A Terminal Area PBL Prediction System for DFW

A state-of-the-science mesoscale numerical weather prediction model is being tested in a prototype mode for potential operational use in support of NASA's Terminal Area Productivity (TAP) Program at the Dallas-Fort Worth (DFW) International Airport. The numerical model is the key component of a mesoscale weather prediction system named the Terminal Area PBL Prediction System (TAPPS). TAPPS is being developed and tested for NASA in an effort to improve short period forecasts of wind, wind shear, temperature, and turbulence within stable and convective planetary boundary layers (PBL). This is being done to enhance terminal area productivity by using the weather forecasts as part of the Aircraft Vortex Spacing System (AVOSS). In this paper we will describe the real time numerical modeling system which has three basic components: (i) the numerical model, (ii) the initial data stream, and (iii) the postprocessing system. We also compare the results of several case study simulations with data collected from a field program held during September 1997 at DFW. During this field program, detailed local measurements of the PBL as well as the entire troposphere were taken in an effort to verify the numerical model results. Comparisons indicate that the numerical model is capable of accurately simulating the vertical wind shear structure during the diurnal evolution of the planetary boundary layer. Special emphasis in comparisons between the numerical model and observations are placed on the dynamics of the Great Plains nocturnal low-level jet, which represents the dominant low-level wind shear-production mechanism during many synoptic scale weather regimes.