Past and future sunspot indices: New goals for SoTerIA

Sunspot drawings and images are the base material at our disposal to derive more detailed information about the long-term evolution of the solar cycle, beyond the classical total sunspot index R. In the context of the new SoTerIA project, the SIDC World Data Center "Sunspot" will pursue two complementary goals. We will develop tools to digitize and encode the largely unexploited information recorded in sunspot drawing collections, starting with the Uccle station. Turning towards the future, we will define and evaluate possible global activity indices based on full-disk sunspot CCD imagery. As a support, we will also provide such CCD images from the Uccle solar telescopes. Here, we describe the main steps of this work and the available data sets. We also outline the prospects and resulting products in the 3-year framework of the SoTerIA project. (C) 2010 Published by Elsevier Ltd.