An Overview of Aerosol-Cloud Indirect Effects Estimated From Global Models

The prediction of the indirect effect of aerosols on clouds depends on the predicted aerosol properties as well as on the cloud properties. Here, we summarize recent model and satellite estimates of the effects of aerosols on cloud droplet number concentrations and radiative forcing. The estimates of radiative forcing from satellite observations tend to be significantly smaller than those deduced from global models. We explore several possible reasons for this disparity and suggest ways to improve the estimated radiative forcing.