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| Titel |
Assessment of the MODIS Collections C005 and C004 aerosol optical depth products over the Mediterranean basin |
| VerfasserIn |
C. D. Papadimas, N. Hatzianastassiou, N. Mihalopoulos, M. Kanakidou, B. D. Katsoulis, I. Vardavas |
| 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 ; 9, no. 9 ; Nr. 9, no. 9 (2009-05-07), S.2987-2999 |
| Datensatznummer |
250007267
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| Publikation (Nr.) |
 copernicus.org/acp-9-2987-2009.pdf |
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| Zusammenfassung |
| The second generation Collection 005 (C005) MODIS operational
algorithm for retrieval of aerosol properties was evaluated and
validated for the greater Mediterranean basin
(29.5° N–46.5° N and
10.5° W–38.5° E), a region with an atmosphere under
siege by air pollution and diminishing water resources that are
exacerbated by high aerosol loads and climatic change. The present
study aims to quantify the differences between the C005 and the
previous (C004) MODIS collections, and re-assess the results of
previous studies that have been performed for the region using
MODIS C004 aerosol optical depth (AOD) products. Daily data of AOD
from EOS-Terra covering the 6-year period 2000–2006 were taken from
both C005 and C004 Level-3 datasets, and were inter-compared and
validated against ground-based measurements from 29 AERONET
stations. The C005 data were found to significantly better agree
with the AERONET data than those of C004. The correlation
coefficient between MODIS and AERONET was found to increase from
0.66 to 0.76 and the slope of linear regression MODIS/AERONET from
0.79 to 0.85. The MODIS C005 data still overestimate/underestimate
the AERONET AOD values smaller/larger than 0.25, but to a much
smaller extent than C004 data. The better agreement of C005 with
AERONET data arises from the generally lower C005 values, with
regional mean AOD values equal to 0.27 and 0.22 for C004 and C005,
respectively. This decrease, however, is not uniform over the region
and involves a significant decrease over land and a small increase
over the ocean for AOD values greater than 0.1 (opposite changes
were found under aerosol-clean conditions). Both data sets indicate
a decrease in the regional mean AOD over the period 2000–2006,
equal to 20% based on C005 and 17% based on C004 datasets, though
the intra-annual and inter-annual variation did not change
significantly, thus indicating a systematic correction to C004
values. |
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