Author(s): Raj Kumar

Abstract: We present an analysis of various periodicities in sunspot numbers (SSNs) during Solar Cycles 23 and 24. To identify these periodicities, we applied wavelet analysis method using the Morlet wavelet function. Our results reveal short-term periodicities corresponding to solar rotation, primarily in the 25 to 36-day range, with prominent periods of 25, 27, and 28 days. Additionally, Rieger-type periodicities of 112, 129, 131, and 192 days were detected during both cycles. We also identified intermediate-term periodicities of 263, 290, and 313 days; quasi-biennial oscillations of 528 and 798 days; and longer-term periods of 3.15 and 3.4 years. Our findings suggest that most of these periodicities occur either during solar maxima or during periods when the respective solar activity features were at their peak frequency.

DOI: 10.22271/maths.2025.v10.i3b.2048

Pages: 112-117 | Views: 805 | Downloads: 8

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