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The decay of sunspot groups is a relatively unknown field since most studieshave focused mainly on the decay of sunspots or sunspot groups, but only onsmall samples. As an extension of the recent work of\citet{2020ApJ...892..107M} which is based on a large verified sample, thisstudy investigates not only the long-term behavior of the decay of sunspotgroups but also the dynamics of their parts. The aim of the present work is tosearch for dependencies of the decay process in order to find physicalconditions that modify or contribute to the decay. The investigations are basedon the catalog of SoHO Debrecen Sunspot Database (SDD ) and the GreenwichPhotoheliographic Results (GPR) as well as the Debrecen Photoheliographic Data(DPD). Altogether more than 750 sunspot groups were considered. The decay rateshave been calculated for the total, umbral and penumbral area of the groups andin the case of the SDD's groups they have been calculated for both the leadingand the following parts. The decay rates depend linearly on the maximum areasand ranged from 30-50 MSH/day for the sunspot groups and penumbrae and 5-10MSH/day for the umbrae throughout the cycle. The decay rates fall significantlyduring the Gnevyshev gap and show 4+4 Schwabe cyclical variations in theascending/descending phases, but it is always higher in the northernhemisphere. There is a slight decrease of the decay rates in the activity rangetoward higher latitudes.

On the Decay of Sunspot Groups and Their Internal Parts in Detail