Hurricane

New lab at UM can create hurricane conditions on demand

Brian Haus, professor in the department of ocean sciences at the University of Miami Rosenstiel School of Marine and Atmospheric Sciences, in Miami, Florida looks on as a storm rages inside the world's largest indoor hurricane simulator, known as SUSTAIN (short for SUrge-STructure-Atmosphere Interaction) on April 30, 2015. The world's largest hurricane simulator is now complete and experts hope it will improve forecasters' ability to predict how strong a storm will get, which has been a key weak spot for science until now. When lead scientist Brian Haus switches on the 1,700 horsepower engine, paddles begin to roil the 38,000 gallons (144,000 liters) of fresh water, though salt water can also be used. Aquamarine waves arc gracefully against the acrylic windows, then grow increasingly frenetic as a Category 5 wind blows over the top at a speed of 156 miles per hour (251 kilometers per hour). Soon, spray droplets scatter across the sides of the steel-framed tank, which measures 75 feet (23 meters) long, 20 feet (six meters) wide and 6.5 feet (two meters) deep.
Brian Haus, professor in the department of ocean sciences at the University of Miami Rosenstiel School of Marine and Atmospheric Sciences, in Miami, Florida looks on as a storm rages inside the world's largest indoor hurricane simulator, known as SUSTAIN (short for SUrge-STructure-Atmosphere Interaction) on April 30, 2015. The world's largest hurricane simulator is now complete and experts hope it will improve forecasters' ability to predict how strong a storm will get, which has been a key weak spot for science until now. When lead scientist Brian Haus switches on the 1,700 horsepower engine, paddles begin to roil the 38,000 gallons (144,000 liters) of fresh water, though salt water can also be used. Aquamarine waves arc gracefully against the acrylic windows, then grow increasingly frenetic as a Category 5 wind blows over the top at a speed of 156 miles per hour (251 kilometers per hour). Soon, spray droplets scatter across the sides of the steel-framed tank, which measures 75 feet (23 meters) long, 20 feet (six meters) wide and 6.5 feet (two meters) deep. AFP/Getty Images

In trying to figure out what makes some hurricanes strengthen into catastrophic monsters, researchers have created a lab that allows them to generate tropical storm conditions with the flip of a switch.

The lab, located at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science, is known as the Surge-Structure-Atmosphere Interaction, or SUSTAIN.

THE TANK

The lab features a clear acrylic tank about 75 feet (23 meters) long and 6.5 feet (2 meters) high. Inside, 38,000 gallons of seawater can be whipped into white-capped waves by a 1,700-horsepower fan that can create Category 5 conditions, with winds topping 157 mph.

Satellite sensors have been mounted on the lab’s high ceilings to look down at hurricane conditions churning in the tank. This will help fine-tune satellites watching real storms, said lab director Brian Haus.

“The satellites, even though they see a really big area, they tend to be sensitive to really small things on the surface. We don’t really know, when you get into extreme conditions, what the satellite is seeing — whether there’s a spot reflecting off sea spray or bubbles or short waves,” Haus said.

IMPORTANT BUBBLES

During a recent test-run, Haus stood atop the tank, his shoes dry and his clothes unruffled while frothy, sea-green waves raced beneath him. He also stood underneath the tank and along its sides, watching sea spray blast bubbles and water droplets down the tank.

By studying the way hurricane-force winds interact with spray coming off the surface of seawater, researchers aim to improve real-time tropical storm observations made by satellites, ocean buoys and drones and other sensors launched from “hurricane hunter” aircraft.

Hurricanes run like engines, fueled by warm ocean waters. Some aspects still stump researchers, because they can’t clearly see what’s happening where a storm’s winds meet the water’s surface.

Researchers are testing small drones to fly down into those dark and stormy places, while a variety of other sensors from buoys and underwater gliders and satellites collect data for hurricane forecasting models. All those tools still are prone to technical difficulties in extreme conditions.

Researchers think that understanding the role those tiny elements play in the transfer of energy from the ocean to a storm may crack the mystery of what causes some storms to fizzle while others strengthen.

INTENSITY FORECASTS

Predictions for a storm’s path have improved significantly over the last couple decades, narrowing the so-called “cone of uncertainty” that influences preparations. However, forecasters have made little headway when it comes to improving predictions for how strong a tropical storm will become.

Research like the observations in the SUSTAIN lab will be vital to making storm intensity forecasts better, said Rick Knabb, director of the National Hurricane Center in Miami.

“Intensity forecasting, especially rapid intensification and especially when that happens near the coastline — that remains our highest priority forecast improvement need,” Knabb said.

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