珠江口大气化石源CO2示踪与陆源排放量估算

化石燃料燃烧是人为碳排放最大来源，因此持续监测和减量化石燃料消费对全球实现碳达峰及碳中和目标尤为重要。传统利用排放清单（“自下而上”）估算化石源CO2（FFCO2）排放量的方法存在较大误差和漏报可能。14C可作为独立示踪剂定量FFCO2排放，且大气观测结合模型模拟（“自上而下”）定量精度更高。而背景点的选取直接决定FFCO2浓度，是定量FFCO2排放量的关键。为此，本项目拟在南中国海和粤港澳大湾区相接的沿海区域开展走航观测与定点观测，通过研究海上大气Δ14CO2空间分布与离岸距离的关系，确定进行沿海区域FFCO2研究的最佳背景点位置。在此基础上，利用定点观测数据并构建FLEXPART-WRF反演模型估算大湾区FFCO2排放量。研究结果可提供核查大湾区化石源碳排放量的关键数据，服务大湾区碳达峰及碳中和目标，并为我国沿海区域碳减排核查评估提供新视角及政策措施制定提供重要科学依据。

Fossil fuel combustion is the largest source of man-made carbon emissions, so continuous monitoring and reduction of fossil fuel consumption are particularly important for achieving global targets of carbon emission peak and carbon neutrality. There is a large error in estimating Fossil Fuel CO2 (FFCO2) emissions based on emission inventory (“bottom-up”). While 14C can be a tracer to quantify FFCO2 emissions with higher accuracy by a combined method of atmospheric observation and model simulation (“top-down”). Noting that the selection of background site is a key factor in quantifying FFCO2 emissions since the value of Δ14CO2 at this site is a variable in determining the concentration of FFCO2. This proposal intends to carry out navigational and fixed-point observations in coastal areas connecting the South China Sea with the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) to find out the best location of the background site by studying the relationship between the Δ14CO2 concentrations and offshore distance. The FFCO2 emission in the GBA is subsequently estimated by applying the FLEXPART-WRF inverse model combined with the fixed-point observations of parameters. The results of this study can provide scientific data to verify FFCO2 emissions in the GBA, and thus serve the carbon emission peak and carbon neutrality goal, as well as provide a new perspective for the verification and evaluation of carbon emission reduction and an important scientific basis for the formulation of related policies and measures in the coastal areas of China.