Nearly 10 years ago, Hurricane Katrina laid waste to the Gulf Coast. While moving over the warm waters of the Gulf of Mexico, the storm unexpectedly revved up from a Category 3 hurricane to Category 5—the worst possible scenario. With winds faster than 157 miles per hour, Katrina pushed a wall of water three times higher than predicted over Louisiana's levees, killing 1,833 people and causing at least $80 billion in property damages.
Part of Katrina's deadly toll might have been avoided if scientists could better predict how severe a hurricane is going be. “The ability to forecast the track of the hurricane has been steadily improving over the past 25 years,” says Chris Ruf, an atmospheric scientist at the University of Michigan. “But the forecasting for intensity hasn't really improved at all.”
Fortunately, Ruf thinks he can break that lackluster track record. In 2016, his team will launch eight small satellites into orbit around the Earth's equator. For the first time, they'll be able to continuously measure wind speeds in the hellish core of a developing hurricane. Those wind speeds indicate how strong the storm will become.
It's relatively easy to predict where a hurricane will travel, based on the air flow around it. But a hurricane's strength depends largely on how fast its winds are moving. Hurricanes with faster winds pick up more water. Later, as that evaporated water cools and condenses, it releases heat. “That's the energy that pumps up hurricanes,” says Ruf, “so if you can track the wind speed, you can track the energy.”
Plenty of weather satellites measure wind speed, but they don't work so well in the rain—meaning they're pretty much useless when it comes to seeing into the heart of a hurricane.
Ruf's constellation of microsatellites, named CYGNSS, gets around that problem in a smart way. It takes advantage of the GPS signals that satellites are constantly beaming down to Earth. Those signals use a longer wavelength than typical weather satellites, which means they can penetrate through rain without suffering too much damage. CYGNSS's GPS receivers (like the one in your phone) listen in on those signals, and when they bounce back from Earth, the satellites measure how distorted the signal became on the surface. More distortion means a rougher ocean, which means a tougher storm.
