Resum
It is found that quasi-2-day oscillations persist in the geomagnetic activity indices a, as and am and time variations of the oscillation characteristics are examined. The 3-hourly indices for 1964-1986 are used for analysis. The main results are: 1) the oscillation persists almost continuously, 2) there are not significant hemispheric differences of the oscillation period and amplitude, 3) the dominant period is 48 hours, 4) there is expressed a semi-annual variation of the oscillation period with minimum in solstices and maximum in equinoxes, 5) the oscillation amplitude is modulated by semi-annual and long-term geomagnetic variations. A possible way for inducing such oscillations in the time variations of geomagnetic activity indices is proposed.
Idioma original | Anglès |
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Pàgines (de-a) | 1233-1239 |
Nombre de pàgines | 7 |
Revista | Journal of Geomagnetism and Geoelectricity |
Volum | 48 |
Número | 10 |
DOIs | |
Estat de la publicació | Publicada - 1996 |
Publicat externament | Sí |