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| Titel |
Comparison of AOD between CALIPSO and MODIS: significant differences over major dust and biomass burning regions |
| VerfasserIn |
X. Ma, K. Bartlett, K. Harmon, F. Yu |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 6, no. 9 ; Nr. 6, no. 9 (2013-09-16), S.2391-2401 |
| Datensatznummer |
250085064
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| Publikation (Nr.) |
 copernicus.org/amt-6-2391-2013.pdf |
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| Zusammenfassung |
| Cloud–Aerosol Lidar and Infrared Pathfinder Satellite
Observations (CALIPSO) provide global vertical profiles of aerosol optical
properties for the first time. In this study, we employed about 6 yr
(2006–2011) of CALIPSO level 3 monthly mean gridded aerosol optical
depth (AOD) products (daytime and nighttime) for cloud-free conditions, to
compare with the Moderate Resolution Imaging Spectroradiometer (MODIS) Terra/Aqua level 3 monthly mean AOD dataset for the
same time period. While the spatial distribution and seasonal variability of
CALIPSO AOD is generally consistent with that of MODIS, CALIPSO is overall
lower than MODIS as MODIS has higher frequency than CALIPSO for most bins of
AOD. The correlation between MODIS and CALIPSO is better over ocean than
over land. We focused on four regions that have large systematic
differences: two over dust regions (the Sahara and Northwest China) and two
over biomass burning regions (South Africa and South America). It is found
that CALIPSO AOD is significantly lower than MODIS AOD over dust regions
during the whole time period, with a maximum difference of 0.3 over the
Saharan region and 0.25 over Northwest China. For biomass burning regions,
CALIPSO AOD is significantly higher than MODIS AOD over South Africa, with a
maximum difference of 0.25. Additionally CALIPSO AOD is slightly higher than
MODIS AOD over South America for most of the time period, with a few
exceptions in 2006, 2007, and 2010, when biomass burning is significantly
stronger than during other years. We analyzed the impact of the satellite
spatial and temporal sampling issue by using level 2 CALIPSO and MODIS
products, and these systematic differences can still be found. The results of
this study indicate that systematic differences of CALIPSO relative to MODIS
are closely associated with aerosol types, which vary by location and
season. Large differences over dust and biomass burning regions may suggest
that assumptions made in satellite retrievals, such as the assumed lidar
ratios for CALIPSO retrievals over dust and biomass burning regions or the
surface reflectance information and/or the aerosol model utilized by the MODIS
algorithm, are not appropriate. |
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