Where Do Solar Storms Prefer to Originate From: Hemispheric and Longitudinal Patterns in Solar Cycles 23 and 24

Abstract Using synoptic maps, we analyzed the relationship between active longitudes, the most populated longitudes of energetic flares, the distribution of magnetically complex active regions, and the preferred locations of those that produced the largest flares. We found that solar activity was stronger in the northern hemisphere during the rising phases of both cycles, shifting to the southern hemisphere around solar maximum. In solar cycle 24, stronger activity returned to the northern hemisphere during the declining phase—a pattern not seen in cycle 23. Strong magnetic elements and large flares showed significant clustering along persistent active longitudes, particularly from the solar maximum through the declining phase. These active longitudes remained stable for four to nine Carrington rotations before shifting by approximately 160°–180°, and their evolution displayed clear periodic behavior with cycles ranging from 0.6 to 2.02 yr, consistently seen both in the magnetic and flare data. During the solar minimum between cycles 23 and 24, active longitudes clustered near 200° longitude for about 3 yr, with cycle 24 beginning with a dominant activity at this location. Furthermore, 71% of β – γ – δ -type active regions that produced X-class flares emerged along these active longitudes. This highlights their significance for the strongest solar eruptions and offers valuable potential information for midterm flare prediction in both hemispheric and longitudinal domains, even at the onset of new cycles.