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| RADAR is actually an acronym which stands for
RAdio Detection And Ranging. |
| Our scientific understanding of the physical
properties and principles of radio waves made RADAR
possible. If a series of radio waves are sent out from a
transmitter, and the waves don't return, then the air must
have been clear for them to travel through. If the radio
waves are transmitted, and then bounce back, then some
reflective material ("reflector") must have blocked their path. |
| The travel time for the waves to return to the
RADAR receiver can be easily measured. Then, since radio
waves travel at a constant speed (186,282 miles per second),
the distance to the "reflector" can be calculated and its
location determined. |
| The only challenging part is to determine the
nature of the "reflector." Radio waves can be reflected by
many objects. Is there a tank or an elephant in the road
ahead? Is that a rainshower or an airplane in the
air? Fortunately, time and practice have revealed strategies
for determining the shape and structure of reflective
objects. Different RADAR systems have been developed for
detecting different objects. |
| In particular, meteorologists use
Doppler RADAR
to locate areas of rain, snow, and other
precipitation. Water droplets and ice crystals reflect radio
waves. RADAR detects precipitation and creates RADAR images
for meteorologists to analyze. They use this information to
forecast the weather in your community. |
| Today, most meteorologists use Next Generation
RADAR, or NexRAD, the most advanced nationwide weather RADAR
system. Doppler RADAR is part of the NexRAD system.
Have you noticed that the reliability of weather
forecasts has improved in recent years? Thank NexRAD. Using
a powerful computer network, NexRAD measures precipitation,
tracks storm formation, and records wind strengths. Your
local meteorologist can't offer any guarantees, but, since
NexRAD, you can put more faith in the forecast. |
