Impact of aerosols on the global dimming and brightening

世界表面太阳辐射在20世纪80年代以前呈下降趋势（全球变暗），到现在呈上升趋势（全球变亮）。为了评估气溶胶对增光增光的影响，我们从世界各国表面宽带太阳辐射的长期测量中估计了气溶胶的两种光学性质，即气溶胶量和光吸收。利用1976年至2008年在日本14个地点的测量数据，我们发现在20世纪80年代，光吸收气溶胶的数量有所增加。气溶胶量的增加和光吸收的增加都意味着地表太阳辐射的减少。日本的变暗和变亮归因于气溶胶的这些变化。1995 - 2010年，全球28个站点气溶胶量增加，但光吸收减弱。因此，气溶胶对所分析的28个站点的增白影响较小。

Surface solar radiation in the world has a decreasing trend until the 1980s(global dimming) and an increasing trend up to now(global brightening). In order to evaluate the impact of aerosols on the dimming and brightening, we estimated two aerosol optical properties, which represent the aerosol amount and light absorption, from the long-term measurements of the surface broadband solar radiation in the world. Using the measurements from 1976 to 2008 at 14 sites in Japan, we found the increase of the amount of light absorptive aerosols in the 1980s. Both an increase of aerosol amount and an increase of light absorption mean a decrease of surface solar radiation. The dimming and brightening in Japan was attributed to these changes in aerosols. At 28 sites in the world, the aerosol amount increased from 1995 to 2010, but the light absorption weakened. Therefore, the impact of aerosols on the brightening at the analyzed 28 sites was small.