EGU23-11128
https://doi.org/10.5194/egusphere-egu23-11128
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

McPrA - a new trace gas profile retrieval algorithm for MAX-DOAS

Jiangyi Zheng1,2, Pinhua Xie1,2,3, Xin Tian3, Jin Xu1, Ang Li1, Bo Ren2, Feng Hu1,2, Zhaokun Hu1, Yinsheng Lv1,2, and Zhidong Zhang1,2
Jiangyi Zheng et al.
  • 1Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China.
  • 2University of Science and Technology of China, Hefei, 230026, China.
  • 3Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei, 230601, China.

Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) has been widely used in the three-dimensional monitoring of air pollutants. It is of great significance for MAX-DOAS to reconstruct the state of air pollutants by establishing an accurate vertical profile retrieval algorithm. At present, the profile retrieval algorithm of MAX-DOAS mainly adopts the iterative method based on a priori profile, which leads to strong dependence on priori profiles. We try to reduce the dependence on priori profiles by first calculating the vertical column density and then calculating the vertical distribution from observation. Therefore, we propose a new MAX-DOAS trace gas profile inversion algorithm - McPrA (Monte Carlo profile inversion algorithm by Anhui Institute of Optics and Fine Mechanics (AIOFM)). The algorithm uses Monte Carlo method to solve the optimal estimation problem of the gas profile. Firstly, the gas vertical column density is obtained through the air mass factor calculated by the radiative transfer model SCIATRAN. Secondly, the vertical distribution of trace gas is retrieved by combining the weight function with the a priori profile. Besides, we introduce the normalization process in the vertical distribution solution to make the prior profile better match the weight function. McPrA can set the vertical resolution of profile by modifying the grid, and we increase the vertical resolution of gas profile to 50m. By conducting sensitivity experiments on parameters such as Monte Carlo sampling, covariance matrix and the priori profiles, the optimal configuration of retrieval parameter is obtained. At the same time, the degree of freedom is more than 3.0. Finally, comparative verification experiments were carried out to compare with in situ data from LP-DOAS and National Air Quality Monitoring Station. The correlation coefficient for NO2 VMR at the first layer retrieved by McPrA in 50 m grid reached above 0.89. The comparison of NO2 profiles retrieval by McPrA with that from WRF-Chem and simulation of synthetic data also shows that McPrA algorithm can retrieve trace gas profiles accurately.

How to cite: Zheng, J., Xie, P., Tian, X., Xu, J., Li, A., Ren, B., Hu, F., Hu, Z., Lv, Y., and Zhang, Z.: McPrA - a new trace gas profile retrieval algorithm for MAX-DOAS, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-11128, https://doi.org/10.5194/egusphere-egu23-11128, 2023.