EYE ON THE STORM
UW scientists provide critical hurricane data
MADISON - While Hurricane Harvey washed through neighborhoods in and around Houston last week, a small group of University of Wisconsin-Madison scientists noticed something unusual off the coast of Africa. The more they examined water temperature readings, wind speeds, air moisture levels and clouds, the more alarmed they grew. Another hurricane was in its infancy and its trajectory was ominous. “It came off Africa and went west-northwest, but then oddly it dipped west-southwest,” said Derrick Herndon, associate researcher in the Tropical Cyclone Research Group at the UW-Madison Space Science and Engineering Center.
“That worried us because those storms are strong in intensity and they usually head toward the United States.”
As a result of their research, the Tropical Cyclone Research Group was the first to notice Irma — before it became a tropical storm, before it earned a nickname and before it became a Category 5 hurricane. The UW scientists have been analyzing its intensity ever since, just as they did earlier with Hurricane Harvey.
The UW team gets its information from geostationary satellites 22,500 miles above Earth, as well as polar orbiting satellites 500 miles up. Geostationary satellites, which are positioned over one spot, offer continuous images, while the orbiting satellites provide pictures every 12 hours as they revolve around the north and south poles.
Information from the Madison researchers is combined with data streaming in from other spots to help forecasters at the National Hurricane Center in Miami figure out the intensity of hurricanes like Harvey and Irma and their likely path. While the UW scientists don’t issue forecasts, the information they provide is critical to meteorologists who then release warnings that help people decide whether to flee or hunker down.
Why Madison?
Although Madison may seem an unlikely spot for such research, it’s role is rooted in groundbreaking work of atmospheric science professor Verner Suomi, who is widely credited with developing imaging technologies that spawned modern weather satellites in the 1960s and ‘70s.
Suomi, who died in 1995, is considered the father of satellite meteorology and his instruments
are still used to interpret the enormous amount of information flowing in from satellites.
“I get asked a lot: What does Wisconsin have to do with hurricanes?” said Chris Velden, a Wauwatosa native who is senior scientist in the Tropical Cyclone Research Group. “In the 1980s, we were one of the only places in the world getting real-time satellite information.”
Since most hurricanes are spawned in the middle of oceans — too far for storm-tracking planes, radar and other weather gathering methods — the work done by the UW scientists is invaluable.
“These products help the forecasters diagnose the large-scale tropical weather, basin to basin, but also look at inner core tropical cyclone features,” Shirley Murillo, deputy director of NOAA’s Hurricane Research Division in Miami, said in an email Thursday.
The ‘war room’
The group of seven researchers has been very busy this hurricane season. They were in the midst of Harvey when Irma popped up. And even as their hands are full with Irma, they’re also following two more hurricanes — Katia and Jose.
Their work is done in a building near Camp Randall Stadium whose roof is filled with huge satellite dishes and a golf ball-like polar satellite transceiver. On days when critical information
is pouring into their computers, they frequently gather to compare data and observations in a windowless office dubbed the “war room.”
Thursday morning, they were joined by more than a dozen visitors representing the likes of the National Weather Service, the National Oceanic and Atmospheric Administration, even The Weather Channel. Herndon and Sarah Griffin, an associate researcher, shared satellite images, graphs and charts that to the untrained eye looked like a jumble of numbers and jagged lines. A rainbow-hued infrared image of Irma filled a large overhead screen; another screen showed a visible satellite image of the storm — the white clouds swirling like vanilla ice cream in a malt machine.
“It’s very symmetric in its structure, a very well-defined storm,” Herndon said.
Irma is what’s called a Cape Verde hurricane, hurricanes that originate in the Atlantic Ocean near the Cape Verde islands after moving off the coast of western Africa.
Griffin showed images of wind shear and information gleaned from weather-tracking planes flying in and out of the hurricane’s path. The group talked about the multiple computer models predicting the path of Irma through Florida and possibly Georgia. And then Herndon showed an image of surface water
temperatures and water depth in Irma’s path.
The scientists looked intently at the numbers and shifted in their chairs. They knew what it meant — that the 80plus degree water will act like kindling to Irma as the hurricane pushes through the Caribbean, sucking up more heat and moisture on its journey to Florida.
“We’re really concerned about the water temperatures. The hurricane has not even found the warmest water, the best environment yet. This gives you an idea of the intensity source,” cautioned Herndon.
“Irma has been an over-achiever. The maximum potential intensity is 200 knots in the Florida Straits,” Herndon said.
If it happens, that means 230 mph sustained winds of at least one minute or more — as opposed to occasional gusts — throughout the storm.
Thursday morning it was too early to tell whether that will happen, but the scientists discussed the stark possibilities of what could happen to heavily populated areas like Miami and Atlanta.
“I think one of the toughest aspects is that although we get excited because this is what we do, we know they’re very dangerous and are killers,” Velden said of the hurricanes. “You have to take a little pride in being a small slice of the process that lets people know what will happen so they can get out of the way.”