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 N e decrease at F2-layer heights originated from different physical mechanisms in the two cases. The ne...
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ftdoajarticles:oai:doaj.org/article:fe1c574e78584dde8048da29806aa758 2023-05-15T16:04:36+02:00 Physical mechanism of strong negative storm effects in the daytime ionospheric F2 region observed with EISCAT A. Mikhailov K. Schlegel 1998-05-01T00:00:00Z https://doi.org/10.1007/s00585-998-0602-z https://doaj.org/article/fe1c574e78584dde8048da29806aa758 EN eng Copernicus Publications https://www.ann-geophys.net/16/602/1998/angeo-16-602-1998.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.1007/s00585-998-0602-z 0992-7689 1432-0576 https://doaj.org/article/fe1c574e78584dde8048da29806aa758 Annales Geophysicae, Vol 16, Pp 602-608 (1998) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 1998 ftdoajarticles https://doi.org/10.1007/s00585-998-0602-z 2022-12-31T10:36:37Z 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 N e decrease at F2-layer heights originated from different physical mechanisms in the two cases. The negative F2-layer storm effect with an N m F2 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 + + N 2 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 Directory of Open Access Journals: DOAJ Articles Annales Geophysicae 16 5 602 608 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
spellingShingle |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 A. Mikhailov K. Schlegel Physical mechanism of strong negative storm effects in the daytime ionospheric F2 region observed with EISCAT |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
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 N e decrease at F2-layer heights originated from different physical mechanisms in the two cases. The negative F2-layer storm effect with an N m F2 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 + + N 2 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 |
A. Mikhailov K. Schlegel |
author_facet |
A. Mikhailov K. Schlegel |
author_sort |
A. Mikhailov |
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 |
Copernicus Publications |
publishDate |
1998 |
url |
https://doi.org/10.1007/s00585-998-0602-z https://doaj.org/article/fe1c574e78584dde8048da29806aa758 |
genre |
EISCAT |
genre_facet |
EISCAT |
op_source |
Annales Geophysicae, Vol 16, Pp 602-608 (1998) |
op_relation |
https://www.ann-geophys.net/16/602/1998/angeo-16-602-1998.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.1007/s00585-998-0602-z 0992-7689 1432-0576 https://doaj.org/article/fe1c574e78584dde8048da29806aa758 |
op_doi |
https://doi.org/10.1007/s00585-998-0602-z |
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Annales Geophysicae |
container_volume |
16 |
container_issue |
5 |
container_start_page |
602 |
op_container_end_page |
608 |
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1766400198490193920 |