Time-dependent properties of sunspot groups

Aims. In this paper, we aim to study the time dependence of sunspot group areas in a large sample composed various databases spanning over 130 years, used state-of-the-art statistical methods. Methods. For carefully selected but unbiased sample, use Bayesian modelling fit temporal evolution combined umbral and penumbral area spot groups with skew-normal function determine existence any asymmetry growth or decay. Our primary selection criteria guaranteed that only well-defined maximum were taken into account. We also analysed covariance resulting model parameters their correlations physical sunspots ongoing solar cycle. Results. results show well-observed reach at least 50 millionths hemisphere can be fitted surprisingly well our model. Furthermore, significant – described by skew parameter curves between growing decaying phases groups. addition, found weak correlation values hemispherical latitude.