10.9
IMPROVING WIND ESTIMATES FOR TIME OF FLIGHT CALCULATIONS BY ADDING NEAR REAL-TIME AIRCRAFT REPORTS TO RUC

NASA is developing the Center-TRACON Automation System (CTAS), a set of Air Traffic Management (ATM) Decision Support Tools (DST) for enroute (Center) and terminal (TRACON) airspace designed to enable controllers to increase capacity and flight efficiency. A crucial component of the CTAS, or other ATM DSTs, is the estimation of the time-to-fly (TTF) for aircraft along flight path segments. The estimation of TTF is also crucial to many elements of "free flight." Accurate TTF estimation requires accurate knowledge of the wind through which the aircraft are flying. There are currently envisioned to be two sources of wind data for CTAS: the Rapid Update Cycle (RUC) for the Center airspace, a numerical weather prediction model developed by the NOAA Forecast System Laboratory (FSL) and run operationally by the NWS, and the Integrated Terminal Weather System (ITWS) Terminal Winds (TW) for the TRACON airspace, developed at MIT Lincoln Laboratory under funding from the FAA. The ITWS TW system takes in RUC data and refines the RUC forecasts with local measurements of the wind.

This paper presents results from a one-year study based on the application of the TW algorithm to the Center airspace as a value-added improvement to the baseline RUC product. This study¹ has three goals: (1) determine the errors in the baseline 60 km resolution RUC forecast wind fields relative to the needs of enroute DSTs such as CTAS, (2) determine the benefit of using the TW algorithm to refine the RUC forecast wind fields with near real-time aircraft reports, and (3) identify factors that influence wind field errors in order to improve accuracy and estimate errors in real time.

The addition of recent aircraft reports significantly improves the accuracy of the RUC forecast wind fields. The addition of the recent observations also significantly reduces correlations among the errors, which is an important consideration in accurate TTF estimation. The errors in the wind fields increase with increasing wind speed, in part due to an underestimation of wind speed, which increases with increasing wind speed. The errors in the TW wind fields decrease with increasing numbers of aircraft reports (RUC could not be rerun with varying amounts of input data). The TW system provides an estimate of the error variance at each grid point, and the errors in the TW wind fields increase as the TW estimates of the error variance increase. Different types of weather also are seen to influence wind field accuracy.

Reference:

¹ This study is part of a larger effort funded by NASA which includes the NOAA/FSL.

* This work was sponsored by the National Aeronautics and Space Administration The views expressed are those of the authors and do not reflect the official policy or position of the U.S. Government.

⁺ Opinions, interpretations, conclusions and recommendations are those of the authors and are not necessarily endorsed by the United States Air Force

The 8th Conference on Aviation, Range, and Aerospace Meteorology