Phase Relation Between Large and Simple Sunspot Groups in Solar Cycles 22 – 24

Abstract

In order to investigate the phase relation between the temporal variations of sunspot groups of various classes, firstly we use the separation scheme that was introduced by Kilcik et al. (Solar Phys.289, 4365, 2014b) to separate sunspot groups into large sunspot groups (D, E, and F classes in the modified Zurich classification) and simple sunspot groups (A and B classes) in Solar Cycles 22 – 24 collected by the United States Air Force/Mount Wilson Observatory (USAF/MWL). Then, using lagged-cross-correlation analysis and the block-bootstrap method, we calculate the correlation coefficients against time lags and determine the statistical significance of phase relation between large and simple sunspot groups in Solar Cycles 22 – 24, respectively. The main results that we obtained are summarized as follows: i) During Solar Cycles 22 and 24, the results – large sunspot groups lead or lag simple sunspot groups – are statistically insignificant and large sunspot groups should be in phase with simple sunspot groups. ii) During Solar Cycle 23, large sunspot groups statistically significantly lag simple sunspot groups in temporal phase.