Under sponsorship from the FAA Aviation Weather Research Program (AWR) and the NASA Aviation Safety Program (AvSP), and in collaboration with NOAA’s Forecast Systems Laboratory (FSL), we are developing and evaluating turbulence forecasting algorithms of upper-level clear-air turbulence (CAT). The goal is to produce automated, operational forecasts having probabilities of detection and false alarm rates competitive with human forecasts. The main emphasis has been on construction of a fuzzy-logic based algorithm that combines available measurements in the form of pilot reports of turbulence with output from operational numerical forecast models such as the RUC2. This algorithm, dubbed ITFA, the Integrated Turbulence Forecasting Algorithm, is now routinely available to the aviation community through the Aviation Digital Data Services (ADDS) web site. Although this product is still experimental and is constantly undergoing upgrades, the predictions do in fact seem to be competitive with human forecasts, based on careful evaluations of performance metrics. Currently it is restricted to upper levels (above 20,000 ft) over the continental U.S. (conus). However the concept is also being implemented to provide operational turbulence forecasts over Taiwan under sponsorship of the Taiwan Civil Aeronautics Authority (CAA) using MM5 forecast data as input (click here for sample forecasts).

Obviously, real progress in forecasting atmospheric turbulence requires a better understanding of its genesis and life cycles than we currently have. Towards that end, we are also involved in more fundamental turbulence research areas. In collaboration with NCAR’s MMM division, we are currently using high resolution numerical simulations to attempt to model upper level CAT encounters, with the goal of understanding what exactly caused the event and how it was related to larger observable scale features. These linkages between the large scale flow and turbulence can then in turn be used to develop new turbulence forecasting algorithms. We are also planning a major field experiment for next winter, with concentration on CAT measurements, again with the goal of achieving better understandings of the relationship between the large scale flow and upper level turbulence.

Research Lead: Bob Sharman