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| Titel |
AERONET-based models of smoke-dominated aerosol near source regions and transported over oceans, and implications for satellite retrievals of aerosol optical depth |
| VerfasserIn |
A. M. Sayer, N. C. Hsu, T. F. Eck, A. Smirnov, B. N. Holben |
| 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 ; 14, no. 20 ; Nr. 14, no. 20 (2014-10-31), S.11493-11523 |
| Datensatznummer |
250119133
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| Publikation (Nr.) |
 copernicus.org/acp-14-11493-2014.pdf |
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| Zusammenfassung |
| Smoke aerosols from biomass burning are an important component of the global
aerosol system. Analysis of Aerosol Robotic Network (AERONET) retrievals of
aerosol microphysical/optical parameters at 10 sites reveals variety between
biomass burning aerosols in different global source regions, in terms of
aerosol particle size and single scatter albedo (SSA). Case studies of smoke
observed at coastal/island AERONET sites also mostly lie within the range of
variability at the near-source sites. Differences between sites tend to be
larger than variability at an individual site, although optical properties
for some sites in different regions can be quite similar. Across the sites,
typical midvisible SSA ranges from ~ 0.95–0.97 (sites dominated by boreal
forest or peat burning, typically with larger fine-mode particle radius and
spread) to ~ 0.88–0.9 (sites most influenced by grass, shrub, or crop
burning, typically smaller fine-mode particle radius and spread). The
tropical forest site Alta Floresta (Brazil) is closer to this second
category, although with intermediate SSA ~ 0.92. The strongest absorption
is seen in southern African savannah at Mongu (Zambia), with average
midvisible SSA ~ 0.85. Sites with stronger absorption also tend to have
stronger spectral gradients in SSA, becoming more absorbing at longer
wavelengths. Microphysical/optical models are presented in detail so as to
facilitate their use in radiative transfer calculations, including extension
to UV (ultraviolet) wavelengths, and lidar ratios. One intended application is to serve as
candidate optical models for use in satellite aerosol optical depth (AOD)
retrieval algorithms. The models presently adopted by these algorithms over
ocean often have insufficient absorption (i.e. too high SSA) to represent
these biomass burning aerosols. The underestimates in satellite-retrieved AOD
in smoke outflow regions, which have important consequences for applications
of these satellite data sets, are consistent with the level of underestimated
absorption. |
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