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| Titel |
Geomagnetic control of the foF2 long-term trends |
| VerfasserIn |
A. V. Mikhailov, D. Marin |
| 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. 6 ; Nr. 18, no. 6, S.653-665 |
| Datensatznummer |
250014020
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| Publikation (Nr.) |
 copernicus.org/angeo-18-653-2000.pdf |
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| Zusammenfassung |
Further development of the method proposed by
Danilov and Mikhailov is presented. The method is applied to reveal the foF2
long-term trends on 30 Northern Hemisphere ionosonde stations. Most of them show
significant foF2 trends. A pronounced dependence of trend magnitude on
geomagnetic (invariant) latitude is confirmed. Periods of negative/positive foF2
trends corresponding to the periods of long-term increasing/decreasing
geomagnetic activity are revealed for the first time. Pronounced diurnal
variations of the foF2 trend magnitude are found. Strong positive foF2
trends in the post-midnight-early-morning LT sector and strong negative trends
during daytime hours are found on the sub-auroral stations for the period with
increasing geomagnetic activity. On the contrary middle and lower latitude
stations demonstrate negative trends in the early-morning LT sector and small
negative or positive trends during daytime hours for the same period. All the
morphological features revealed of the foF2 trends may be explained in
the framework of contemporary F2-region storm mechanisms. This newly proposed
F2-layer geomagnetic storm concept casts serious doubts on the hypothesis
relating the F2-layer parameter long-term trends to the thermosphere cooling due
to the greenhouse effect.
Key words: Ionosphere (ionosphere-atmosphere
interactions; ionospheric disturbances) |
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