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| Titel |
Relationships between the AE, ap and Dst indices near solar minimum (1974) and at solar maximum (1979) |
| VerfasserIn |
M. M. Fares Saba, W. D. Gonzalez, A. L. Clúa de Gonzalez |
| 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 ; 15, no. 10 ; Nr. 15, no. 10, S.1265-1270 |
| Datensatznummer |
250012973
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| Publikation (Nr.) |
 copernicus.org/angeo-15-1265-1997.pdf |
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| Zusammenfassung |
| Three-hourly average values of the Dst, AE
and ap geomagnetic activity indices have been studied for 1 year's duration near
the solar minimum (1974) and also at the solar maximum (1979). In 1979 seven
intense geomagnetic storms (Dst <–100 nT) occurred, whereas in 1974 only
three were reported. This study reveals: (1) the yearly average of AE is greater
in 1974 than in 1979, whereas the inverse seems to be true for the yearly
average of Dst, when a higher number of intense storms is present. These
averages indicate the kind of activity occurring on the sun as shown in earlier
work. (2) The seasonal variation of Dst is higher than that of ap and is almost
negligible in AE. (3) The correlation coefficient of ap × AE is in general the
highest, as the magnetometers that monitor both indices are close, and is
surpassed only by the ap × Dst correlation during geomagnetic storms, when the
influence of the ring current is dominant. The correlation of ap × Dst also
shows a seasonal variability. (4) For the first time a study of correlation
between ap and a linear combination of AE and Dst has also been made. We found
higher correlation coefficients in this case as compared to those between ap ×
Dst and ap × AE. |
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