Isoprene oxidation mechanisms: measurements and modelling of OH and HO<sub>2</sub> over a South-East Asian tropical rainforest during the OP3 field campaign
Forests are the dominant source of volatile organic compounds into the atmosphere, with isoprene being the most significant species. The oxidation chemistry of these compounds is a significant driver of local, regional and global atmospheric composition. Observations made over Borneo during the OP3...
| Main Authors: | , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2011-07-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/11/6749/2011/acp-11-6749-2011.pdf |
| _version_ | 1811255550961254400 |
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| author | C. E. Reeves D. Oram P. S. Monks A. C. Lewis R. J. Leigh J. Hopkins D. M. Brookes A. R. Rickard T. Ingham R. Commane M. J. Evans P. M. Edwards D. Stone D. Stewart D. E. Heard |
| author_facet | C. E. Reeves D. Oram P. S. Monks A. C. Lewis R. J. Leigh J. Hopkins D. M. Brookes A. R. Rickard T. Ingham R. Commane M. J. Evans P. M. Edwards D. Stone D. Stewart D. E. Heard |
| author_sort | C. E. Reeves |
| collection | DOAJ |
| description | Forests are the dominant source of volatile organic compounds into the atmosphere, with isoprene being the most significant species. The oxidation chemistry of these compounds is a significant driver of local, regional and global atmospheric composition. Observations made over Borneo during the OP3 project in 2008, together with an observationally constrained box model are used to assess our understanding of this oxidation chemistry. In line with previous work in tropical forests, we find that the standard model based on MCM chemistry significantly underestimates the observed OH concentrations. Geometric mean observed to modelled ratios of OH and HO<sub>2</sub> in airmasses impacted with isoprene are 5.32<sub>−4.43</sub><sup>+3.68</sup> and 1.18<sub>−0.30</sub><sup>+0.30</sup> respectively, with 68 % of the observations being within the specified variation. We implement a variety of mechanistic changes into the model, including epoxide formation and unimolecular decomposition of isoprene peroxy radicals, and assess their impact on the model success. We conclude that none of the current suggestions can simultaneously remove the bias from both OH and HO<sub>2</sub> simulations and believe that detailed laboratory studies are now needed to resolve this issue. |
| first_indexed | 2024-04-12T17:26:35Z |
| format | Article |
| id | doaj.art-a5d1f1be811b42edafa9293c683fa3c2 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-12T17:26:35Z |
| publishDate | 2011-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-a5d1f1be811b42edafa9293c683fa3c22022-12-22T03:23:18ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242011-07-0111136749677110.5194/acp-11-6749-2011Isoprene oxidation mechanisms: measurements and modelling of OH and HO<sub>2</sub> over a South-East Asian tropical rainforest during the OP3 field campaignC. E. ReevesD. OramP. S. MonksA. C. LewisR. J. LeighJ. HopkinsD. M. BrookesA. R. RickardT. InghamR. CommaneM. J. EvansP. M. EdwardsD. StoneD. StewartD. E. HeardForests are the dominant source of volatile organic compounds into the atmosphere, with isoprene being the most significant species. The oxidation chemistry of these compounds is a significant driver of local, regional and global atmospheric composition. Observations made over Borneo during the OP3 project in 2008, together with an observationally constrained box model are used to assess our understanding of this oxidation chemistry. In line with previous work in tropical forests, we find that the standard model based on MCM chemistry significantly underestimates the observed OH concentrations. Geometric mean observed to modelled ratios of OH and HO<sub>2</sub> in airmasses impacted with isoprene are 5.32<sub>−4.43</sub><sup>+3.68</sup> and 1.18<sub>−0.30</sub><sup>+0.30</sup> respectively, with 68 % of the observations being within the specified variation. We implement a variety of mechanistic changes into the model, including epoxide formation and unimolecular decomposition of isoprene peroxy radicals, and assess their impact on the model success. We conclude that none of the current suggestions can simultaneously remove the bias from both OH and HO<sub>2</sub> simulations and believe that detailed laboratory studies are now needed to resolve this issue.http://www.atmos-chem-phys.net/11/6749/2011/acp-11-6749-2011.pdf |
| spellingShingle | C. E. Reeves D. Oram P. S. Monks A. C. Lewis R. J. Leigh J. Hopkins D. M. Brookes A. R. Rickard T. Ingham R. Commane M. J. Evans P. M. Edwards D. Stone D. Stewart D. E. Heard Isoprene oxidation mechanisms: measurements and modelling of OH and HO<sub>2</sub> over a South-East Asian tropical rainforest during the OP3 field campaign Atmospheric Chemistry and Physics |
| title | Isoprene oxidation mechanisms: measurements and modelling of OH and HO<sub>2</sub> over a South-East Asian tropical rainforest during the OP3 field campaign |
| title_full | Isoprene oxidation mechanisms: measurements and modelling of OH and HO<sub>2</sub> over a South-East Asian tropical rainforest during the OP3 field campaign |
| title_fullStr | Isoprene oxidation mechanisms: measurements and modelling of OH and HO<sub>2</sub> over a South-East Asian tropical rainforest during the OP3 field campaign |
| title_full_unstemmed | Isoprene oxidation mechanisms: measurements and modelling of OH and HO<sub>2</sub> over a South-East Asian tropical rainforest during the OP3 field campaign |
| title_short | Isoprene oxidation mechanisms: measurements and modelling of OH and HO<sub>2</sub> over a South-East Asian tropical rainforest during the OP3 field campaign |
| title_sort | isoprene oxidation mechanisms measurements and modelling of oh and ho sub 2 sub over a south east asian tropical rainforest during the op3 field campaign |
| url | http://www.atmos-chem-phys.net/11/6749/2011/acp-11-6749-2011.pdf |
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