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| Titel |
Aerosol optical properties in the North China Plain during HaChi campaign: an in-situ optical closure study |
| VerfasserIn |
N. Ma, C. S. Zhao, A. Nowak, T. Müller, S. Pfeifer, Y. F. Cheng, Z. Z. Deng, P. F. Liu, W. Y. Xu, L. Ran, P. Yan, T. Göbel, E. Hallbauer, K. Mildenberger, S. Henning, J. Yu, L. L. Chen, X. J. Zhou, F. Stratmann, A. Wiedensohler |
| 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 ; 11, no. 12 ; Nr. 11, no. 12 (2011-06-23), S.5959-5973 |
| Datensatznummer |
250009868
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| Publikation (Nr.) |
 copernicus.org/acp-11-5959-2011.pdf |
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| Zusammenfassung |
| The largest uncertainty in the estimation of climate forcing stems from
atmospheric aerosols. In early spring and summer of 2009, two periods of
in-situ measurements on aerosol physical and chemical properties were
conducted within the HaChi (Haze in China) project at Wuqing, a town between Beijing and
Tianjin in the North China Plain (NCP). Aerosol optical properties,
including the scattering coefficient (σsp), the hemispheric
back scattering coefficient (σbsp), the absorption coefficient
(σap), as well as the single scattering albedo (ω), are
presented. The diurnal and seasonal variations are analyzed together with
meteorology and satellite data. The mean values of σsp, 550 nm
of the dry aerosol in spring and summer are 280±253 and 379±251 Mm−1,
respectively. The average σap for the two periods is
respectively 47±38 and 43±27 Mm−1. The mean values of ω
at the wavelength of 637 nm are 0.82±0.05 and 0.86±0.05 for
spring and summer, respectively. The relative high levels of σsp
and σbsp are representative of the regional aerosol pollution
in the NCP. Pronounced diurnal cycle of $σsp,
σap and ω are found, mainly influenced by the evolution
of boundary layer and the accumulation of local emissions during nighttime. The
pollutants transported from the southwest of the NCP are more significant
than that from the two megacities, Beijing and Tianjin, in both spring and
summer. An optical closure experiment is conducted to better understand the
uncertainties of the measurements. Good correlations (R>0.98) are found
between the values measured by the nephelometer and the values calculated
with a modified Mie model. The Monte Carlo simulation shows an uncertainty of
about 30 % for the calculations. Considering all possible uncertainties of
measurements, calculated σsp and σbsp agree well
with the measured values, indicating a stable performance of instruments and
thus reliable aerosol optical data. |
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