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| Titel |
The role of atomic chlorine in glacial-interglacial changes in the carbon-13 content of atmospheric methane |
| VerfasserIn |
James Levine, Eric Wolff, Anna Jones, Louise Sime |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250046406
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| Zusammenfassung |
| Methane (CH4) is an important atmospheric constituent on account of its potency
as a greenhouse gas and its influence on the tropospheric oxidising capacity. The
ice-core record of δ13CH4 has largely been used to constrain past changes in CH4
sources. However, CH4 sinks also affect δ13CH4, and changes in the strength of a
relatively minor one, oxidation by atomic chlorine in the marine boundary layer
(ClMBL), have been invoked to explain spatial and inter-annual variations in δ13CH4.
Here, we explore for the first time the contribution that changes in the strength of
the ClMBL sink could have made to changes in δ13CH4 on glacial-interglacial
timescales.
Combining wind and temperature data from a variety of general circulation models with a
simple formulation for the concentration of ClMBL, we find that circulation-driven changes
in the strength of this sink, alone, could have been responsible for changes in δ13CH4 of the
order of 10% of the glacial-interglacial difference observed. In light of the many other factors
affecting ClMBL that we have not explored, we highlight the need to quantify past changes in
the strength of this sink, and consider these when interpreting glacial-interglacial changes in
δ13CH4. |
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