The traditional method to detect a hurricane's strength has been to fly airplanes through the most intense winds into the eye of the storm, carrying out wind-speed measurements as they go. But that approach requires specialized planes priced at $100 million each, with a single flight costing $50,000. Nicholas Makris, associate professor of mechanical and ocean engineering and director of MIT's Laboratory for Undersea Remote Sensing, has developed a method that uses hydrophones (underwater microphones) deep below the surface in the path of an oncoming hurricane, to measure wind power as a function of the sound's intensity.
Makris and former graduate student Joshua Wilson noted that in 1999, Hurricane Gert happened to pass over a hydrophone anchored 800 meters above the mid-Atlantic Ridge, at the latitude of Puerto Rico. The same storm
was monitored by airplanes within the next 24 hours. "There was almost a perfect relationship between the power of the wind and the power of the wind-generated noise," Makris said. "There was less than 5 percent error - about the same as the errors you get from aircraft measurements."
Makris believes a line of acoustic sensors could be dropped from a small plane into the ocean ahead of an approaching hurricane's path, and provide detailed information on the storm's strength to aid planning and decision- making about possible evacuations. The total cost for such a deployment would be a fraction of the cost of even a single flight into the storm. Makris believes such sensors could be permanently deployed offshore in storm-prone areas, such as the Sea of Bengal off India and Bangladesh.
