Comparison Between Spatial Profiles of Tropospheric NO₂ Column with Remote Sensing Techniques and WRF-CMAQ Derivation

Obtaining instantaneous and accurate pollutant profiles and distributions are vital to combat environmental problems, however due to the lack of complete ground monitoring network within China, there is no way to obtain complete spatial profiles solely based on in-situ measurements. In this paper, we make use of applying remote sensing techniques into available satellite datasets, and adopt reformulation methodology of Air Mass Factor (AMF) in Berkeley High Resolution Product (BEHR), which accounts for difference in sensitivity of satellite to NO₂ near surface and within upper troposphere, to retrieve tropospheric NO₂ vertical column density (VCD) distribution within Southern China, in a higher spatial resolution comparing with existing satellite retrieval techniques. Then, we compare the numerical figures with tropospheric NO₂ column density obtained based on WRF-CMAQ simulation and traditional OMI NASA standard product, and found that BEHR retrieval results are well-agreed with CMAQ column sum when comparing with NASA retrieval, with R² value ranging from 0.7198 in April to 0.8714 in July between BEHR and CMAQ comparison. This is the first attempt in combining high-resolution retrieval products to reformulate spatial distribution of tropospheric VCD in areas with huge spatial variabilities like China.