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| Titel |
Optimizing CALIPSO Saharan dust retrievals |
| VerfasserIn |
V. Amiridis, U. Wandinger, E. Marinou, E. Giannakaki, A. Tsekeri, S. Basart, S. Kazadzis, A. Gkikas, M. Taylor, J. Baldasano, A. Ansmann |
| 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 ; 13, no. 23 ; Nr. 13, no. 23 (2013-12-13), S.12089-12106 |
| Datensatznummer |
250085877
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| Publikation (Nr.) |
 copernicus.org/acp-13-12089-2013.pdf |
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| Zusammenfassung |
| We demonstrate improvements in CALIPSO (Cloud–Aerosol Lidar and Infrared Pathfinder
Satellite Observations) dust extinction retrievals over
northern Africa and Europe when corrections are applied regarding the Saharan dust
lidar ratio assumption, the separation of the dust portion in detected dust
mixtures, and the averaging scheme introduced in the Level 3 CALIPSO
product. First, a universal, spatially constant lidar ratio of 58 sr instead
of 40 sr is applied to individual Level 2 dust-related backscatter products.
The resulting aerosol optical depths show an improvement compared with
synchronous and collocated AERONET (Aerosol Robotic Network) measurements. An absolute bias of the
order of −0.03 has been found, improving on the statistically significant
biases of the order of −0.10 reported in the literature for the original
CALIPSO product. When compared with the MODIS (Moderate-Resolution Imaging
Spectroradiometer) collocated aerosol optical depth (AOD) product, the
CALIPSO negative bias is even less for the lidar ratio of 58 sr. After
introducing the new lidar ratio for the domain studied, we examine potential
improvements to the climatological CALIPSO Level 3 extinction product: (1) by
introducing a new methodology for the calculation of pure dust extinction
from dust mixtures and (2) by applying an averaging scheme that includes zero
extinction values for the nondust aerosol types detected. The scheme is
applied at a horizontal spatial resolution of 1° × 1° for ease of
comparison with the instantaneous and collocated dust extinction profiles
simulated by the BSC-DREAM8b dust model. Comparisons show that the
extinction profiles retrieved with the proposed methodology reproduce the
well-known model biases per subregion examined. The very good agreement of
the proposed CALIPSO extinction product with respect to AERONET, MODIS and
the BSC-DREAM8b dust model makes this dataset an ideal candidate for the
provision of an accurate and robust multiyear dust climatology over northern
Africa and Europe. |
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