Researcher to deploy high-tech tools for better storm forecasting


Jason Dunion, an associate scientist at the University of Miami’s Cooperative Institute for Marine and Atmospheric Studies, is leading a 2022 hurricane field program that will test new aerial drones capable of flying at altitudes deemed unsafe for hunters Hurricanes and other reconnaissance aircraft.

As a little boy, Jason Dunion stared at the portable weather station he received for his eighth birthday at the front door of his New England home, taking temperature and humidity readings and recording his own storm emissions affecting his community.

Today, as a scientist at the University of Miami’s Cooperative Institute for Marine and Atmospheric Studies (CIMAS), Dunion still measures storm dynamics. But the instruments he now uses to study them are quantum leaps above the weather station of his childhood.

From powerful radar systems that provide detailed wind data near the eyewall of tropical cyclones to drones that fly as low as 100 feet above the ocean surface and provide information about the critical air-sea interface , Dunion uses a multitude of high-tech devices. to help scientists answer some of the mysteries of the storms.

These instruments are used aboard Hurricane Hunter aircraft that fly into the heart of storms, acquiring the critical information needed to make reliable forecasts and models. And this year, as part of Dunion’s new role as director of the Hurricane Field Program – a collaboration between CIMAS, part of the University’s Rosenstiel School of Marine and Atmospheric Science, and the National Oceanic and Atmospheric Administration hurricanes – he will oversee these flying missions, which use highly modified P-3 Orion aircraft and a high-speed, high-flying Gulfstream IV jet.

Doppler radar is the keystone of these flights. “What we know least about is the inner core of storms, because most satellites can’t see through that cirrus canopy at the top,” Dunion explained. “But Doppler gives us an X-ray picture of what storm winds look like in the core, from almost the surface of the ocean to the top of the storm system, up to 50,000 feet.”

Radar clarity has helped take the guesswork out of forecasting storms, allowing a multitude of models to better predict storm intensity. “It was a real game-changer,” Dunion said.

He’s been on around 60 Hurricane Hunter missions, flying straight into storms like Dorian, Irma and Sally – eight-hour outings he describes as intense roller coasters.

“The eyewall, which is just outside the eye, has the worst weather and the highest cloud tops. And that’s usually where you’re going to see the strongest winds” , Dunion said, noting that scientists aboard these flights can feel up to four G-forces, which is greater than what astronauts have endured during NASA space shuttle launches.

“We are tethered and can lose or gain altitude a few hundred feet in seconds. And at the same time, we work with the radar and we deploy dropsondes [devices]“, continued Dunion. “But just inside this powerful wind field is the eye of the hurricane, where it is incredibly calm. You can literally unbuckle and get out of your seat.

Of the dozens of missions he’s flown on, Hurricane Dorian’s teeth leak in early September 2019 was the worst.

“As the storm approached the Bahamas, conditions came together for it to intensify. At the same time, steering currents collapsed and it was expected to pass over Grand Bahama,” Dunion said. “We flew into the storm, and at one point the updraft was about four Gs. I felt like a feather in the wind. It was a potent Category 5 the moment we entered the eyes. The cloud tops were probably near 50,000 feet, and we’re not going to top the storm; we plow in the middle of it.

With increasingly powerful storms and with recent hurricane seasons characterized by above-normal activity, improving tropical cyclone forecasting and modeling through instrumentation becomes even more crucial, stressed Union.

While Doppler radar, dropsondes and other devices will continue to be mainstays of hurricane information gathering, other tools like drones are rapidly emerging as the next generation of storm reconnaissance. And this summer, Dunion is helping lead NOAA’s field program that will test a new class of remote-controlled aerial drones designed to fly at altitudes too perilous for airplanes: just a few feet above the surface of the ocean.

Dropsondes, which are deployed from aircraft and stabilized by a small parachute, offer insight into what is happening at this level. “But that’s just a taste of what we want to know,” Dunion said. “It can be dangerous to fly too low, and we wouldn’t want to fly low in a storm like Dorian. But we can fly a drone at this altitude, close to the all-important surface of the ocean. This is where all the energy from the ocean is transferred to the atmosphere, right at this interface.

If testing goes well, the drones will be launched in some of this season’s storms over the Atlantic.

Dunion will also help test a new light detection and ranging (LiDAR) system, which offers a new way to measure wind speed. “He has huge potential,” he revealed. “To measure the winds with a Doppler radar, you need rain droplets. But a wind-powered LiDAR can measure winds in clear air because it looks at moving air molecules. They will allow us to know not only the winds of the inner core but also those of the periphery.

He will also pursue his own field of research: satellite remote sensing of hurricanes, which has led to the development of new instrumentation for monitoring tropical cyclones and Saharan dust storms and the prediction of hurricane genesis.

Dunion recently received the Richard H. Hagemeyer Award for his substantial long-term contributions to the advancement of hurricane research.

“And just thinking,” Dunion said. “This [his career] it all started with this little weather station I got as a birthday present.


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