Concentration fluctuation data from dispersion experiments carried out in stable and unstable conditions

Mole, N.; Jones, Christopher D.

doi:10.1007/bf00705507

Cited by 28 publications

(29 citation statements)

References 24 publications

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“…The stability conditions in the CBD during JU03 were similar by day and night. In contrast, the open terrain daytime and nighttime results of Mole and Jones (1994) were obtained in distinctly unstable and stable conditions, respectively. Yee et al (1993) measured probability densities during open terrain experiments that were mostly similar in form to those found during JU03.…”

Section: Discussionmentioning

confidence: 74%

“…Concentration variability decreased towards the plume centreline and downwind as plume spread and internal plume mixing began to replace plume meander as the dominant control on concentration fluctuations away from the source. Although their measurements were only 5-15 m downwind of the source, Mole and Jones (1994) observed much larger daytime concentration variability compared to nighttime. The stability conditions in the CBD during JU03 were similar by day and night.…”

Section: Discussionmentioning

confidence: 88%

“…The finding by Mole and Jones (1994) of no large differences in the shapes of probability density functions in stable and unstable conditions is consistent with the JU03 finding of minimal differences between unconditional and conditional probability densities, and between day and night probability densities, when classified by intensity i. These results suggest that if the mean and standard deviation can be determined, whether conditional or unconditional, an estimate of the probability density function for a specified urban location at any time of day can be made.…”

Section: Discussionmentioning

confidence: 95%

“…Lewellen and Sykes (1986) found i mostly in the range of 0.4-1.5 at distances from 1-3 km with sometimes larger values at greater distances. At distances of 5-15 m, Mole and Jones (1994) reported i from 3.1-5.7, S from 4.3-9.3, and K from 23-168 in unstable conditions. The values were all much lower in stable conditions.…”

Section: Concentration Statisticsmentioning

confidence: 92%

“…This definition of intermittency is used here although some have discussed the difficulty in defining intermittency and proposed alternatives (Chatwin and Sullivan 1993;Mole and Jones 1994).…”

Section: Experimental Description and Analytical Methodsmentioning

confidence: 99%

See 4 more Smart Citations

Analysis of Urban Atmosphere Plume Concentration Fluctuations

Finn

Clawson

Carter

et al. 2010

Boundary-Layer Meteorol

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Concentration variability in the fast-response tracer dataset for continuous, near-surface, point source releases in the urban core from the Joint Urban 2003 field study is analyzed. Concentration variability for conditionally and unconditionally sampled time series is characterized by probability densities, concentration fluctuation intensity, skewness, and kurtosis. Significant day-night differences in plume dispersion are observed. Relative to daytime, nighttime plumes were more likely to have reduced concentration fluctuation intensities, higher normalized surface concentrations, suppressed vertical mixing, and a greater prevalence of Gaussian-like distributions rather than log-normal or mixed mode distributions. This was in spite of the similar stability and turbulence conditions in the urban core for day and night. The potential roles of flow meander and thermal stability in explaining these differences are examined. Probability densities of concentration are found to be a strong function of fluctuation intensity. There are few differences in probability densities between day and night when classified by fluctuation intensity. There are no appreciable differences between conditional and unconditional probability densities and only small differences between conditional and unconditional sampling statistics relative to the larger differences usually observed in more homogeneous settings. Fluctuation intensity, skewness, and kurtosis are higher for the daytime experiments, and closer to the source, but show little difference between conditional and unconditional results over most of their range of values.

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Section: Discussionmentioning

confidence: 74%

Section: Discussionmentioning

confidence: 88%

Section: Discussionmentioning

confidence: 95%

Section: Concentration Statisticsmentioning

confidence: 92%

Section: Experimental Description and Analytical Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Analysis of Urban Atmosphere Plume Concentration Fluctuations

Finn

Clawson

Carter

et al. 2010

Boundary-Layer Meteorol

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Turbulent Diffusion

Chatwin¹,

Sullivan²

2006

Encyclopedia of Environmetrics

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From the point of view of the environment, arguably the most important practical property of fluids (i.e. liquids and gases) in motion is how they transport heat and matter. Examples of the latter include the spreading of foreign gases (e.g. SO2, NO2 and many others) and particulates in the atmosphere, the dispersion of plankton in the seas and oceans, and the distribution of salt in estuaries. Nearly all fluid motions in the environment are turbulent. This means that the motion is unpredictable, changing apparently at random in both space and time.

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