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Titel |
Seasonal and regional aerosol characteristics in East Asia investigated with 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 |
Konferenz |
EGU General Assembly 2010
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 12 (2010) |
Datensatznummer |
250033029
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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 Community Multiscale Air
Quality (CMAQ) v4.3 modeling system. In this study, two MODIS AOD products (ÏMODIS:
ÏM-BAER and ÏNASA) retrieved through a modified Bremen Aerosol Retrieval (M-BAER)
algorithm and NASA collection 5 (C005) algorithm were compared with the AOD (ÏCMAQ)
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 ÏMODIS
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 ÏMODIS 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 ÏMODIS and ÏCMAQ showed
strong spatial, temporal and seasonal variations. For example, during the summer
episode, ÏMODIS and ÏCMAQ 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, ÏMODIS and ÏCMAQ were higher due largely to high levels of NH4NO3
formed over the urban and industrial centers, as well as over Chinese agricultural and
livestock farming areas with high NH3 emissions. ÏCMAQ was in general larger than
ÏMODIS during the year, except for spring. The high biases (ÏCMAQ > ÏMODIS)
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 Ïext
and ÏCMAQ. Therefore, the importance of NH4NO3 in estimating Ïshould not
be ignored, particularly in studies of the East Asian air quality. In addition, the
accuracy of ÏM-BAER and ÏNASA was evaluated by a comparison with the AOD
(ÏAERONET) from the AERONET sites in East Asia. Both ÏM-BAER and ÏNASA
showed a strong correlation with ÏAERONET 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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