Regional Characteristics of NO₂ Column Densities from Pandora Observations during the MAPS-Seoul Campaign
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Chong H., et al. "Regional characteristics of NO₂ column densities from Pandora observations during the MAPS-Seoul campaign" Aerosol Air Qual Res. 18, no. 9 (September 2018):2207-2219. https://doi.org/10.4209/aaqr.2017.09.0341.
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Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
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This item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.
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Abstract
Vertical column density (VCD) of nitrogen dioxide (NO₂) was measured using Pandora spectrometers at six sites on the Korean Peninsula during the Megacity Air Pollution Studies-Seoul (MAPS-Seoul) campaign from May to June 2015. To estimate the tropospheric NO₂ VCD, the stratospheric NO₂ VCD from the Ozone Monitoring Instrument (OMI) was subtracted from the total NO₂ VCD from Pandora. European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis wind data was used to analyze variations in tropospheric NO₂ VCD caused by wind patterns at each site. The Yonsei/SEO site was found to have the largest tropospheric NO₂ VCD (1.49 DU on average) from a statistical analysis of hourly tropospheric NO₂ VCD measurements. At rural sites, remarkably low NO₂ VCDs were observed. However, a wind field analysis showed that trans-boundary transport and emissions from domestic sources lead to an increase in tropospheric NO₂ VCD at NIER/BYI and KMA/AMY, respectively. At urban sites, high NO₂ VCD values were observed under conditions of low wind speed, which were influenced by local urban emissions. Tropospheric NO₂ VCD at HUFS/Yongin increases under conditions of significant transport from urban area of Seoul according to a correlation analysis that considers the transport time lag. Significant diurnal variations were found at urban sites during the MAPS-Seoul campaign, but not at rural sites, indicating that it is associated with diurnal patterns of NO₂ emissions from dense traffic.