Optical properties of aerosols—comparison of measurements with model calculations

Sloane, Christine S.

doi:10.1016/0004-6981(83)90059-8

Cited by 105 publications

(53 citation statements)

References 23 publications

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“…The complex refractive index and density of different chemical component were presented in some literature (Dalzell et al, 1969;Ouimette et al, 1982;Hasan et al, 1983;Sloane, 1983Sloane, , 1984Sloane et al, 1985;Sloane, 1986). In this paper, the chemical components considered in later optical calculation are sulfate, nitrate, OC, EC, and other species.…”

Section: Characteristics Of Extinction Effects Of Aerosolmentioning

confidence: 84%

Effect of Aerosols on Visibility and Radiation in Spring 2009 in Tianjin, China

Hai

Zhang

et al. 2012

Aerosol Air Qual. Res.

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Meteorological and aerosol data were measured at the atmospheric boundary layer observation station in Tianjin, China, and were analyzed to study the effects of aerosol mass, composition, and size distributions on visibility and short-wave radiation flux. The results show that fine particles played important roles in controlling visibility in Tianjin. The major contributors to light extinction coefficients included sulfate (28.7%), particulate organic matter (27.6%), elemental carbon (19.2%), and nitrate (6.1%). In addition to the measurement of aerosol composition, the size distribution of aerosol number concentrations were also measured and classified between haze days and non-haze days during spring. The extinction characteristics of ambient aerosol in haze days and non-haze days were calculated using Mie theory model. The average extinction coefficient and scattering coefficient of atmospheric aerosols were 0.253 1/km and 0.213 1/km in non-haze days, while 0.767 1/km and 0.665 1/km in haze days. A radiation transmission model LOWTRAN7 is also applied in this study. The model calculated radiant flux densities in haze days and non-haze days, which showed a fairly agreement with the observation results, showing that the heavy aerosol loadings in Tianjin had significantly impact on atmospheric visibility and radiation fluxes.

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Section: Characteristics Of Extinction Effects Of Aerosolmentioning

confidence: 84%

Effect of Aerosols on Visibility and Radiation in Spring 2009 in Tianjin, China

Hai

Zhang

et al. 2012

Aerosol Air Qual. Res.

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“…In literature (Sloane et al, 1983(Sloane et al, , 1984Sloane and Wolff, 1985;Sloane et al, 1991;Ouimette and Flagan, 1982;Seinfeld and Pandis, 1998), the density of BC is reported as a range from 1.00 g/cm 3 to 2.00 g/cm 3 . Accordingly, an average value of 1.5 g/cm 3 is used, and the uncertainty (3σ ) is assigned to be 33 % covering the possible range.…”

Section: Methods Of Optical Closure For Dry Aerosolsmentioning

confidence: 99%

Aerosol optical properties in the North China Plain during HaChi campaign: an in-situ optical closure study

et al. 2011

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Abstract. The largest uncertainty in the estimation of climate forcing stems from atmospheric aerosols. In early spring and summer of 2009, two periods of in-situ measurements on aerosol physical and chemical properties were conducted within the HaChi (Haze in China) project at Wuqing, a town between Beijing and Tianjin in the North China Plain (NCP). Aerosol optical properties, including the scattering coefficient (σ sp ), the hemispheric back scattering coefficient (σ bsp ), the absorption coefficient (σ ap ), as well as the single scattering albedo (ω), are presented. The diurnal and seasonal variations are analyzed together with meteorology and satellite data. The mean values of σ sp, 550nm of the dry aerosol in spring and summer are 280±253 and 379±251 Mm −1 , respectively. The average σ ap for the two periods is respectively 47±38 and 43±27 Mm −1 . The mean values of ω at the wavelength of 637 nm are 0.82±0.05 and 0.86±0.05 for spring and summer, respectively. The relative high levels of σ sp and σ bsp are representative of the regional aerosol pollution in the NCP. Pronounced diurnal cycle of σ sp , σ ap and ω are found, mainly influenced by the evolution of boundary layer and the accumulation of local emissions during nighttime. The pollutants transported from the southwest of the NCP are more significant than that from the two megacities, Beijing and Tianjin, in both spring and summer. An optical closure experiment is conducted to better under-

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“…Assuming the particles to be modeled by a single, average refractive index value is an obvious compromise. Scattering computations for polydispersions of spherical, inhomogeneous particles can produce significantly different values for various optical parameters depending on how the different constituents whch the particles are comprised of are mixed or averaged (Gillespie et al, 1978;Ackerman and Toon, 1981;Sloane, 1983). Nonetheless, our approach in assessing the observed Sa values is to apply the spherical, homogeneous particle assumptions and see if the observations can be reasonably explained by this level of analysis, instead of first attempting somethng more complicated.…”

Section: Electron Microscope Analysismentioning

confidence: 99%

Lidar and Balloon-Borne Cascade Impactor Measurements of Aerosols: A Case Study

Reagan

Apte

Bruhns

et al. 1984

Aerosol Science and Technology

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Aerosol size distributions, elemental components, complex refractive indices, extinction profiles and extinctionto-backscatter ratios have been measured and inferred from balloon-borne cascade impactor and lidar observations made during a cooperative joint experiment conducted during the period 4-10 April, 1980 in Tucson, AZ. Size distributions obtained from quartz crystal microbalance (QCM) cascade impactor measurements at different heights (1 to 1000 m) and times over a period of several days were fairly similar in form, being clearly bimodal in their mass distributions with the coarse particle mode being dominant. Electron microscope and energy dispersive X-ray analyses of particles deposited on the QCM stages over the particle radii range -0.5-4.0 ym revealed that the particle samples were elementally dominated by both sulfur and crustal type (Al, Ca, Mg and Si) elements. Complex refractive index estimates for a wavelength of 649 nm were obtained by comparing the lidar inferred aerosol extinction-to-backscatter ratios with theoretically computed values calculated for the impactor-derived size distributions. The real part of the index was estimated to be 1.45 for most cases, while the estimates for the imaginary part ranged between 0.000 and 0.01. Aerosol extinction coefficients calculated for the impactor-derived size distributions were found to be somewhat smaller but in fair agreement with the extinction coefficients retrieved from the lidar measurements.

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Optical properties of aerosols—comparison of measurements with model calculations

Cited by 105 publications

References 23 publications

Effect of Aerosols on Visibility and Radiation in Spring 2009 in Tianjin, China

Effect of Aerosols on Visibility and Radiation in Spring 2009 in Tianjin, China

Aerosol optical properties in the North China Plain during HaChi campaign: an in-situ optical closure study

Lidar and Balloon-Borne Cascade Impactor Measurements of Aerosols: A Case Study

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