Seasonal mixing heights and inversions at Edmonton, Alberta

Myrick, Rachel; Sakiyama, S. K.; Angle, R.P.; Sandhu, Harpinder

doi:10.1016/1352-2310(94)90049-3

Cited by 39 publications

(13 citation statements)

References 23 publications

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“…The correlat ions are statistically significant at 1% level of significance indicating the strong influence of solar radiation on mixing height. The results are in agreement with those of Roy et al [10] and Myrick et al [14].…”

Section: Wind Speed and Directionsupporting

confidence: 83%

“…Even during weak convection, which occurred before sunset, the mixing height was also within 650 m. The highest mixing height during convection period was 2785 m, 2606 m, 2307 m, and 1189 m in winter, summer, monsoon, and post-monsoon respectively. Mixing heights were highest between 12:00 IST and 14:00 IST due to highest convection during this period in all the seasons [11,14]. According to Gera et al [7], lower lat itudes receive more solar energy due to higher solar zenith angle compared to higher latitudes.…”

Section: Mixing Heightmentioning

confidence: 99%

“…With continuous solar heating, the layer starts rising, indicating the transfer of heat, mo mentu m and energy fro m the earth's surface [11][12][13]. In winter, convection period started late due to low surface heating [14].…”

Section: Categorisati On Of Sodar Echogramsmentioning

confidence: 99%

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Studies on Meteorological Parameters and Mixing Height in Gold Mining Area

Roy¹,

Gupta²,

Singh³

2012

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Gold mining at Ko lar Go ld Fields is closed but some industries in this area are in operation and some may like to be established. Data on at mospheric and meteorological parameters were generated using SODA R (Sound Detection and Ranging) and auto matic weather station in different seasons. Over 2000 sodar echograms were recorded and classified into six categories like rising layer, thermal plu me (free), ground based layer (spiky top), ground based layer (flat top), ground based mu ltiple layers and dot echo structures. Using echograms, unstable period was determined to know the d iluting capability of at mosphere for pollutants in the seasons. The highest duration of mixing heights revealed the period of h ighest dispersion. Based on the sodar echograms and mixing height, stability classes for the d ifferent times of the day were evaluated, which can be used for the estimation of dispersion coefficients. Influence of wind speed, wind direction, temperature, hu midity, solar rad iation and rainfall on mixing heights was studied. Statistical model was developed for the prediction of mixing height. Model adequacy was checked using F-statistics, normal d istribution curve and correlation between predicted and measured values of mixing heights.

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Section: Wind Speed and Directionsupporting

confidence: 83%

Section: Mixing Heightmentioning

confidence: 99%

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Studies on Meteorological Parameters and Mixing Height in Gold Mining Area

Roy¹,

Gupta²,

Singh³

2012

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“…This criterion is used as the working definition in many of the examples provided in this paper. It should be recognized however, that other definitions exist that are using either air pollution (Maughan et al, 1982;Baxter, 1991;Myrick et al, 1994;Seibert et al, 2000) or turbulence parameters (Holzworth, 1972;Norton and Hoidale, 1976;Deardorff et al, 1980;Cai and Steyn, 1993;Vogelezang and Holtslag, 1996;Beyrich, 1997;Adler and Kalthoff, 2014;Dai et al, 2014) to indicate the CBL top. For example, Seibert et al (2000) define the CBL top as "the height of the layer adjacent to the ground over which pollutants or any constituents emitted within this layer or entrained into it become vertically dispersed by convection or mechanical turbulence within a time scale of about an hour."…”

