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| Titel |
Reconciling the changes in methane sources and sinks between the last glacial maximum and the pre-industrial era |
| VerfasserIn |
James Levine, Eric Wolff, Anna Jones, Louise Sime, Paul Valdes, Glenn Carver, Nicola Warwick, Alex Archibald, John Pyle |
| 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 |
250046405
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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. We
know from the ice record that its concentration, [CH4], at the last glacial maximum
(LGM; 21kyr before present) was roughly half that in the pre-industrial era (PI;
~200yr before present), about 360 ppbv compared to around 700 ppbv, but how
much of the difference was source-driven, and how much was sink-driven, remains
uncertain.
Here, in view of a recent upward-revision of the estimated change in CH4 emissions from
wetlands during this period, and the possible recycling of OH consumed in isoprene
oxidation, we use an atmospheric chemistry-transport model to: re-examine the main factors
affecting the oxidising capacity between the LGM and the PI; estimate their net effect on
[CH4], with and without a possible OH recycling mechanism; and show how this can be
reconciled with both the larger change in wetland emissions and the observed change in
[CH4]. |
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