Spatiotemporal Variability of Greenhouse Gas Concentrations at the WMO/GAW Observational Sites in Korea

Atmospheric greenhouse gases (GHGs) affect Earth’s radiation balance and are the primary drivers of climate change. This study analyzed the spatiotemporal variability of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) at domestic World Meteorological Organization/Global Atmosphere Watch (WMO/GAW) sites located at Anmyeondo (AMY), Jeju Gosan, and Ulleungdo, examining the local influences on GHG variations and comparing the relationships between gases. Long-term records from the AMY site were used to investigate temporal changes in CO₂–CH₄. The results showed that short-term variations were influenced by local emissions, sink processes, and anthropogenic signals, whereas medium-to-long-term variations displayed clear seasonality driven by vegetation and meteorological changes, with continuously increasing trends. The sites strongly reflected the effects of nearby point sources, and the ∆CO₂–∆CH₄ relationships revealed site-specific spatiotemporal differences. At AMY, 46–49% of top-quartile CO₂, CH₄, and N₂O enhancements occurred under easterly winds from nearby industrial and agricultural sources, whereas 14–16% under northwesterly flow indicated episodic transport from eastern China, highlighting the site’s combined exposure to domestic and foreign emissions. The observed strengthening long-term ∆CO₂–∆CH₄ correlation may be related to continuously increasing emissions in East Asia. However, uncertainties remain, owing to changes resulting from the 2012 instrument replacement and calibration scale. Overall, this study provides baseline insights into domestic GHG variability and offers fundamental information for understanding East Asian emissions and supporting climate policy.