UV variability in Moscow according to long-term UV measurements and reconstruction model

Long-term measurements of erythemally weighted UV irradiance (Q(er)) have been analyzed for the 1999-2006 period as well as UV variability according to a reconstruction model since 1968. The estimates of different atmospheric parameters effects, including NO2 content, on Q(er) have been obtained on seasonal and interannual scales. It has been shown that NO2 content in conditions of large megalopolis provides average Q(er) decrease of about 1.5-2%. The seasonal variations of the observed UV indices are discussed from the point of view of the impact on health. Using the reconstruction model we showed a distinct growth in Q(er) since 1980 due to changes in total ozone (+2.5% per decade), effective cloud amount transmission (+2.1% per decade) and aerosol loading (+1.1% per decade). However, there is no change in Q(er) over the longer 1968-2006 period due to significant decrease in effective cloud amount transmission (-11% per decade) in 1968-1980.