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Evaluation of TROPOMI and OMI Tropospheric NO<sub>2</sub> Products Using Measurements from MAX-DOAS and State-Controlled Stations in the Jiangsu Province of China
oleh: Kun Cai, Shenshen Li, Jibao Lai, Yu Xia, Yapeng Wang, Xuefei Hu, Ang Li
Format: | Article |
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Diterbitkan: | MDPI AG 2022-05-01 |
Deskripsi
The tropospheric vertical column density of NO<sub>2</sub> (Trop NO<sub>2</sub> VCD) can be obtained using satellite remote sensing, but it has been discovered that the Trop NO<sub>2</sub> VCD is affected by uncertainties such as the cloud fraction, terrain reflectivity, and aerosol optical depth. A certain error occurs in terms of data inversion accuracy, necessitating additional ground observation verification. This study uses surface NO<sub>2</sub> mass concentrations from the China National Environmental Monitoring Center (CNEMC) sites in Jiangsu Province, China in 2019 and the Trop NO<sub>2</sub> VCD measured by MAX-DOAS, respectively, to verify the Trop NO<sub>2</sub> VCD product (daily and monthly average data), that comes from the TROPOspheric Monitoring Instrument (TROPOMI) and Ozone Monitoring Instrument (OMI). The results show that the spatial distributions of NO<sub>2</sub> in TROPOMI and OMI exhibit a similar tendency and seasonality, showing the characteristics of being high in spring and winter and low in summer and autumn. On the whole, the concentration of NO<sub>2</sub> in the south of Jiangsu Province is higher than that in the north. The Pearson correlation coefficient (r) between the monthly average TROPOMI VCD NO<sub>2</sub> and the CNEMC NO<sub>2</sub> mass concentration is 0.9, which is greater than the r (0.78) between OMI and CNEMC; the r (0.69) between TROPOMI and the MAX-DOAS VCD NO<sub>2</sub> is greater than the r (0.59) between OMI and the MAX-DOAS. As such, the TROPOMI is better than the previous generation of OMI at representing the spatio-temporal distribution of NO<sub>2</sub> in the regional scope. On the other hand, the uncertainties of the satellite products provided in this study can constrain regional air quality forecasting models and top-down emission inventory estimation.