on behalf of the European Geosciences Union
2008
|
Subjects: | |
Online Access: | https://hdl.handle.net/10037/2383 |
id |
ftunivtroemsoe:oai:munin.uit.no:10037/2383 |
---|---|
record_format |
openpolar |
spelling |
ftunivtroemsoe:oai:munin.uit.no:10037/2383 2024-06-02T08:05:58+00:00 Generation of the lower-thermospheric vertical wind estimated with the EISCAT KST radar at high latitudes during periods of moderate geomagnetic disturbance Brekke, Asgeir Oyama, S Watkins, B. J. Maeda, S. Shinagawa, H. Nozawa, S. Ogawa, Y. Lathuillere, C. Kofman, W. 2008-06-11 2843460 bytes application/pdf https://hdl.handle.net/10037/2383 eng eng Copernicus Publications on behalf of the European Geosciences Union Annales Geophysicae, 26, 1491–1505, 2008 0992-7689 https://hdl.handle.net/10037/2383 URN:NBN:no-uit_munin_2133 openAccess VDP::Mathematics and natural science: 400::Physics: 430::Astrophysics astronomy: 438 Ionosphere Ionosphere-atmosphere interactions Polar ionosphere Meteorology and atmospheric dynamics Thermospheric dynamics Journal article Tidsskriftartikkel Peer reviewed 2008 ftunivtroemsoe 2024-05-07T08:42:34Z This is the publishers version/PDF (Published in Annales Geophysicae, An Open Access Journal of the European Geosciences Union) Lower-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 −1 in association with an ionospheric heating event. Large downward speeds in excess of −30ms −1 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. Article in Journal/Newspaper EISCAT Kiruna Sodankylä Tromsø University of Tromsø: Munin Open Research Archive Kiruna Sodankylä ENVELOPE(26.600,26.600,67.417,67.417) Tromsø |
institution |
Open Polar |
collection |
University of Tromsø: Munin Open Research Archive |
op_collection_id |
ftunivtroemsoe |
language |
English |
topic |
VDP::Mathematics and natural science: 400::Physics: 430::Astrophysics astronomy: 438 Ionosphere Ionosphere-atmosphere interactions Polar ionosphere Meteorology and atmospheric dynamics Thermospheric dynamics |
spellingShingle |
VDP::Mathematics and natural science: 400::Physics: 430::Astrophysics astronomy: 438 Ionosphere Ionosphere-atmosphere interactions Polar ionosphere Meteorology and atmospheric dynamics Thermospheric dynamics Brekke, Asgeir Oyama, S Watkins, B. J. Maeda, S. Shinagawa, H. Nozawa, S. Ogawa, Y. Lathuillere, C. Kofman, W. Generation of the lower-thermospheric vertical wind estimated with the EISCAT KST radar at high latitudes during periods of moderate geomagnetic disturbance |
topic_facet |
VDP::Mathematics and natural science: 400::Physics: 430::Astrophysics astronomy: 438 Ionosphere Ionosphere-atmosphere interactions Polar ionosphere Meteorology and atmospheric dynamics Thermospheric dynamics |
description |
This is the publishers version/PDF (Published in Annales Geophysicae, An Open Access Journal of the European Geosciences Union) Lower-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 −1 in association with an ionospheric heating event. Large downward speeds in excess of −30ms −1 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. |
format |
Article in Journal/Newspaper |
author |
Brekke, Asgeir Oyama, S Watkins, B. J. Maeda, S. Shinagawa, H. Nozawa, S. Ogawa, Y. Lathuillere, C. Kofman, W. |
author_facet |
Brekke, Asgeir Oyama, S Watkins, B. J. Maeda, S. Shinagawa, H. Nozawa, S. Ogawa, Y. Lathuillere, C. Kofman, W. |
author_sort |
Brekke, Asgeir |
title |
Generation of the lower-thermospheric vertical wind estimated with the EISCAT KST radar at high latitudes during periods of moderate geomagnetic disturbance |
title_short |
Generation of the lower-thermospheric vertical wind estimated with the EISCAT KST radar at high latitudes during periods of moderate geomagnetic disturbance |
title_full |
Generation of the lower-thermospheric vertical wind estimated with the EISCAT KST radar at high latitudes during periods of moderate geomagnetic disturbance |
title_fullStr |
Generation of the lower-thermospheric vertical wind estimated with the EISCAT KST radar at high latitudes during periods of moderate geomagnetic disturbance |
title_full_unstemmed |
Generation of the lower-thermospheric vertical wind estimated with the EISCAT KST radar at high latitudes during periods of moderate geomagnetic disturbance |
title_sort |
generation of the lower-thermospheric vertical wind estimated with the eiscat kst radar at high latitudes during periods of moderate geomagnetic disturbance |
publisher |
Copernicus Publications on behalf of the European Geosciences Union |
publishDate |
2008 |
url |
https://hdl.handle.net/10037/2383 |
long_lat |
ENVELOPE(26.600,26.600,67.417,67.417) |
geographic |
Kiruna Sodankylä Tromsø |
geographic_facet |
Kiruna Sodankylä Tromsø |
genre |
EISCAT Kiruna Sodankylä Tromsø |
genre_facet |
EISCAT Kiruna Sodankylä Tromsø |
op_relation |
Annales Geophysicae, 26, 1491–1505, 2008 0992-7689 https://hdl.handle.net/10037/2383 URN:NBN:no-uit_munin_2133 |
op_rights |
openAccess |
_version_ |
1800750851709468672 |