Global and diffuse solar radiation in Spain: Building a homogeneous dataset and assessing their trends

► We develop a new dataset of surface solar radiation records in Spain. ► The global and diffuse solar radiation series have been homogenized. ► The global solar radiation shows a significant increase over the 1985-2010 period. ► The diffuse component shows a significant decrease during the same period. ► These results point towards a recent decrease of clouds and/or aerosols.