HR: 10:20h
AN: A42B-01    [Abstracts]
TI: Aerosol Indirect Climatic Effect Assessments using the NASA Global Modeling Initiative
AU: * Meskhidze, N
EM: nmeskhidze@eas.gatech.edu
AF: School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332 United States
AU: Nenes, A
EM: nenes@eas.gatech.edu
AF: School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332 United States
AU: Nenes, A
EM: nenes@eas.gatech.edu
AF: Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332 United States
AB: Aerosol-cloud-radiation interaction (the aerosol "indirect effect") remains a major uncertainty in assessments of anthropogenic climate change. Incomplete characterization of chemical complexity and heterogeneity of the aerosols that act as CCN and the wide range of length scales involved in cloud droplet formation process are major limitations in current GCM indirect effect assessments. Because of its computational burden, treatments of aerosol-cloud interactions in GCMs mainly rely on parameterizations. In this work we present anthropogenic indirect forcing calculations obtained from NASA Global Modeling Initiative (GMI) three-dimensional (3-D) model. Simulations were repeated using a variety of aerosol-cloud parameterizations, ranging from empirical relationships between cloud droplet number concentration and total aerosol mass [Boucher and Lohmann, 1995], up to current state-of-the art physically-based aerosol activation parameterization [Nenes and Seinfeld, 2003; Fountoukis and Nenes, 2005]. We have also evaluated the forcing sensitivity to different met fields and trace gas emission datasets. Boucher, O., and U. Lohmann (1995), The sulfate-CCN-cloud albedo effect-A sensitivity study with 2 general-circulation models, Tellus, Ser. B, 47, 281- 300. Fountoukis, C., and A. Nenes (2005), Continued development of a cloud droplet formation parameterization for global climate models, J. Geophys. Res., 110, D11212, doi:10.1029/2004JD005591. Nenes, A., and J. H. Seinfeld (2003), Parameterization of cloud droplet formation in global climate models, J. Geophys. Res., 108, 4415, doi:10.1029/2002JD002911.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1626 Global climate models (3337, 4928)
DE: 3310 Clouds and cloud feedbacks
DE: 3311 Clouds and aerosols
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005