Earth Science: Geology, the Environment, and the UniverseChapter 13:
The Nature of StormsProblem of the WeekDoppler Radar: A Key to Tracking Severe Weather Go to this site for background material on Doppler Radar. An Investigation
of Doppler Radar An
Investigation of Doppler Radar
Radar The three radar images in this exercise are fairly straightforward and
give students an opportunity to practice the skills of interpretation
and analysis. Radar is dependent on the degree of reflectivity of the objects hit by
the radar waves; in general, the larger the objects, the greater the reflectivity.
Reflectivity is dependent on two factors - the number and diameter of
the precipitation drops. The radar can detect swarms of bugs, birds, dust, and buildings or it
may "see" several drops in close proximity and show it as a small hailstone.
Because of this, meteorologists must evaluate all the atmospheric data
in the area to determine, if what they are seeing in the radar image is
consistent with the other recorded conditions before they report a storm. The "DBZ" seen on the key, in Problem 1, is the measure of the energy
level of the returning radar beam that is reflected back by the precipitation.
The higher DBZ levels indicate more intense precipitation. The "DBZ" seen on the key, in Problem 1, is the measure of
the energy level of the returning radar beam that is reflected back by
the precipitation. The higher DBZ levels indicate more intense precipitation.
The Keys: The colors used in the keys of these three images are fairly representative
of the variety seen in radar images. There is not a set standard. However,
greens and blues tend to be low intensity precipitation, yellow, reds,
and pinks higher intensity, and gray is sometimes used to indicate hail
(very high reflectivity).
Answer - Problem 1: There is a line of intense storm activity that runs from the southwest
part of Texas to the northeast part of the state. The reds and the pinks
indicate the high intensity areas. There is one particularly intense area
of precipitation near the center of the state. A forecaster might describe
this system as a "squall line," as a "frontal system," or as an amateur,
a line of severe thunderstorms that extend across the state, from the
northeastern part to the southwestern part. It appears to be moving in
a southeasterly direction. (The intense areas of precipitation are often
nearer the leading edge of a moving storm system.) A forecaster might describe this system as a "squall line,"
as a "frontal system," or as an amateur, a line of severe thunderstorms
that extend across the state, from the northeastern part to the southwestern
part. It appears to be moving in a southeasterly direction. (The intense
areas of precipitation are often nearer the leading edge of a moving storm
system.)
Answer - Problem 2: The tornado signatures are shown within the pink circles. 1. (14.0K) 2. (36.0K)
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