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Titel |
Weak ionization of the global ionosphere in solar cycle 24 |
VerfasserIn |
Y. Q. Hao, H. Shi, Z. Xiao, D. H. Zhang |
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 ; 32, no. 7 ; Nr. 32, no. 7 (2014-07-21), S.809-816 |
Datensatznummer |
250121082
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Publikation (Nr.) |
copernicus.org/angeo-32-809-2014.pdf |
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Zusammenfassung |
Following prolonged and extremely quiet solar activity from 2008 to 2009, the
24th solar cycle started slowly. It has been almost 5 years since then. The
measurement of ionospheric critical frequency (foF2) shows the fact
that solar activity has been significantly lower in the first half of cycle
24, compared to the average levels of cycles 19 to 23; the data of global
average total electron content (TEC) confirm that the
global ionosphere around the cycle 24 peak is much more weakly ionized, in
contrast to cycle 23. The weak ionization has been more notable since the
year 2012, when both the ionosphere and solar activity were expected to be
approaching their maximum level. The undersupply of solar extreme ultraviolet
(EUV) irradiance somewhat continues after the 2008–2009 minimum, and is
considered to be the main cause of the weak ionization. It further implies
that the thermosphere and ionosphere in the first solar cycle of this
millennium would probably differ from what we have learned from the previous
cycles of the space age. |
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