Evidence of a possible turning point in solar UV-B over Canada, Europe and Japan Atmospheric Chemistry and Physics DOI 10.5194/acp-12-2469-2012 5 March 2012 This study examines the long-term variability of UV solar irradiances at 305 nm and 325 nm over selected sites in Canada, Europe and Japan. Site selection was restricted to the availability of the most complete UV spectroradiometric datasets during the period 1990–2011. The analysis includes the long-term variability of total ozone, aerosol optical depth and cloud fraction at the sites studied. Read more