HR: 0830h
AN: A11E-0023    [PDF]
TI: A Comparison and Summary of Aerosol Optical Properties as Observed from Aircraft, Ship and Land During ACE-Asia
AU: * Masonis, S
EM: sarahd@atmos.washington.edu
AF: Department of Atmospheric Sciences, University of Washington Box 351640, 408 ATG, Seattle, WA 98195 United States
AU: Quinn, P
EM: Patricia.K.Quinn@noaa.gov
AF: NOAA Pacific Marine Environmental Lab, 7600 Sand Point Way NE, Seattle, WA 98115 United States
AU: Jefferson, A
EM: Anne.Jefferson@noaa.gov
AF: NOAA Climate Monitoring and Diagnostics Lab, 325 Broadway, Boulder, CO 80305 United States
AU: Clarke, A
EM: tclarke@soest.hawaii.edu
AF: Department of Oceanography, University of Hawaii 1000 Pope Rd., Honolulu, HI 96822 United States
AU: Carrico, C
EM: carrico@lamar.colostate.edu
AF: Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523 United States
AU: Carrico, C
EM: carrico@lamar.colostate.edu
AF: Department of Civil and Environmental Engineering, University of Illinois, Urbana, IL 61801 United States
AU: Hegg, D
EM: deanhegg@atmos.washington.edu
AF: Department of Atmospheric Sciences, University of Washington Box 351640, 408 ATG, Seattle, WA 98195 United States
AB: In-situ measurements of aerosol optical properties were made from multiple research platforms during the ACE-Asia experiment, which took place between March 31 and May 04, 2001. A focus of these measurements was to constrain the optical properties of pollutants and desert dust in the region of China, Korea and Japan so that they can be more accurately represented in radiative forcing models. Each of the platforms involved in ACE-Asia covered a different geographic area and, in some cases, different vertical segments of the atmosphere. The most comprehensive set of information can thus be gained by combining this suite of measurements. First, however, we need to test whether these platforms made equivalent measurements of the aerosol optical properties. This is done by comparing visible-wavelength scattering, absorption, hemispheric backscatter, light scattering hygroscopic growth, Angstrom exponent, hemispheric backscatter fraction, single scatter albedo, and light scattering fine mode fraction as measured in-situ from four of the ACE-Asia platforms: the National Center for Atmospheric Research C-130; the Office of Naval Research Center for Interdisciplinary Remotely-Piloted Aircraft Studies Twin Otter; the National Oceanographic and Atmospheric Administration's ship R.V. Ron Brown; and the South Korean surface station Gosan on Jeju Island. Results will be shown for both direct inter-platform comparisons and for comparisons of campaign-wide data sets. Based on the discrepancies seen in the direct inter-platform comparisons we can infer how much of the difference in the campaign-wide data sets can be attributed to instrumental discrepancies and how much to real differences in the atmospheric aerosol sampled by the platforms. This analysis serves two purposes: 1) it helps us identify biases or errors in any given platform's data set and 2) it helps us to understand how accurately each platform's measurements can be extrapolated to represent the broader ACE-Asia study region. For the C-130, Ron Brown and Gosan data sets optical properties were separately measured for the sub- and super-micron aerosol. This allows us to take cases where the fine mode fraction of scattering, FMF$_{scat}$, was high and define the optical properties of pollution from the sub-micron data set. Similarly, we take cases where FMF$_{scat}$ was low and define the optical properties of dust using the super-micron data set. Finally, we show how the optical properties of the total aerosol change as a function of FMF$_{scat}$. Our sub-micron and super-micron data can be used directly in a model for the optical properties of the fine and coarse mode aerosol, respectively. Also, modelers can use sub-micron versus total mass fractions and mass scattering efficiencies to calculate FMF$_{scat}$ then compare their calculated optical properties as a function of FMF$_{scat}$ against our measured relationships.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0345 Pollution--urban and regional (0305)
DE: 0394 Instruments and techniques
DE: 1610 Atmosphere (0315, 0325)
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting