Mass tracking for chemical analysis: the causes of ozone formation in southern Ontario during BAQS-Met 2007
A three-level nested regional air pollution model has been used to study the processes leading to high ozone concentrations in the southern Great Lakes region of North America. The highest resolution simulations show that complex interactions between the lake-breeze circulation and the synoptic flow...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2010-11-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/10/11151/2010/acp-10-11151-2010.pdf |
| _version_ | 1819123456953810944 |
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| author | P. A. Makar J. Zhang W. Gong C. Stroud D. Sills K. L. Hayden J. Brook I. Levy C. Mihele M. D. Moran D. W. Tarasick H. He D. Plummer |
| author_facet | P. A. Makar J. Zhang W. Gong C. Stroud D. Sills K. L. Hayden J. Brook I. Levy C. Mihele M. D. Moran D. W. Tarasick H. He D. Plummer |
| author_sort | P. A. Makar |
| collection | DOAJ |
| description | A three-level nested regional air pollution model has been used to study the processes leading to high ozone concentrations in the southern Great Lakes region of North America. The highest resolution simulations show that complex interactions between the lake-breeze circulation and the synoptic flow lead to significant enhancements in the photochemical production and transport of ozone at the local scale. Mass tracking of individual model processes show that Lakes Erie and St. Clair frequently act as photochemical ozone production regions, with average mid-day production rates of up to 3 ppbv per hour. Enhanced ozone levels are evident over these two lakes in 23-day-average surface ozone fields. Analysis of other model fields and aircraft measurements suggests that vertical circulation enhances ozone levels at altitudes up to 1500 m over Lake St. Clair, whereas subsidence enhances ozone over Lake Erie in a shallow layer only 250 m deep. Mass tracking of model transport shows that lake-breeze surface convergence zones combined with the synoptic flow can then carry ozone and its precursors hundreds of kilometers from these source areas, in narrow, elongated features. Comparison with surface mesonet ozone observations confirm the presence, magnitude, and timing of these features, which can create local ozone enhancements on the order of 30 ppbv above the regional ozone levels. Sensitivity analyses of model-predicted ozone and HO<sub>x</sub> concentrations show that most of the region is VOC-limited, and that the secondary oxidation pathways of aromatic hydrocarbons have a key role in setting the region's ozone and HO<sub>x</sub> levels. |
| first_indexed | 2024-12-22T07:08:39Z |
| format | Article |
| id | doaj.art-26cb5b02f20c4be7891500542b009c61 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-22T07:08:39Z |
| publishDate | 2010-11-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-26cb5b02f20c4be7891500542b009c612022-12-21T18:34:35ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242010-11-011022111511117310.5194/acp-10-11151-2010Mass tracking for chemical analysis: the causes of ozone formation in southern Ontario during BAQS-Met 2007P. A. MakarJ. ZhangW. GongC. StroudD. SillsK. L. HaydenJ. BrookI. LevyC. MiheleM. D. MoranD. W. TarasickH. HeD. PlummerA three-level nested regional air pollution model has been used to study the processes leading to high ozone concentrations in the southern Great Lakes region of North America. The highest resolution simulations show that complex interactions between the lake-breeze circulation and the synoptic flow lead to significant enhancements in the photochemical production and transport of ozone at the local scale. Mass tracking of individual model processes show that Lakes Erie and St. Clair frequently act as photochemical ozone production regions, with average mid-day production rates of up to 3 ppbv per hour. Enhanced ozone levels are evident over these two lakes in 23-day-average surface ozone fields. Analysis of other model fields and aircraft measurements suggests that vertical circulation enhances ozone levels at altitudes up to 1500 m over Lake St. Clair, whereas subsidence enhances ozone over Lake Erie in a shallow layer only 250 m deep. Mass tracking of model transport shows that lake-breeze surface convergence zones combined with the synoptic flow can then carry ozone and its precursors hundreds of kilometers from these source areas, in narrow, elongated features. Comparison with surface mesonet ozone observations confirm the presence, magnitude, and timing of these features, which can create local ozone enhancements on the order of 30 ppbv above the regional ozone levels. Sensitivity analyses of model-predicted ozone and HO<sub>x</sub> concentrations show that most of the region is VOC-limited, and that the secondary oxidation pathways of aromatic hydrocarbons have a key role in setting the region's ozone and HO<sub>x</sub> levels.http://www.atmos-chem-phys.net/10/11151/2010/acp-10-11151-2010.pdf |
| spellingShingle | P. A. Makar J. Zhang W. Gong C. Stroud D. Sills K. L. Hayden J. Brook I. Levy C. Mihele M. D. Moran D. W. Tarasick H. He D. Plummer Mass tracking for chemical analysis: the causes of ozone formation in southern Ontario during BAQS-Met 2007 Atmospheric Chemistry and Physics |
| title | Mass tracking for chemical analysis: the causes of ozone formation in southern Ontario during BAQS-Met 2007 |
| title_full | Mass tracking for chemical analysis: the causes of ozone formation in southern Ontario during BAQS-Met 2007 |
| title_fullStr | Mass tracking for chemical analysis: the causes of ozone formation in southern Ontario during BAQS-Met 2007 |
| title_full_unstemmed | Mass tracking for chemical analysis: the causes of ozone formation in southern Ontario during BAQS-Met 2007 |
| title_short | Mass tracking for chemical analysis: the causes of ozone formation in southern Ontario during BAQS-Met 2007 |
| title_sort | mass tracking for chemical analysis the causes of ozone formation in southern ontario during baqs met 2007 |
| url | http://www.atmos-chem-phys.net/10/11151/2010/acp-10-11151-2010.pdf |
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