基于散射光、利用痕量气体指纹吸收特性反演气体浓度的方法称为被动差分吸收光谱法(passive DOAS)。因其具体结构简单,易于平台搭载等优点近年来获得了长足发展。被动DOAS中利用太阳散射光作为光源解析大气污染气体柱浓度时,会受到太阳弗朗和费光谱的“填充线”即Ring效应的强烈影响,尤其是对浓度很低的痕量气体,致使不易获取其浓度、影响其测量精度。文章以反演大气中NO2气体为例,介绍了稳定天气条件下Ring效应造成的影响、分析了Ring效应影响与太阳天顶角的关系,提出了根据不同太阳天顶角选取不同Ring光谱参与拟合的修正方法,并且利用该处理方法反演了在３天稳定天气条件下不同仰角下的斜柱浓度。实验证明该修正方法的可行性。

The method of retrieving the concentration of trace gases using of the diagnostic absorption of trace gases based on the scattered sunlight is called passive DOAS.It has been developed so fast in recent years because it remains simple and is prone to being combined with different platform.While retrieving the column density of trace gases with the scattered sunlight as light source,it will be affected strongly by solar Fraunhofer lines,which is also called Ring effect.It makes it hard to retrieve trace gases concentration and affects measurement precision,especially for lower concentration.The influence of Ring effect and its relation with solar zenith angle in stable day will be introduced in the present paper,and the modification will be provided so that different Ring spectrum is selected according to different solar zenith angle.The slant column density (SCD) of NO2 for 3 stable days was retrieved with this modification.It was proved that the modification is possible.