Reconstruction of a Monthly Homogeneous Sunspot Area Series Since 1832.

In this work, a procedure to elaborate a homogeneous sunspot area series using the Royal Greenwich Observatory/USAFINOAA data (from 1874 to the present) and the De la Rue and co-workers data (from 1832 to 1868) is presented. These two data series correspond to time intervals that do not overlap and a direct comparison between them could not be carried out. We used the International Sunspot Number (Ri) and the Group Sunspot Number (RG) as a link between the two original series. Thus, two homogeneous sunspot area series have been built using a simple mathematic procedure based on linear relations. [ABSTRACT FROM AUTHOR]