Atmospheric CO2 and CO at Jingdezhen station in central China: Understanding the regional transport and combustion efficiency. (1st February 2020) - Xia, Lingjun
Abstract: Greenhouse gas observation networks have been extensively established in eastern, southern, western, and northern China, but are rare in the developing central China. In this study, atmospheric CO2 and CO were measured in-situ at Jingdezhen (JDZ) station (29.37 °N, 117.22 °E, 87.3 m a.s.l) in central China during Dec. 2017–Nov. 2018. The observation data were filtered as regionally representative and polluted conditions, based on the analysis of diurnal CO2 and CO variations and the impacts of wind directions and speeds. The average CO2 and CO mixing ratios of regionally representative compositions during the study period were 416.2 ppm and 294.9 ppb, respectively, relative to 433.8 ppm and 408.9 ppb for the polluted events. Cluster analysis of HYSPLIT backward trajectories indicated that long-distance transport of air masses originating from northwestern China, eastern China and Jiangxi made the main contributions to variability in regionally representative air. The trajectories passing through urban areas of YRD (Yangtze River Delta), Anhui province in central China, and Nanchang in Jiangxi province carried polluted air masses that probably lead to the increase of CO2 and CO mixing ratios. The enhancements of CO2 (△CO2 ) and CO (△CO) in polluted conditions relative to the regionally representative conditions presented stronger correlations (R = 0.78, p < 0.001) in wintertime relative to the other seasons at JDZ station, suggesting anthropogenic emissions from fossil fuel and biomass combustion significantly affected CO2 atmospheric loading in the cold season. Lower △CO2 /△CO ratio (39.0 ppm/ppm) was observed in December 2017 than other months in winter, and the air mass transport mostly originated from northern China in Dec, implying the strong impact of biomass burning emission sources with low combustion efficiency from northern China. The particular polluted event during 18–21 January in 2018 with high slope value (70.7 ppm/ppm) of △CO2 vs △CO was also investigated, and the analysis of air-mass transport routes indicated high combustion efficiency might be found in Central China such as Jiangxi and Hunan provinces. Highlights: Atmospheric CO2 and CO were measured at Jingdezhen (JDZ) station in Central China. Regional transport made significant contribution to CO2 and CO mole fractions. High ratios of △CO2 vs △CO in winter at JDZ indicated high combustion efficiency.