Aerosol impact on the brightening in Japan
Aerosol impact on the brightening in Japan
复制标题
DOI：
10.1029/2011jd017158
复制
发表时间：
2012-04
影响因子：
--
通讯作者：
R. Kudo;A. Uchiyama;Osamu Ijima;Nozomu Ohkawara;S. Ohta
中科院分区：
文献类型：
--
作者：
R. Kudo;A. Uchiyama;Osamu Ijima;Nozomu Ohkawara;S. Ohta
[1]利用地面宽带辐射计在晴空条件下测量的直接辐射和散射辐射，估算了日本14个观测点从20世纪70年代到21世纪初0.75 μm气溶胶光学厚度（AOD）和单次散射辐射（SSA）的长期变化。AOD和SSA发生了显著变化：AOD下降了0.02，SSA上升了0.21。由估算的气溶胶光学厚度和太阳敏感度计算的晴空条件下地面太阳辐照度与大气顶部太阳辐照度的比值显示出+0.05的明显增亮，其中+0.01是由于气溶胶光学厚度的减小，+0.04是由于太阳敏感度的增大。云强迫的地面太阳辐照度，估计之间的差异，在多云的天空条件下测量的地面太阳辐照度和晴空条件下，没有表现出显着的趋势。这些发现表明，日本的增亮是由气溶胶光学特性的变化，特别是SSA，而不是由云的变化引起的。
[1] The long-term changes in aerosol optical depth (AOD) and single scattering albedo (SSA) at 0.75 μm from the 1970s to the 2000s at 14 sites in Japan were estimated from the direct and diffuse irradiances measured by ground-based broadband radiometers under clear-sky conditions. Noticeable changes in AOD and SSA were seen: AOD decreased by 0.02, and SSA increased by 0.21. The ratio of surface solar irradiance to solar irradiance at the top of the atmosphere under clear-sky conditions, calculated from the estimated AOD and SSA, showed apparent brightening of +0.05, of which +0.01 was attributed to a decrease of AOD and +0.04 to an increase of SSA. The cloud forcing of the surface solar irradiance, estimated as the difference between the surface solar irradiance measured under cloudy-sky conditions and that under clear-sky conditions, showed no significant trend. These findings suggest that the brightening in Japan has been caused by changes in aerosol optical properties, especially SSA, rather than by cloud changes.