[Simulation of Anthropogenic CO₂ Emissions in the Yangtze River Delta Based on Different Emission Inventories]

Nowadays, great uncertainty still exists on the urban- and regional-scale anthropogenic CO₂ emission estimation based on emission inventories. In order to achieve the carbon peaking and neutrality targets for China, it is urgent to accurately estimate anthropogenic CO₂ emissions at regional scales, especially in large urban agglomerations. Using two inventories (EDGAR v6.0 inventory and a modified inventory combining EDGAR v6.0 with GCG v1.0) as prior anthropogenic CO₂ emission datasets andtaking themas input data respectively, this study utilized the WRF-STILT atmospheric transport model to simulate atmospheric CO₂ concentration in the Yangtze River Delta region from December 2017 to February 2018. The simulated atmospheric CO₂ concentrations were further improved by referencing atmospheric CO₂ concentration observation at a tall tower in Quanjiao County of Anhui Province and using the scaling factors obtained from the Bayesian inversion method. An estimation of anthropogenic CO₂ emission flux in the Yangtze River Delta regionwas finally accomplished. The results indicated that:①in winter, in comparison to the atmospheric CO₂ concentration simulated based on EDGAR v6.0, the atmospheric CO₂ concentration simulated based on the modified inventory was more consistent with observed values. ②The simulated atmospheric CO₂ concentration was higher than observation at night and lower than observation during the daytime. The CO₂ emission data of emission inventories could not fully reflect the diurnal variation in anthropogenic emissions, andtheoverestimation, caused by the simulated low-atmospheric boundary layer height at night, of the contribution from point sources with higher emission height near the observation station were the main reasons. ③The simulation performance on atmospheric CO₂ concentration was greatly affected by the emission bias of the EDGAR grid points that significantly contributed to concentrations of the observation station, and this indicated that the uncertainty in the spatial distribution in EDGAR emission was the main factor influencing the simulation accuracy. ④The posterior anthropogenic CO₂ emission flux in the Yangtze River Delta from December 2017 to February 2018 was around (0.184±0.006) mg·(m²·s)^-1and (0.183±0.007) mg·(m²·s)^-1 based on EDGAR and the modified inventory, respectively. It is suggested that the inventories with higher temporal and spatial resolutions and more accurate spatial emission distribution should be selected as the prior emissions to obtain a more accurate estimation of the regional anthropogenic CO₂ emissions.