Issue |
A&A
Volume 424, Number 1, September II 2004
|
|
---|---|---|
Page(s) | 311 - 315 | |
Section | The Sun | |
DOI | https://doi.org/10.1051/0004-6361:20040550 | |
Published online | 17 August 2004 |
Long-term variation in distribution of sunspot groups
1
Eötvös University, Department of Astronomy, 1518 Budapest, Pf. 32., Hungary e-mail: [E.Forgacs-Dajka;B.Major]@astro.elte.hu
2
Konkoly Observatory of HAS, 1525 Budapest, Pf. 67, Hungary
3
Baja Astronomical Observatory of Bács-Kiskun County, 6500 Baja, Szegedi út, Kt. 766, Hungary e-mail: borko@alcyone.bajaobs.hu
Received:
29
March
2004
Accepted:
21
May
2004
We studied the relation between the distribution of sunspot groups and the
Gleissberg cycle. As the magnetic field is related to the area of the sunspot groups, we used
area-weighted sunspot group data. On the one hand, we confirm the previously reported long-term cyclic
behaviour of the sum of the northern and southern sunspot group mean latitudes, although we
found a somewhat longer period
( years). We introduced the difference between the ensemble average area of sunspot groups
for the two hemispheres,
which turns out to show similar behaviour. We also investigated a further aspect of the Gleissberg cycle where while in the 19th
century the consecutive Schwabe cycles are sharply separated from each other, one century later
the cycles overlap each
other more and more.
Key words: methods: data analysis / Sun: activity / Sun: magnetic fields / sunspots
© ESO, 2004
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