| Autor: |
Attolini, M., Galli, M., Cini Castagnoli, G. |
| Zdroj: |
Solar Physics; Feb1985, Vol. 95 Issue 2, p391-395, 5p |
| Abstrakt: |
The Zürich sunspot relative number Rseries has been analysed by the cyclogram method. The amplitude and the frequency variations of the Fourier 11 yr component between 1700-1983 A.D., were determined in a continuous way. Four distinct time intervals with significantly different characteristics of the periodicities are observed and discussed. Their second harmonics are also considered. The periodicity changes are contemporary to those of the 11 yr cycles. Around the year 1903 it seems that an important event has happened in the Sun. In fact the 11.4 yr cycle periodicity, that was very stable since at least 1825 started to change gradually to smaller values and similarly it happened to the second harmonic which also stopped and abruptly changed of phase of 90°. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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