Anthropogenic carbon dioxide origin tracing study in Anmyeon-do, South Korea: Based on STILT-footprint and emissions data

Tracking the origin of greenhouse gases (GHGs) is critical for understanding regional GHG concentration variation and developing effective policies to reduce GHG emissions. This study provides quantitative information about the surface contribution to enhancement of carbon dioxide (CO₂) concentration at Anmyeon-do (AMY), South Korea, using Stochastic Time-Inverted Lagrangian Transport (STILT) model and anthropogenic CO₂ emission data. CO₂ enhancement simulated by the STILT and emission data was positively correlated with measured CO₂ anomalies at AMY with a correlation coefficient above 0.5. High and low CO₂ days were selected using ground measurements of the CO₂ mixing ratio at AMY during the winter season of 2018-2019. The surface contributions for the high and low CO₂ days at AMY were compared quantitatively. When the high concentration was observed in AMY, the CO₂ enhancements were dominated by domestic regions, especially from the metropolitan area in South Korea, due to the high footprint and large CO₂ emissions. From the perspective of foreign regions, the surface contribution of eastern China regions (Shandong, Jiangsu-Shanghai) increased during high CO₂ days compared to low CO₂ days at AMY. During the high CO₂ days, the ratio between CO₂ and carbon monoxide, a co-emitted species, is large when the surface contribution of eastern China regions is relatively strong due to different regional combustion efficiency (i.e., high combustion efficiency in South Korea compared to that in China). The surface contribution based on STILT and emission data is useful for understanding the cause of high GHG concentration at the receptor (AMY in this study).