Spatial Statistical Analyses of Global Trends of Ultraviolet B Fluxes in the Continental United States

Abstract

Many environmental factors, such as stratospheric ozone, aerosols, and clouds, may affect ultraviolet (UV) irradiance. The aim of this study is to investigate the possible association between ultraviolet B (UVB) radiation and total cloud amount, ozone, and aerosols simultaneously, leading to the assessment of possible impacts of climate change on UVB flux variations in the continental United States (U.S.). Spatiotemporal correlation analyses were conducted, based on data collected from the Total Ozone Mapping Spectrometer (TOMS) and the International Satellite Cloud Climatology Project (ISCCP), with a geographic information system (GIS). Findings indicate that in the past 22 years, while ozone decreased and aerosols increased across the U.S., the UVB decrease in the northern states was consistent with an increase in aerosols and total cloud amount. Therefore, to some extent, the trend characteristics of UVB over the U.S. between 1980 and 2002 were simultaneously affected by such dominant factors as total ozone and by such auxiliary factors as aerosol and total cloud amount. Climate change impact resulting in higher total cloud amount in the northern states might result in lower UVB in the future.