Impact of model grid spacing on regional- and urban- scale air quality predictions of organic aerosol

Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 7. Stroud C.A.; Makar P.A.; Moran M.D.; et al. - Copernicus GmbH, 2011

Regional-scale chemical transport model predictions of urban organic aerosol to date tend to be biased low relative to observations, a limitation with important implications for applying such models to human exposure health studies. We used a nested version of Environment Canada's AURAMS model (42- to- 15- to- 2.5-km nested grid spacing) to predict organic aerosol concentrations for a temporal and spatial domain corresponding to the Border Air Quality and Meteorology Study (BAQS-Met), an air-quality field study that took place in the southern Great Lakes region in the summer of 2007. The use o ...

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Impact of model grid spacing on regional- and urban- scale air quality predictions of organic aerosol

  Available online: http://dx.doi.org/10.5194/acp-11-3107-2011

C.A. Stroud ; P.A. Makar ; M.D. Moran ; W. Gong ; S. Gong ; J. Zhang ; K. Hayden ; C. Mihele ; J.R. Brook ; J.P.D. Abbatt ; J.G. Slowik

in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 7 [04/01/2011] . - p.3107-3118

Regional-scale chemical transport model predictions of urban organic aerosol to date tend to be biased low relative to observations, a limitation with important implications for applying such models to human exposure health studies. We used a nested version of Environment Canada's AURAMS model (42- to- 15- to- 2.5-km nested grid spacing) to predict organic aerosol concentrations for a temporal and spatial domain corresponding to the Border Air Quality and Meteorology Study (BAQS-Met), an air-quality field study that took place in the southern Great Lakes region in the summer of 2007. The use of three different horizontal grid spacings allowed the influence of this parameter to be examined. A domain-wide average for the 2.5-km domain and a matching 15-km subdomain yielded very similar organic aerosol averages (4.8 vs. 4.3 μg m−3, respectively). On regional scales, secondary organic aerosol dominated the organic aerosol composition and was adequately resolved by the 15-km model simulation. However, the shape of the organic aerosol concentration histogram for the Windsor urban station improved for the 2.5-km simulation relative to those from the 42- and 15-km simulations. The model histograms for the Bear Creek and Harrow rural stations were also improved in the high concentration "tail" region. As well the highest-resolution model results captured the midday 4 July organic-aerosol plume at Bear Creek with very good temporal correlation. These results suggest that accurate simulation of urban and large industrial plumes in the Great Lakes region requires the use of a high-resolution model in order to represent urban primary organic aerosol emissions, urban VOC emissions, and the secondary organic aerosol production rates properly. The positive feedback between the secondary organic aerosol production rate and existing organic mass concentration is also represented more accurately with the highest-resolution model. Not being able to capture these finer-scale features may partly explain the consistent negative bias reported in the literature when urban-scale organic aerosol evaluations are made using coarser-scale chemical transport models.

Language(s): English

Format: Digital (Free)

Tags: Aerosols ; Methodology ; Urban zone ; Weather forecasting ; Air quality ; Research Add tag

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Transport analysis of ozone enhancement in Southern Ontario during BAQS-Met

Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. He H.; Tarasick D.W.; Hocking W.K.; et al. - Copernicus GmbH, 2011

Twice-daily ozonesondes were launched from Harrow, in southwestern Ontario, Canada, during the BAQS-Met (Border Air Quality and Meteorology Study) field campaign in June and July of 2007. A co-located radar windprofiler measured tropopause height continuously. These data, in combination with continuous surface ozone measurements and geo-statistical interpolation of satellite ozone observations, present a consistent picture and indicate that a number of significant ozone enhancements in the troposphere were observed that were the result of stratospheric intrusion events. The combined observatio ...

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Transport analysis of ozone enhancement in Southern Ontario during BAQS-Met

  Available online: http://dx.doi.org/10.5194/acp-11-2569-2011

H. He ; D.W. Tarasick ; W.K. Hocking ; T.K. Carey-Smith ; Y. Rochon ; J. Zhang ; P.A. Makar ; M. Osman ; J. Brook ; M.D. Moran ; D.B.A. Jones ; C. Mihele ; J.C. Wei ; G. Osterman ; P.S. Argall ; J. McConnell ; M.S. Bourqui

in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 3 [03/01/2011] . - p.2569-2583

Twice-daily ozonesondes were launched from Harrow, in southwestern Ontario, Canada, during the BAQS-Met (Border Air Quality and Meteorology Study) field campaign in June and July of 2007. A co-located radar windprofiler measured tropopause height continuously. These data, in combination with continuous surface ozone measurements and geo-statistical interpolation of satellite ozone observations, present a consistent picture and indicate that a number of significant ozone enhancements in the troposphere were observed that were the result of stratospheric intrusion events. The combined observations have also been compared with results from two Environment Canada numerical models, the operational weather prediction model GEM (as input to FLEXPART), and a new version of the regional air quality model AURAMS, in order to examine the ability of these models to accurately represent sporadic cross-tropopause ozone transport events. The models appear to reproduce intrusion events with some skill, implying that GEM dynamics (which also drive AURAMS) are able to represent such events well. There are important differences in the quantitative comparison, however; in particular, the poor vertical resolution of AURAMS around the tropopause causes it to bring down too much ozone in individual intrusions.

Language(s): English

Format: Digital (Free)

Tags: Canada ; Measure ; Observations ; Ozone ; Troposphere Add tag

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