Studying the science of storms

Clouds associated with Hurricane Michael blow past Lake Sumter in 2018.

A strong storm such as Hurricane Dorian emerges from the depths of the Atlantic Ocean. Warm, moist air rises over the ocean to form its body of clouds, created when the air enters cooler altitudes and comes back as water vapor. As this process continues, the storm grows larger. Energy from the ocean’s surface feeds the storm and helps it barrel toward land. It unleashes torrents of wind that, at highest strength, could blow at a speed greater than 
156 mph. That’s more than double the speed of the cheetah, the world’s fastest land animal, or SeaWorld’s Mako, Central Florida’s fastest roller coaster. At its strongest, the storm can spit out torrential rain, churn up tornadoes and is responsible for coastal tidal surges. It’s no science fiction film script, it’s the creation of one of the most powerful storms on Earth.

The hurricane is just one of the weather phenomena that places Florida at the epicenter for studying the science of storms. 

Florida is dubbed the Sunshine State, but the sun’s rays are not exclusive here as thunderstorms that make us the lightning capital, coastline rip currents, occasional tornado activity and those destructive hurricanes all make appearances across the peninsula.

Florida’s weather environment doubles as a weather laboratory. And researchers here are taking full advantage of it.

This time of year tropical weather research gets the focus, but anything Mother Nature can dish out is open for intense study.

Hurricane experts urged people to plan with an expectation that at least one storm would make landfall. It follows their common belief that it takes just one hurricane landfall to make a season active.

Residents also may expect more reliable forecasting than years prior thanks to new research and forecasting advancements.

South Florida, where Hurricane Andrew struck 25 years ago, is home to the National Hurricane Center. This bureau of the National Oceanic and Atmospheric Administration leads tropical cyclone forecasting and engages in research to improve forecasting.

It’s also where Florida International University and the University of Miami each have simulators capable of testing the impacts of hurricanes up to Category 5 strength, with wind speeds exceeding 156 mph.

And the Sunshine State is home to two colleges — FIU and the University of Florida — that the National Science Foundation designated national testing facilities for wind engineering. This research focuses on how severe weather impacts materials used to build houses.

Improving Forecasting

When hurricanes strike Florida, researchers from Florida universities and government agencies drive the study of these storms.

This research aims to improve the science behind forecasting hurricanes, the public’s understanding and awareness of hurricanes, and how building materials could be improved to better withstand hurricanes.

While the National Hurricane Center’s primary purpose is to monitor hurricane activity in the tropics, it also has a team of scientists who study the agency’s own forecasting.

Scientists are revising the center’s existing database of historic storms to identify areas impacted the hardest, what controls the year-to-year cycle of hurricanes, and long-term trends, said Chris Landsea, science and operations officer for the hurricane center.

“It benefits everybody to have an accurate record,” he said. “Our database is used by the people who set the building codes, and they want to set building codes that withstand hurricanes.”

Other research involves computer forecast models designed to simulate hurricane activity. These models, according to the hurricane center, include:

Dynamical models, the most complex modeling scientists use. These require high-speed computers to solve equations of motion that may predict atmospheric conditions.

Statistical models, which are based on historical relationships between a tropical cyclone’s activity, location, date and other details.

Statistical-dynamical models, which blend the above two.

Trajectory models, where researchers determine how a storm moves from the flow of a separate dynamical model.

Ensemble/consensus models, which combine forecasts from multiple models.

Ongoing research using computer forecast models has improved forecast accuracy drastically, Landsea said.

“Errors decreased by about half in about 20 years,” Landsea said. “In a generation, we’ve made some incredible improvements.”

One of the most visible outcomes of those improvements came just this year: the debut of a smaller cone of uncertainty, which shows the likely track of a storm’s center.

The smaller cone reflects greater accuracy in predicting which areas a storm may impact, Landsea said.

“Three-day forecasts have an error of about 125 miles, so if we say a hurricane is going to land in Melbourne, the (cone of uncertainty) would land in West Palm Beach,” he said. “20 years ago, it would have been closer to Savannah, Georgia.”

Re-enacting Nature

Not all hurricane simulation happens on computers.

