Impacts of HOx regeneration and recycling in the oxidation of isoprene: Consequences for the composition of past, present and future atmospheres

Archibald, A.T.; Levine, James G.; Abraham, N.L.; Cooke, M.C.; Edwards, P.M.; Heard, D.E.; Jenkin, M.E.; Karunaharan, A.; Pike, R.C.; Monks, P.S.; Shallcross, D.E.; Telford, P.J.; Whalley, L.K.; Pyle, J.A.. 2011 Impacts of HOx regeneration and recycling in the oxidation of isoprene: Consequences for the composition of past, present and future atmospheres. Geophysical Research Letters, 38 (5), L05804. 6, pp. 10.1029/2010GL046520

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Abstract/Summary

A global chemistry-climate model is used to assess the impact on atmospheric composition of the regeneration and recycling of HOx in the photo-oxidation of isoprene. The impact is explored subject to present-day, pre-industrial and future climate/emission scenarios. Our calculations show that, in all cases, the inclusion of uni-molecular isomerisations of the isoprene hydroxy-peroxy radicals leads to enhanced production of HOx radicals and ozone. The global burden of ozone increases by 25–36 Tg (8–18%), depending on the climate/emissions scenario, whilst the changes in OH lead to decreases in the methane lifetime of between 11% in the future and 35% in the pre-industrial. Critically the size of the change in methane lifetime depends on the VOC/NOx emission ratio. The results of the present-day calculations suggest a certain amount of parameter refinement is still needed to reconcile the updated chemistry with field observations (particularly for HO2+RO2). However, the updated chemistry could have far-reaching implications for: future-climate predictions; projections of future oxidising capacity; and our understanding of past changes in oxidising capacity.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1029/2010GL046520
Programmes:	BAS Programmes > Polar Science for Planet Earth (2009 - ) > Chemistry and Past Climate
ISSN:	0094-8276
NORA Subject Terms:	Meteorology and Climatology Chemistry Atmospheric Sciences
Date made live:	19 May 2011 14:51 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/14045

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1029/2010GL046520

Programmes:

BAS Programmes > Polar Science for Planet Earth (2009 - ) > Chemistry and Past Climate

ISSN:

0094-8276

NORA Subject Terms:

Meteorology and Climatology
Chemistry
Atmospheric Sciences

Date made live:

19 May 2011 14:51 +0 (UTC)