Open AccessLIDAR‐based F‐factor for wind shear alerting: different smoothing algorithms and application to departing flights
Author(s) -
Lee Y. F.,
Chan P. W.
Publication year - 2014
Publication title -
meteorological applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 59
eISSN - 1469-8080
pISSN - 1350-4827
DOI - 10.1002/met.1434
Subject(s) - wind shear , lidar , meteorology , smoothing , shear (geology) , wind speed , runway , amplification factor , environmental science , computer science , algorithm , mathematics , statistics , geology , geography , remote sensing , cartography , petrology , amplifier , computer network , bandwidth (computing)
Rapid fluctuations of wind shear hazard factor (or F ‐factor) calculated from the headwind profile measured by D oppler L ight D etection and R anging ( LIDAR ) may make it difficult for use in wind shear alerting at an airport such as H ong K ong I nternational A irport ( HKIA ). Preprocessing by flight simulator or post‐processing by averaging over a certain length are attempted in this study to smooth the F ‐factor and enhance its skills on wind shear alerting. The F ‐factor so obtained is used for alerting of wind shear (headwind change exceeding 15 knots) for departing flights. Through case studies and statistical studies, the LIDAR ‐based F ‐factors are found to have good correlation with the F ‐factor determined from flight data (the Q uick A ccess R ecorder, or QAR , data from the commercial jets). Using the relative operating characteristics ( ROC ) curves, the LIDAR ‐based F ‐factor obtained by smoothing over a window size of 300–500 m is found to have good skills in wind shear alerting, and the performance is comparable with, or even better than, the LIDAR ‐based F‐factor using the flight simulator approach. By choosing an optimal alerting threshold specific for each runway corridor, the F ‐factor successfully alerts 86% of pilot wind shear reports with the percentage of time on alert of 12%, which is found to be satisfactory for real‐time use. The performance of the F ‐factor on stronger wind shear (headwind change of 25 knots or more) is also studied.