空管资料3(21)

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User Interface Examples – Wx radar
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User Interface Examples - touchscreen
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THANK YOU FOR YOUR ATTENTION
Vaisala windshear
detection solution
Juhani Polvinen
Vaisala Airports
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Agenda
Wind shear in general
 Terrain-induced wind shear
 Microbursts
 LLWAS
Windprofiler integration
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Why Is Wind Shear Detection
Important?
 If Low Level Wind Shear is encountered close to the ground
during aircraft take-off or landing procedures, it can be very
dangerous
 the change in velocity or direction can drastically alter lift,
indicated airspeed (IAS), and thrust requirements
 Can exceed aircraft climb capabilities
 US wind shear related Incidents between 1964 and 1985
 Over 25 US airline accidents
 625 fatalities
 200 injuries
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Low Level Wind Shear Is a Major Safety
Hazard at Airport!
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Low Level Wind Shear
 Causes of wind shear:
Terrain effects
Convective weather
Fronts
Temperature inversion
Wake vortices
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Terrain wind shear
Hills, mountains
 Land-sea interaction
 Interaction between general and local wind fields
Very difficult to forecast without good measurements
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Terrain wind shear, day-night variations
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Terrain wind shear, day-night variations
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Terrain wind shear, day-night variations
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Terrain wind shear, case Juneau
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How to Measure Terrain wind shear?
Wind profiler is an excellent tool for terrain wind shear
detection
Doppler weather radar can also detect terrain wind shear, but
sometimes ground clutter is a problem
Usually combination of several systems is needed
 LLWAS system can not be used for terrain wind shear
detection
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Downburst
Microburst characteristics:
– Downdraft
– Intense localized downdraft exceeding 720 feet per minute at 300
feet, AGL
– Can exceed aircraft climb capabilities (all classes of aircraft)
–Windshear resulting from large downdrafts
– Result from large downdrafts striking the ground and spreading out
horizontally
– Winds can change direction by as much as 180 degrees and reach
velocities of 100 knots as far as 16 km ahead of the storm
– May increase as much as 50% between the surface and 1500 feet.
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Downburst
Courtesy of NCAR
Downdraft
While the pilot
compensates for the
headwind by dipping
the nose, the aircraft
enters a downdraft.
A headwind slows and
lifts the aircraft above its
normal flight path.
A tailwind dangerously
reduces the aircraft’s
speed.
The glide path of a
normal landing.
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Downburst
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How to Measure Downbursts?
Wind Profiler
 One point measurement
 No Horisontal shear
 Verical wind shear
Doppler Radar
 Mainly in rain
 Resolution, time lag
 Excellent in combination with LLWAS
 Lidar
 Does not work in rain
 Expensive
 Anemometers
 Horisontal shear
 Fast response time
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How to Measure Fronts and
Temperature inversion
Wind profiler is an excellent tool for detecting Fronts and
Temperature inversions
Doppler radar is also good sensor for detecting Fronts and
Temperature inversions but clear air causes some problems
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Wind Shear Values
Vaisala will:
• Consult and design the ideal
windshear alert solution (technical
and services).
• Ensure professional project
management, delivery, training and
installation of the technical solution.
• Ensure reliable lifecycle support
Customer gets:
　
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