Simulations of aerosol entrainment in clouds

Dr. William R. Cotton

Colorado State University

In recent years we have performed large eddy simulations of Arctic stratus clouds and of subtropical marine stratocumulus clouds. Based on observations, we have initialized the model with vertical profiles of cloud condensation nuclei (CCN) in which below-cloud air is very clean and above-inversion air is moderately polluted. We then explicitly simulate the entrainment of the CCN into the clouds, their activation as cloud droplets, and subsequent evolution of cloud microphysics and dynamics. The implications of the model results to potential climatic changes by indirect effects of anthropogenic aerosol will be discussed.