The latitudinal distributions of sunspot areas and magnetic fields and their correlation with the background solar magnetic field in the cycle 23

The quasi 3D latitudinal distributions (butterfly diagrams) of sunspot areas and magnetic fields obtained within the whole μ-hemispheres in longitudes from the Solar Feature Catalogues for 9 years (1996–2005) of the cycle 23 are correlated with those of the low-resolution solar magnetic fields (SMF) obtained from Wilcox Solar Observatory. During the whole period of observations the sunspot areas reveal a strong positive correlation with SMF appearing at zero timelag and repeating at the 2–2.5 year time lags after or before the cycle start. The high positive correlation coefficients are also distributed into the four zones reflecting the sunspot migration directions: the two pre-polar zones above ±45° with the positive correlation increasing towards the poles (the sunspot migration towards the poles) and the two pre-equatorial zones from −40° to +40° (the ‘royal zone’) with the positive correlation increasing toward the equator as seen in the butterfly diagrams. This correlation suggests a modulating effect of the symmetric component of SMF on the magnitude of magnetic field in flux tubes emerging as sunspots. The symmetric SMF components have the same signs in each hemisphere and they are changed to opposite over the period 2–2.5 year. Then, if the signs of the symmetric SMF coincides with the leading polarity signs in a one hemisphere and opposite in the other one, the flux tube emergence (and sunspot appearance) is supported by SMF in the first one and suppressed in the other. While in 2.5 years when the SMF sign is changed to the opposite, the flux emergence is supported in the other hemisphere but suppressed in the first one.