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| Titel |
Identification of key aerosol populations through their size and composition resolved spectral scattering and absorption |
| VerfasserIn |
F. Costabile, F. Barnaba, F. Angelini, G. P. Gobbi |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 5 ; Nr. 13, no. 5 (2013-03-05), S.2455-2470 |
| Datensatznummer |
250018466
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| Publikation (Nr.) |
 copernicus.org/acp-13-2455-2013.pdf |
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| Zusammenfassung |
| Characterizing chemical and physical aerosol properties is important
to understand their sources, effects, and feedback mechanisms in the
atmosphere. This study proposes a scheme to classify aerosol
populations based on their spectral optical properties (absorption
and scattering). The scheme is obtained thanks to the outstanding
set of information on particle size and composition these properties
contain. The spectral variability of the aerosol single scattering
albedo (dSSA), and the extinction, scattering and absorption Angstrom exponents
(EAE, SAE and AAE, respectively) were observed on the basis of two-year
measurements of aerosol optical properties (scattering and
absorption coefficients at blue, green and red wavelengths)
performed in the suburbs of Rome (Italy). Optical measurements of
various aerosol types were coupled to measurements of particle
number size distributions and relevant optical properties
simulations (Mie theory). These latter allowed the investigation of the
role of the particle size and composition in the bulk aerosol
properties observed. The combination of simulations and measurements
suggested a general "paradigm" built on dSSA, SAE and AAE to
optically classify aerosols. The paradigm proved suitable to
identify the presence of key aerosol populations, including soot,
biomass burning, organics, dust and marine particles. The work
highlights that (i) aerosol populations show distinctive
combinations of SAE and dSSA times AAE, these variables being linked
by a linear inverse relation varying with varying SSA; (ii) fine
particles show EAE > 1.5, whilst EAE < 2 is found for both coarse
particles and ultrafine soot-rich aerosols; (iii) fine and coarse
particles both show SSA > 0.8, whilst ultrafine urban Aitken mode and soot
particles show SSA < 0.8. The proposed paradigm agrees with aerosol
observations performed during past major field campaigns, this indicating
that relations concerning the paradigm have a general validity. |
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