资源环境科技发展态势分析平台

We provide a comprehensive review of the proxy data on the C-13/C-12 ratios and uncertainties of emissions of reactive carbonaceous compounds into the atmosphere, with a focus on CO sources. Based on an evaluated set-up of the EMAC model, we derive the isotope-resolved data set of its emission inventory for the 1997-2005 period. Additionally, we revisit the calculus required for the correct derivation of uncertainties associated with isotope ratios of emission fluxes. The resulting delta C-13 of overall surface CO emission in 2000 of -(25.2 +/- 0.7)parts per thousand is in line with previous bottom-up estimates and is less uncertain by a factor of 2. In contrast to this, we find that uncertainties of the respective inverse modelling estimates may be substantially larger due to the correlated nature of their derivation. We reckon the delta C-13 values of surface emissions of higher hydrocarbons to be within -24 to -27 parts per thousand (uncertainty typically below +/- 1 parts per thousand), with an exception of isoprene and methanol emissions being close to -30 and -60 parts per thousand, respectively. The isotope signature of ethane surface emission coincides with earlier estimates, but integrates very different source inputs. delta C-13 values are reported relative to V-PDB.