Evaluation of a unified regional air-quality modeling system (AURAMS) using PrAIRie2005 field study data: The effects of emissions data accuracy on particle sulphate predictions

Cho, S.; Makar, Paul A.; Lee, W.S.; Herage, T.; Liggio, John; Li, S.M.; Wiens, B.; Graham, Lisa

doi:10.1016/j.atmosenv.2008.12.048

Cited by 23 publications

(14 citation statements)

References 8 publications

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“…The flow is split after the critical orifice, with 90% of the flow making a sharp turn and being pulled through the optical cell. The other 10% is pulled directly to the pump, relying on inertia to remove particles larger than 300 nm and eliminating the use of a particle filter, which may cause interferences from ammonium (Gras, 1984;Cheng and Tsai, 1997;Chow et al, 1998). The inlet also includes two ports for the introduction of calibration gas and background gas, designed so that these flows encounter the inlet in the same way as ambient sampling.…”

Section: Qc-tildasmentioning

confidence: 99%

The influence of gas-particle partitioning and surface-atmosphere exchange on ammonia during BAQS-Met

et al. 2011

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Abstract. The Border Air Quality and Meteorology study (BAQS-Met) was an intensive field campaign conducted in Southwestern Ontario during the summer of 2007. The focus of BAQS-Met was determining the causes of the formation of ozone and fine particulate matter (PM 2.5 ), and of the regional significance of trans-boundary transport and lake breeze circulations on that formation. Fast (1 Hz) measurements of ammonia were acquired using a Quantum Cascade Laser Tunable Infrared Differential Absorption Spectrometer (QC-TILDAS) at the Harrow supersite. Measurements of PM 2.5 ammonium, sulfate and nitrate were made using an Ambient Ion Monitor Ion Chromatograph (AIM-IC) with hourly time resolution. The median mixing ratio of ammonia was 2.5 ppb, with occasional high spikes at night resulting from local emissions. Measurements were used to assess major local emissions of NH 3 , diurnal profiles and gas-particle partitioning. The measurements were compared with results from A Unified Regional Air-quality Modelling System (AU-RAMS). While the fraction of total ammonia (NH x ≡NH 3 + NH + 4 ) observed in the gas phase peaks between 0.1 and 0.8, AURAMS tended to predict fractions of either less than 0.05 or greater than 0.8. The model frequently predicted acidic aerosol, in contrast with observations wherein NH x almost always exceeded the observed equivalents of sulfate. One explanation for our observations is that the net flux of ammonia from the land surface to the atmosphere increases when aerosol sulfate is present, effectively buffering the mixing ratio of gas phase ammonia, a process not included in the model. A simple representation of an offline bi-directional flux parameterization using the ISORROPIA thermodynamic model was successful at reducing the population of zero gas fraction points, but not the higher gas fraction points.

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Section: Qc-tildasmentioning

confidence: 99%

The influence of gas-particle partitioning and surface-atmosphere exchange on ammonia during BAQS-Met

et al. 2011

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“…The model has three main components: (1) a prognostic meteorological model GEM (Global Environmental Multiscale model: Côté et al, 1998); (2) an emissions processing system, (Sparse Matrix Operator Kernel Emissions: Houyoux et al, 2000;CEP, 2003); and (3) an off-line regional chemical transport model, the AURAMS Chemical Transport Model (CTM: cf. Cho et al, 2009;Makar et al, 2009;Gong et al, 2006). The AURAMS model was run with three nested grids at 42, 15 and 2.5 km horizontal resolution, driven by 15 km (for the two courser resolutions) and 2.5 km GEM simulations.…”

