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Wind shear alerting at Hong Kong International Airport. S.Y. Lau Hong Kong Observatory. In Hong Kong…. Significant windshear : 1 in 500 flights 5 typical causes Winds blowing across terrain (terrain-induced) Sea breeze Gust fronts Microbursts Low-level jets.
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Wind shear alerting at Hong Kong International Airport S.Y. Lau Hong Kong Observatory WMO Symposium Toulouse 2005
In Hong Kong… • Significant windshear : 1 in 500 flights • 5 typical causes • Winds blowing across terrain(terrain-induced) • Sea breeze • Gust fronts • Microbursts • Low-level jets WMO Symposium Toulouse 2005
WMO Symposium Toulouse 2005
Winds Blowing Across Terrain (Terrain-induced) • In lighter wind conditions, low-level temperature inversion also triggers windshear (spring months) • Windy occasions like during TC… WMO Symposium Toulouse 2005
Equipment along runway TDWR Weather Buoys LIDAR Equipment suite WMO Symposium Toulouse 2005
LIDAR Scanner ATCX Building Roof-top LIDAR – Fully Operational in Mid-2004 Installed in mid-2002 IR (2 μm) → eye-safe WMO Symposium Toulouse 2005
Shear line Shear line Radial shear algorithm Shear line discernible on LIDAR velocity picture Shear line identified by algorithm WMO Symposium Toulouse 2005
Hazard Coverage Area WMO Symposium Toulouse 2005
Hazard Coverage Area Red: Arrival - 1.0 deg PPI. Departure - 4.5 deg PPI Blue: Arrival - 0.0 deg PPI. Departure - 1.0 deg PPI WMO Symposium Toulouse 2005
Glide-path Scan laser beam N glide path WMO Symposium Toulouse 2005
30 March 2005Synoptic pattern Hong Kong WMO Symposium Toulouse 2005
Ascent from King’s Park 4.7°C WMO Symposium Toulouse 2005
Locally around HKIA WMO Symposium Toulouse 2005
4 3 1 5 2 Temperature WMO Symposium Toulouse 2005
LIDAR animation WMO Symposium Toulouse 2005
LIDAR 1.0 degree PPI scan at 0049 UTC 30 March 2005 • 45 WS reports (00 – 03 UTC): 0005 07RA -15 KT 4NM 0029 07RA -30 KT 1NM 0032 07RA 35 KT 1NM 0045 07RA 25 KT 1NM 0049 07LA -20 KT 2NM Cold colours(blue, green) – moving towards LIDAR Warm colours (yellow, orange, pink) – moving away from LIDAR WMO Symposium Toulouse 2005
RAGA … WMO Symposium Toulouse 2005
0° elevation PPI scans Glide Path Scan at 00:48 UTC Elevation Azimuth 2.2° 63.9° – -1.0° 4.05° Elevation Azimuth 2.3° 75.5° – 0.0° 91.3° Elevation Azimuth 2° 255.8° – -1.0° 271.3° Elevation Azimuth 2° 247.0° – -0.9° 236.3° WMO Symposium Toulouse 2005
GLYGA … WMO Symposium Toulouse 2005
Wind direction, speed and headwind derived from on-board data from aircraft arriving at 0049 UTC. 24KT GLYGA head wind profile WMO Symposium Toulouse 2005
Pilot- centered Equipment- centered WMO Symposium Toulouse 2005
WMO Symposium Toulouse 2005
WMO Symposium Toulouse 2005
2nd peak 1st peak Frequency Distribution by Month • Significant windshear: 1 in every 500 flights • Significant TURB: 1 in every 2,000 flights WMO Symposium Toulouse 2005
Windshear algorithms for automatic alerting based on LIDAR data • Radial shear Alert Generation Algorithm (RAGA) - Adaptation of TDWR approach (shear along radar beams) • GLIde path shear alert Generation Algorithm (GLYGA) – Shear along glide paths WMO Symposium Toulouse 2005