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| Titel |
An investigation into seasonal and regional aerosol characteristics in East Asia using model-predicted and remotely-sensed aerosol properties |
| VerfasserIn |
C. H. Song, M. E. Park, K. H. Lee, H. J. Ahn, Y. Lee, J. Y. Kim, K. M. Han, J. Kim, Y. S. Ghim, Y. J. Kim |
| 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. 22 ; Nr. 8, no. 22 (2008-11-17), S.6627-6654 |
| Datensatznummer |
250006454
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| Publikation (Nr.) |
 copernicus.org/acp-8-6627-2008.pdf |
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| Zusammenfassung |
| In this study, the spatio-temporal and seasonal distributions of EOS/Terra
Moderate Resolution Imaging Spectroradiometer (MODIS)-derived aerosol
optical depth (AOD) over East Asia were analyzed in conjunction with US EPA
Models-3/CMAQ v4.3 modeling. In this study, two MODIS AOD products (τMODIS: τM-BAER and τNASA)
retrieved through a modified Bremen Aerosol Retrieval (M-BAER) algorithm and
NASA collection 5 (C005) algorithm were compared with the AOD (τCMAQ) that was calculated from the US EPA Models-3/CMAQ model
simulations. In general, the CMAQ-predicted AOD values captured the spatial
and temporal variations of the two MODIS AOD products over East Asia
reasonably well. Since τMODIS cannot provide information on the
aerosol chemical composition in the atmosphere, different aerosol formation
characteristics in different regions and different seasons in East Asia
cannot be described or identified by τMODIS itself. Therefore,
the seasonally and regionally varying aerosol formation and distribution
characteristics were investigated by the US EPA Models-3/CMAQ v4.3 model
simulations. The contribution of each particulate chemical species to τMODIS
and τCMAQ showed strong spatial, temporal
and seasonal variations. For example, during the summer episode, τMODIS and τCMAQ were mainly raised due to high
concentrations of (NH4)2SO4 over Chinese urban and industrial
centers and secondary organic aerosols (SOAs) over the southern parts of
China, whereas during the late fall and winter episodes, τMODIS
and τCMAQ were higher due largely to high levels of
NH4NO3 formed over the urban and industrial centers, as well as in
areas with high NH3 emissions. τCMAQ was in general larger
than τMODIS during the year, except for spring. The high biases
(τCMAQ>τMODIS) may be due to the excessive
formation of both (NH4)2SO4 (summer episode) and
NH4NO3 (fall and winter episodes) over China, possibly from the
use of overestimated values for NH3 emissions in the CMAQ modeling.
According to CMAQ modeling, particulate NH4NO3 made a 14%
(summer) to 54% (winter) contribution to σext and τCMAQ. Therefore, the importance of NH4NO3 in estimating
τ should not be ignored, particularly in studies of the East
Asian air quality. In addition, the accuracy of τM-BAER and τNASA
was evaluated by a comparison with the AOD (τAERONET)
from the AERONET sites in East Asia. Both τM-BAER and
τNASA showed a strong correlation with τAERONET around
the 1:1 line (R=0.79), indicating promising potential for the application of
both the M-BAER and NASA aerosol retrieval algorithms to satellite-based air
quality monitoring studies in East Asia. |
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