• Open Access

Recent regional surface solar radiation dimming and brightening patterns: inter-hemispherical asymmetry and a dimming in the Southern Hemisphere



Recent variations in surface solar radiation (SSR) at the beginning of the 21st century (2000–2007) were determined at scales ranging from local/regional to hemispherical/global, on the basis of radiative transfer computations and information from satellites, reanalyses and surface measurements. Under all-sky conditions, in the Northern Hemisphere (NH) there is no clear dimming/brightening signal after 2000, whereas in the SH there is a more clear dimming arising from both increasing clouds and aerosols. Dimming is observed over land and ocean in the Southern Hemisphere (SH), and over oceans in the NH, whereas a slight brightening occurred over NH land. However, opposite tendencies are found even within the same continent, indicating the need to assess SSR changes at regional/local scales apart from hemispherical/global ones. Copyright © 2011 Royal Meteorological Society