East Asia and Western Pacific METEOROLOGY AND CLIMATE

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following two kinds:
(a) Macroburst:
This is a large downburst with outburst wind extending
over 4 km(2.5 miles)in horizontal dimension. Damaging winds
,lasting 5 to 30 minutes, could be as high as 60 m/sec.
(b) Microburst:
This is a small downburst with outburst wind extending
only 4 km (2.5 miles ) or less, damaging winds as high as
75 m/sec.
The height of downburts usually remains about 1 km or
less. Flying over 1000 m can reduce or even avoid the
risks(Lin, 1984).
3. The non-meterologists' knowledge of the Doppler radar
data
Aviational weather services involve many units. These
services not only need the weather observators to provide
various weather data, but also data concerned have to be
reported to the users, aviation controllers, operational
dispatchers of the airlines, v and then the pilots in the
cockpit through ATS.
; -• Therefore, in order to secure flying safety, every
people related to aviational services should clearly
understand the weather at the airport and nearby after and
before flying, especially they should inquire about the
weather detailedly at-the schedualed. time of taking off
and landing.
In order to protect the aircraft and passengers, the
pilots should change the time of taking off or landing if
they are flying,in an area where the Doppler indicates the
appearance of significant weather or they are going to be
influenced'by the said hazardous weather.
Unfortunately, the display of significant weather on
the PPI of Doppler radar is easily neglected by the weather
forecasters and airlines personnel, because this kind of
weather usually lasts not more than 10 minutes. In order to