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Comparison of Aerosol Optical Properties and Water Vapor Among Ground and Airborne Lidars and Sun Photometers During TARFOXWe compare aerosol optical thickness (AOT) and precipitable water vapor (PWV) measurements derived from ground and airborne lidars and sun photometers during the Tropospheric Aerosol Radiative Forcing Observational Experiment. Such comparisons are important to verify the consistency between various remote sensing measurements before employing them in any assessment of the impact of aerosols on the global radiation balance. Total scattering ratio and extinction profiles measured by the ground-based NASA Goddard Space Flight Center scanning Raman lidar system, which operated from Wallops Island, Virginia (37.86 deg N, 75.51 deg W); are compared with those measured by the Lidar Atmospheric Sensing Experiment (LASE) airborne lidar system aboard the NASA ER-2 aircraft. Bias and root-mean-square differences indicate that these measurements generally agreed within about 10%. Aerosol extinction profiles and estimates of AOT are derived from both lidar measurements using a value for the aerosol extinction/backscattering ratio S(sub a) = 60 sr for the aerosol extinction/backscattering ratio, which was determined from the Raman lidar measurements. The lidar measurements of AOT are found to be generally within 25% of the AOT measured by the NASA Ames Airborne Tracking Sun Photometer (AATS-6). However, during certain periods the lidar and Sun photometer measurements of AOT differed significantly, possibly because of variations in the aerosol physical characteristics (e.g., size, composition) which affect S(sub a). Estimates of PWV, derived from water vapor mixing ratio profiles measured by LASE, are within 5-10% of PWV derived from the airborne Sun photometer. Aerosol extinction profiles measured by both lidars show that aerosols were generally concentrated in the lowest 2-3 km.
Document ID
20020066597
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Ferrare, R. (NASA Langley Research Center Hampton, VA United States)
Ismail, S. (NASA Langley Research Center Hampton, VA United States)
Browell, E. (NASA Langley Research Center Hampton, VA United States)
Brackett, V. (Science Applications International Corp. Hampton, VA United States)
Clayton, M. (NASA Langley Research Center Hampton, VA United States)
Kooi, S. (Science Applications International Corp. Hampton, VA United States)
Melfi, S. H. (Maryland Univ. Baltimore County Catonsville, MD United States)
Whiteman, D. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Schwemmer, G. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Evans, K. (Maryland Univ. Baltimore County Catonsville, MD United States)
Date Acquired
August 20, 2013
Publication Date
April 27, 2000
Publication Information
Publication: Journal of Geophysical Research
Volume: 105
Issue: D8
ISSN: 0148-0227
Subject Category
Environment Pollution
Report/Patent Number
Paper-1999JD901202
Funding Number(s)
CONTRACT_GRANT: NCC2-1094
Distribution Limits
Public
Copyright
Other