Physical mechanism of strong negative storm effects in the daytime ionospheric F2 region observed with EISCAT
A self-consistent method for daytime F-region modelling was applied to EISCAT observations during two periods comprising the very disturbed days 3 April 1992 and 10 April 1990. The observed strong Ne decrease at F2-layer heights originated from different physical mechanisms in the two cases. The neg...
Published in: | Annales Geophysicae |
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Springer Verlag
1998
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00037305 2023-05-15T16:04:36+02:00 Physical mechanism of strong negative storm effects in the daytime ionospheric F2 region observed with EISCAT Mikhailov, A. Schlegel, K. 1998-05 electronic https://doi.org/10.1007/s00585-998-0602-z https://noa.gwlb.de/receive/cop_mods_00037305 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00037259/angeo-16-602-1998.pdf https://angeo.copernicus.org/articles/16/602/1998/angeo-16-602-1998.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/s00585-998-0602-z https://noa.gwlb.de/receive/cop_mods_00037305 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00037259/angeo-16-602-1998.pdf https://angeo.copernicus.org/articles/16/602/1998/angeo-16-602-1998.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/s00585-998-0602-z 2022-02-08T22:43:34Z A self-consistent method for daytime F-region modelling was applied to EISCAT observations during two periods comprising the very disturbed days 3 April 1992 and 10 April 1990. The observed strong Ne decrease at F2-layer heights originated from different physical mechanisms in the two cases. The negative F2-layer storm effect with an NmF2 decrease by a factor of 6.4 on 3 April 1992 was produced by enhanced electric fields (E≈85 mV/m) and strong downward plasma drifts, but without any noticeable changes in thermospheric parameters. The increase of the O+ + N2 reaction rate resulted in a strong enrichment of the ionosphere with molecular ions even at F2-layer heights. The enhanced electric field produced a wide mid-latitude daytime trough on 03 April 1992 not usually observed during similar polarization jet events. The other strong negative storm effect on 10 April 1990 with a complete disappearance of the F2-layer maximum at the usual heights was attributed mainly to changes in neutral composition and temperature. A small value for the shape parameter S in the neutral temperature profile and a low neutral temperature at 120 km indicate strong cooling of the lower thermosphere. We propose that this cooling is due to increased nitric oxide concentration usually observed at these heights during geomagnetic storms. Key words. Atmospheric composition and structure · Thermosphere · Ionosphere · Ion chemistry and composition · Atmosphere interactions Article in Journal/Newspaper EISCAT Niedersächsisches Online-Archiv NOA Annales Geophysicae 16 5 602 608 |
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article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Mikhailov, A. Schlegel, K. Physical mechanism of strong negative storm effects in the daytime ionospheric F2 region observed with EISCAT |
topic_facet |
article Verlagsveröffentlichung |
description |
A self-consistent method for daytime F-region modelling was applied to EISCAT observations during two periods comprising the very disturbed days 3 April 1992 and 10 April 1990. The observed strong Ne decrease at F2-layer heights originated from different physical mechanisms in the two cases. The negative F2-layer storm effect with an NmF2 decrease by a factor of 6.4 on 3 April 1992 was produced by enhanced electric fields (E≈85 mV/m) and strong downward plasma drifts, but without any noticeable changes in thermospheric parameters. The increase of the O+ + N2 reaction rate resulted in a strong enrichment of the ionosphere with molecular ions even at F2-layer heights. The enhanced electric field produced a wide mid-latitude daytime trough on 03 April 1992 not usually observed during similar polarization jet events. The other strong negative storm effect on 10 April 1990 with a complete disappearance of the F2-layer maximum at the usual heights was attributed mainly to changes in neutral composition and temperature. A small value for the shape parameter S in the neutral temperature profile and a low neutral temperature at 120 km indicate strong cooling of the lower thermosphere. We propose that this cooling is due to increased nitric oxide concentration usually observed at these heights during geomagnetic storms. Key words. Atmospheric composition and structure · Thermosphere · Ionosphere · Ion chemistry and composition · Atmosphere interactions |
format |
Article in Journal/Newspaper |
author |
Mikhailov, A. Schlegel, K. |
author_facet |
Mikhailov, A. Schlegel, K. |
author_sort |
Mikhailov, A. |
title |
Physical mechanism of strong negative storm effects in the daytime ionospheric F2 region observed with EISCAT |
title_short |
Physical mechanism of strong negative storm effects in the daytime ionospheric F2 region observed with EISCAT |
title_full |
Physical mechanism of strong negative storm effects in the daytime ionospheric F2 region observed with EISCAT |
title_fullStr |
Physical mechanism of strong negative storm effects in the daytime ionospheric F2 region observed with EISCAT |
title_full_unstemmed |
Physical mechanism of strong negative storm effects in the daytime ionospheric F2 region observed with EISCAT |
title_sort |
physical mechanism of strong negative storm effects in the daytime ionospheric f2 region observed with eiscat |
publisher |
Springer Verlag |
publishDate |
1998 |
url |
https://doi.org/10.1007/s00585-998-0602-z https://noa.gwlb.de/receive/cop_mods_00037305 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00037259/angeo-16-602-1998.pdf https://angeo.copernicus.org/articles/16/602/1998/angeo-16-602-1998.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/s00585-998-0602-z https://noa.gwlb.de/receive/cop_mods_00037305 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00037259/angeo-16-602-1998.pdf https://angeo.copernicus.org/articles/16/602/1998/angeo-16-602-1998.pdf |
op_rights |
https://open-access.net/ uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1007/s00585-998-0602-z |
container_title |
Annales Geophysicae |
container_volume |
16 |
container_issue |
5 |
container_start_page |
602 |
op_container_end_page |
608 |
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1766400197214076928 |