Vertical Profile of Aerosol in Spring in Beijing Based on Multi-Axis Differential Optical Absorption Spectroscopy Detection
JIANG Cheng1, TANG Gui-qian2*, LI Qi-hua1*, LIU Bao-xian3, WANG Meng2, WANG Yue-si2
1. Institute of Physical Science and Information Technology, Anhui University, Hefei 230601, China
2. State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
3. School of Environment, Tsinghua University, Beijing 100084, China
Abstract：Aerosol vertical profile is a necessary means to evaluate the source and transport of pollutants. Aerosol pollution has a direct impact on the environment and human health. In April—May 2019, we observed the vertical profile of atmospheric spectra in the Beijing area in spring using the ground-based Multi-axis differential optical absorption spectroscopy (MAX-DOAS) of the Institute of Atmospheric Physics, Chinese Academy of Sciences (39.98°N, 116.39°E). MAX-DOAS can effectively monitor aerosols by virtue of its real-time, online and continuous advantages. MAX-DOAS is based on the optical estimation method (OEM), and the least square spectral fitting method, the radiation transmission model SCIATRAN is used as the forward model, and the HEIPRO algorithm is used to invert the vertical profile of the aerosol extinction coefficient. The aerosol optical depth (AOD) was obtained by integrating the aerosol extinction coefficient in its path. The AOD observed by ground-based solar photometer and particle mass concentration observed by high tower was compared with the AOD and aerosol extinction coefficient observed by MAX-DOAS respectively, to verify the applicability of the MAX-DOAS algorithm. The results show that the correlation coefficient of AOD measured by MAX-DOAS and solar photometer is 0.92 with a slope of 0.89. The Pearson correlation coefficient between the extinction coefficient of three-layer aerosol and the mass concentration of PM2.5 reaches 0.69 (60 m), 0.77 (160 m) and 0.75 (280 m) respectively from low to high. In addition, the average aerosol extinction coefficient was compared with the average PM2.5 mass concentration of the corresponding three layers (60, 160 and 280 m), and the trend was consistent. Similarly, to verify whether MAX-DOAS can accurately identify the long-distance transport of pollutants, we determine the sand and dust weather through Angstrom exponent and determine the static and stable weather by calculating the gradient Richardson number and boundary layer height. It is analyzed that MAX-DOAS can respond quickly to sand and static and stable weather under special weather conditions. The average extinction coefficient of aerosols was used to explore, and it was found that the vertical profile of aerosols showed an exponential decay trend with height increasing. The average extinction coefficient of aerosols at the height of 1.5 km was about 50% of that near the ground, while the extinction coefficient above 1.5 km decreased rapidly with height increasing. When the height reached about 2 km, the average extinction coefficient of the aerosol decreased to 0.1 km-1. The above results show that MAX-DOAS has high applicability in detecting atmospheric aerosol vertical profiles.
蒋 诚，唐贵谦，李启华，刘保献，王 蒙，王跃思. 基于多轴差分光学吸收光谱探测的北京春季气溶胶垂直廓线[J]. 光谱学与光谱分析, 2022, 42(01): 265-271.
JIANG Cheng, TANG Gui-qian, LI Qi-hua, LIU Bao-xian, WANG Meng, WANG Yue-si. Vertical Profile of Aerosol in Spring in Beijing Based on Multi-Axis Differential Optical Absorption Spectroscopy Detection. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2022, 42(01): 265-271.
