| Session Details | |
| Section | AS - Atmospheric Sciences |
| Session Title | Microphysical Processes in Cloud Resolving, Numerical Weather Prediction, and Climate Models |
| Main Convener | Dr. Wei-Kuo Tao (Goddard Space Flight Center, NASA, United States) |
| Co-convener(s) | Prof. Jen-Ping Chen (National Taiwan University, Taiwan) Prof. Jen-Ping Chen (National Taiwan University, Taiwan) Prof. Song-You Hong (Yonsei University, Korea, South) |
| Session Description | Continuing advances in computing power are allowing atmospheric prediction models to be run at progressively finer scales of resolution, using increasingly more sophisticated physical parameterizations and numerical methods. The representation of cloud microphysical processes is a key component of these models, and during the past decade both research and operational numerical weather prediction (NWP) models have started using more complex microphysical schemes originally developed from high-resolution cloud resolving models (CRMs). Cloud resolving models, which are run at horizontal resolutions on the order of 1-2 km or less, explicitly simulate complex dynamical and microphysical processes associated with deep, precipitating atmospheric convection. Because operational NWP models are run at coarser resolutions, the effects of atmospheric convection must be parameterized, leading to large sources of error that most dramatically impact quantitative precipitation forecasts (QPF). A recent report to the United States Weather Research Program (USWRP) Science Steering Committee specifically calls for the replacement of implicit cumulus parameterization schemes with explicit bulk schemes as part of a community effort to improve QPF. It is not clear, however, whether such a strategy alone will resolve the difficult and outstanding challenges that face mesoscale numerical weather prediction. In addition, many global circulation models (GCMs) and climate models are predicting cloud processes using diagnostic and prognostic methods. The coarser resolution of these models make the representation of partial cloud fraction more important, particularly with respect to the large sensitivities and complexities involved with cloud-radiation interactions. Some operational weather centers are, in fact, attempting to unify physics development, including the use of cloud parameterization schemes over a wide range of temporal and spatial scales of motion. The goal of this session is to discuss the issues concerning the representation of microphysical processes in cloud resolving, weather, and climate models, bringing together those knowledgeable in the areas of cloud microphysical observations, numerical modeling, and weather and climate forecasting. |