Physical mechanism of strong negative storm effects in the daytime ionospheric F2 region observed with EISCAT
International audience 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 i...
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ftccsdartic:oai:HAL:hal-00316395v1 2023-11-12T04:16:36+01:00 Physical mechanism of strong negative storm effects in the daytime ionospheric F2 region observed with EISCAT Mikhailov, A. Schlegel, K. Institute for Applied Geophysics the Russian Academy of Sciences Moscow, Russia (RAS) Max-Planck-Institut für Aeronomie (MPI Aeronomie) Max-Planck-Gesellschaft 1998 https://hal.science/hal-00316395 https://hal.science/hal-00316395/document https://hal.science/hal-00316395/file/angeo-16-602-1998.pdf en eng HAL CCSD European Geosciences Union hal-00316395 https://hal.science/hal-00316395 https://hal.science/hal-00316395/document https://hal.science/hal-00316395/file/angeo-16-602-1998.pdf info:eu-repo/semantics/OpenAccess ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00316395 Annales Geophysicae, 1998, 16 (5), pp.602-608 [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/article Journal articles 1998 ftccsdartic 2023-10-21T23:08:33Z International audience 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. Article in Journal/Newspaper EISCAT Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
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Open Polar |
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Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
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ftccsdartic |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Mikhailov, A. Schlegel, K. Physical mechanism of strong negative storm effects in the daytime ionospheric F2 region observed with EISCAT |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience 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. |
author2 |
Institute for Applied Geophysics the Russian Academy of Sciences Moscow, Russia (RAS) Max-Planck-Institut für Aeronomie (MPI Aeronomie) Max-Planck-Gesellschaft |
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 |
HAL CCSD |
publishDate |
1998 |
url |
https://hal.science/hal-00316395 https://hal.science/hal-00316395/document https://hal.science/hal-00316395/file/angeo-16-602-1998.pdf |
genre |
EISCAT |
genre_facet |
EISCAT |
op_source |
ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00316395 Annales Geophysicae, 1998, 16 (5), pp.602-608 |
op_relation |
hal-00316395 https://hal.science/hal-00316395 https://hal.science/hal-00316395/document https://hal.science/hal-00316395/file/angeo-16-602-1998.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782333663248121856 |