From the distance it looks like a water tower. When I got closer
I noticed it looks more like a soccer ball with the hexagons and
heptagons sewn patches. Then it hit me. It is a RADAR, but what
type? I started a small research and found out that this one of the
four doppler radars that NOAA has in KS. I have found this things
before so I identified it. NOAA has a bunch of radars in the state
but there are four big ones. One is here in Wichita. The other
three are in Goodland, Dodge City and Alma.
Its designtaion is ICT and it is fully automatic. From this
distance you can clearly notice the patches. This is not a park and
grab. You are looking for a small bison tube hidden across the
street from the weather station. Please bring your own pen (BYOP).
Please DO NOT PARK in the NOAA parking lot or in the FAA parking
lot near by, and of course DO NOT PULL OVER because this road has a
lot of traffic and barely shoulder room to park. You will need to
park and walk a bit to the cache. It will give you time to
appreciate the magnificent piece of technology this radar is. I
used some wiring holding ties to keep the cache from falling to the
bottom of its hideout.
Doppler Radar
A Doppler radar is a specialized radar that makes use of the
doppler effect to produce velocity data about objects at a
distance. It does this by beaming a microwave signal towards a
desired target and listening for its reflection, then analyzing how
the frequency of the returned signal has been altered by the
object's motion. This variation gives direct and highly accurate
measurements of the radial component of a target's velocity
relative to the radar. Doppler radars are used in aviation,
sounding satellites, meteorology, police speed guns, and
radiology.
The specific term "Doppler Radar", due in part to its extremely
common use by television meteorologists in on-air weather
reporting, has erroneously become popularly synonymous with the
type of radar used in meteorology. Most modern weather radars use
the pulse-doppler technique to examine the motion of precipitation,
but it is only a part of the processing of their data. So, while
these radars use a highly specialized form of doppler radar, the
term is much broader in its meaning and its applications.
Doppler Effect
The Doppler effect (or Doppler shift), named after Austrian
physicist Christian Doppler who proposed it in 1842, is the change
in frequency of a wave for an observer moving relative to the
source of the waves. It is commonly heard when a vehicle sounding a
siren approaches, passes and recedes from an observer. The received
frequency is increased (compared to the emitted frequency) during
the approach, it is identical at the instant of passing by, and it
is decreased during the recession. This variation of frequency also
depends on the direction the wave source is moving with respect to
the observer; it is maximum when the source is moving directly
toward or away from the observer, and diminishes with increasing
angle between the direction of motion and the direction of the
waves, until when the source is moving at right angles to the
observer, there is no shift.
An analogy would be pitcher throwing one ball every second in a
person's direction (a frequency of 1 ball per second). Assuming
that the balls travel at a constant velocity, if the pitcher is
stationary, the man will catch one ball every second. However, if
the pitcher is jogging towards the man, he will catch balls more
frequently because the balls will be less spaced out (the frequency
increases). The inverse is true if the pitcher is moving away from
the man; he will catch balls less frequently due to the pitcher's
backward motion (the frequency decreases). If the pitcher were to
move at an angle but with the same speed, the variation of the
frequency at which the receiver would catch the ball would be less
as the distance between the two would change more slowly. Note
that, from the point of view of the pitcher, the frequency remains
constant (whether he's throwing balls or transmitting microwaves).
Since with electromagnetic radiation like microwaves frequency is
inversely proportional to wavelength, the wavelength of the waves
is also affected. Thus, the relative difference in velocity between
a source and an observer is what gives rise to the doppler
effect.
From here you can appreciate this fine piece of technology that
helps us forecast the weather, track nasty storms, and helps
prevent so much damage even saving lives. Take some time to check
it out. Next time you watch the news and the forecast report at
home you will know where that information comes from and that you
have visited one of the stations here in Kansas.