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Proceedings Paper

Raman-Mie lidar measurements of low and optically thin cloud
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Paper Abstract

In this paper, we implement and compare two complementary methods for the measurement of low cloud optical depth with a Raman-Mie lidar over the metropolitan area of New York City. The first approach, based on the method of S. Young, determines the cloud optical depth by regressing the elastic signal against a molecular reference signal above and below the cloud. Due to high aerosol loading below and above the low cloud, correction for aerosol influence was necessary and achieved with the combined Raman-elastic returns. The second approach uses N2-Raman signal to derive cloud extinction profiles and then integrate them to determine optical depth. We find excellent agreements between these two retrievals for cloud optical depths as large as 1.5. Extinction-to-backscatter ratio within the low cloud is obtained and is shown to be consistent to values calculated from liquid water cloud model. The varied lidar ratios at cloud edge may imply the changes of cloud droplet size providing clues to the CCN seeding process. Furthermore, multiple-scattering effects on retrieving cloud optical depths are estimated by using an empirical model and specific lidar parameters.

Paper Details

Date Published: 26 September 2007
PDF: 10 pages
Proc. SPIE 6681, Lidar Remote Sensing for Environmental Monitoring VIII, 66810T (26 September 2007); doi: 10.1117/12.734126
Show Author Affiliations
Yonghua Wu, City College, CUNY (United States)
Shuki Chaw, City College, CUNY (United States)
Barry Gross, City College, CUNY (United States)
Viviana Vladutescu, City College, CUNY (United States)
Leona Charles, City College, CUNY (United States)
Nianwen Cao, City College, CUNY (United States)
Fred Moshary, City College, CUNY (United States)
Sam Ahmed, City College, CUNY (United States)

Published in SPIE Proceedings Vol. 6681:
Lidar Remote Sensing for Environmental Monitoring VIII
Upendra N. Singh, Editor(s)

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