An Underestimated Negative Cloud Feedback from Cloud Lifetime Changes
Over the Southern Ocean, cloud properties are controlled by an especially tangled web of condensation, phase change, evaporation, and precipitation processes. Microphysics (and thus aerosol-cloud interactions) likely plays a key role in how sensitive these clouds are to warming, requiring a unified approach to aerosol-cloud interactions and cloud feedbacks. In climate models, the parameterized cloud and turbulence processes that govern the models' response to climate perturbations (aerosols, greenhouse gases, and global warming) are poorly constrained and marred by compensating errors in cloud source and sink processes. As a result, uncertainties on model projections have not shrunk even as models have greatly improved in their representation of the present-day cloud state. We explore process errors in modeled precipitation and their consequences for climate projections. We highlight opportunities for better observational and process-modeling understanding of individual processes and how this improved cloud physics understanding can be translated into better parameterizations.