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Titel |
Characteristics of the ionospheric total electron content of the equatorial ionization anomaly in the Asian-Australian region during 1996-2004 |
VerfasserIn |
Zhao Biqiang, Wan Weixing, Liu Libo, Zhipeng Ren |
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 ; 27, no. 10 ; Nr. 27, no. 10 (2009-10-12), S.3861-3873 |
Datensatznummer |
250016675
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Publikation (Nr.) |
copernicus.org/angeo-27-3861-2009.pdf |
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Zusammenfassung |
Ionospheric total electron content (TEC) of the
equatorial ionization anomaly (EIA) is studied by analyzing dual-frequency
signals of the Global Position System (GPS) acquired from a network of
receivers around the Asian-Australian region during 1996–2004. The latitude,
occurrence time, strength of the most developed EIA crest, and
crest-to-trough ratio (CTR) for both the noon and post-sunset sector
obtained from a daily TEC contour map have been used to study the solar cycle
variations of EIA in the Asian-Australian region. The results reveal that
semiannual and seasonal variations were the dominant factor that controls
the morphology of the EIA structure which can be identified in the past
studies (e.g. Wu et al., 2008). It is also found that the latitude and local time
position of the anomaly crest show a hemispheric asymmetry because (a) The
northern crest of EIA is expanded during the equinox indicating a weak
semiannual variation while the southern crest is inhibited during
June–August presenting a strong seasonal variation, and (b) The local time
of the northern crest appears ~1.3 h earlier than that of the
southern crest in June while showing no difference at December. Solar activity
dependence is more evident in the EIA crest region than in the EIA trough
region and least in the post-sunset sector at equinox. A seasonal linear
relationship is derived between the post-sunset CTR and solar flux, which
should be caused by the solar-dependant equatorial E×B vertical
drift. |
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