Observations of atmospheric ¹⁴CO₂ at Anmyeondo GAW station, South Korea: implications for fossil fuel CO₂ and emission ratios

Abstract

Abstract. To understand the Korean Peninsula's carbon dioxide (CO2) emissions and sinks as well as those of the surrounding region, we used 70 flask-air samples collected during May 2014 to August 2016 at Anmyeondo (AMY; 36.53∘ N, 126.32∘ E; 46 m a.s.l.) World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) station, located on the west coast of South Korea, for analysis of observed 14C in atmospheric CO2 as a tracer of fossil fuel CO2 contribution (Cff). Observed 14C ∕ C ratios in CO2 (reported as Δ values) at AMY varied from −59.5 ‰ to 23.1 ‰, with a measurement uncertainty of ±1.8 ‰. The derived mean value Cff of (9.7±7.8) µmol mol−1 (1σ) is greater than that found in earlier observations from Tae-Ahn Peninsula (TAP; 36.73∘ N, 126.13∘ E; 20 m a.s.l., 28 km away from AMY) of (4.4±5.7) µmol mol−1 from 2004 to 2010. The enhancement above background mole fractions of sulfur hexafluoride (Δx(SF6)) and carbon monoxide (Δx(CO)) correlate strongly with Cff (r>0.7) and appear to be good proxies for fossil fuel CO2 at regional and continental scales. Samples originating from the Asian continent had greater Δx(CO) : Cff(RCO) values, (29±8) to (36±2) nmol µmol−1, than in Korean Peninsula local air ((8±2) nmol µmol−1). Air masses originating in China showed (1.6±0.4) to (2.0±0.1) times greater RCO than a bottom-up inventory, suggesting that China's CO emissions are underestimated in the inventory, while observed RSF6 values are 2–3 times greater than inventories for both China and South Korea. However, RCO values derived from both inventories and observations have decreased relative to previous studies, indicating that combustion efficiency is increasing in both China and South Korea.

Miroc4を基にした化学輸送モデルと逆解法とを用いた大気中一酸化二窒素の動態解析

“…The agreement between the simulated and observed N2O matches well at AMY, Korea after inversion, where the regional emissions are constrained by the site at HAT, Japan. AMY site samples airmass of local emission activities related to agriculture, such as rice paddies, sweet potatoes, and onions, and long-range transport from mainland China (Lee et al 2020).…”

Canopy Leaching Rather than Desorption of PM2.5 From Leaves Is the Dominant Source of Throughfall Dissolved Organic Carbon in Forest

“…For example, the background Δ 14 C‐CO 2 was 16.6‰ at NOAA/ESRL's Niwot Ridge, Colorado, USA, in 2014–2016 (site code NWR, 40.05°N, 105.58°W, 3,475 masl) (Lee et al., 2020). The relatively low Δ 14 C‐CO 2 observed at Anmyeondo in South Korea can be attributed to increased fossil fuel emissions from the Asian continent (Lee et al., 2020). If the Δ 14 C phs was set as 16.6‰, the estimated mean contribution of deposited PM 2.5 to throughfall DOC 2.7 would increase from 3% to 7%.…”

“…At this threshold the calculated contribution of each source (refer to Equations 1-4 below) changes by less than 1%, thereby not affecting the overall conclusions. The Δ 14 C phs was set as −6.2 ± 18.8‰, which is the Δ 14 C of atmospheric CO 2 at the Global Atmosphere Watch station, located in Anmyeondo, South Korea in 2016 (Lee et al, 2020).…”

Short-term reduction of regional enhancement of atmospheric CO2 in China during the first COVID-19 pandemic period

“…The WLG station was not used as the main background station in this study, as it provides flask-sampled data and the amount of data during the analysis period is small. The choice of background did not lead to significant changes in our results because the enhancement in AMY is largely affected by regional and local signals (Turnbull et al 2011b, Lee et al 2020.…”

“…The ∆CO/∆CO 2 ratio refers to the proportion of emitted CO relative to emitted CO 2 from the same anthropogenic combustion sources. It can be used to distinguish the source region/type and for estimating the combustion efficiency (Suntharalingam et al 2004, Wang et al 2010, Turnbull et al 2011a, Tohjima et al 2014, Niu et al 2018, Tang et al 2018, Lee et al 2020, Sim et al 2020. A higher ∆CO/∆CO 2 ratio indicates that the source regions have incomplete combustion, and that most of the source types are domestic coal and biofuel combustion, with low contributions of vehicles with catalytic converters.…”