Analysis of the Solar Radiation Variation of China in Recent 30 Years

The variation trends of global radiation, direct solar radiation and scattering solar radiation data in China from 1960 to 1990 are analyzed. The results show that the global radiation and direct radiation in most part of China had very obvious decreasing trends in recent years. The same conclusion is got after partly removing the effect cloud. The variable patterns of the cloud amount and surface visual range in recent 30 years were calculated, and the results show that the visual ranges in most part of China decreased, but the variations of cloud amount were not obvious. Based on the above analysis, the preliminary conclusion is drawn that the increase of the atmospheric turbidity is one of the possible reasons for the obvious decrease of the surface solar radiation.