Publications

The Federal Aviation Administration (FAA) Integrated Terminal Weather System (ITWS) is supporting the development of products aimed at providing automated guidance to the air traffic managers for the anticipation of changes in ceiling and visibility (C&V) conditions and wake vortex behavior in the terminal area. Fine-resolution, one-dimensional (column) numerical models are being considered to provide information on the evolution of the local fine-scale structure of the lower atmosphere over the terminal area. The Code Brouillard Eau Liquids (COBEL) column model is being investigated for potential use within the ITWS. This one-dimensional numerical model has been developed for the short-term prediction of fog events in the north of France. This report describes initial progress in adapting the COBEL model to a wider range of meteorological conditions. A parameterization of surface frost deposition was implemented and a slight error in the computation of stability in a saturated atmosphere was corrected. Tests suggest that these modifications represent important features of the newest version of the COBEL model. Other significant modifications to the COBEL model were performed. Pressure tendencies and vertical motion (vertical advection) were implemented as additional external forcings to the column model. Sensitivity tests show that these forcings play important roles in determining the onset, evolution and dissipation of low stratiform clouds. Some further applications of the model are briefly discussed and future development efforts are suggested.

We present an overview of the product development strategy and discuss some of the technical considerations. It will be necessary to overcome significant scientific challenges in order to be successful. Our optimism comes from the improved operational meteorological data in the terminal area, from the ability to access and to process these data rapidly, and from ongoing advances in data assimilation for mesoscale models. Our role is to coordinate the fusion of these technical and scientific advances into operational aviation weather products and to evaluate the effectiveness of these products. Major scientific contributions are anticipated from the Forecast Systems Laboratory (FSL), the National Center for Atmospheric Research (NCAR), Pennsylvania State University, and Colorado State University.