Pilot's Guide to Avionics 2017-2018 - 61
reen. Yellow. Red. Magenta. These colors
Doppler systems can provide added capabilities,
graphically define weather intensity on weather
among them short-range turbulence detection that
radar displays, whether seeing the images in
identifies turbulence in the atmosphere by detecting
aggregate - as seen on weather datalink graphics and
particulates, such as precipitation or dust.
broadcast sources - and on the displays of airborne
To pilots like this one, real-world weather situations
weather radar systems installed
require real-time imagery when
in airline, general aviation and
faced with inclement weather. That
means learning the strengths of
With the growth in Automatic
airborne weather radar along with
Dependent Surveillanceits limitations - and how datalink
Broadcast use, flight crews
weather complements the live radar.
increasingly learn the benefits
from the Flight Information
Airborne weather radar:
System-Broadcast and its
the weather world in real time
By now, most technicians and
many pilots and citizens understand
weather radar, available via
how Doppler weather radar works.
ADS-B In and subscription
This specialized radar capitalizes
on the Doppler effect to detect the
Business pilots confess of
velocity of objects at a distance.
their growing use of FIS-B's
Doppler effect accomplishes this
datalink to "extend my weather
by bouncing a microwave signal
vision" beyond what onboard
off the desired target - weather,
weather radar delivers. Not only
in this case - and analyzing how
is airborne weather radar limited
the object's movement alters the
in range, it also sees nothing
frequency of the reflected signal.
off to the sides - or behind the
The result: direct, highly accurate measurements of
the target's velocity relative to the radar.
What makes airborne weather radar worth the
Doppler allows radar to measure the speed of wind
expense, weight and training, pilots say, is its
immediacy. Datalink weather lacks that immediacy -
but it offers a much bigger picture.
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