Extended Abstract (536K)JP2.9
Evaluation of wind algorithms for reporting wind direction for use in air traffic control towers
Thomas A. Seliga, Volpe National Transportation Systems Center, Cambridge, MA; and D. A. Hazen
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 wind directions over different time intervals to future winds over a 2-minute time interval. It is assumed that the latter interval is considered to be most applicable to aircraft on final approach, since it 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 several natural weather conditions, are used for the analyses. The statistical t-test is used to compare average wind directions under differing backward-looking averaging times. The angular range in wind direction associated with occurrences of wind gusts was tested using the standard F-test for comparing standard deviations, since the range in wind directions is statistically similar to the standard deviation. Properties of wind direction data are also examined via normalized histograms and cumulative distribution plots. The north wind anomaly and anemometer inertial effects are accounted for in the calculations using the standard ICAO methodology. The results demonstrate that the established algorithms recommended by ICAO and used generally throughout the U.S. are reasonable for the application.
Joint Poster Session 2, Observation and Datasets-Part II (Joint between the 16th Conference on Applied Climatology and the 14th Symposium on Meteorological Observations and Instrumentation)
Wednesday, 17 January 2007, 2:30 PM-4:00 PM, Exhibit Hall C
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