Thursday, May 03, 2012

Students get hands-on experience with next-generation weather radar

Students get hands-on experience with next-generation weather radar

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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.