Asymmetry of sunspot area and their periodicity during solar cycles 22-24

In this paper, we have analyzed the north-south asymmetry of sunspot area on the monthly basis during solar cycles 22, 23 and 24. Asymmetry of sunspot area is dominant in the southern hemisphere over northern hemisphere for the period 2006 (A = -0.85), as well as northern hemisphere over southern hemisphere for the period 2011 (A=0.50). Asymmetry of sunspot area for ~06 months running smoothed has minimum over the period 2006 and oscillatory motion have been found over the interval 1994 to 1998. The ~6 months smoothed (running) variation of the southern hemisphere of sunspot area show, the spline curve for the period 1993 to 1998 and 2003 to 2008. The northern hemisphere is dominated at the very beginning of the solar cycle while the southern hemisphere dominates in the decline phase of the solar cycle 22 to 24. The statistically significant mid-term periodicity between 5.5 years to 120 days of the north-south asymmetry of sunspot area has been investigated using Fast Fourier Transform (FFT) and Morlet Wavelet Transformation (WT). Quasi-biennial oscillation for asymmetry of sunspot area has been seen plateau type for the period 1990 to 1994 and 2014 to 2016. (author)