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

He, Hao; Tarasick, D. W.; Hocking, W. K.; Carey‐Smith, Trevor; Rochon, Y.; Zhang, J.; Makar, Paul A.; Osman, M.; Brook, Jeffrey R.; Moran, Michael D.; Jones, Dylan B. A.; Mihele, C.; Wei, Jennifer; Osterman, G. B.; Argall, P. S.; McConnell, J. C.; Bourqui, M. S.

doi:10.5194/acp-11-2569-2011

Cited by 25 publications

(25 citation statements)

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“…These results emphasize the importance of photochemistry within the lower troposphere during spring and summer. The relative contribution of stratospheric ozone to the tropospheric ozone budget is a controversial issue and has been debated for many years (e.g., Kim and Lee, 2010;He et al, 2011). Our analysis shows that both stratospheric downward transport and photochemical production within the troposphere influence the distribution of tropospheric ozone over Beijing.…”

Section: The Seasonality Of Tropospheric Ozonementioning

confidence: 85%

Tropospheric ozone trend over Beijing from 2002–2010: ozonesonde measurements and modeling analysis

et al. 2012

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Abstract. Using a combination of ozonesonde data and numerical simulations of the Chemical Lagrangian Model of the Stratosphere (CLaMS), the trend of tropospheric ozone (O 3 ) during 2002-2010 over Beijing was investigated. Tropospheric ozone over Beijing shows a winter minimum and a broad summer maximum with a clear positive trend in the maximum summer ozone concentration over the last decade. The observed significant trend of tropospheric column ozone is mainly caused by photochemical production (3.1 % yr −1 for a mean level of 52 DU). This trend is close to the significant trend of partial column ozone in the lower troposphere (0-3 km) resulting from the enhanced photochemical production during summer (3.0 % yr −1 for a mean level of 23 DU). Analysis of the CLaMS simulation shows that transport rather than chemistry drives most of the seasonality of tropospheric ozone. However, dynamical processes alone cannot explain the trend of tropospheric ozone in the observational data. Clearly enhanced ozone values and a negative vertical ozone gradient in the lower troposphere in the observational data emphasize the importance of photochemistry within the troposphere during spring and summer, and suggest that the photochemistry within the troposphere significantly contributes to the tropospheric ozone trend over Beijing during the last decade.

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Section: The Seasonality Of Tropospheric Ozonementioning

confidence: 85%

Tropospheric ozone trend over Beijing from 2002–2010: ozonesonde measurements and modeling analysis

et al. 2012

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“…Initial North American domain simulated surface O 3 was biased +15 ppb compared to observations. Vertical O 3 profiles at Harrow (He et al, 2011) showed that the model bias was even greater in the upper troposphere. Makar et al (2010a) used ozonesonde data to evaluate the model's prediction of the O 3 vertical column, noting that middle tropospheric concentrations had large positive biases.…”

Section: Evaluating the Model Capability To Simulate O 3 Particle Fmentioning

confidence: 99%

“…Vertical information was obtained at Harrow using ozonesondes released every 12 h (He et al, 2011), and via a wind profiler near Harrow (Hocking, 1997). Vertical information at Ridgetown was obtained via tethersonde profiling of O 3 and meteorology on select days, a scanning LIDAR ) and a MAX-DOAS system (Halla et al, 2011) for NO 2 and Aerosol Optical Depth (AOD).…”

Section: Fixed Sitesmentioning

confidence: 99%

“…The BAQS-Met special issue of Atmospheric Chemistry and Physics contains 20 research papers (Chan et al, 2011;Ellis et al, 2011;Flagg and Taylor, 2011;Halla et al, 2011;Hayden et al, 2011;He at al., 2011;Lee et al, 2011;Levy et al, 2010;Jeong et al, 2010Jeong et al, , 2011Makar et al, 2010a, b;Markovic et al, 2011;Sills et al, 2011;Sjostedt et al, 2011;Slowik et al, 2011;Stroud et al, 2011Stroud et al, , 2012Wentzell et al, 2010) covering aspects of regional particle physics, chemistry and source apportionment, secondary organic and inorganic particle formation, the influence of the lakes on ozone and particles; lake breeze kinematics and behaviour, remote measurements (surface and satellite) of NO 2 and AOD and high-resolution meteorological modelling of regional air quality. The intent of the current paper is to describe the objectives and the main hypotheses considered by the BAQS-Met study and the main results.…”

