In this talk, Dr. Liu will introduce an aerosol module and aerosol-cloud interaction parameterizations in NCAR Community Atmospheric Model version 5 (CAM5). The modal aerosol module (MAM) in CAM5 predicts both aerosol mass and number, and internal/external mixing between aerosol components. The interface of aerosol with a two-moment stratiform cloud microphysics scheme includes droplet activation in warm clouds and ice nucleation in mixed-phase and cold ice clouds.

Dr. Liu will also present an evaluation of aerosol and cloud microphysics predictions from CAM5 with observations. We find that the modeled low bias in black carbon concentrations in the remote regions (e.g., Arctic) is clearly because of the too strong aerosol wet scavenging. Cloud microphysics in CAM5 captures the cloud structure and liquid/ice partitioning in mixed-phase clouds evaluated with the DOE ARM Mixed-Phase Arctic Cloud Experiment (M-PACE) observations. At the end, CAM5 is used to study the anthropogenic aerosol effect on the hydrological cycle in East Asia.