Sheared Anvil Clouds from Shallow Cumulus Cloud Tops in Response to Aerosol-Induced Deepening

Both observations and large eddy modeling have demonstrated that aerosol perturbations can promote deepening of shallow cumulus clouds. The tallest of these cumulus clouds have the potential to generate anvil clouds at altitudes of maximum trade inversion. Once formed, veil clouds associated with these anvils contribute to cloud cover and exert a radiative effect on the system. This can be thought of as an additional effect of cloud deepening via aerosol-cloud interaction, and a counter argument to recent studies suggesting a negligible aerosol effect on shallow cumulus cloud cover through buffering mechanisms. In this work, the mechanism and importance of veil clouds associated with cumulus deepening will be studied with large eddy simulations that include a newly implemented two-moment bin microphysics scheme. By perturbing a typical shallow cumulus state, various meteorological conditions are examined to identify conditions that favor veil clouds, and to quantify their contribution to the aerosol-cloud radiative effect.