Study of periodicity in sunspot numbers during solar cycle 23-24 using fast Fourier transform technique
Author(s): Raj Kumar
Abstract: We present here a study of long term periodicities
and hemispheric periodicities in sunspot numbers (SSNs) during solar cycle 23
and 24. We have utilized Fast Fourier Transform (FFT) technique for the
determination of periodicities. We found a long term periodicities of 3, 4, 6
and 12 years for SSNs when examined for cycle 23 and 24 combindly. We found
short term periodicities corresponding to the solar rotational periods in the
range of 25 to 36 days. We found mainly 26, 27, 28 and 36 days periodicities in
this category. Other short term periods of 45 and 83 days were exhibited by
SSNs. Rieger type periodicities of 112, 131, 133 and 182 days were observed for
SSNs when studied for long term periodicities by taking the monthly time
series. Annual period of 1 year and quasi Biennial periods of 1.5, 2 and 2.4
years were observed in this study of SSNs.
Raj Kumar. Study of periodicity in sunspot numbers during solar cycle 23-24 using fast Fourier transform technique. Int J Stat Appl Math 2025;10(1):208-213. DOI: 10.22271/maths.2025.v10.i1b.2040
