HR: 1340h
AN: A13A-0882    [Abstracts]
TI: Microphysical Modeling of New Particle Formation and Growth in Tropospheric Volcanic Plumes
AU: * Du, H
EM: huadu@asrc.cestm.albany.edu
AF: Atmospheric Sciences Research Center, State University of New York at Albany, 251 Fuller Road, Albany, NY 12203, United States
AU: Yu, F
EM: yfq@asrc.cestm.albany.edu
AF: Atmospheric Sciences Research Center, State University of New York at Albany, 251 Fuller Road, Albany, NY 12203, United States
AB: Volcanic eruption is an important natural cause of regional and global climate changes. New aerosols formed inside volcanic plumes influence earth radiation budget by backscattering the solar radiation and serving as the cloud condensation nuclei (CCN). Previous volcanic aerosol studies focused more on aerosol dynamics and climate effects of stratospheric volcanic plumes with little attention paid to tropospheric ones. Recent global modeling studies of new particle formation indicate that volcano eruption can be an important source of new particles in the troposphere, at least in a regional scale. Due to the non-linear dependence of nucleation rates on precursor gas concentrations, it is important to understand the impact of sub-grid dilution and microphysics processes on the volcanic particle source strength. In this study, a size and composition resolved aerosol microphysics model is employed to study the formation and evolution of particles in volcanic plumes. We find that binary H2SO4-H2O homogeneous nucleation (BHN), while generally negligible in the ambient troposphere, can lead to significant new particle formation in tropospheric volcanic plumes. It should be noted that we use the recently improved kinetic BHN model (Yu, J. Chem. Phys., 127, 054301, 2007) which has been constrained by multiple laboratory measurements and has reduced uncertainties. Our simulations also indicate the newly formed particles can grow to CCN size within about one day because of relatively high precursor gas concentrations in the volcanic plume. The effects of various key parameters (volcanic injection altitude, initial SO2 concentration, dilution processes, ambient conditions, etc.) on number concentrations and size ranges of nucleated particles will be discussed as well.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting