College of LAS « Illinois

Atmospheric Sciences

Recipe for a Supertwister

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Computer visualizations from the laboratory of atmospheric scientist Robert Wilhelmson were featured on the PBS TV series "NOVA" last March during a special called "Hunt for the Supertwister." The simulation begins with data on wind speed, atmospheric pressure, humidity, and the other weather conditions that precede tornados and then follows the erupting thunderstorm and resulting tornado. The simulation produced 650 billion bytes of data that was processed and visualized using the high-performance computers at the National Center for Supercomputing Applications, which is based at
U of I.

In a typical year, 1,200 tornadoes cause 70 fatalities and 1,500 injuries nationwide. Most of the damage, and deaths, are due to a small percentage of these storms, the so-called supertwisters. Scientists know that the strongest tornadoes are generated in a particular type of rotating thunderstorm called a supercell. The swirling winds inside a supercell can produce tornadoes, but not all supercells do. The work being done by Wilhelmson is part of an effort to identify what triggers tornadoes. By simulating these storms as they evolve, researchers can analyze the formation of a tornado in much the same way that physicians use CAT scans to diagnose disease.


Atmospheric scientist Matthew Gilmore, who is a member of Wilhelmson's research team, describes the visualization as a "3D virtual storm chase." Events that occur at blinding speed in the field can be slowed to a crawl for close study. The scientists can then interrogate the data in many ways, looking at cross-sections, employing different points of view, and zooming in on small details.

Wilhelmson is a pioneer of storm visualization who has won countless awards, including an Academy Award nomination for his 1989 animation of a thunderstorm.

Read more about Robert Wilhelmson and see some of his animations.

Summer 2004