适于反演陆面大气气溶胶光学厚度的物理量

A New Dimensionless Parameter Suitable for Retrieving Atmospheric Aerosol Optic Depth on Land

针对水平均一的晴天大气、朗伯下垫面的特殊条件，在一定理论分析的基础上，利用具有“频率相近、但气体吸收系数相差很大”特征的一对观测频率，构造了一个对地面反照率不敏感，但对气溶胶光学厚度敏感的无量纲物理量．进而借助ＬｏｗｔｒａｎＤｉｓｏｒｔ 耦合模式的数值实验，确定了观测的最佳方位，并比较了最佳观测方位下对地面反照率和气溶胶光学厚度的不同敏感性．

On the condition that the surface is Lanbertain and the sky is cloudless, a new dimensionless parameter is defined with the flux and intensity received on the ground at two different frequencies nearly equal to each other but with large differential gas absorption. The stimulated data obtained by the Lowtran Disort coupled model show that the parameter is not quite sensitive to surface albedo but highly sensitive to the whole atmospheric aerosol optic depth at the best observing direction.