HR: 14:25h
AN: A43E-04    [Abstracts]
TI: Global contribution of nucleation to aerosol number and cloud condensation nuclei
AU: * Pierce, J R
EM: jrpierce@andrew.cmu.edu
AF: Department of Chemical Engineering, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, PA 15213, United States
AU: Adams, P J
EM: petera@andrew.cmu.edu
AF: Department of Civil and Environmental Engineering, Department of Engineering of Public Policy, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, PA 15213, United States
AB: The contribution of new particle formation (nucleation) to the tropospheric burdens of aerosol number, or condensation nuclei (CN), and cloud condensation nuclei (CCN) is very uncertain. To evaluate these contributions, we perform global aerosol microphysical simulations to explore how uncertainties in nucleation mechanisms and nucleation rates affect the CN and CCN concentrations. The global model used is the GISS II- prime general circulation model with the size-resolved aerosol microphysics module, TOMAS (1-3). Various parameterizations of binary, ternary and ion-induced nucleation theories are tested in the model to determine how they affect the spatial and temporal distribution of CN and CCN (4-6). For example, a robust feature of global aerosol microphysics models is that binary nucleation parameterizations predict high nucleation rates in the upper troposphere, but the impact of these particles on boundary layer CCN concentrations requires investigation. A novel pseudo steady-state approximation is applied to gas phase sulfuric acid allowing for longer time steps during the calculation of nucleation and condensation and a significant decrease the computation time. (1) Hansen, J. et al., Mon. Weather Rev., 111, (1983). (2) Adams, P. J., and J. H. Seinfeld, J. Geophys. Res., 107, (2002). (3) Pierce, J. P., and Adams, P. J., J. Geophys. Res., 110, (2005) (4) Vehkamaki, H., et al., J. Geophys. Res., 107, (2002). (5) Napari, I., et al., J. Geophys. Res., 107, (2002). (6) Modgil, M. S., et al., J. Geophys. Res., 110, (2005).
DE: 1610 Atmosphere (0315, 0325)
DE: 1626 Global climate models (3337, 4928)
DE: 3311 Clouds and aerosols
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting