Unmanned aircraft can fly longer than their manned counterparts, making them useful for meteorological missions such as Nasa’s Hurricane and Severe Storm Sentinel (HS3) program. The agency is using two Global Hawk drones, originally designed for strategic reconnaissance, to fly 30-hour missions at altitudes of over 55,000 feet.
HS3 explores how hurricanes form and change in intensity. In particular it is examining the role of the Saharan Air Layer, a layer of warm, dry air that often overlies cooler air at the surface of the Atlantic. This may have an inhibiting effect on hurricane formation.