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| Titel |
Aerosol physical and chemical properties retrieved from ground-based remote sensing measurements during heavy haze days in Beijing winter |
| VerfasserIn |
Z. Li, X. Gu, L. Wang, D. Li, Y. Xie, K. Li, O. Dubovik, G. Schuster, P. Goloub, Y. Zhang, L. Li, Y. Ma, H. Xu |
| 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. 20 ; Nr. 13, no. 20 (2013-10-16), S.10171-10183 |
| Datensatznummer |
250085755
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| Publikation (Nr.) |
 copernicus.org/acp-13-10171-2013.pdf |
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| Zusammenfassung |
| With the increase in economic development over the past thirty years, many large
cities in eastern and southwestern China are experiencing increased haze
events and atmospheric pollution, causing significant impacts on the regional
environment and even climate. However, knowledge on the aerosol physical and
chemical properties in heavy haze conditions is still insufficient. In this
study, two winter heavy haze events in Beijing that occurred in 2011 and 2012 were
selected and investigated by using the ground-based remote sensing
measurements. We used a CIMEL CE318 sun–sky radiometer to retrieve haze aerosol
optical, physical and chemical properties, including aerosol optical depth
(AOD), size distribution, complex refractive indices and aerosol fractions
identified as black carbon (BC), brown carbon (BrC), mineral dust (DU),
ammonium sulfate-like (AS) components and aerosol water content (AW). The
retrieval results from a total of five haze days showed that the aerosol
loading and properties during the two winter haze events were comparable.
Therefore, average heavy haze property parameters were drawn to present a
research case for future studies. The average AOD is about 3.0 at
440 nm,
and the Ångström exponent is 1.3 from 440 to 870 nm. The fine-mode AOD is
2.8 corresponding to a fine-mode fraction of 0.93. The coarse particles
occupied a considerable volume fraction of the bimodal size distribution in
winter haze events, with the mean particle radius of 0.21 and
2.9 μm for the fine and coarse modes respectively. The real part of
the refractive indices exhibited a relatively flat spectral behavior with an
average value of 1.48 from 440 to 1020 nm. The imaginary part showed
spectral variation, with the value at 440 nm (about 0.013) higher than the other
three wavelengths (about 0.008 at 675 nm). The aerosol composition retrieval
results showed that volume fractions of BC, BrC, DU, AS and AW are 1,
2, 49, 15 and 33%, respectively, on average for the investigated
haze events. The preliminary uncertainty estimation and comparison of these
remote sensing results with in situ BC and PM2.5 measurements are also
presented in the paper. |
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