A research facility at Florida International University in Miami includes the Wall of Wind, made of 12 fans that can generate winds up to 157 mph, Category 5 strength. It also can simulate rain using a water injection system.

Because of the Wall of Wind, FIU is one of two universities in Florida that the National Science Foundation named a national testing facility for wind engineering, said Erik Salna, associate director for FIU’s Extreme Events Institute and the International Hurricane Research Center.

“It’s moved the Wall of Wind into the national (research) spotlight,” he said.

The simulator is like a practice run for surviving hurricanes, demonstrating the impacts of wind forces, turbulence and heavy rainfall.

And it’s all to find out how tropical cyclones impact buildings and building materials, Salna said.

“We find where the peak wind speeds are in parts of the roof (and) we put water into the wood flow where water accumulates the most,” he said.

The goal is to help improve how buildings, and components of buildings such as solar panels, can be built, Salna said.

Research from the Wall of Wind made a difference, as university scientists’ recommendations inspired provisions on roofs and roofing equipment in the 2010 Florida Building Code, FIU stated.

Scientists also developed a new roofing material that can better resist hurricanes, Salna said.

Florida’s other national testing facility for wind engineering is the University of Florida’s Powell Family Structures and Materials Laboratory, though its research isn’t exclusively focused on hurricanes.

At the facility, researchers also test hazards from tornadoes, earthquakes and “human-devised threats,” UF stated. The facility includes one of the largest boundary layer wind tunnels in the world, as well as a wind load simulator that can replicate conditions of a Category 5 hurricane or EF5 tornado.

The University of Miami has a hurricane simulator similar to the Wall of Wind.

Its Surge Structure Atmosphere Interaction Facility, or SUSTAIN, can replicate a Category 5 storm and is used to research air-sea interactions and storm surges.

UM researchers recently collaborated with NOAA scientists on a study about how atmospheric waves from the centers of hurricanes may explain a storm’s intensity and location.

“Of course, hurricanes are very well observed by satellites,” said Dave Nolan, an atmospheric sciences professor at UM. “But these waves can reveal processes occurring in the eyewall of a hurricane that are obscured from the view of satellites by thick clouds.”

Learning about these atmospheric waves could provide information that leads to better hurricane forecasts, Nolan said.

Florida State University, one of the leading weather research institutions based on grant funding from the National Science Foundation, has a team of 78 researchers in its Center for Ocean-Atmospheric Prediction Studies.

FSU’s research not only focuses on the science of severe weather, but also relationships severe weather has with health and agriculture, said Mark Bourassa, the center’s associate director.

“We have people looking into hurricane impacts on insurance, air-sea exchange of energy, momentum and materials such as water vapor and sea salt, and how different environmental conditions influence hurricane evolution in models,” he said.

Researchers also work with observations from within hurricanes, Bourassa said. One person on FSU’s team flies into hurricanes for NOAA.

Planes, Drones and Satellites

NOAA researchers also use NASA-developed unmanned aircraft that fly into hurricanes to obtain data, similar to manned “hurricane hunters.”

Bigger than drones but smaller than commercial jets, unmanned planes are advantageous to hurricane researchers compared with manned planes, said Gerald Heymsfield, a research meteorologist with NASA‘s Goddard Space Flight Center in Greenbelt, Maryland.

These planes get more flight time — 24 hours in the sky, compared with eight hours for a manned aircraft — without risk to human lives, he said.

“You can cover a larger period of a storm while it’s developing,” Heymsfield said.

While NOAA did the research, NASA provided the unmanned aircraft known as the Global Hawk used to conduct the research, he said. NASA built the Global Hawk in California from a retired Air Force plane.

In 2016, the Global Hawk studied Hurricane Matthew before and during its approach to Florida’s coast.

Its research identified winds, latent heat, precipitation and cloud variables from Matthew using high-altitude radar, NOAA stated.

But it’s not the only aerial instrument studying storms.

NOAA also conducted research on Matthew using a drone called the Coyote, a project of the Waltham, Massachusetts-based company Raytheon. The Coyote can fly through and collect data from the most dangerous parts of a storm.