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Lidar Measurements During INTEX-B. Thomas J. Duck Department of Physics and Atmospheric Science Dalhousie University. Atmospheric-Optics Laboratory http://aolab.phys.dal.ca/. At Pemberton Helicopters. Helping Hands. Operations at Twilight. INTEX-B Measurements Summary.
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Lidar Measurements During INTEX-B Thomas J. Duck Department of Physics and Atmospheric Science Dalhousie University Atmospheric-Optics Laboratory http://aolab.phys.dal.ca/
INTEX-B Measurements Summary • 11 May 2006, 01-11 UTC • 14 May 2006, 01-09 UTC • 15 May 2006, 02-16 UTC • 16 May 2006, 0400-0435 UTC • 16 May 2006, 0640-1830 UTC • 17 May 2006, 03-10 UTC • 17 May 2006, 1700-1930 UTC
Lidar Backscatter Ratio (R) • Ratio of total to molecular signal • Clear air: R=1 • Typical aerosol pollution: 2<R<5 • Clouds R>10 • Can be formed using either: • molecular channel of lidar • radiosonde density profile
CLOUDS AEROSOLS
THIN COULDS AND AEROSOLS? AEROSOLS
AEROSOLS SIGNAL INDUCED NOISE?
CLOUDS AEROSOLS NOTE SHORT TIME INTERVAL
HIGH ALTITUDE AEROSOLS
HIGH ALTITUDE AEROSOLS (AGAIN!) THIN CLOUDS AEROSOLS
CLOUDS AEROSOLS
Data Issues • Products: • aerosol/molecular backscatter ratio • can convert to backscattering cross-section • aerosol extinction • aerosols are too optically thin for this • can estimate given assumption of lidar ratio • Signal-induced noise • need to apply correction to get lower altitudes
Some Context: Alaskan Smoke over NS during ICARTT 11/12 July 2004
FLEXPART Column Retroplume (for measurement on next day)
Next Steps • Refine/improve data products • FLEXPART footprint determination • in collaboration with Andreas Stohl • may provide useful input to GEOS-Chem work • Use AMS info for lidar ratio estimate (?) • Comparisons with sondes, Met charts • reasons for constant descent? • water vapour impact?
The End Thomas J. Duck <tom.duck@dal.ca> Atmospheric-Optics Laboratory http://aolab.phys.dal.ca/