Section: Introductionmentioning

confidence: 99%

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Exploring the nature of air quality over southwestern Ontario: main findings from the Border Air Quality and Meteorology Study

et al. 2013

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Abstract. This paper serves as an overview and discusses the main findings from the Border Air Quality and Meteorology Study (BAQS-Met) in southwestern Ontario in 2007. This region is dominated by the Great Lakes, shares borders with the United States and consistently experiences the highest ozone (O 3 ) and fine particulate matter concentrations in Canada. The purpose of BAQS-Met was to improve our understanding of how lake-driven meteorology impacts air quality in the region, and to improve models used for forecasting and policy scenarios. Results show that lake breeze occurrence frequencies and inland penetration distances were significantly greater than realized in the past. Due to their effect on local meteorology, the lakes were found to enhance secondary O 3 and aerosol formation such that local anthropogenic emissions have their impact closer to the populated source areas than would otherwise occur in the absence of the lakes. Substantial spatial heterogeneity in O 3 was observed with local peaks typically 30 ppb above the regional values. Sulfate and secondary organic aerosol (SOA) enhancements were also linked to local emissions being transported in the lake breeze circulations. This study included the first detailed evaluation of regional applications of a high-resolution (2.5 km grid) air quality model in the Great Lakes region. The model showed that maxima in secondary pollutants occur in areas of convergence, in localized updrafts and in distinct pockets over the lake surfaces. These effects are caused by lake circulations interacting with the synoptic flow, with each other or with circulations induced by urban heat islands. Biogenic and anthropogenic emissions were both shown to play a role in the formation of SOA in the region. Detailed particle measurements and multivariate receptor models reveal that while individual particles are internally mixed, they often exist within more complex external mixtures. This makes it difficult to predict aerosol optical properties and further highlights the challenges facing aerosol modelling. The BAQSMet study has led to a better understanding of the value of high-resolution (2.5 km) modelling for air quality and meteorological predictions and has led to several model improvements.

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“…In this study, the simulations were driven by the NCEP FNL data. This model has been extensively validated (Stohl et al, 1998;Cristofanelli et al, 2003) and widely used in studies of the influence of various meteorological processes on pollution transport (Cooper et al, 2004(Cooper et al, , 2005(Cooper et al, , 2006Hocking et al, 2007;Ding et al, 2009;Barret et al, 2011;He et al, 2011;Chen et al, 2012). In running FLEXPART, a large number of particles are released from defined locations (latitude, longitude, and altitude) at a time.…”

Section: The Flexpart Trajectory Modelmentioning

confidence: 99%

Uplifting of carbon monoxide from biomass burning and anthropogenic sources to the free troposphere in East Asia

et al. 2015

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Abstract. East Asia has experienced rapid development with increasing carbon monoxide (CO) emission in the past decades. Therefore, uplifting CO from the boundary layer to the free troposphere in East Asia can have great implications on regional air quality around the world. It can also influence global climate due to the longer lifetime of CO at higher altitudes. In this study, three cases of high CO episodes in the East China and a trajectory dispersion model FLEXPART, we found different CO signatures in the elevated CO and distinct transport pathways and mechanisms for these cases. In the 2003 case, emissions from large forest fires near Lake Baikal dominated the elevated CO, which had been rapidly transported upward by a frontal system from the fire plumes. In the 2004 case, anthropogenic CO from the North China Plain experienced frontal lifting and mostly reached ∼ 700 hPa near the East China Sea, while CO from biomass burning over Indochina experienced orographic lifting, lee-side-troughinduced convection, and frontal lifting through two separate transport pathways, leading to two distinct CO enhancements around 700 and 300 hPa. In the 2005 case, the observed CO of ∼ 300 ppbv around 300 hPa originated from anthropogenic sources over the Sichuan Basin and the North China Plain and from forest fires over Indochina. The high CO was transported to such altitudes through strong frontal lifting, interacting with convection and orographic lifting. These cases show that topography affects vertical transport of CO in East Asia via different ways, including orographic uplifting over the Hengduan Mountains, assisting frontal lifting in the North China Plain, and facilitating convection in the Sichuan Basin. In particular, topography-induced lee-side troughs over Indochina led to strong convection that assisted CO uplifting to the upper troposphere. This study shows that the new daytime MOPITT near-infrared (NIR) and thermalinfrared (TIR) data (version 5 or above) have enhanced vertical sensitivity in the free troposphere and may help qualitative diagnosis of vertical transport processes in East Asia.

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

Cited by 25 publications

References 82 publications

Tropospheric ozone trend over Beijing from 2002–2010: ozonesonde measurements and modeling analysis

Tropospheric ozone trend over Beijing from 2002–2010: ozonesonde measurements and modeling analysis

Exploring the nature of air quality over southwestern Ontario: main findings from the Border Air Quality and Meteorology Study

Uplifting of carbon monoxide from biomass burning and anthropogenic sources to the free troposphere in East Asia

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