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| Titel |
Long term ionospheric electron content variations over Delhi |
| VerfasserIn |
J. K. Gupta, L. Singh |
| 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. 12 ; Nr. 18, no. 12, S.1635-1644 |
| Datensatznummer |
250014108
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| Publikation (Nr.) |
 copernicus.org/angeo-18-1635-2000.pdf |
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| Zusammenfassung |
Ionospheric electron content (IEC) observed
at Delhi (geographic co-ordinates: 28.63°N, 77.22°E; geomagnetic co-ordinates:
19.08°N, 148.91°E; dip Latitude 24.8°N), India, for the period 1975–80 and
1986–89 belonging to an ascending phase of solar activity during first halves of
solar cycles 21 and 22 respectively have been used to study the diurnal,
seasonal, solar and magnetic activity variations. The diurnal variation of
seasonal mean of IEC on quiet days shows a secondary peak comparable to the
daytime peak in equinox and winter in high solar activity. IECmax
(daytime maximum value of IEC, one per day) shows winter anomaly only during
high solar activity at Delhi. Further, IECmax shows positive
correlation with F10.7 up to about 200 flux units at equinox and 240
units both in winter and summer; for greater F10.7 values, IECmax
is substantially constant in all the seasons. IECmax and magnetic
activity (Ap) are found to be positively correlated in summer
in high solar activity. Winter IECmax shows positive correlation with
Ap in low solar activity and negative correlation in high
solar activity in both the solar cycles. In equinox IECmax is
independent of Ap in both solar cycles in low solar activity.
A study of day-to-day variations in IECmax shows single day and
alternate day abnormalities, semi-annual and annual variations controlled by the
equatorial electrojet strength, and 27-day periodicity attributable to the solar
rotation.
Key words: Ionosphere (equatorial ionosphere) ·
Magnetospheric physics (magnetosphere · ionosphere interactions) · Radio
science (ionospheric physics) |
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