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| Titel |
Initial investigation of the wavelength dependence of optical properties measured with a new multi-pass Aerosol Extinction Differential Optical Absorption Spectrometer (AE-DOAS) |
| VerfasserIn |
R. T. Chartier, M. E. Greenslade |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 5, no. 4 ; Nr. 5, no. 4 (2012-04-05), S.709-721 |
| Datensatznummer |
250002774
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| Publikation (Nr.) |
 copernicus.org/amt-5-709-2012.pdf |
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| Zusammenfassung |
| Atmospheric aerosols directly affect climate by scattering and absorbing
radiation. The magnitude of the impact is dependent upon the wavelength of
light, but is often estimated near 550 nm. When light scattering and
absorption by aerosols is approximated, the wavelength dependence of the
refractive index for specific components is lost. As a result, climate
models would have inherent uncertainties for aerosol contributions to
radiative forcing when considering the entire solar spectrum. An aerosol
extinction differential optical absorption spectrometer has been developed
to directly measure aerosol extinction at mid-ultraviolet to near infrared
wavelengths. The instrument consists of a spectrometer coupled to a closed
White-type multi-pass gas cell with an adjustable path length of up to
approximately 20 m. Laboratory measurements of various gases are compared
with known absorption cross sections. Additionally, the extinction of
monodisperse samples of polystyrene latex spheres are measured and compared
to Mie theory generated with refractive index values from the literature to
validate the new instrument. The polystyrene experiments also emphasize the
ability of the new instrument to retrieve the wavelength dependent
refractive index, especially in the ultraviolet wavelength regions where
variability is expected. The spectrometer will be a significant advancement
for determining wavelength dependent complex refractive indices in future
laboratory studies as well as provide the ability to monitor ambient aerosol
light extinction. |
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