HEMISPHERIC ASYMMETRY OF SOLAR ACTIVITY PHENOMENA: NORTH-SOUTH EXCESSES, ROTATIONAL PERIODS AND THEIR LINKS TO THE MAGNETIC FIELD

摘要

We present a cycle dependent analysis of various solar activity phenomena, namely Sunspot Numbers and Ha flares, including the time range 1975-2000. The data are studied on a statistical basis with relation to their spatial distribution, significance of the north-south asymmetry and rotational periods. For the considered time span we obtain significant values of north-south asymmetries. For the northern hemisphere the significant excesses are revealed during the increasing and maximum phase of a solar cycle whereas a southern excess dominates near the end of a cycle. Furthermore, we obtain differences in rotational periods and activity gaps between both hemispheres that suggest an independent evolution in hemispheric activity for these indices. Hence, a weak interdependence of the magnetic field system originating in the two hemispheres is suggested. Additionally we find differences in the dominant rotational periods of photospheric and chromospheric tracers.