"Scanning Raman Lidar Measurements of Aerosol Backscatter and Extinction Profiles During TARFOX"
The NASA/GSFC Scanning Raman Lidar (SRL) was deployed at Wallops Island, VA for TARFOX. During this experiment, the SRL operated exclusively during the daytime, acquiring 95 hours of aerosol backscattering and extinction measurements on 15 days. The lidar measured aerosol backscatter at the laser wavelength of 355 nm as well as Raman scattering from nitrogen at 387 nm. Aerosol extinction profiles computed using the Raman return signals are compared with those derived by inversion of the lidar return signals at the laser wavelength. Initial results indicate good agreement using an extinction/backscatter ratio of approximately 60 steradians. Further results regarding the variability of this ratio will be presented.
Aerosol extinction profiles are computed for all days of operations by inversion of the lidar return at the laser wavelength using the extinction/backscattering ratio derived from the Raman nitrogen data. Aerosol scattering ratio profiles are also computed and are used to locate clouds. Aerosol optical thicknesses (355 nm) computed by integrating the lidar extinction profiles between the surface and an altitude of 5 km and those measured by a sunphotometer (340 nm) also located at Wallops Island agree within about 5% on average during cloudfree days. Both instruments also showed good agreement in observing variations in aerosol optical thickness which occurred during several days.
The lidar measurements show the presence of elevated layers of aerosols during several days. The contributions of these elevated layers to the total aerosol optical thickness will also be discussed.
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Last updated Apr-30-1997
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