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How studying simulated tornadoes could help save real lives

May 3, 2017 at 6:20 PM EDT
In our NewsHour Shares moment of the day, meet a scientist who uses supercomputers to study thunderstorms and the most powerful tornadoes in hopes that they’ll save lives.
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NewsHour shares web small logoIn our NewsHour Shares series, we show you things that caught our eye recently on the web. What about you? Leave your suggestions in the comments below, or tweet to @NewsHour using #NewsHourShares. We might share it on air.

JUDY WOODRUFF: Now to our NewsHour Shares, something that caught our eye that may be of interest to you, too.

It’s springtime, and that means it’s peak tornado season in the nation’s Central Plains.

We recently spoke with one Wisconsin researcher who thinks modeling massive twisters with supercomputers could help save lives.

LEIGH ORF, University of Wisconsin: My name is Leigh Orf, and I am a scientist at the University of Wisconsin.

I study thunderstorms. Specifically, I study the supercell thunderstorms that produce the most powerful tornadoes, using computers to simulate them.

Only a small fraction of supercells produce tornadoes, and only a small fraction of that fraction produce the kind of tornado that we’re trying to study.

But the reason we are studying it is because, if you think of 2011 with Joplin, Missouri, Tuscaloosa, Alabama, El Reno, Oklahoma, these are the big, long-track EF-5 tornadoes that just do incredible amounts of damage and, if people can’t get out of the way of those storms, a lot of fatalities.

A computer model like the one we’re using essentially emulates or simulates the real atmosphere as faithfully as we scientists know how to make it work. We use the equations of physics to essentially grow a cloud in a specific environment.

What goes into the model are atmospheric conditions of winds, temperature, pressure, and humidity. And from there on, it’s just — the model just integrates forward in time.

This sequence is designed to give you a sense of the scale of the storm. And what’s really striking about this is, you can see how small the tornado is, at least with respect to the full storm.

But the reason I do this is to give people an understanding of how — why we need supercomputers to study this, because the whole storm really needs to be at this very high resolution in order to capture the tornado.

This highlights the streamwise vorticity current, which is a feature we have identified in these simulations that seems to be important to maintaining the strength of the storm and, therefore, the tornado. These are just massless. We call them parcels, air parcels in meteorology.

If you are hanging out in the streamwise vorticity area where those yellow parcels are, the tornado is coming right at you. They take a horizontal path, and then they kind of go tilted upward into the storm’s updraft.

Depending upon where you put these source regions, you can see the air is doing very different things. The red region is the streamwise vorticity current. The darker green region, this is air that’s in the cold pool of the supercell, and it seems to be directly feeding the tornado.

The whole reason we do this kind of research is essentially to produce better forecasts of when these things are going to happen. Too many people still die from tornadoes in — around the world, but in the United States, too.

We have a false alarm problem where we issue a warning when the tornado is not happening. And then we have the problem where the tornado is already happening, but we haven’t issued a warning.

So, the challenge is to do a much better job at producing these warnings even before the storm has formed. And the first step is to first understand the storm. You can’t forecast a storm until you understand it, and we’re just getting to the point where we’re better understanding what’s going on.

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