Section: Model Descriptionmentioning

confidence: 99%

Aircraft study of the impact of lake-breeze circulations on trace gases and particles during BAQS-Met 2007

et al. 2011

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Abstract. High time-resolved aircraft data, concurrent surface measurements and air quality model simulations were explored to diagnose the processes influencing aerosol chemistry under the influence of lake-breeze circulations in a polluted region of southwestern Ontario, Canada. The analysis was based upon horizontal aircraft transects conducted at multiple altitudes across an entire lake-breeze circulation. Air mass boundaries due to lake-breeze fronts were identified in the aircraft meteorological and chemical data, which were consistent with the frontal locations determined from surface analyses. Observations and modelling support the interpretation of a lake-breeze circulation where pollutants were lofted at a lake-breeze front, transported in the synoptic flow, caught in a downdraft over the lake, and then confined by onshore flow. The detailed analysis led to the development of conceptual models that summarize the complex 3-D circulation patterns and their interaction with the synoptic flow. The identified air mass boundaries, the interpretation of the lake-breeze circulation, and the air parcel circulation time in the lake-breeze circulation (3.0 to 5.0 h) enabled formation rates of organic aerosol (OA/ CO) and SO 2− 4 to be determined. The formation rate for OA (relative to excess CO in ppmv) was found to be 11.6-19.4 µg m −3 ppmv −1 h −1 and the SO 2− 4 formation rate was 5.0-8.8 % h −1 . The formation rates are enhanced relative to regional background rates implying that lake-breeze circulations are an important dynamic in the formation of SO 2− 4 and secondary organicCorrespondence to: K. L. Hayden (katherine.hayden@ec.gc.ca) aerosol. The presence of cumulus clouds associated with the lake-breeze fronts suggests that these enhancements could be due to cloud processes. Additionally, the effective confinement of pollutants along the shoreline may have limited pollutant dilution leading to elevated oxidant concentrations.

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“…To better understand the BAQS-Met observations, output from the GEM/AURAMS regional air-quality modeling system (Cho et al, 2009;Côté et al, 1998;Makar et al, 2009), which was run with three nested grids with 42, 15 and 2.5 km horizontal grid spacing ( Fig. 1), are also analyzed in this paper.…”

Section: Datasetsmentioning

confidence: 99%

Unraveling the complex local-scale flows influencing ozone patterns in the southern Great Lakes of North America

et al. 2010

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Abstract. This study examines the complexity of various processes influencing summertime ozone levels in the southern Great Lakes region of North America. Results from the Border Air Quality and Meteorology (BAQS-Met) field campaign in the summer of 2007 are examined with respect to land-lake differences and local meteorology using a large array of ground-based measurements, aircraft data, and simulation results from a high resolution (2.5 km) regional airquality model, AURAMS.Analyses of average ozone mixing ratio from the entire BAQS-Met intensive campaign period support previous findings that ozone levels are higher over the southern Great Lakes than over the adjacent land. However, there is great heterogeneity in the spatial distribution of surface ozone over the lakes, particularly over Lake Erie during the day, with higher levels located over the southwestern end of the lake. Model results suggest that some of these increased ozone levels are due to local emission sources in large nearby urban centers. While an ozone reservoir layer is predicted by the AURAMS model over Lake Erie at night, the land-lake differences in ozone mixing ratios are most pronounced during the night in a shallow inversion layer of about 200 m above the surface. After sunrise, these differences have a limited effect on the total mass of ozone over the lakes and land during the day, though they do cause elevated ozone levels in the lake-breeze air in some locations.The model also predicts a mean vertical circulation during the day with an updraft over Detroit-Windsor and downdraft over Lake St. Clair, which transports ozone up to 1500 m above ground and results in high ozone over the lake.Correspondence to: J. Brook (jeff.brook@ec.gc.ca) Oscillations in ground-level ozone mixing ratios were observed on several nights and at several ground monitoring sites, with amplitudes of up to 40 ppbv and time periods of 15-40 min. Several possible mechanisms for these oscillations are discussed, but a complete understanding of their causes is not possible given current data and knowledge.

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Evaluation of a unified regional air-quality modeling system (AURAMS) using PrAIRie2005 field study data: The effects of emissions data accuracy on particle sulphate predictions

Cited by 23 publications

References 8 publications

The influence of gas-particle partitioning and surface-atmosphere exchange on ammonia during BAQS-Met

The influence of gas-particle partitioning and surface-atmosphere exchange on ammonia during BAQS-Met

Aircraft study of the impact of lake-breeze circulations on trace gases and particles during BAQS-Met 2007

Unraveling the complex local-scale flows influencing ozone patterns in the southern Great Lakes of North America

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