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Hegg, D, Covert, D, Univ. of Washington, Atmospheric Sciences, WA

Clear-column closure studies of lower tropospheric aerosol extinction during ACE-Asia using airborne sunphotometer , airborne in-situ and ship-based lidar measurements Beat Schmid et al. NASA Ames/ BAER Institute, Sonoma, CA. Co-authors.

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Hegg, D, Covert, D, Univ. of Washington, Atmospheric Sciences, WA

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  1. Clear-column closure studies of lower tropospheric aerosol extinction during ACE-Asia using airborne sunphotometer, airborne in-situ and ship-based lidar measurementsBeat Schmid et al. NASA Ames/BAER Institute, Sonoma, CA

  2. Co-authors Hegg, D, Covert, D, Univ. of Washington, Atmospheric Sciences, WA 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 Welton, E, GEST/UMBC, NASA Goddard Space Flight Center, Greenbelt, MD

  3. NASA Ames Airborne Sunphotometers (AATS) AOD and H2O AATS-6 (380-1020 nm) AATS-14 (350-1558 nm) C-130 Twin Otter

  4. AATS vertical profiles during ACE-Asia l AATS-14 l AATS-6

  5. Absorption Particle Soot Absorption Photometer (PSAP, =550nm) noisy (averaging) low RH Corrections (Bond et al., 1999) scattering contribution … inlet-cutoff (Da=8m)* correct to ambient RH* Scattering Nephelometers TSI:  = 450, 550, 700 nm, low RH RR:  = 550 nm, RH=20,60,85% Corrections (Anderson&Ogren, 1998) light source angular truncation (7°-170°) inlet-cutoff (Da=8m)* correct to ambient RH In situ measurement ofExtinction= + *correction not required or done

  6. Extinction the “hard way”: Compute from in situ measurement of size distribution and composition • 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 Wang et al. 2002, JGR (in press) } needs composition

  7. Chemical Composition and size distributions, flight 11, April 17, 2001 Wang et al. [2002]

  8. Extinction closure between AATS-14 and Neph+PSAP for 14 profiles

  9. H2O closure between AATS-14 and in-situ for 26 profiles

  10. How well did past campaigns do on AATS vs Neph+PSAP comparisons? U.S. East Coast, 1996 (Hegg et al., 1997, Hartley et al., 2000) Eastern Asia, 2001 C-130: Redemann et al., 2003 Twin Otter: Schmid et al., 2003 Canary Islands, 1997 (Schmid et al., 2000) U.S. East Coast, 2001 Hobbs et al., (in preparation) Southern Africa (Magi et al., 2002)

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