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| Titel |
CALIPSO observations of transatlantic dust: vertical stratification and effect of clouds |
| VerfasserIn |
W. Yang, A. Marshak, T. Várnai, O. V. Kalashnikova, A. B. Kostinski |
| 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 ; 12, no. 23 ; Nr. 12, no. 23 (2012-12-03), S.11339-11354 |
| Datensatznummer |
250011634
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| Publikation (Nr.) |
 copernicus.org/acp-12-11339-2012.pdf |
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| Zusammenfassung |
| We use CALIOP nighttime measurements of lidar backscatter, color and
depolarization ratios, as well as particulate retrievals during the
summer of 2007 to study transatlantic dust properties downwind of Saharan
sources, and to examine the influence of nearby clouds on dust. Our analysis
suggests that (1) under clear skies, while lidar backscatter and color ratio
do not change much with altitude and longitude in the Saharan Air Layer
(SAL), depolarization ratio increases with altitude and decreases westward
in the SAL; (2) the vertical lapse rate of dust depolarization ratio,
introduced here, increases within SAL as plumes move westward; (3) nearby
clouds barely affect the backscatter and color ratio of dust volumes within
SAL but not so below SAL. Moreover, the presence of nearby clouds tends to
decrease the depolarization of dust volumes within SAL. Finally, (4) the
odds of CALIOP finding dust below SAL next to clouds are about ⅔ of those
far away from clouds. This feature, together with an apparent increase in
depolarization ratio near clouds, indicates that particles in some dust
volumes loose asphericity in the humid air near clouds, and cannot be
identified by CALIPSO as dust. |
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