中文摘要：

气溶胶可以吸收和散射太阳辐射，影响地表辐射收支平衡，使到达地表的太阳总辐射减少，同时散射辐射在总辐射中所占的比例增加。本文基于MODIS气溶胶产品和CERES云产品等大气遥感资料，利用Fu-Liou辐射传输模式对全球地表辐射进行了有无气溶胶的两组模拟试验。将考虑气溶胶的试验模拟值与BSRN站点观测值进行对比，结果显示地表总辐射模拟的R值达到0．92，地表散射辐射模拟的R值达到0．84，模拟值与观测值有着比较好的一致性。比较两组模拟结果显示，2007年气溶胶导致全球地表总辐射平均减少了9．16W／m^2，降低幅度较大的地区往往气溶胶光学厚度（AOD）也较高。对于散射辐射来说，气溶胶在全球不同地区却有着不同的正负效应：地表反照率高的地区，气溶胶往往使得散射辐射大幅增加；而云分数较高的地区，气溶胶往往导致散射辐射大幅度下降。2007年气溶胶导致全球地表散射辐射平均增加了8．17W／m^2。

英文摘要：

Aerosols can absorb and scatter solar radiation and cause the total solar radiation reaching the surface to drop and the fraction of diffuse radiation to increase, influencing the surface radiation budget. Here, MODIS Aerosol Optical Depth （AOD） was compared with AERONET AOD observations for 2007 and good agreement was found, except when AOD is larger than 0.7 the uncertainty of MODIS AOD increases. Then global surface radiation with and without consideration of aerosols was calculated by the Fu-Liou atmospheric radiative transfer model based on MODIS aerosol products, CERES cloud products and other remote sensing data. The model calculated surface solar radiation with consideration of aerosols was compared to observations made at Baseline Surface Radiation Network （BSRN） sites. Good correlations exist between the calculated and measured total radiation with an R of 0.92, and between the calculated and measured diffuse radiation with an R of 0.84. The aerosol direct radiative effect was calculated based on the two scenarios of aerosols. Our calculations showed that in 2007, aerosols decreased global total radiation by 9.16 W/m2 on average. Large decreases generally occurred in places with high AOD. For diffuse radiation, aerosol-induced changes were either positive or negative. Large increases generally occurred in places with high surface albedo, while large decreases generally occurred in places with high cloud fraction. The global aerosol-induced diffuse radiation change averaged 8.17 W/m^2 in 2007. Aerosol direct radiative effects cause photosynthetic active radiation to increase, which may influence the global carbon cycle of terrestrial ecosystems and result in an increase in the carbon sink function of terrestrial ecosystems.