Empirical relationship to convert ΔXCO₂ to ΔXCO₂FF

Results obtained by applying the DAM method to CT2019 xCO₂ for East China. (a) Different monthly ΔxCODAM2 components: total ΔxCODAM2 (TOT) and its FF (red) and biogenic (BIO, green) components and their sum (FF + BIO). The non-shaded time periods October to May indicate the periods analysed in this publication. (b) East China October-to-May FF CO₂ emissions (red dots) and estimated emissions COFF(DAM)₂ (black crosses) as obtained from total ΔxCODAM₂ (TOT as shown in panel a) using the formula shown in panel (b). (c) Scatter plot of estimated versus true (i.e. CT2019) FF emissions. (d) Relative difference of estimated and true emissions.