Evaluation of wind algorithms for reporting wind speed and gust for use in air traffic control towers

The recommended methods of deriving wind speed, wind direction and gust values for use by controllers in air traffic control towers have been established by the International Civil Aviation Organization (ICAO). Standard practice is to use the most recent 2-minute averages for wind speed and wind direction reports, and the most recent 10-minute maximum wind speed to determine the wind gust report. This paper compares the properties of past winds over different time intervals to future winds over a 2-minute time interval. The latter interval is considered to be most applicable to aircraft on final approach and is representative of the time it takes for a modern aircraft to reach the touchdown point on the runway from the outer marker which ranges from round 4- to 7-nm from the runway threshold. One-second wind data, covering many natural weather conditions, are used for the analyses. Statistical t-test is used to compare average wind speeds. The gust wind attribute was tested using the standard F-test for comparing standard deviations of sample wind speeds, since the maximum value or gust is statistically similar to the standard deviation. Properties of wind data are also analyzed via normalized histograms and cumulative distribution plots. The results demonstrate that the established algorithms recommended by ICAO and used generally throughout the U.S. are reasonable for the application.