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By the time students complete Bob Rauber’s course in radar
meteorology, he expects them to understand how weather radars work and how
they’re used to measure precipitation and detect severe weather.
Toward those ends, they do their reading, attend class
lectures and even take a virtual tour of one of the nation’s most sophisticated
radar stations. But as Rauber himself says, “there’s nothing more exciting in
atmospheric science than living through the weather you study, especially when
you are using sophisticated, state-of-the-art instruments.”
Rauber’s students have gotten such an opportunity over the past couple
of weeks, thanks to a truck-mounted Doppler radar unit that’s been visiting the
U of I campus.
I was able to ride along with one group of them on the day a cold front
passed through, which brought with it rain, wind and an opportunity to really
use the equipment.
Our group, which included professor Rauber, myself, the driver of the radar
unit, and three students, set out just after noon. The slow-moving front had
already passed over campus, so we drove east on I-74 to catch up with it. After
a quick road lunch in Danville, we headed north on country roads searching for
a place to set up.
We were looking for a relatively unobstructed shot for the radar—a spot
on high ground away from farmhouses and outbuildings—and a firm enough road
shoulder to support the truck. We found one on State-Line Road.
Quarters are submarine-tight in the operations cab of the radar unit,
which accommodates only three students at a time, so professor Rauber stood
outside on the step-up to direct the exercise through an open door. (Even
switching seats to take turns at the controls required real ingenuity on the
part of the students.)
Before powering up the radar, Rauber deployed a more basic weather
instrument, a finger held aloft. The air felt cold, he reported, and the wind
was blowing from the north. That, the students knew, meant we were still on the
back side of the front.
Then came the students’ turn.
With coaching from Rauber and the operator, they each had a turn at the keyboard
of the computer, where they learned to adjust the radar scan to sweep the area
encompassing the important features of precipitation in the front—the location
of its leading edge, its height and the level at which falling precipitation
turned from snow (which is the state of nearly all precipitation when it forms)
into rain.
The students worked together remarkably well, helping one another
remember how to execute certain functions with the equipment and do the calculations
needed to make sense of what they were seeing on the screen in front of them.
They had answered the most important questions before 3:00 p.m., which
allowed some time for exploring other facets of using radar, such as
distinguishing between precipitation and ground clutter.
As we spoke on our return trip to campus, Rauber emphasized that the
radar the students were working with is an upgraded type, one the National
Weather Service is currently installing across the country. With it,
forecasters and research scientists like the ones he is educating will be able
to better understand and predict the behavior of storms, to the benefit of everyone.
