Atmospheric scientist Leigh Orf, from the University of Wisconsin-Madison, wants to unravel the mysteries of how tornadoes form but he needs more than just a laptop.
Phenomena such as huge supercell thunderstorms involve large amounts of data that would require a more powerful machine, so Orf and colleagues turned to a supercomputer to simulate the phenomenon.
Using the Bluewaters machine at the University of Illinois, the researchers simulated the tornado-producing thunderstorm that ravaged the central Great Plains in 2011.
Bluewaters is one of the world's most powerful supercomputers. It is used by scientists and engineers across the United States to tackle problems ranging from predicting the behavior of biological systems to simulating how the cosmos evolved. Org and colleagues tapped on the power of this machine to have a better understanding of how tornadoes form.
Orf said that it is not necessarily because the weather is complex that the use of a supercomputer is essential. The simulation involves a three-dimensional space measuring about 75 miles wide, 75 miles long, and 12.4 miles tall that is further subdivided into nearly 2 billion parts. Orf said that the feature is big and needs to be very highly resolved.
El Reno Tornado
In May 2011, Oklahoma had several tornadoes and supercells spawning funnel clouds that damaged properties and claimed lives. One of the tornadoes, which touched down on May 24 and known as "El Reno," was of particular interest because of its power. It was registered as an EF-5, the Enhanced Fujita scale's strongest tornado category. The tornado was on the ground for almost two hours and caused damage along a path stretching 63 miles.
Using the Bluewaters supercomputer, Orf and colleagues recreated the El Reno tornado. The simulation revealed in high resolution a number of small tornadoes that formed prior to the formation of the main tornado.
The mini-tornadoes started to merge as the funnel cloud developed, boosting the tornado's strength and intensifying the wind speeds. New structures eventually formed, including what is known as the streamwise vorticity current, or SVC.
"For the first time we've been able to peer into the inner workings of a supercell that produces a tornado, and we're able to see that process occur," Orf said. "We have the full storm, and we can see everything going on inside of it."
Researchers hope that the simulation, which needed about three days of time on 20,000 cores of the supercomputer, would provide better insights on the formation of strong and deadly tornadoes spawned by powerful thunderstorms.
"We've completed the EF-5 simulation, but we don't plan to stop there," said Orf. "We are going to keep refining the model and continue to analyze the results to better understand these dangerous and powerful systems."
The increasing frequency of tornadoes and thunderstorms that kill people and damage properties have been associated with climate change. Scientists suspect that the rising temperatures serve as triggers for these events.
The simulations made by Orf and colleagues can give meteorologists helpful insights on the inner workings of thunderstorms and tornadoes.