scholarly journals Predicting Low-Level Wind Shear Using 200-m-Resolution NWP at the Hong Kong International Airport

2020 ◽  
Vol 59 (2) ◽  
pp. 193-206 ◽  
Author(s):  
Kai-Kwong Hon

Abstract“Low-level wind shear” is a known aviation safety hazard and refers to a sustained change in head wind encountered by an aircraft during takeoff or landing. Because of their small spatiotemporal scales and high variability, automatic alerting of wind shears at airports around the world is almost exclusively detection based (using remote sensing equipment). Numerical modeling studies so far mainly cover individual cases and lack systematic validation. This paper presents the first statistical evaluation of numerical weather prediction (NWP) model performance in predicting low-level wind shear at a major international airport over a 2-yr continuous period. The 200-m-resolution Aviation Model (AVM) of the Hong Kong Observatory is used to generate runway-specific wind shear forecasts at 1-min output intervals for the Hong Kong International Airport (HKIA), known for its susceptibility to wind shear occurrence. The AVM forecasts are then validated against over 800 actual reports of wind shear by aircraft pilots over the two major arrival runway corridors, 07LA and 25RA, at HKIA between 2014 and 2015 using a verification scheme with the same level of spatiotemporal stringency as operational alerting systems at HKIA. With “relative operating characteristic” analysis, positive skill is consistently observed across both runway corridors throughout the study period and across all considered forecast lead times out to 6 h ahead. This study serves to establish and document the current capability of fine-resolution NWP in predicting the phenomenon of low-level wind shear for aviation weather applications.

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
K. K. Hon ◽  
P. W. Chan ◽  
Y. Y. Chiu ◽  
Wenbo Tang

Hong Kong Observatory currently uses a series of meteorological instruments, including long-range LIDAR (light detection and ranging) systems, to provide alerting services of low-level windshear and turbulence for Hong Kong International Airport. For some events that are smaller in spatial dimensions and are rapidly changing, such as low altitude windshear and turbulence associated with buildings or man-made structures, it would be necessary to involve meteorological instruments that offer greater spatial resolution. Therefore, the Observatory has set up a short-range LIDAR on the roof of the AsiaWorld-Expo during the summers over the past several years, conducting field research on the feasibility of strengthening early alerting for windshear and turbulence over the north runway’s eastern arrival runway (Runway 25RA) and developing an automated early alerting algorithm. This paper takes the pilot reports for Runway 25RA during the 2013 field research as verification samples, using different thresholds for radial wind velocity spatial and temporal changes detected by the short-range LIDAR to calculate the relative operating characteristic (ROC) curve, and analyzes its early alerting performance.


2012 ◽  
Vol 21 (1) ◽  
pp. 94-104 ◽  
Author(s):  
David Carruthers ◽  
Andrew Ellis ◽  
Julian Hunt ◽  
P. W. Chan

2012 ◽  
Vol 29 (2) ◽  
pp. 207-220 ◽  
Author(s):  
P. W. Chan ◽  
Y. F. Lee

Abstract Long-range lidar systems have been used operationally at the Hong Kong International Airport for wind shear alerting. They are used for monitoring the headwinds over the last 3 n mi of all of the runway corridors of the Hong Kong International Airport (HKIA). This paper discusses the results of a trial of using short-range lidar (SRL) in the alerting of wind shear over a particular runway corridor by performing more frequently updated wind measurements over a specific section of this corridor in which many wind shear reports are received. The radial resolution of the lidar is 75 m and the data are updated every 20 s. Three different ways of wind shear alerting based on SRL’s data are studied, namely, the deviations of the measured radial velocities from the uniform background flow (the “velocity fluctuation”), eddy dissipation rate (EDR), and autocorrelation of radial velocity. The performance of these methods is studied by comparing with the pilot wind shear reports. The velocity fluctuation has the best skill in capturing the wind shear reports. By combining the wind shear alerts from SRL with those from the Wind Shear and Turbulence Warning System (WTWS), it is possible to achieve a probability of detection (POD) of pilot wind shear reports of about 90%, with a percentage of time on alert (PTA) of about 10% only. This even outperforms the existing overall wind shear alerting service (WTWS plus subjective wind shear warnings issued by aviation weather forecasters) by significantly reducing PTA. As such, the present study shows that it is possible to combine wind shear alerts from SRL and WTWS for automatic wind shear alerting without the need of human intervention, at least for a particular runway corridor of HKIA.


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