How do Cl concentrations matter for the simulation of CH₄ and <italic>δ</italic>¹³C (CH₄) and estimation of the CH₄ budget through atmospheric inversions?

Abstract CH 4 CH 4 CH 4 CH 4 CH 4 δ 13 C (CH 4), can also provide additional constraints and helps to discriminate between emission categories. Nevertheless, to be able to use the information contained in these observations, the models must correctly account for processes influencing δ 13 C (CH 4). The oxidation by chlorine (Cl) likely contributes less than 5 % to the total oxidation of atmospheric CH 4 13 C, compared with 12 C in atmospheric CH 4 δ 13 C (CH 4). When integrating the Cl sink in their setup to constrain the CH 4 CH 4 δ 13 C (CH 4), and CH 4 CH 4 Tg CH 4 yr - 1 in global CH 4 CH 4 δ 13 4) source), although these differences are much smaller if only recent Cl fields are used. More specifically, each increase by 1000 molec. cm - 3 in the mean tropospheric Cl concentration would result in an adjustment by + Tg CH 4 yr - 1, for global CH 4 - δ 13 4) source. Our study also shows that the CH 4 δ 13 C (CH 4) seasonal cycle amplitude can be significantly modified by up to 10 %–20 %, depending on the latitude. In an atmospheric inversion performed with isotopic constraints, this influence can result in significant differences in the posterior source mixture. For example, the contribution from wetland emissions to the total emissions can be modified by about 0.8 % to adjust the globally averaged δ 13 4) source, corresponding to a 15 Tg CH 4 yr - 1 change. This adjustment is small compared to the current wetland source uncertainty, albeit far from negligible. Finally, tested Cl concentrations have a large influence on the simulated δ 13 C (CH 4) vertical profiles above 30 km and a very small impact on the simulated CH 4 CH 4 δ 13 C (CH 4) vertical profiles well, especially in the troposphere, and it is difficult to prefer one Cl field over another based uniquely on the available observations of the vertical profiles.

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch

References and Relationships

• Bibliographic citation: How do Cl concentrations matter for the simulation of CH₄ and δ¹³C (CH₄) and estimation of the CH₄ budget through atmospheric inversions? ; volume:22 ; number:23 ; year:2022 ; pages:15489-15508 ; extent:20 ; Atmospheric chemistry and physics ; 22, Heft 23 (2022), 15489-15508 (gesamt 20)

Contributors, Places and Time

• Creator: Thanwerdas, Joël ; Saunois, Marielle ; Pison, Isabelle ; Hauglustaine, Didier ; Berchet, Antoine ; Baier, Bianca ; Sweeney, Colm ; Bousquet, Philippe

Further information

• DOI: 10.5194/acp-22-15489-2022
• URN: urn:nbn:de:101:1-2022121504344449281128
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 31.07.2025, 3:56 PM CEST