A statistical study of diurnal, seasonal and solar cycle variations of F-region and topside auroral upflows observed by EISCAT between 1984 and 1996
A statistical analysis of F-region and topside auroral ion upflow events is presented. The study is based on observations from EISCAT Common Programmes (CP) 1 and 2 made between 1984 and 1996, and Common Programme 7 observations taken between 1990 and 1995. The occurrence frequency of ion upflow eve...
Published in: | Annales Geophysicae |
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Format: | Article in Journal/Newspaper |
Language: | English |
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Springer Verlag
1998
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00037209 2023-05-15T16:04:37+02:00 A statistical study of diurnal, seasonal and solar cycle variations of F-region and topside auroral upflows observed by EISCAT between 1984 and 1996 Foster, C. Lester, M. Davies, J. A. 1998-10 electronic https://doi.org/10.1007/s00585-998-1144-0 https://noa.gwlb.de/receive/cop_mods_00037209 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00037163/angeo-16-1144-1998.pdf https://angeo.copernicus.org/articles/16/1144/1998/angeo-16-1144-1998.pdf eng eng Springer Verlag Annales Geophysicae -- http://www.bibliothek.uni-regensburg.de/ezeit/?1458425 -- https://www.ann-geophys.net/ -- https://www.ann-geophys.net/volumes.html -- http://link.springer.com/journal/585 -- 1432-0576 https://doi.org/10.1007/s00585-998-1144-0 https://noa.gwlb.de/receive/cop_mods_00037209 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00037163/angeo-16-1144-1998.pdf https://angeo.copernicus.org/articles/16/1144/1998/angeo-16-1144-1998.pdf https://open-access.net/ uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 1998 ftnonlinearchiv https://doi.org/10.1007/s00585-998-1144-0 2022-02-08T22:43:37Z A statistical analysis of F-region and topside auroral ion upflow events is presented. The study is based on observations from EISCAT Common Programmes (CP) 1 and 2 made between 1984 and 1996, and Common Programme 7 observations taken between 1990 and 1995. The occurrence frequency of ion upflow events (IUEs) is examined over the altitude range 200 to 500 km, using field-aligned observations from CP-1 and CP-2. The study is extended in altitude with vertical measurements from CP-7. Ion upflow events were identified by consideration of both velocity and flux, with threshold values of 100 m s–1 and 1013 m–2 s–1, respectively. The frequency of occurrence of IUEs is seen to increase with increasing altitude. Further analysis of the field-aligned observations reveals that the number and nature of ion upflow events vary diurnally and with season and solar activity. In particular, the diurnal distribution of upflows is strongly dependent on solar cycle. Furthermore, events identified by the velocity selection criterion dominate at solar minimum, whilst events identified by the upward field-aligned flux criterion dominated at solar maximum. The study also provides a quantitative estimate of the proportion of upflows that are associated with enhanced plasma temperature. Between 50 and 60% of upflows are simultaneous with enhanced ion temperature, and approximately 80% of events are associated with either increased F-region ion or electron temperatures. Key words. Ionosphere (auroral ionosphere; particle acceleration) Article in Journal/Newspaper EISCAT Niedersächsisches Online-Archiv NOA Annales Geophysicae 16 10 1144 1158 |
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Open Polar |
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Niedersächsisches Online-Archiv NOA |
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ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Foster, C. Lester, M. Davies, J. A. A statistical study of diurnal, seasonal and solar cycle variations of F-region and topside auroral upflows observed by EISCAT between 1984 and 1996 |
topic_facet |
article Verlagsveröffentlichung |
description |
A statistical analysis of F-region and topside auroral ion upflow events is presented. The study is based on observations from EISCAT Common Programmes (CP) 1 and 2 made between 1984 and 1996, and Common Programme 7 observations taken between 1990 and 1995. The occurrence frequency of ion upflow events (IUEs) is examined over the altitude range 200 to 500 km, using field-aligned observations from CP-1 and CP-2. The study is extended in altitude with vertical measurements from CP-7. Ion upflow events were identified by consideration of both velocity and flux, with threshold values of 100 m s–1 and 1013 m–2 s–1, respectively. The frequency of occurrence of IUEs is seen to increase with increasing altitude. Further analysis of the field-aligned observations reveals that the number and nature of ion upflow events vary diurnally and with season and solar activity. In particular, the diurnal distribution of upflows is strongly dependent on solar cycle. Furthermore, events identified by the velocity selection criterion dominate at solar minimum, whilst events identified by the upward field-aligned flux criterion dominated at solar maximum. The study also provides a quantitative estimate of the proportion of upflows that are associated with enhanced plasma temperature. Between 50 and 60% of upflows are simultaneous with enhanced ion temperature, and approximately 80% of events are associated with either increased F-region ion or electron temperatures. Key words. Ionosphere (auroral ionosphere; particle acceleration) |
format |
Article in Journal/Newspaper |
author |
Foster, C. Lester, M. Davies, J. A. |
author_facet |
Foster, C. Lester, M. Davies, J. A. |
author_sort |
Foster, C. |
title |
A statistical study of diurnal, seasonal and solar cycle variations of F-region and topside auroral upflows observed by EISCAT between 1984 and 1996 |
title_short |
A statistical study of diurnal, seasonal and solar cycle variations of F-region and topside auroral upflows observed by EISCAT between 1984 and 1996 |
title_full |
A statistical study of diurnal, seasonal and solar cycle variations of F-region and topside auroral upflows observed by EISCAT between 1984 and 1996 |
title_fullStr |
A statistical study of diurnal, seasonal and solar cycle variations of F-region and topside auroral upflows observed by EISCAT between 1984 and 1996 |
title_full_unstemmed |
A statistical study of diurnal, seasonal and solar cycle variations of F-region and topside auroral upflows observed by EISCAT between 1984 and 1996 |
title_sort |
statistical study of diurnal, seasonal and solar cycle variations of f-region and topside auroral upflows observed by eiscat between 1984 and 1996 |
publisher |
Springer Verlag |
publishDate |
1998 |
url |
https://doi.org/10.1007/s00585-998-1144-0 https://noa.gwlb.de/receive/cop_mods_00037209 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00037163/angeo-16-1144-1998.pdf https://angeo.copernicus.org/articles/16/1144/1998/angeo-16-1144-1998.pdf |
genre |
EISCAT |
genre_facet |
EISCAT |
op_relation |
Annales Geophysicae -- http://www.bibliothek.uni-regensburg.de/ezeit/?1458425 -- https://www.ann-geophys.net/ -- https://www.ann-geophys.net/volumes.html -- http://link.springer.com/journal/585 -- 1432-0576 https://doi.org/10.1007/s00585-998-1144-0 https://noa.gwlb.de/receive/cop_mods_00037209 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00037163/angeo-16-1144-1998.pdf https://angeo.copernicus.org/articles/16/1144/1998/angeo-16-1144-1998.pdf |
op_rights |
https://open-access.net/ uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1007/s00585-998-1144-0 |
container_title |
Annales Geophysicae |
container_volume |
16 |
container_issue |
10 |
container_start_page |
1144 |
op_container_end_page |
1158 |
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1766400212852539392 |