HR: 11:05h
AN: A42B-04    [Abstracts]
TI: Aerosol-cloud-surface fluxes interaction simulated in a large-eddy model
AU: * Jiang, H
EM: Hongli.Jiang@noaa.gov
AF: CIRA/NOAA, 325 Broadway R/ET2, Boulder, CO 80305 United States
AU: Feingold, G
EM: Graham.Feingold@noaa.gov
AF: NOAA/ETL, 325 Broadway R/ET2, Boulder, CO 80305 United States
AB: Large-eddy simulations are performed to investigate the effect of increases in aerosol on liquid water path (LWP), cloud fraction, optical depth, and precipitation formation in warm, continental cumulus clouds. A sounding from the Smoke Aerosols, Clouds, Rainfall and Climate (SMOCC) experiment was used to initiate the model. Sets of simulations that either neglect, or include the direct effect of partially absorbing aerosol are performed for a range of aerosol concentrations. In the absence of aerosol direct effect, an increase in aerosol loading results in a reduction in precipitation however the clouds do not experience significant changes in LWP, cloud fraction, and cloud depth. Aerosol effects on LWP and cloud fraction are small compared to the dynamical variability of the clouds at any given aerosol concentration. When the aerosol radiative effects are included, the modification in atmospheric heating profiles, and reduction in surface latent and sensible heat fluxes resulting from the presence of these particles, have a significant effect on cloud parameter and boundary layer evolution. There is significant reduction in the strength of convection, LWP, cloud fraction and cloud depth. These results suggest that in continental regions surface processes must be included in calculations of the response of cloud and precipitation to increase in aerosol. Neglect of these surface processes may result in an overestimate of the second aerosol indirect effect.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0321 Cloud/radiation interaction
DE: 3307 Boundary layer processes
DE: 3311 Clouds and aerosols
DE: 3314 Convective processes
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005