Research of NO₂ vertical profiles with look-up table method based on MAX-DOAS

Abstract

Obtaining the vertical distribution profile of trace gas is of great significance for studying the diffusion procedure of air pollution. In this article, a look-up table method based on multi-axis differential optical absorption spectroscopy (MAXDOAS) technology is established for retrieving the tropospheric NO2 vertical distribution profiles. This method retrieves the aerosol extinction profiles with minimum cost function. Then, the aerosol extinction profiles and the atmospheric radiation transfer model (RTM) are employed to establish the look-up table for retrieving the NO2 vertical column densities (VCDs) and profiles. The measured NO2 differential slant column densities (DSCDs) are compared with the NO2 DSCDs simulated by the atmospheric RTM, and the NO2 VCDs, the weight factor of NO2 in the boundary layer, and the boundary layer height are obtained by the minimization process. The look-up table is established to retrieve NO2 VCDs based on MAX-DOAS measurements in Huaibei area, and the results are compared with the data from Copernicus Atmospheric Monitoring Service(CAMS) model. It isfound that there are nearly consistent and the correlation coefficient R2 is morethan 0.86. The results show that this technology provides a more convenient and accurate retrieval method for the stereoscopic monitoring of atmospheric environment.

Method of measuring atmospheric CO₂ based on Fabry-Perot interferometer

“…香港城 市大学Chan等 [14] 使用法布里-珀罗干涉仪在中红 外波长范围3900 -5220 nm内对大气CO 2 进行色 散红外光谱测量. 本文利用自主设计的基于法布 里-珀罗干涉仪的CO 2 的测量系统, 通过控制驱动 电压调节法布里-珀罗干涉仪的两镜片间距, 改变 干涉谱, 实现10 nm步长的中心波长的干涉峰调 节, 通过一次扫描记录整个吸收光谱, 基于差分吸 收光谱原理对测量光谱进行最小二乘法拟合 [15][16][17] , 得到测量气体的浓度信息. 法布里-珀罗干涉仪的自由光谱范围(FSR)为 两个相邻干涉峰的距离, 其表达式如下 [18] :…”