Characterizing CO2 enhancements at major hotspots in South Korea using OCO-3 XCO2 retrievals

Consistent and long-term monitoring and understanding spatiotemporal distributions of carbon dioxide (CO₂) in the atmosphere and local emission sources are essential to achieve the carbon neutrality by 2050. Quantifying accurate spatiotemporal CO₂ enhancements is uneasy task because of its relatively long lifetimes in the atmosphere compared with methane and nitrogen dioxide. If the observatory is situated close to the area affected by transboundary air pollutants and local emission sources (e.g., cities, power plant, industrial areas etc.), estimating CO₂ enhancements are even more challenging. Satellite CO₂ observations are powerful to examine local to regional CO₂ enhancements from the emission hotspot regions with wider spatial coverage compared with ground-based observatory. Especially, NASA's Orbiting Carbon Observatory-3 (OCO-3) has demonstrated its feasibility to quantify local CO₂ emissions from the emission hotspots. To better understand source-sink characteristics of CO₂ in South Korea, we examined spatiotemporal distributions in local CO₂ enhancements of the several hotspots from the OCO-3 Level 2 bias-corrected column-averaged dry-air mole fractions of CO₂ (X_CO2) v10.4r. We determined CO₂ enhancements utilizing monthly climatology statistics from the Fourier Transform Spectrometer (FTS) X_CO2, Anmyeon-do (36.5382^◦N, 126.3311^◦E) in South Korea, subtracted from OCO-3 X_CO2 at each pixel. We used FTS-X_CO2 measurements from the update Total Carbon Column Observing Network (TCCON) GGG2020 retrieval algorithm. Our preliminary results suggest that CO₂ enhancements over the major hotspots in South Korea showed wide ranges from -5 ~ 12 ppm measured from Snapshot Area Maps (SAMs) measurement modes. This large variability may be associated with the definition of enhancement determination, geographical location, and seasonal wind characteristics. We will discuss these potential error sources of uncertainties and how we can enhancement estimates to better quantify CO₂ emissions. We anticipate our study provide insights for the robust and reliable quantifications of CO₂ enhancements, establish an advanced level of the greenhouse gases and air quality monitoring strategy in South Korea.