 |
| Titel |
Quasi-biennial and quasi-triennial oscillations in geomagnetic activity indices |
| VerfasserIn |
R. P. Kane |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 15, no. 12 ; Nr. 15, no. 12, S.1581-1594 |
| Datensatznummer |
250013042
|
| Publikation (Nr.) |
 copernicus.org/angeo-15-1581-1997.pdf |
|
|
|
|
|
| Zusammenfassung |
| Data for geomagnetic activity index aa for
1868–1994 were subjected to spectral analysis for 12 intervals each of 11
consecutive years. In each interval, QBO and QTO (quasi-biennial and
quasi-triennial oscillations) were observed at ~2.00, 2.15, 2.40, 2.70 y and ~3.20,
3.40 y, but not all in all intervals. These fluctuations are absent near (2–3 y
before and after) the sunspot minima and are present only as 2 or 3 peaks in aa
indices, one near or before the sunspot maximum and the other (one or two,
generally the larger ones) in the declining phase of the sunspot cycle.
Comparison with the solar wind (1965 onwards) showed a fairly good match,
indicating that the aa variations were mostly due to similar variations
in the solar wind, which must have their origin in solar physical processes. A
few aa variations did not match with solar wind. When compared with
terrestrial phenomena, no match was found with stratospheric low-latitude zonal
wind QBO; but some QTO in aa matched QTO in ENSO (El Nino/Southern
Oscillation). This may or may not be a chance coincidence and needs further
exploration. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|