An unmanned aircraft provided climate scientists an unprecedented look at the innermost workings of a tropical storm Sept. 16, gathering low-altitude wind speed data and other types of information that could one day be used to predict the severity of approaching hurricanes.
The Aerosonde aircraft, equipped with meteorological sensors, GPS receivers and satellite communications gear, flew directly into the lower regions of Tropical Storm Ophelia as it churned off the Atlantic coast of the United States. Ophelia had been downgraded from a hurricane just hours before the unmanned drone ventured into an area that is often too dangerous for the piloted aircraft typically dispatched to observe severe storms up close.
“The biggest thing was just to see if we could do it,” said Joe Cione, a research meteorologist with the U.S. National Oceanic and Atmospheric Administration (NOAA). “The second thing was to provide the real-time data to the hurricane center.”
The Aerosonde project is a joint effort of NOAA and NASA. The aircraft was supplied by Aerosonde, an Australian aeronautical technology company that has a cooperative agreement with NASA.
NOAA tried to launch the aircraft twice last year but was forced to cancel due to weather conditions and range constraints at NASA’s Wallops Flight Facility, Va., the Aerosonde’s take-off and landing site. Six attempts were made this year before scientists finally were able to get off the ground in time for Ophelia.
The Aerosonde was outfitted with a mounted version of the GPS dropwinsonde, which typically parachutes into storms after being dropped by an aircraft and measures wind speed, temperature and barometric pressure, Cione said. The drone also was equipped with an infrared sensor to measure the sea-surface temperature beneath the storm, he said.
Some of the data collected by the Aerosonde was relayed immediately via the Iridium satellite communications system to NOAA’s National Hurricane Center and Atlantic Oceanographic and Meteorological Laboratory, both in Miami. Cione said he expects to receive additional data that was not relayed during the Aerosonde’s 10-hour flight Sept. 30 for detailed analysis.
The Aerosonde can fly a total of approximately 2,400 kilometers per flight, so storms must be located close enough to the shore for a mission to be feasible, Cione said. NOAA had hoped to fly the aircraft into Ophelia while it was still a fullblown hurricane, but the storm weakened before the drone’s arrival .
“In retrospect, it was not a bad thing; it gave us a good test mission to see if it could survive it,” Cione said. Once inside the storm, the Aerosonde flew as low as approximately 366 meters, an altitude too dangerous for piloted aircraft, he said.
“Since manned aircraft can’t go down there, the result is we don’t know what’s going on down there,” Cione said. “With a GPS dropwindsone, you get a snapshot, but we wanted to sample the whole region to get a good understanding of what’s happening. That region is very important because it’s where the ocean meets the atmosphere, where energy is transferred from the ocean to the atmosphere.”
The Aerosonde project is funded for 60 more hours of flight time this year. Cione is attempting to switch the launch location to Florida for the 2006 hurricane season, and to secure the funding for several more missions next year.
“We hope to get a hurricane next time,” Cione said.
The Aerosonde will next be used by the U.S. Air Force in mid-October for a mission in Guam, said Peter Bale, manager of Aerosonde North America, which is based at Wallops.
“We’re actually going to be chasing super typhoons,” Bale said, adding that the remote Pacific island lacks an accurate early warning system for severe weather .
Cione expressed hope that Aerosonde-collected data eventually will be incorporated into the operational weather forecast models at NOAA’s Environmental Modeling Center in Camp Springs, Md.
