HR: 16:15h
AN: A14B-02    [Abstracts]
TI: Providing Size-Resolved Mixing State Inputs to Improve Aerosol Optics Models: Comparison of ACE-Asia Aerosol Chemical Measurements for Different Source Regions With Simultaneous Optical Measurements
AU: * Sullivan, R C
EM: rcsulliv@ucsd.edu
AF: Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 United States
AU: Poon, G
A14B-02 AF: Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 United States
AU: Guazzotti, S
A14B-02 AF: Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 United States
AU: Sodeman, D
A14B-02 AF: Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89512 United States
AU: Holecek, J
A14B-02 AF: Scripps Intitution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 United States
AU: Spencer, M
A14B-02 AF: Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 United States
AU: Prather, K
EM: kprather@ucsd.edu
AF: Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 United States
AU: Prather, K
EM: kprather@ucsd.edu
AF: Scripps Intitution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 United States
AB: Measurements made of the aerodynamic size and chemical composition of single aerosol particles on board the R/V Ronald H. Brown sailing between Hawaii and the Sea of Japan during ACE-Asia in 2001 revealed a complex mixture of mineral dust, organic carbon, elemental carbon, sulfates, nitrates, chloride, ammonium, and sea salt. The air mass source regions included influences from the Pacific Ocean, Miyakejima volcano, Gobi and Taklimakan Deserts, Shanghai, Japan, and Korea. The particle composition sampled from each of these regions showed unique changes in the aerosol's mixing state. This complexity presents major challenges in accurately modeling the optical properties of the Asian aerosol. The degree of closure between the measured chemical and optical properties of this aerosol and those predicted by models has been presented by Quinn et al. [JGR, 109, D19S01, doi: 10.1029/2003JD004010, 2004]. Differences between measured and calculated aerosol absorption coefficients were partly attributed to the assumption of internally mixed homogeneous spheres for the aerosol population. Good correlations between measured and calculated aerosol mass and light scattering were found but relied on particle shapes not confirmed by measurements. To better our understanding of the relationship between aerosol chemistry and optical measurements, and provide more detailed inputs to improve the predictions of optical models, we present size-resolved single-particle mixing state results obtained by an ATOFMS for the seven air mass source regions described by Quinn et al. (2004). Our results do not support the assumption of a homogeneous internally mixed aerosol population for many of the source regions. Particular focus is given to the mixing state and chemical associations of sulfate, nitrate, chloride, ammonium, OC, EC, dust, and sea salt. We demonstrate the segregation of ammonium, sulfate, and nitrate within individual particles throughout the study and discuss the different processes that could account for the observed differences in particle chemistry. Finally, our size-resolved single-particle mixing state results for ACE-Asia will be compared to those obtained during other several other marine field campaigns.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0360 Radiation: transmission and scattering
DE: 0365 Troposphere: composition and chemistry
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005