The United States experiences more tornadoes than any other country. About 1,200 tornadoes touch down each each year in the U.S. with most occurring during tornado season, from March through June. Given the devastating consequences to life and property, understanding these terrible twisters is an important goal of meteorologists, and supercomputing is crucial to this endeavor.
Backed by the power of the Blue Waters supercomputer, researchers at the University of Wisconsin–Madison were able to gain insight into the inner-workings of tornadoes and the supercells that produce them. The resulting visualizations capture the tornado formation process, tornadogenesis, in detail.
The research team, led by Leigh Orf, a scientist with the Cooperative Institute for Meteorological Satellite Studies (CIMSS) at the University of Wisconsin–Madison, simulated a supercell thunderstorm that set off a cluster of tornadoes on the Oklahoma landscape over a four-day period in May 2011.
“One after the other, supercells spawned funnel clouds that caused significant property damage and loss of life,” notes a writeup on the research. “On May 24, one tornado in particular – the “El Reno” – registered as an EF-5, the strongest tornado category on the Enhanced Fujita scale. It remained on the ground for nearly two hours and left a path of destruction 63-miles long.”
The research shed light on essential tornado drivers but it also validated the unpredictable nature of tornadoes. There’s a requirement of “non-negotiable” parts, said Orf, including “abundant moisture, instability and wind shear in the atmosphere, and a trigger that moves the air upwards, like a temperature or moisture difference.” But even when these conditions are met, a tornado does not necessarily result.
“In nature, it’s not uncommon for storms to have what we understand to be all the right ingredients for tornadogenesis and then nothing happens,” said Orf. “Storm chasers who track tornadoes are familiar with nature’s unpredictability, and our models have shown to behave similarly.”
The EF-5 simulation was carried out on the Blue Waters Supercomputer at the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign. The computation was completed in about three days versus the decades that would be required on a standard desktop computer.
The research team plans to keep refining the model so they can keep unraveling the mysteries of tornado formation. Increasing scientific knowledge of severe weather events, such as these, has important implications for enhancing life-saving storm warning systems.
Video of May 24, 2011 supercell simulation:
For the full story, see the University of Wisconsin–Madison news article by Eric Verbeten.