The controversial early brightening in the first half of 20th century: a contribution from pyrheliometer measurements in Madrid (Spain)

M. Antón, J. M. Vaquero, A. J. P. Aparicio

A long-term decrease in downward surface solar radiation from the 1950s to the 1980s ("global dimming") followed by a multi-decadal increase up to the present ("brightening") have…