Closure between Measured and Modeled Light Scattering Coefficients for Laboratory Test Aerosols and Dry Ambient Aerosols

摘要

Anthropogenic aerosol particles have received increased attention as a result of the ability of these aerosol to scatter and absorb light, resulting in visibility degradation and the potential to cool or warm the earth's atmosphere. The properties of these aerosol particles are either estimated with measurements or models and then used as inputs to visibility and global climate models to better assess their effects. This paper compares measured and modeled aerosol properties that were obtained from laboratory test aerosol experiments and from a 30-day intensive field campaign studying atmospheric aerosol. Aerosol properties reported here include the total and back light scattering coefficients (sigma_(sp) and sigma_(bsp), respectively) at controlled relative humidity (RH) conditions. In the laboratory, sigma_(sp) and sigma_(bsp) were obtained at RH values between 40% and 85% for sub-mum diameter NaCl particles measured with three integrating nephelometers. Modeled results were obtained using Mie Light scattering code, measured size distributions, and particle size growth curves as a function of RH. Closure between measured and modeled sigma_(sp) results for NaCl at dry and wet conditions are within 4 % and ～10%), respectively. The ambient aerosol field measurements occurred at Bondville, IL, a NOAA-CMDL regional aerosol monitoring station located in the Midwest U.S. Closure between measured and modeled results for dry sigma_(sp) and sigma_(bsp) for sub-mum diameter particles are within 10%) and 14%), respectively.