Technology Examined For Weather Threat
Looking for ways to
prevent air crashes that have claimed hundreds of lives, including
'50s singing stars Buddy Holly and Ritchie Valens, researchers are
testing a pair of radars they hope will detect icing conditions.
Using the radars together should help determine the amount of tiny
droplets of water in the air, too small for most radars, that are
colder than freezing but still liquid. Marcia Politovich, director
of the icing program at the National Center for Atmospheric
Research (NCAR) in Boulder (CO) said Wednesday that the icing
research experiment is continuing through the end of March. The
team attached a small Ka-band radar to a large S-band unit, similar
to the radars used by the National Weather Service. The researchers
hope to report their findings later in the year.
"This will take out a lot of the guess work," explained
Politovich. "We think it will show exactly where the water is. That
information could ultimately turn into an important warning system
for pilots."
While they can detect normal rain, it's hard for the longer
wavelength S-band radars to detect the tiny water drops, 1/10th the
size of a raindrop, that form in these deadly icing clouds. The
Ka-band signals are absorbed by liquid water, Politovich explained,
but not by ice or snow. So by comparing the signals from the two
radars, the scientists hope to be able to calculate the presence of
the tiny liquid water drops, so they can warn pilots to avoid
dangerous areas.
The test unit operates from the ground near Boulder, she said,
and if the system works, Ka-band units could easily be added to
National Weather Service and airport radars.
In addition, Politovich
said, it may be possible to pair Ka-band radar with the units on
aircraft and develop a similar method to detect areas of icing
danger. Combining the names of the radar types, S-Pol for polarized
S-band radar and the Ka-band radar, the researchers are calling
their test unit S-Polka.
In addition to the 1959 Iowa crash that killed Holly, Valens and
J. P. Richardson, who was known as the Big Bopper, other
icing-related crashes have included:
- An American Eagle ATR-72 en route to Chicago that went into a
high-speed dive and crashed near Roselawn (IN) on October 31,1994.
None of the 68 people aboard survived.
- A Comair Embraer 120 en route from Cincinnati that crashed on
approach to the Detroit airport on January 9, 1997, killing all 29
people on board.
If NCAR's testing proves successful, this list will remain as
is, with little or no growth.