Document Type
Article
Publication Date
12-3-2012
Abstract
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.
Publication Title
Atmospheric Chemistry and Physics
Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.
Recommended Citation
Yang, W.,
Marshak, A.,
Varnai, T.,
Kalashnikova, O. V.,
&
Kostinski, A.
(2012).
CALIPSO observations of transatlantic dust: vertical stratification and effect of clouds.
Atmospheric Chemistry and Physics,
12, 11339-11354.
http://doi.org/10.5194/acp-12-11339-2012
Retrieved from: https://digitalcommons.mtu.edu/physics-fp/189
Version
Publisher's PDF
Publisher's Statement
Published by Copernicus Publications on behalf of the European Geosciences Union. Article deposited here in compliance with publisher policy. Publisher's version of record: https://doi.org/10.5194/acp-12-11339-2012