Day-to-day thermosphere parameter variation as deduced from Millstone Hill incoherent scatter radar observations during March 16-22, 1990 magnetic storm period
A self-consistent method for day-time F2-region modelling was applied to the analysis of Millstone Hill incoherent scatter observations during the storm period of March 16-22, 1990. The method allows us to calculate in a self-consistent way neutral composition, temperature and meridional wind as...
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Copernicus Publications
1997-11-01
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Series: | Annales Geophysicae |
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doaj-595c5944301d4c0d89033d54594ce92f2020-11-24T22:35:03ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05761997-11-01151429143810.1007/s00585-997-1429-8Day-to-day thermosphere parameter variation as deduced from Millstone Hill incoherent scatter radar observations during March 16-22, 1990 magnetic storm periodA. V. Mikhailov0M. Förster1Institute for Applied Geophysics, Moscow, RussiaGeoForschungsZentrum, Potsdam, GermanyA self-consistent method for day-time F2-region modelling was applied to the analysis of Millstone Hill incoherent scatter observations during the storm period of March 16-22, 1990. The method allows us to calculate in a self-consistent way neutral composition, temperature and meridional wind as well as the ionized species height distribution. Theoretically calculated <i>N<sub>e</sub></i>(h) profiles fit the observed daytime ones with great accuracy in the whole range of heights above 150 km for both quiet and disturbed days. The overall increase in <i>T</i><sub>ex</sub> by 270 K from March 16 to March 22 reflects the increase of solar activity level during the period in question. A 30% decrease in [O] and a two-fold increase in [<i>N</i><sub>2</sub>] are calculated for the disturbed day of March 22 relative to quiet time prestorm conditions. Only a small reaction to the first geomagnetic disturbance on March 18 and the initial phase of the second storm on March 20 was found in [O] and [<i>N</i><sub>2</sub>] variations. The meridional neutral wind inferred from plasma vertical drift clearly demonstrates the dependence on the geomagnetic activity level being more equatorward on disturbed days. Small positive F2-layer storm effects on March 18 and 20 are totally attributed to the decrease in the northward neutral wind but not to changes in neutral composition. A moderate (by a factor of 1.5) O/<i>N</i><sub>2</sub> ratio decrease relative to the MSIS-83 model prediction is required to describe the observed <i>N<sub>m</sub>F</i>2 decrease on the most disturbed day of March 22, but virtually no change of this ratio is needed for March 21.https://www.ann-geophys.net/15/1429/1997/angeo-15-1429-1997.pdf |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
A. V. Mikhailov M. Förster |
spellingShingle |
A. V. Mikhailov M. Förster Day-to-day thermosphere parameter variation as deduced from Millstone Hill incoherent scatter radar observations during March 16-22, 1990 magnetic storm period Annales Geophysicae |
author_facet |
A. V. Mikhailov M. Förster |
author_sort |
A. V. Mikhailov |
title |
Day-to-day thermosphere parameter variation as deduced from Millstone Hill incoherent scatter radar observations during March 16-22, 1990 magnetic storm period |
title_short |
Day-to-day thermosphere parameter variation as deduced from Millstone Hill incoherent scatter radar observations during March 16-22, 1990 magnetic storm period |
title_full |
Day-to-day thermosphere parameter variation as deduced from Millstone Hill incoherent scatter radar observations during March 16-22, 1990 magnetic storm period |
title_fullStr |
Day-to-day thermosphere parameter variation as deduced from Millstone Hill incoherent scatter radar observations during March 16-22, 1990 magnetic storm period |
title_full_unstemmed |
Day-to-day thermosphere parameter variation as deduced from Millstone Hill incoherent scatter radar observations during March 16-22, 1990 magnetic storm period |
title_sort |
day-to-day thermosphere parameter variation as deduced from millstone hill incoherent scatter radar observations during march 16-22, 1990 magnetic storm period |
publisher |
Copernicus Publications |
series |
Annales Geophysicae |
issn |
0992-7689 1432-0576 |
publishDate |
1997-11-01 |
description |
A self-consistent method for day-time
F2-region modelling was applied to the analysis of Millstone Hill incoherent
scatter observations during the storm period of March 16-22, 1990. The method
allows us to calculate in a self-consistent way neutral composition, temperature
and meridional wind as well as the ionized species height distribution.
Theoretically calculated <i>N<sub>e</sub></i>(h) profiles fit the observed
daytime ones with great accuracy in the whole range of heights above 150 km for
both quiet and disturbed days. The overall increase in <i>T</i><sub>ex</sub> by
270 K from March 16 to March 22 reflects the increase of solar activity level
during the period in question. A 30% decrease in [O] and a two-fold increase in
[<i>N</i><sub>2</sub>] are calculated for the disturbed day of March 22 relative
to quiet time prestorm conditions. Only a small reaction to the first
geomagnetic disturbance on March 18 and the initial phase of the second storm on
March 20 was found in [O] and [<i>N</i><sub>2</sub>] variations. The meridional
neutral wind inferred from plasma vertical drift clearly demonstrates the
dependence on the geomagnetic activity level being more equatorward on disturbed
days. Small positive F2-layer storm effects on March 18 and 20 are totally
attributed to the decrease in the northward neutral wind but not to changes in
neutral composition. A moderate (by a factor of 1.5) O/<i>N</i><sub>2</sub>
ratio decrease relative to the MSIS-83 model prediction is required to describe
the observed <i>N<sub>m</sub>F</i>2 decrease on the most disturbed day of March
22, but virtually no change of this ratio is needed for March 21. |
url |
https://www.ann-geophys.net/15/1429/1997/angeo-15-1429-1997.pdf |
work_keys_str_mv |
AT avmikhailov daytodaythermosphereparametervariationasdeducedfrommillstonehillincoherentscatterradarobservationsduringmarch16221990magneticstormperiod AT mforster daytodaythermosphereparametervariationasdeducedfrommillstonehillincoherentscatterradarobservationsduringmarch16221990magneticstormperiod |
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