Uncertainties of fluxes and <sup>13</sup>C  ∕ <sup>12</sup>C ratios of atmospheric reactive-gas emissions

Abstract

Abstract. We provide a comprehensive review of the proxy data on the 13 C / 12 C 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 δ 13 C of overall surface CO emission in 2000 of −(25.2 ± 0.7) ‰ 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 δ 13 C values of surface emissions of higher hydrocarbons to be within −24 to −27 ‰ (uncertainty typically below ±1 ‰), with an exception of isoprene and methanol emissions being close to −30 and −60 ‰, respectively. The isotope signature of ethane surface emission coincides with earlier estimates, but integrates very different source inputs. δ 13 C values are reported relative to V-PDB.

Stable carbon isotopic composition of biomass burning emissions – implications for estimating the contribution of C<sub>3</sub> and C<sub>4</sub> plants

“…δ 13 C signatures of BB products are widely used in several scientific fields. Since the 1980s, stable carbon isotopes measured in air pollution have been used to distinguish emissions from BB and other sources (Aguilera and Whigham, 2018;Andersson et al, 2020;Cachier et al, 1985;Gromov et al, 2017;Kawashima and Haneishi, 2012). Palaeoecologists use pyrolysed carbon signatures in soils to trace vegetation changes (Hall et al, 2008;Masi et al, 2013;Wynn et al, 2020).…”

“…Sapart et al, 2012). In many of these applications, the isotopic signature of the pyrolysis product is assumed to represent the signature of the precursor vegetation (Gromov et al, 2017). In a fire, however, organic matter undergoes volatilization and oxidation during which isotopic fractionation takes place.…”

Stable carbon isotopic composition of biomass burning emissions – implications for estimating the contribution of C3 and C4 plants

“…δ 13 C signatures of BB products are widely used in several scientific fields. Since the 1980s, stable carbon isotopes measured in air pollution have been used to distinguish emissions from BB and other sources (Aguilera and Whigham, 2018;Andersson et al, 2020;Cachier et al, 1985;Gromov et al, 2017;Kawashima and Haneishi, 2012). Paleo-ecologists use pyrolyzed carbon signatures in soils to trace vegetation changes (Hall et al, 2008;Masi et al, 2013;Wynn et al, 2020).…”

“…Isotopic signatures in BB emissions trapped in ice cores are used to reconstruct ancient fire regimes (e.g., Sapart et al, 2012). In many of these applications, the isotopic signature of the pyrolysis product is assumed to represent the signature of the precursor vegetation (Gromov et al, 2017). In a fire, however, organic matter undergoes volatilization and oxidation during which isotopic fractionation takes place.…”

Stable carbon isotopic composition of biomass burning emissions – implications for estimating the contribution of C3 and C4 plants

“…δ 13 C signatures of BB products are widely used in several scientific fields. Since the 1980s, stable carbon isotopes measured in air pollution have been used to distinguish emissions from BB and other sources (Aguilera and Whigham, 2018;Andersson et al, 2020;Cachier et al, 1985;Gromov et al, 2017;Kawashima and Haneishi, 2012). Palaeoecologists use pyrolysed carbon signatures in soils to trace vegetation changes (Hall et al, 2008;Masi et al, 2013;Wynn et al, 2020).…”