Measurement of the Absorption Coefficient of Atmospheric Dust

Lindberg, James D.; Laude, Larry S.

doi:10.1364/ao.13.001923

Cited by 92 publications

(19 citation statements)

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“…Only one day, 5 April, when the extinction was very low, yielded a high real component (1.54) consistent with ammonium sulfate and silica which are so frequently named as chief aerosol constituents. The imaginary component estimates determined from the data (average of 0.004) are in agreement with values obtained for the 500-700 nm wavelength range from a number of other desert aerosol experiments ( e g , De Luisi et al, 1970;Grams et al, 1974;Lindberg and Laude, 1974;Spinhirne et al, 1980). Although imaginary indices in the range of 0.001-0.01 do not correspond to any specific substance commonly associated with atmospheric aerosols, the occurrence of values in t h s range is possibly a result of small amounts of carbon mixing with otherwise very weakly absorbing particles (Lindberg and Gillespie, 1977;Ackerman and Toon, 1981).…”

Section: Electron Microscope Analysissupporting

confidence: 87%

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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Section: Electron Microscope Analysissupporting

confidence: 87%

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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“…All methods presently in use make some assumptions in order to measure the absorption coefficient; the most frequently applied are listed among the following: integrating sphere (Fischer, 1970;Weintzenberg, 1982), integrating plate (Lin et al, 1973;Weiss et al, 1979;Stevens et al, 1982), integrating sandwich , laser transmission method (Rosen et al, 1978), photoacoustic methods (Yasa et al, 1979;Stevens et al, 1982), and powder technology methods (Kortiim, 1969;Lindberg and Laude, 1974). Intercomparison of the different methods gives considerable disagreement: the integrating plate method and laser transmission method differ by a factor of 2.5 although they are highly correlated (Sadler et al, 1981), the laser transmission method giving higher values.…”

Section: Methods Of Determining the Absorption Coefficientmentioning

confidence: 99%

“…The factor is between 1.3 and 2.4 and depends on the orientation of the filter (Szkarlat and Japar, 1981). The absorption coefficient measured by the diffuse reflectance technique has an uncertainty within a factor of 2.0 (Lindberg and Laude, 1974). The discrepancy between the various methods is larger for aerosols absorbing only slightly, since the scattering by the particles partly is misinterpreted as light absorption.…”

Section: Methods Of Determining the Absorption Coefficientmentioning

confidence: 99%

Absorption Coefficient of the Vienna Aerosols: Comparison of Two Methods

Horváth

Habenreich

1989

Aerosol Science and Technology

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The absorption coefficient of the atmospheric aerosol average 20% light absorption and for the winter aerosol over Vienna has been determined by two independent with an average of 40% light absorption, they agree methods: the integrating plate method and by subtracting almost perfectly. When considering small corrections the light scattering coefficient obtained with an integratowing to truncation in the nephelometer, the light abing nephelometer from the light extinction coefficient sorption measured by the integrating plate is consistently obtained by telephotometer. The raw data are highly too high by 30%-40%. This is in agreement with previcorrelated and, both for the summer aerosol with an ously published results for other locations.

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“…For the third technique, the emissivity of the sample is measured at a specific temperature and then related to the absorption coefficient [4]. Another technique is to gather light diffusely scattered from a material and relate this to its scattering and absorption characteristics [5]. For all of these methods, some problems are encountered.…”

Section: Pellet Spectrophonementioning

confidence: 99%