Effect of anthropogenic activities on the UV variation in China

The research of UV radiation has merited considerable attention over the past 30 years, since UV radiation can cause damage in many biological systems. The amount of O₃ and chemical emissions gases, such as SO₂ and NO₂ have altered over China, as anthropogenic activities intensity increases. The total quantity change of these gases would influence the UV radiation level reaching the earth´s surface due to all scattering and absorption processes throughout the atmosphere. Thus, it is very meaningful for us to study the spatial and temporal characteristics of UV radiation and the relationship between the UV radiation and O₃, NO₂, SO₂ in China based on remote sensing data. In this paper, we divided China into eight natural geographic regions, which were South China region, Southwest region, Central China region, Sichuan Basin region, Tibetan Plateau region, North China region, Inner Mongolia-Northwest region and Northeast region according to China Natural Geographic Regionalization and some previous research work on ozone in China. The calculation results revealed that (1) The spatial characteristics of the annual and seasonal UV radiation in China had obvious differences in latitudinal direction. The summer averaged UV radiation was the biggest among four seasons, followed by spring, autumn, and winter. (2) The annual and seasonal UV radiation of Northeast region was the smallest in eight natural geographic regions. The highest value of the annual, spring and autumn averaged UV radiation was Southwest region. The highest value of the summer averaged UV radiation was Tibetan Plateau region. The highest value of the winter averaged UV radiation was South China region. (3) The seasonal change amplitude of UV radiation was dissimilar in eight natural geographic regions of China, and most of them presented increased, which showed that the UV radiation in China had an increasing tendency. (4) There was signi- - ficantly negative correlation between UV radiation and total ozone. Nevertheless, the correlations between NO₂, SO₂ and UV radiation were poor.