Aerosol effects in mixed-phase clouds in GFDL AM3+

Mixed-phase clouds are clouds that typically occur between 0 and -40 degree C and contain both liquid and ice phase condensate. Understanding the effects of aerosols in these clouds in global models is a challenge. One reason is the coexistence of liquid and ice phase microphysics and the interactions between them. Another is the coarse space and time resolution of global models, which requires the usage of parameterizations. In this study, we aim to improve the simulation of aerosol effects in mixed-phase clouds in the GFDL AM3+ model by introducing a parameterization of black carbon ice nucleation. With a double moment cloud microphysics scheme, the GFDL AM3+ model has the capacity to simulate detailed perturbations to cloud microphysics through the addition of black carbon ice nucleation. We will compare the simulated cloud field and aerosol radiative forcing to the original model and to satellite observations.