多轴差分吸收光谱技术测量对流层SO2垂直廓线及柱浓度

Measuring Vertical Profile and Vertical Column Density of SO2 in Troposphere by Multi-Axis Differential Optical Absorption Spectroscopy

针对被动多轴差分吸收光谱技术(MAX-DOAS)反演痕量气体SO2中吸收强度弱以及易受反演波段和大气气溶胶状态影响的问题,研究了基于地基MAX-DOAS的对流层SO2垂直廓线及垂直柱浓度的反演方法。通过反演误差对比确定了SO2的最佳反演波段(307~330 nm),并精确获取了差分斜柱浓度。鉴于大气中气溶胶状态是影响SO2等痕量气体反演的重要因素,反演中采用两步反演方法:第一步通过测量O4气体的差分斜柱浓度来反演气溶胶廓线;第二步将气溶胶廓线输入到辐射传输模型中,利用痕量气体浓度垂直反演算法获取对流层(0~4 km)中SO2的垂直分布廓线和垂直柱浓度。将SO2廓线在0~100 m的反演结果和地面点式仪器数据进行对比,结果发现两者的一致性较高。研究表明,基于MAX-DOAS反演对流层中SO2的垂直分布及垂直柱浓度是一种有效的手段。

Sulfur dioxide(SO2)retrieval results obtained by the multi-axis differential optical absorption spectroscopy(MAX-DOAS)have weak absorption intensity and are vulnerable to inversion bands and the state of aerosol.An inversion method for the vertical profile and vertical column density of tropospheric SO2 using ground-based MAX-DOAS is investigated.The SO2 optimum inversion band(307-330 nm)is determined by comparing the inversion errors.The differential slant column density is obtained precisely.As the state of aerosols in the atmosphere is an important factor affecting the inversion of trace gases such as SO2,a two-step inversion method is used.The first step is to retrieve the aerosol profile by measuring the differential slant column density of O4 gas.The second step is to input the aerosol profile into the radiation transmission model,and the vertical distribution profile(0-4 km)and vertical column density of the tropospheric SO2 are obtained by the vertical inversion algorithm of trace gas concentration.The 0-100 m inversion results of the SO2 profile are compared to ground point instrument data,and the comparison results demonstrate that the two techniques agree well.The study shows that MAX-DOAS is an effective method for retrieving the vertical distribution and vertical column density of tropospheric SO2.