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| Titel |
The measurement of aerosol optical properties at a rural site in Northern China |
| VerfasserIn |
P. Yan, J. Tang, J. Huang, J. T. Mao, X. J. Zhou, Q. Liu, Z. F. Wang, H. G. Zhou |
| 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 ; 8, no. 8 ; Nr. 8, no. 8 (2008-04-24), S.2229-2242 |
| Datensatznummer |
250006062
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| Publikation (Nr.) |
 copernicus.org/acp-8-2229-2008.pdf |
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| Zusammenfassung |
| Atmospheric aerosols constitute one of the largest sources of uncertainty in
the estimation of radiative forcing for climate. From April 2003 to January
2005, in situ measurements of aerosol optical properties were conducted at a
rural site in Northern China, Shangdianzi Global Atmosphere Watch (GAW)
regional station (SDZ), about 150 km from Beijing. Mean values (standard
deviation, S.D.) of scattering and absorption coefficients for the entire
period are 174.6 Mm−1 (189.1 Mm-1) and 17.5 Mm−1 (13.4 Mm-1), respectively. These values are approximately one third of the
reported values for scattering coefficients and one fifth of those for
absorption coefficients obtained in the Beijing urban area. The mean single
scattering albedo (SSA) for the entire period was estimated as 0.88 (0.05),
which is about 0.07 higher than the values reported for the Beijing urban
area, and also higher than the values (0.85) used in a reported climate
simulation for China and India. Both the absorption and scattering
coefficients showed a seasonal cycle with the lowest values in winter, while
the highest values occurred in summer for absorption coefficients and in
fall for scattering coefficients. The mean SSA values were lowest in spring
and highest in winter. The daily variations of aerosol absorption and
scattering coefficients were strongly influenced by synoptic changes
throughout the observation period. A trajectory cluster analysis was applied
to discern the source characteristics of aerosol optical properties for
different air masses. The cluster-mean aerosol scattering coefficients,
absorption coefficients and SSA were all high when the air masses moved from
SW and SE-E directions to the site and aerosols were influenced with heavy
pollution from the dense population centers and industrial areas. The
cluster-mean SSA for air masses coming from the polluted areas was not only
higher than those with trajectories from the "clean" directions, but also
higher than the reported values for the regions with high pollution
emissions (such as the Beijing urban area). This fact might reflect the
substantial secondary aerosol production during transport. The
characteristics of aerosol optical properties measured at this rural site
suggest significant impacts of human activities on the regional aerosol. |
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