Search for Possible Connections of Sunspot Features and Torsional Waves
  The torsional oscillation is a well established observational fact and there are theoretical attempts for its description but no final solution has yet been accepted. One of the possible candidates for its cause is the presence of sunspots modifying the streaming conditions. The present work focuses on the temporally varying latitudinal distribution of several sunspot features, such as the spot sizes and spot numbers. These features are different faces of the butterfly diagram. In fact some weak spatial correlations can be recognized. 
J. Murak\"ozy, A. Ludm\'any
astro-ph.SR