Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Statistical analysis of nephelometer regional field data
Abstract Visual air quality can be specified in terms of the visual range calculated from a point measurement of the particle scattering coefficient. This paper invesligales the difference between point and spatially averaged scatlering coefficient in terms of its impact on calculated visual range and plume-horizon contrast Nephelometer measurements taken simultaneously at three different locations during a three-week period from 28 June to 13 July 1979 were investigated to determine their spatial variability. The investigation showed three distinct types of atmospheric conditions that could be characterized both by nephelomeler data and by the origin of the ambient air; a regional-haze period, which corresponded to a fairly homogeneous atmosphere; a forest-lire period, which corresponded to a rather inhomogcncous atmosphere and a clear-background period. For these three periods, the correlation coefficients between nephelomeler data for total scattering (i.e. Rayleigh plus particulate scattering) from two distinct sites were 0.772, 0.044 and 0.263, respectively. The standard deviations in the calculation of a spatially averaged scattering coefficient from independent nephelometer measurements were calculated to be ± 0.100 × 10−4 m −1 for the overall threeweek period, and ± 0.073 × 10−1 m −1, ±0.120 × 10−4 m −1 and ± 0.041 × 10−4 m −1 for the regional-haze period, the forest-fire period and the clear-background period, respectively. These standard deviations were used to estimate the corresponding uncertainties in visual range calculations and to estimate the sensitivity of plume visibility model predictions to these uncertainties. Relative deviations in plume contrasts were calculated for four typical case studies. The deviations ranged from 1 to 43 per cent for absolute contrast values above 0.02, depending on plume-observer distance, wavelength and the original visual range value.
Statistical analysis of nephelometer regional field data
Abstract Visual air quality can be specified in terms of the visual range calculated from a point measurement of the particle scattering coefficient. This paper invesligales the difference between point and spatially averaged scatlering coefficient in terms of its impact on calculated visual range and plume-horizon contrast Nephelometer measurements taken simultaneously at three different locations during a three-week period from 28 June to 13 July 1979 were investigated to determine their spatial variability. The investigation showed three distinct types of atmospheric conditions that could be characterized both by nephelomeler data and by the origin of the ambient air; a regional-haze period, which corresponded to a fairly homogeneous atmosphere; a forest-lire period, which corresponded to a rather inhomogcncous atmosphere and a clear-background period. For these three periods, the correlation coefficients between nephelomeler data for total scattering (i.e. Rayleigh plus particulate scattering) from two distinct sites were 0.772, 0.044 and 0.263, respectively. The standard deviations in the calculation of a spatially averaged scattering coefficient from independent nephelometer measurements were calculated to be ± 0.100 × 10−4 m −1 for the overall threeweek period, and ± 0.073 × 10−1 m −1, ±0.120 × 10−4 m −1 and ± 0.041 × 10−4 m −1 for the regional-haze period, the forest-fire period and the clear-background period, respectively. These standard deviations were used to estimate the corresponding uncertainties in visual range calculations and to estimate the sensitivity of plume visibility model predictions to these uncertainties. Relative deviations in plume contrasts were calculated for four typical case studies. The deviations ranged from 1 to 43 per cent for absolute contrast values above 0.02, depending on plume-observer distance, wavelength and the original visual range value.
Statistical analysis of nephelometer regional field data
Babson, Betsy L. (Autor:in) / Bergstrom, Robert W. (Autor:in) / Samuelson, Mel A. (Autor:in) / Seigneur, Christian (Autor:in) / Waggoner, Alan (Autor:in) / Malm, William C. (Autor:in)
Atmospheric Environment ; 16 ; 2335-2346
01.01.1982
12 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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