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Study on airborne sunphotometer measurements of aerosol in ACE-Asia, validating SeaWiFS AOD, absorption, scattering corrections, closure experiments with lidar, and in-situ size distribution measurements.
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Airborne sunphotometer measurements of aerosol in ACE-Asia and their comparisons to correlative measurements Beat Schmid et al. BAER Institute, Sonoma, CA Presented by Michael Box University of New South Wales, Sydney
Co-authors Hegg, D, Covert, D, Univ. of Washington, Atmospheric Sciences, WA Hsu, C, Welton, E, GEST/UMBC, NASA Goddard Space Flight Center, Greenbelt, MD Redemann, J, Bay Area Environmental Research, Institute, Sonoma, CA Livingston, J , SRI, International, Menlo Park, CA Russell P, NASA, Ames Research Institute, Moffett Field, CA Wang, J, Flagan, R, Seinfeld, J, California Institute of Technology, Pasadena, CA Bates, D, University of, Miami, Coral Gables, FL Jonsson, H, CIRPAS, Marina, CA
Make Observations to Improve Models of Aerosol Concentrations and Impacts. Title Slide 16
Groundbased observations Lidars, aerosol chemistry & physics, optical properties, and radiation
NASA Ames Airborne Sunphotometers (AATS) AOD (350-1558 nm) and H2O AATS-6 AATS-14 C-130 Twin Otter
ACE-Asia C-130 Flight Tracks C-130 Twin Otter Ron Brown
Flying low over the ocean Validation of SeaWiFS AOD (Hsu et al. algo) with Aircraft Sun photometer Validation
AATS vertical profiles during ACE-Asia l AATS-14 l AATS-6
Absorption Particle Soot Absorption Photometer (PSAP, =550nm) noisy (averaging) low RH Corrections scattering contribution inlet-cutoff (Da=8m)* correct to ambient RH* Scattering Nephelometers = 450, 550, 700 nm, low RH = 550 nm, RH=20,60,85% Corrections light source angular truncation (7°-170°) inlet-cutoff (Da=8m)* correct to ambient RH In situ measurement ofExtinction= + *correction not required or done
Closure between airborne sunphotomter and in-situ for 9 profiles
In situ measurement of size distribution and computation of extinction • Twin DMA, D=15-1000 nm (close to ambient RH) • Aerodynamic Particle Sizer, D=0.5 - 8 mm (drier than ambient RH), • adjust to ambient RH • compute extinction, needs m } needs composition Wang et al. 2002, JGR (submitted)
Closure experiment with airborne sunphotometer and lidar on ship R/V Ron Braun CIRPAS Twin Otter Twin Otter Ron Brown