Extreme Low Frequency Acoustic Measurement System

NASA’s Langley Research Center has developed a system to detect and locate atmospheric clear air turbulence (CAT) by means of a ground-based infrasonic array to serve as an early warning system for aircraft. This system could augment existing systems such as pilot reports (PIREPs), airborne lidar, and airborne radar. The NASA system offers a benefit since the existing electromagnetic methods lack targets at 30,000-40,000 feet and will not detect CAT. Because CAT and severe storms emit infrasound that propagates over vast distances through the Earth’s atmosphere, the Langley system offers an excellent early warning opportunity. The system has been able to detect known events — such as detection of the launch of the Space Shuttle in Florida all the way from Virginia. It also has correlated data with NOAA’s PIREPs information.