One hot, humid day in July 1986, a news helicopter was recording footage of a festival in Minneapolis when the pilot and cameraman spotted a tornado over a nearby Brooklyn park. They made their way towards it, and he filmed the powerful twister for 25 minutes, captivating viewers who watched it live on television.
Watching the helicopter hover perhaps less than a half-mile from the twister was Robin Tanamachi, a child growing up in Minneapolis at the time. “We were seeing all this really beautiful internal vortex structure,” she says. “I’m totally hooked, and I know I’m not alone.” Tanamachi is now a research meteorologist at Purdue University in West Lafayette, Indiana, where he investigates twister mysteries. and is one of many researchers looking for details of its formation that could support future predictions.
Tornadoes can be an elusive research subject. Scientists have figured out the basic ingredients needed to spin twisters by tracking storms and using computer simulations, but two important questions continue to haunt them. So why do some thunderstorms form tornadoes and others don’t? And how exactly do tornadoes rotate?
Despite the logistically and scientifically difficult nature of the research, scientists are motivated to keep up the challenge. Tornadoes can kill dozens to hundreds of people in the United States each year and cause billions of dollars in damage. Now, researchers are using cutting-edge technology to track killer storms that cause tornadoes, flying drones into storms, and using more computing power than ever before to simulate tornadoes and answer questions. I’m looking for.
“Today, we are simulating the atmosphere with unprecedented spatial resolution. We are observing storms with unprecedented temporal and spatial resolution,” said Howie, an atmospheric scientist at the University of Oklahoma at Norman.・Mr. Bluestein says. “But there are still many problems and many things that need to be resolved.”
Scientists have determined how tornadoes form by studying what’s happening in the atmosphere around tornadoes and the ground beneath them, and comparing what they find in the field with new high-resolution thunderstorm models that generate tornadoes. We may have found new clues about it. Researchers are pursuing these new clues while trying to understand when and where tornadoes form and how climate change will affect them.
chase the answer
Ever since scientists began studying tornadoes in earnest in the mid-20th century, they’ve compiled a pretty good overview of the steps required to generate a twister. Most destructive tornadoes are caused by supercell thunderstorms. Supercell thunderstorms typically have very tall clouds that spread out in an anvil shape at the top. A characteristic of supercells is that they can span several kilometers in width. rotating updraft It is called a mesocyclone that lasts several hours. This rotation is caused by wind shear, which brings the wind closer to the ground and causes it to spin horizontally like a spiral soccer ball. These winds are vertical in an updraft, like a top.
Several things need to happen for a supercell to become a tornado. First, the giant mesocyclone at the center of the storm must rotate the air closer to the ground. Next, we need to extend this vortex upwards. Stretching narrows the twister’s footprint, causing it to spin faster, similar to what happens when a figure skater pulls his arm while spinning.
Richard Rotunno, an atmospheric scientist at the National Center for Atmospheric Research, said the first clues to figuring out the physics of tornadoes are scientists trying to figure out what kind of winds could blow down a barn or pluck a chicken. They said they obtained this information from secondary information and damage reports when they were trying to find out. Based in Boulder, Colorado, author of Overview. Tornado fluid mechanics In the 2013 Annual Review of Fluid Mechanics.
The construction of the Interstate Highway System in the 1950s created a grid across the flat Great Plains, allowing enterprising scientists to get in front of storms and sometimes observe tornadoes firsthand. The development of his Doppler radar for meteorology brought great advances. The technology obtains information about wind and precipitation by emitting pulses of energy and detecting the reflected signals. Radar made it possible to detect mesocyclones, which became the basis for tornado prediction and was a boon for trackers. Trackers regularly stopped at payphones and called the lab for up-to-date radar information.
