IJSRP, Volume 3, Issue 2, February 2013 Edition [ISSN 2250-3153]
Aswathy Mary Prince , Dr. Sanish Thomas , Er. Ravi Jon , Dr. D.P Jayapandian
In this paper, we are going to explore the feasibility of periodicity of sunspot number activity during the solar cycles 21, 22, 23 & 24. The Sunspots are cooler and darker regions on the Sun photosphere comparing to the surrounding regions. Sunspots usually appear in pairs. The two sunspots of a pair have different polarities, one would be a magnetic north and the other is a magnetic south, and can be joined by magnetic field lines. The number of sunspots that can be seen on the surface of sun increases and decreases in a regular pattern known as a solar cycle with a maximum number of sunspots occurring every 11.5 years. This paper shows the comparison between the midrange periodicity in sunspot number for four different cycles.