利用天顶光光谱和天空光光谱测量大气NO_2含量和角空间分布

研究了一种用地基天顶光-天空光光谱数据反演大气NO2倾斜柱体密度的有效方法。利用该方法计算了同一方位不同倾角（10°～85°）下的倾斜柱体密度（在0.5～11×1016 molecule·cm^-2范围），以及同一倾角不同方位的NO2倾斜柱体密度（1016～1017molecule·cm^-2量级）。结果与实际大气状况有很好的相关性。不同方位及倾角的NO2倾斜柱体密度不同，体现出角空间分布特征。该方法中，由同一仪器同时采集天顶光光谱和其他方向的天空光光谱，提高了测量准确度。该方法有利于实时监测空间任意方向NO2的含量，尤其靠近地面的NO2局部污染，更适合多阴雨地区（在地面上很难采集到良好的直射太阳光谱）的污染监测。

Measurement of Atmosphere NO_2 Amounts and Angle Spacial Distribution Using Zenith-Light Spectra and Sky-Light Spectra

A novel approach to retrieving atmosphere NO2 slant column density is described, in which the sunlight scattered in the zenith direction and the skylight are used as the light sources. The slant column density of the same azimuth but different obliquities， which are between 0.5×1016 and 11×1016 molecule·cm-2， with the angle from 85° to 10°， as well as that of the same obliquity but different azimuths，which are between 1016 and 1017 molecule·cm-2， were calculated. The study indicates that the results have good correlation with real atmosphere status. The angle spatial distribution could be embodied by the difference of NO2 slant column density in different azimuths and obliquities. The reference spectrum and sample spectrum were collected with the same instrument at the same time， so the measurement accuracy has been improved. This method favored not only real-time monitoring NO2 content of space arbitrary direction， especially near the ground NO2 pollution emergencies， but also overcast and rainy areas where it is very difficult to collect good direct solar spectrum.