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| Titel |
Investigating the impacts of HOx recycling in the oxidation of isoprene: Sensitivity studies of past, present and future atmospheres using the UKCA model. |
| VerfasserIn |
Alexander T. Archibald, N. Luke Abraham, Paul J. Telford, Mike E. Jenkin, John A. 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 |
250046998
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| Zusammenfassung |
| For several decades the importance of isoprene to global atmospheric chemistry
has been highlighted. With annual emissions on the order of 500 Tg per year it
represents a major source of reduced carbon in the atmosphere. However, our ability to
understand many of the fundamental processes involving emissions and oxidation of
isoprene remain questionable. In particular recent evidence suggests that the current
understanding of low NOx oxidation of isoprene is poorly represented in numerical
models. In this work we present results from a range of sensitivity experiments that
focus on exploring the effects of inclusion of recent mechanistic changes, based on
laboratory and theoretical studies, concerning the oxidation mechanism of isoprene. We
show that based on our current knowledge, intermolecular reactions of the isoprene
hydroxy-peroxy radicals are the most favourable route to novel chemistries for recycling HOx
radicals in isoprene oxidation. Furthermore, we present global model simulations
performed using the UKCA chemistry climate model to which a modified isoprene
mechanism has been developed. The results of sensitivity studies concerning climate
scenarios relevant to the pre-industrial, present day and future are presented. The
results suggest that inclusion of a HOx recycling mechanism from the oxidation of
isoprene has significant effects to the modelled levels of HOx, more than doubling
the levels of HOx in regions which are currently much lower than observations
suggest. The effects of increased HOx are presented in terms of their impact on
more long lived and climatically important gases such as O3, CO and CH4 and
discussed in terms of local and global scales over the different climate scenarios. |
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