Investigating the association between solar flares and the complexity of sunspot groups and their asymmetric behavior

Solar activity exhibits a range of quasi-periodic variations among different indices, reflecting the complex dynamics of the Sun. In this study, we investigate the temporal variation and hemispheric asymmetry of sunspot counts (SSC), sunspot areas (SSA), and x-ray solar flares during Solar Cycles 23 (SC23), SC24, and the ascending and maximum phase of SC 25 (1996–2024). We analyzed the flare production potential (FPP) and flare efficiency ratio (FER) using the third parameter of the modified Zurich/McIntosh classification system in different hemispheres. We performed cross-correlation analysis to investigate the time-lagged correlations between SSC, SSA, and solar flare. Notable periodicities such as 27-day solar rotation, about 150-day Rieger-type periods, and quasi-biennial oscillations (QBOs) are detected through multitaper and wavelet spectral analyses. Our main findings are: i) Our findings show that an increase in the complexity of sunspot groups is associated with an increase in FPP and FER. This relationship is consistently observed across different hemispheres and solar cycles. These findings provide further statistical support for using the complexity of sunspot groups as a pre-cursor parameter in models to predict solar flares. ii) The number of statistically significant mid-term periods in the northern hemisphere appears to be fewer compared to the southern hemisphere. While QBOs are present in both hemispheres, their spatial and temporal variations manifest unevenly, with the southern hemisphere exhibiting more prominent and distinct evolutionary patterns, particularly during the studied cycles. iii) The periodic behaviors of SSC, SSA, and x-ray solar flare numbers exhibit distinct dependencies on the investigated cycle phase and hemispheric asymmetries, with variations in amplitude and timing across different solar cycles.