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Titel |
The 22-year cycle in the geomagnetic 27-day recurrences reflecting on the F2-layer ionization |
VerfasserIn |
E. M. Apostolov, D. Altadill, M. Todorova |
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 ; 22, no. 4 ; Nr. 22, no. 4 (2004-04-02), S.1171-1176 |
Datensatznummer |
250014831
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Publikation (Nr.) |
copernicus.org/angeo-22-1171-2004.pdf |
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Zusammenfassung |
Solar cycle variations of the amplitudes of the 27-day solar rotation period
reflected in the geomagnetic activity index Ap, solar radio flux F10.7cm
and critical frequency foF2 for mid-latitude ionosonde station Moscow
from the maximum of sunspot cycle 18 to the maximum of cycle 23 are examined.
The analysis shows that there are distinct enhancements of the 27-day
amplitudes for foF2 and Ap in the late declining phase of each solar
cycle while the amplitudes for F10.7cm decrease gradually, and the
foF2 and Ap amplitude peaks are much larger for even-numbered solar cycles
than for the odd ones. Additionally, we found the same even-high and odd-low
pattern of foF2 for other mid-latitude ionosonde stations in Northern
and Southern Hemispheres. This property suggests that there exists a 22-year
cycle in the F2-layer variability coupled with the 22-year cycle in the
27-day recurrence of geomagnetic activity.
Key words. Ionosphere (mid-latitude ionosphere; ionosphere-
magnetosphere interactions) – Magnetospheric
physics (solar wind-magnetosphere interactions) |
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