HR: 14:40h
AN: A43E-05    [Abstracts]
TI: Estimating the Importance of Boundary Layer Nucleation on CCN With a Global Aerosol Model
AU: * Merikanto, J
EM: j.merikanto@leeds.ac.uk
AF: School of Earth and Environment, The University of Leeds, Leeds, LS2 9JT, United Kingdom
AU: Spracklen, D
EM: d.spracklen@leeds.ac.uk
AF: School of Earth and Environment, The University of Leeds, Leeds, LS2 9JT, United Kingdom
AU: Carslaw, K
EM: k.carslaw@leeds.ac.uk
AF: School of Earth and Environment, The University of Leeds, Leeds, LS2 9JT, United Kingdom
AB: Boundary layer nucleation events have been observed frequently at many locations around the world. Recent observations suggest that, at least locally, the nucleation events can significantly contribute to the number of Cloud Condensation Nuclei (CCN). However, the global importance of nucleation events to CCN is still largely unquantified. While the mechanisms governing atmospheric nucleation are still poorly understood, new observation-based parameterizations for atmospheric nucleation enable us to use a global aerosol microphysics model (GLOMAP) to make a first estimate of the total contribution of nucleation events to CCN. We find that nucleation can increase surface-level CCN concentrations over large continental regions by as much as 50%. A factor 1000 uncertainty in the nucleation rate derived from observations translates into a factor 3 uncertainty in CCN change. Our results show that boundary layer nucleation is an important global source of CCN regardless of the uncertainty in the calculated nucleation rates.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 3307 Boundary layer processes
DE: 3311 Clouds and aerosols
DE: 3337 Global climate models (1626, 4928)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting