1,3,2,1,2- 1Department of Oceanography, Kyungpook National University,Daegu, Republic of Korea (lulurhdwn@gmail.com)
- 2Kyungpook Institute of Oceanography, Kyungpook National University, Daegu, Republic of Korea
- 3Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
- 4National Institute of Meteorological Sciences, Korea Meteorological Administration, Seogwipo, Republic of Korea
Atmospheric carbon dioxide (CO₂) and its stable carbon isotope composition (δ¹³C) provide important constraints on CO₂ sources and sinks; however, long-term high-frequency observations remain limited in East Asia.
This study presents continuous observations of atmospheric CO₂ and δ¹³CO₂ obtained at the Gosan station on Jeju Island, South Korea, from 2017 to 2025 using a cavity ring-down spectroscopy (CRDS) analyzer. The 9-year record is based on 1 Hz measurements aggregated into hourly mean values, with measurement precisions of 0.01 ppm for CO₂ and 0.05‰ for δ¹³CO₂.
The observations reveal pronounced seasonal cycles in both CO₂ and δ¹³CO₂, with mean seasonal amplitudes of approximately 8–10 ppm for CO₂ and 0.4–0.5 ‰ for δ¹³CO₂, exceeding those observed at global background sites and reflecting the continental–marine boundary characteristics of the Gosan station. From 2017 to 2021, both the CO₂ growth rate and the long-term decline in δ¹³CO₂ are broadly consistent with global background trends, whereas after 2022, notable deviations from global background behavior are observed in both CO₂ growth rates and δ¹³CO₂ trends. Superimposed on these background variations, pollution-influenced air masses exhibit pronounced changes in δ¹³CO₂. Yearly Keeling plot analysis of CO₂–δ¹³CO₂ relationships for pollution events indicates a progressive enrichment in isotopic source signatures over time, suggesting a temporal shift in dominant emission sources.
To investigate anthropogenic source characteristics associated with these pollution signals, high-CO₂ events are first classified based on air mass transport pathways, and further examined by incorporating high-frequency measurements of carbon monoxide (CO) and nitrous oxide (N₂O) provided by the National Institute of Meteorological Sciences (NIMS), which serve as complementary tracers of combustion-related and non-combustion emission influences, respectively.
How to cite: Jang, J., Kim, J., Choi, H., Choi, J., Yun, J., Jang, J., Kim, S., Shin, D., Yang, S., and Park, S.: Long-Term High-Frequency Measurements of Atmospheric CO₂ and δ¹³CO₂ at Gosan: Implications for Source Characteristics in East Asia, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8986, https://doi.org/10.5194/egusphere-egu26-8986, 2026.
