Unravelling Rieger and Quasi-Biennial Periodic Trends and Asymmetries in Coronal Mass Ejections Using Wavelet Analysis

In this study, we investigate the periodic behavior of coronal mass ejections (CMEs) using statistical and wavelet analysis on SOHO/LASCO (1996–2024) and SEEDS (1996–2022) catalogs. We classified CMEs into joint angular width–speed (cluster I) and width–acceleration (cluster II), further separated into low- and high-latitude, northern and southern hemisphere subsets, and analyzed their relative occurrence rate, waiting times, and search for Rieger-type and quasi-biennial oscillations (QBOs) across solar cycles (SC) 23–24. We found that narrow CMEs occur during declining and minimum phases, while regular and partial/halo CMEs show consistency with SC activity. SEEDS shows a larger fraction of narrow CMEs (≈ 72%) than LASCO (≈ 45%), indicating catalog-dependent sensitivity to faint and small-scale eruptions. Furthermore, waiting times for narrow and regular CMEs are relatively longer (shorter) during the maximum (minimum) of SC23 (24), due to weaker polar fields and enhanced CME escape in the weaker cycle. Also, low-latitude CMEs dominate over high-latitude CMEs in both hemispheres, but the hemispheric asymmetry reverses between cycles. For instance, LASCO low-latitude CMEs show southern dominance in cycle 23 and northern dominance in cycle 24, whereas SEEDS exhibits opposite low-latitude dominance in cycle 23 but converges to northern dominance in cycle 24. Again, high-latitude CMEs display high northern dominance in SC24 with larger short-term variability and weaker correlation with sunspot number in both catalogs. Moreover, Rieger-type periods (≈ 3.7–6.4 months) and QBO signals at 1.3–2.73 year tend to repeat across specific latitudes and CME clusters showing identical ≈ 2.73 year periods in both catalogs, while Rieger-type periods weaken toward higher latitudes and are generally longer in SEEDS than in LASCO, with an anomalously long high-latitude southern Rieger period in cycle 24. Finally, Rieger-type periodicities decrease with increasing CME size in LASCO-decelerating CMEs, while QBO periodicities increase with CME size.