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| Titel |
Annual and semiannual variations in the ionospheric F2-layer. I. Modelling |
| VerfasserIn |
L. Zou, H. Rishbeth, I. C. F. Müller-Wodarg, A. D. Aylward, G. H. Millward, T. J. Fuller-Rowell, D. W. Idenden, R. J. Moffett |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 18, no. 8 ; Nr. 18, no. 8, S.927-944 |
| Datensatznummer |
250014043
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| Publikation (Nr.) |
 copernicus.org/angeo-18-927-2000.pdf |
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| Zusammenfassung |
Annual, seasonal and semiannual variations of
F2-layer electron density (NmF2) and height (hmF2) have been
compared with the coupled thermosphere-ionosphere-plasmasphere computational
model (CTIP), for geomagnetically quiet conditions. Compared with results from
ionosonde data from midlatitudes, CTIP reproduces quite well many observed
features of NmF2, such as the dominant winter maxima at high midlatitudes
in longitude sectors near the magnetic poles, the equinox maxima in sectors
remote from the magnetic poles and at lower latitudes generally, and the form of
the month-to-month variations at latitudes between about 60°N and 50°S. CTIP
also reproduces the seasonal behaviour of NmF2 at midnight and the
summer-winter changes of hmF2. Some features of the F2-layer, not
reproduced by the present version of CTIP, are attributed to processes not
included in the modelling. Examples are the increased prevalence of the winter
maxima of noon NmF2 at higher solar activity, which may be a consequence
of the increase of F2-layer loss rate in summer by vibrationally excited
molecular nitrogen, and the semiannual variation in hmF2, which may be
due to tidal effects. An unexpected feature of the computed distributions of NmF2
is an east-west hemisphere difference, which seems to be linked to the
geomagnetic field configuration. Physical discussion is reserved to the
companion paper by Rishbeth et al.
Key words: Atmospheric composition and structure
(thermosphere-composition and chemistry) - Ionosphere (mid-latitude ionosphere;
modelling and forecasting) |
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