PNNL

Abstract

This study investigates the recent variations in surface solar radiation inferred from a comprehensive set of ground-based observational records updated to 2005. Surface radiation data beyond 2000 are thereby particularly interesting, as they can provide independent and complementary information to the ambitious satellite programs which became operational after 2000. The surface records suggest a continuation of the upward tendency in surface solar radiation (“brightening”) beyond 2000 at numerous stations in Europe and in the US as well as parts of East Asia (Korea). The upward tendency in Antarctica over the 1990s, largely caused by a recovery from the high turbitity induced by the mount Pinatubo volcanic eruption, seem to fade after 2000. The brightening tendency also seems to level off in Japan. In China there is some indication for a renewed decline in dimming, after the stabilization in the 1990s. A continuation of the long lasting dimming is also noted at the sites in India. Overall, the available data suggest also beyond 2000 a widespread continuation of the brightening at many location, which is, however, less pronounced and homogeneous than during the 1990s.