HR: 0800h
AN: A21B-0858    [Abstracts]
TI: Size-resolved Measurements of Aerosol Mass and Carbon Collected During the Dry Season in the Brazilian Amazon
AU: * Soto-Garcˇa, L L
EM: lydializ_23@yahoo.com
AF: Institute for Tropical Ecosystem Studies (ITES)Department of Chemistry, University of Puerto Rico, PO Box 21910, San Juan, PR 00931-1910 Puerto Rico
AU: Mayol-Bracero, O L
EM: omayol@adam.uprr.pr
AF: Institute for Tropical Ecosystem Studies (ITES)Department of Chemistry, University of Puerto Rico, PO Box 21910, San Juan, PR 00931-1910 Puerto Rico
AU: Kirchstetter, T W
EM: twkirchstetter@lbl.gov
AF: Atmospheric Sciences Department Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS70-108B, Berkeley, CA 94720 United States
AU: Novakov, T
EM: tnovakov@lbl.gov
AF: Atmospheric Sciences Department Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS70-108B, Berkeley, CA 94720 United States
AU: Andreae, M O
EM: andreae@mpch-mainz.mpg.de
AF: Biogeochemistry Department Max Planck Institute for Chemistry, P.O. Box 3060 D-55020, Mainz, DEU D-55020 Germany
AU: Deliz-DelValle, M
EM: maylissa@ites.upr.edu
AF: Institute for Tropical Ecosystem Studies (ITES)Department of Chemistry, University of Puerto Rico, PO Box 21910, San Juan, PR 00931-1910 Puerto Rico
AU: Gonz lez, S
EM: susimarg@yahoo.com
AF: Institute for Tropical Ecosystem Studies (ITES)Department of Chemistry, University of Puerto Rico, PO Box 21910, San Juan, PR 00931-1910 Puerto Rico
AU: Artaxo, P
EM: artaxo@if.usp.br
AF: Instituto de Fisica Universidade de Sao Paulo, Rua do Matao, Travessa R, 187, Sao Paulo, BRA 05508-900 Brazil
AU: Maenhaut, W
EM: Willy.Maenhaut@UGent.be
AF: Ghent University (UGent) Department of Analytical Chemistry Institute for Nuclear Sciences, Proeftuinstraat 86, Gent, BEL B-9000 Belgium
AU: Andreae, T W
EM: twa@mpch-mainz.mpg.de
AF: Biogeochemistry Department Max Planck Institute for Chemistry, P.O. Box 3060 D-55020, Mainz, DEU D-55020 Germany
AU: Andreae, T W
EM: twa@mpch-mainz.mpg.de
AF: Instituto de Fisica Universidade de Sao Paulo, Rua do Matao, Travessa R, 187, Sao Paulo, BRA 05508-900 Brazil
AB: Aerosol samples were collected in a pasture site in the Amazon Basin as part of the project LBA-SMOCC 2002 (Large Scale Biosphere Atmosphere Experiment in Amazonia - Smoke Aerosols, Clouds, Rainfall and Climate: Aerosols from Biomass Burning Perturb Global and Regional Climate) during the end of the dry season, the transition period, and the beginning of the wet season. A Dekati low-pressure impactor (DLPI) with 13 stages was used to collect particles with diameters below 10 μm and above 0.03 μm. The mass concentrations collected on the DLPI aluminum substrates were determined by gravimetric analyses. The concentrations of carbonaceous species (elemental carbon and organic carbon) were determined using evolved gas analysis. The mass concentrations of the absorbing fraction were determined by the light transmission method using an optical spectrometer. Real-time measurements of particle number concentrations were performed simultaneously with aerosol filter sampling. The results presented here only include samples collected at the end of the dry season period. The average concentration of carbonaceous aerosol (total carbon) was in the range of 30 - 50 μg m^-3 representing more than 85% of the total aerosol mass. Mass concentrations were higher for the fine fraction than the coarse fraction during the dry period (fine: 56.7 μg m^-3; coarse: 4.1 μg m^-3) due to the proximity of the fires to the sampling site. The size-resolved carbonaceous material measured by the light transmission method showed a clear mode for particles with diameters between 0.1 to 0.6 μm. Light absorption by particles in the range 0.2 to 1.0 μm exhibited strong wavelength dependence, varying by more than λ^-2. By contrast, aerosol particles larger than 1.0 μm exhibited relatively weak spectral dependence. Additional results for the size-resolved concentrations of the carbonaceous aerosol and its light absorbing properties will be presented.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005