Section: Definition and Determination Of Cbl Heightsmentioning

confidence: 99%

Convective Boundary Layer Heights Over Mountainous Terrain—A Review of Concepts

2015

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Mountainous terrain exerts an important influence on the Earth's atmosphere and affects atmospheric transport and mixing at a wide range of temporal and spatial scales. The vertical scale of this transport and mixing is determined by the height of the atmospheric boundary layer, which is therefore an important parameter in air pollution studies, weather forecasting, climate modeling, and many other applications. It is recognized that the spatio-temporal structure of the daytime convective boundary layer (CBL) height is strongly modified and more complex in hilly and mountainous terrain compared to flat terrain. While the CBL over flat terrain is mostly dominated by turbulent convection, advection from multi-scale thermally driven flows plays an important role for the CBL evolution over mountainous terrain. However, detailed observations of the CBL structure and understanding of the underlying processes are still limited. Characteristics of CBL heights in mountainous terrain are reviewed for dry, convective conditions. CBLs in valleys and basins, where hazardous accumulation of pollutants is of particular concern, are relatively well-understood compared to CBLs over slopes, ridges, or mountain peaks. Interests in the initiation of shallow and deep convection, and of budgets and long-range transport of air pollutants and trace gases, have triggered some recent studies on terrain induced exchange processes between the CBL and the overlying atmosphere. These studies have helped to gain more insight into CBL structure over complex mountainous terrain, but also show that the universal definition of CBL height over mountains remains an unresolved issue. The review summarizes the progress that has been made in documenting and understanding spatio-temporal behavior of CBL heights in mountainous terrain and concludes with a discussion of open research questions and opportunities for future research.

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“…Additionally, Edmonton meteorology is characterized by shallow atmospheric mixing height regimes that exist throughout the year, which limit the extent of vertical dispersion of air pollutants. 7 The resulting thermal inversion prevents the release of pollutants from the troposphere. Unlike previously published intraurban analyses, 6 smoothed estimates for ambient air pollutants based on monitoring data were generated for geographic areas in this study, associations were evaluated across distinct subtypes of stroke, and a dose-response model was assessed.…”

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confidence: 99%

Ecological Analysis of Long-Term Exposure to Ambient Air Pollution and the Incidence of Stroke in Edmonton, Alberta, Canada

Johnson

Rowe

Villeneuve

2010

Stroke

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Background and Purpose-Long-term air pollution effects on stroke incidence have not been examined extensively. We investigated the associations between ambient pollution and the incidence of stroke, as well as stroke subtypes, in a northern Canadian city surrounded by energy-sector pollution sources. Methods-Stroke data from an administrative database from 2003 through 2007 were used to estimate annual incidence rates within small geographic regions within Edmonton, Canada. Air pollution levels for each region were estimated from continuous fixed-site monitoring stations in and around Edmonton. We fit models estimating stroke risk in relation to pollution levels; risks were adjusted for age, sex, income, social deprivation, and other factors. Results-Between 2003 and 2007, the average 5-year concentration of NO 2 and CO was positively associated with the incidence of stroke, particularly for hemorrhagic and nonhemorrhagic stroke subtypes (NO 2 : hemorrhagic stroke relative riskϭ1.46; 95% CI, 1.19 -1.80; nonhemorrhagic stroke relative riskϭ1.36; 95% CI, 1.19 -1.56). However, these estimates of risk diminished after controlling for the ecological measures of income and deprivation. Adjustment for ecologically derived indices of smoking, hypertension, and body mass index did not alter the estimates of risk in any meaningful way. Conclusions-Although long-term NO 2 and CO levels were positively associated with a higher incidence of stroke in the entire study area, the risk estimates were strongly attenuated by household income levels. Further research that incorporates individual-level risk factor data would improve our understanding of the relation of longer-term exposures to ambient air pollution and stroke outcomes.

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Seasonal mixing heights and inversions at Edmonton, Alberta

Cited by 39 publications

References 23 publications

Studies on Meteorological Parameters and Mixing Height in Gold Mining Area

Studies on Meteorological Parameters and Mixing Height in Gold Mining Area

Convective Boundary Layer Heights Over Mountainous Terrain—A Review of Concepts

Ecological Analysis of Long-Term Exposure to Ambient Air Pollution and the Incidence of Stroke in Edmonton, Alberta, Canada

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