microburst


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microburst

[′mī·krō‚bərst]
(meteorology)
A downdraft with horizontal extent of about 2.5 miles (4 kilometers) or less, associated with atmospheric convection, often a thundershower.

microburst

microburstclick for a larger image
An aircraft flying from A to F will experience strong headwinds at positions A and B. It will experience increasing tail winds at position D and E. There would be downdraft at positions B, C, and D. The maximum intensity of downdraft will be at position C.
The strong downdraft that spreads horizontally just above the ground to form a sharply defined gust front. An aircraft approaching this microburst or gust front may encounter a headwind followed by a strong downdraft and finally end up with a strong tailwind. The area of microburst extends from 3000 to 10,000 ft (1–3 km) and lasts from to 5 to 15 min. An intense microburst could induce wind speeds as high as 150 knots. Microbursts are normally associated with thunderstorms, but there are also “dry microbursts.” In these dry microbursts, precipitation falling from the thunderstorms into the relatively dry air of the lower atmosphere evaporates readily, and the large negative buoyancy thus produced accelerates the air downward, entraining more very dry air. No precipitation reaches the ground, but a microburst wind shear occurs. Airports equipped with an LLWAS (low-level wind-shear alert system) “network expansion,” LLWAS systems integrated with terminal Doppler weather radar (TDWR), and TDWR systems can detect microburst alerts and wind-shear alerts. Controllers will issue the appropriate wind-shear alerts or microburst alerts (e.g., “Runway 28 arrival microburst alert, 45 knot loss 3 mile final”).
References in periodicals archive ?
While in the same vein, Air Traffic Controllers (ATC) and Flight Crews/Operators have been urged to ensure total compliance with all aerodromes operating minima, the NCAA mentioned some impending adverse weather conditions to include: severe thunderstorms, squall lines microburst or low-level wind-shear as observed or forecast by NiMET.'
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However, incorporating CCF model indicates that the significant event governing for LOC-I during maneuvering phase of flight is "certification/lack of experience" as shown in Figure 15, which is responsible for expediting CRM events (e.g., inadequate control, speed, encountering microburst, and turbulence and improper installation of component).
It could have been deep convection along an occluded front which may have produced a microburst of cold dense air from about 28,000ft.
She was immediately put to work analyzing data from the groundbreaking Joint Airport Weather Studies Experiment, which changed the way the world understood microburst aviation hazards.
A microburst is one of the most serious wind shear fields because its short duration, small scale, and high intensity cause a series of difficulties in forecasting and detection.
Adding to this is the effect of the microburst, which causes a vacuum at certain locations.
But fears it was the end of the world - or perhaps an alien invasion - proved unfounded, with meteorologists instead suggesting the pictures may show a microburst out to sea - a column of sinking air caused by a small downdraft within an intense and rapidly-forming thunderstorm.
The Microburst I, II, and II systems rival the brightness of strobes and are available in different configurations, depending on the aircraft design.
Using air and MicroBurst Technology, Philips claims that Sonicare AirFloss provides an easier way to clean between teeth, removing more plaque between teeth than a manual toothbrush and cleaning the entire mouth in just 30 seconds.
A tornado is different to downburst and microburst. In a tornado, high velocity winds circle a central point, moving inward and upward, whereas in a downburst the wind is directed downward and then outward from the surface landing point.