The objective of this study is to improve our understanding of the aerosol indirect effect with a focus on ice clouds and its impact on climate modeling and simulation through the interactions among aerosols, clouds, radiation, and dynamical processes, using a general circulation model (GCM) and satellite data. The approach of this research will involve both observational analysis and climate modeling. Cloud and aerosol data retrieved from A-Train satellite observations will be analyzed and employed in climate modeling simulations. The new endeavor will include parameterization of the aerosol first indirect effect on ice crystal effective size for use in climate models based on the A-Train satellite data corresponding to 'clean' and 'polluted' clouds. The UCLA atmospheric GCM (AGCM) will be employed to investigate the response of the atmosphere system to the radiative forcings of the aerosol first indirect effect. This study represents one of the first attempts to quantify the climate impact of the aerosol indirect effect using a GCM in connection with A-train satellite data.
In particular, the project will: (1) develop a parameterization of the aerosol first indirect effect on ice crystal effective size for application to GCMs; (2) quantify the radiative forcing of the aerosol first indirect effect in a climate model; (3) identify the relative importance of the aerosol indirect effect with the presence of aerosol direct radiative forcing; (4) investigate the impact of polluted clouds on global and regional climate change associated with the aerosol direct and indirect effects; and (5) examine the existing aerosol indirect effect parameterization on ice clouds that has been developed on the basis of simplified ice microphysics and explore the satellite data to assist in this type of parameterization.
Broader impacts of this research include an advanced understanding of climatic effects of aerosols and potentially improved climate simulations and projection by reducing aerosol related uncertainties in GCMs. A graduate student will be trained and supported.
