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| Titel |
Spaceborne observations of the lidar ratio of marine aerosols |
| VerfasserIn |
K. W. Dawson, N. Meskhidze, D. Josset, S. Gassó |
| 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 ; 15, no. 6 ; Nr. 15, no. 6 (2015-03-23), S.3241-3255 |
| Datensatznummer |
250119570
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| Publikation (Nr.) |
 copernicus.org/acp-15-3241-2015.pdf |
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| Zusammenfassung |
| Retrievals of aerosol optical depth (AOD) from the Cloud-Aerosol Lidar with
Orthogonal Polarization (CALIOP) satellite sensor require the assumption of
the extinction-to-backscatter ratio, also known as the lidar ratio. This
paper evaluates a new method to calculate the lidar ratio of marine aerosols
using two independent sources: the AOD from the Synergized Optical Depth of
Aerosols (SODA) project and the integrated attenuated backscatter from CALIOP. With
this method, the particulate lidar ratio can be derived for individual
CALIOP retrievals in single aerosol layer, cloud-free columns over the
ocean. Global analyses are carried out using CALIOP level 2, 5 km marine
aerosol layer products and the collocated SODA nighttime data from December
2007 to November 2010. The global mean lidar ratio for marine aerosols was
found to be 26 sr, roughly 30% higher than the current value prescribed
by the CALIOP standard retrieval algorithm. Data analysis also showed
considerable spatiotemporal variability in the calculated lidar ratio over
the remote oceans. The calculated marine aerosol lidar ratio is found to
vary with the mean ocean surface wind speed (U10). An increase in
U10 reduces the mean lidar ratio for marine regions from 32 ± 17 sr (for 0 < U10 < 4 m s−1) to 22 ± 7 sr (for
U10 > 15 m s−1). Such changes in the lidar ratio are
expected to have a corresponding effect on the marine AOD from CALIOP. The
outcomes of this study are relevant for future improvements of the SODA and
CALIOP operational product and could lead to more accurate retrievals of
marine AOD. |
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