研究了一种基于被动差分吸收光谱技术(differential optical absorption spectroscopy,DOAS)测量区域(如工业区,城市)内SO₂等大气污染气体排放通量的光学遥测方法。采用安装在汽车上的被动DOAS系统围绕区域进行扫描测量,通过被动DOAS光谱处理方法对系统采集的天顶太阳散射光谱进行处理获取污染气体柱密度,再结合测量时段的气象(风场)信息获得该区域内污染气体对外的净排放通量。文章着重描述了获得污染气体柱密度的差分吸收光谱方法以及区域内污染气体净排放通量的计算方法,并构建了车载被动DOAS系统对北京市五环路以内区域的SO₂和NO₂排放进行外场测量,测得了该区域内SO₂和NO₂净排放通量分别为1.13×10⁴和9.3×10³ kg·h^-1。实验结果表明这种基于被动DOAS的光学遥测方法能够用于区域内污染气体排放通量的快速测量。

An optical remote sensing method based on passive differential optical absorption spectroscopy (DOAS) for the determination of the flux of SO₂ or other gaseous pollutants from an area (such as industrial area,city) which includes many different atmospheric pollution sources was studied in the present paper.Passive DOAS using the zenith scattered sunlight as the light source provides the column density (the integrated concentration of atmospheric absorbers along the light path) and has been successfully applied to the determination of the flux of gaseous pollutants emitted from the volcano or point source.Passive DOAS instrument installed in a car scanned the plume emitted from an area by circling around the area in this paper.Column density of each selected gaseous pollutant was retrieved from zenith scattered sunlight spectra collected by the instrument by spectral analysis method of passive DOAS in their particular absorption spectral range respectively.Combined with the meteorological (wind field) information during the period of measurement,the net flux value of gaseous pollutant from this area during the measurement could be estimated.DOAS method used to obtain the column density of gaseous pollutant in the section plane of the plume emitted from source and the method of net flux calculation of gaseous pollutant from a certain area are described.Also a passive DOAS instrument was developed and installed in a car to scan the gaseous pollutants from the area surrounded by the 5th Ring Road in Beijing city during a field campaign in the summer of 2005.The SO₂ net flux 1.13×10⁴ kg·h^-1 and NO2 net flux 9.3×10³ kg·h^-1 from this area were derived separately after the passive DOAS measured the entire ring road and the wind data were roughly estimated from wind profile radar.The results indicate that this optical remote sensing method based on passive DOAS can be used to rapidly determine the flux of gaseous pollutant (such as SO₂,NO₂) emitted from an area,especially from a city or an industrial area.