ESRL Quarterly Newsletter - Summer 2010

It’s a bird, it’s a’s SuperPlane!

Spring mission demonstrates Global Hawk’s chemistry prowess; next up: Gulf hurricanes

This spring, NASA and NOAA outfitted an unmanned military airplane with atmospheric instruments and sent it on a spectacular series of flights to study the atmosphere over the Pacific Ocean. Now, scientists are aiming the research plane at hurricane formation and intensification in the Gulf of Mexico. Because the aircraft can soar for 30 hours per flight, researchers will get an unprecedented look at hurricanes as they develop and evolve.

“These long-endurance aircraft demonstrations represent a historic achievement for the Earth science community,” said Robbie Hood, NOAA Unmanned Aircraft Systems, UAS, program. “We now have a new observing tool that will allow us to closely study varying land, ocean, or atmospheric conditions in a single flight from the North Pole to the Equator or to stay and observe a rapidly changing event like a hurricane for more than a day.”

The Pacific. The Global Hawk Pacific mission (GloPac) represented the first science mission for the 116-foot wingspan unmanned aircraft, which NASA acquired from the U.S. Air Force two years ago. The drone, which can soar up to 65,000 feet and for 10,000 miles, is piloted remotely from NASA’s Dryden Flight Research Center in California.

During GloPac flights, ESRL scientists and their colleagues anxiously watched computer screens in Dryden mission control. They cheered as data streamed in from instruments designed to measure greenhouse gases, ozone-depleting chemicals, and aerosols.

Within a few weeks and after three long science flights up to 28 hours, scientists checked off all key science goals, according to ESRL’s David Fahey (Chemical Sciences Division), co-mission scientist on GloPac mission. They demonstrated the capability of the Global Hawk to routinely access chemical and dynamical events in different atmospheric regions from 85°N in the Arctic to 12°N in the near tropics.  Highlights included sampling the chemistry and structure of a fragment of polar air, which swirled down into the northern Pacific from the Arctic; catching the edge of a dust plume sweeping across the Pacific; and atmospheric sampling coordinated with a NASA satellite passing overhead.

The GloPac team also gathered stunning photographs—shot from the UAS—of Arctic sea ice, suggesting that the aircraft could be used to survey ice extent and thickness. 

“Part of this was luck,” Fahey said, “but luck favors the prepared.”

The Atlantic. GRIP is next, the NASA Genesis and Rapid Intensification Processes experiment, which will begin targeting hurricanes in late August for six weeks.

For GRIP, the Global Hawk will carry a new suite of instruments, more appropriate for hurricane research—100 dropsondes for measuring temperature, pressure, humidity and winds from high altitude to the surface; a lightning detector; a wind and rain profiler; and a radiometer.

ESRL’s Gary Wick (Physical Sciences Division) is principal investigator for the dropsondes, and he expects to be busy well before August, testing out the new instruments and their deployment system, recently designed and built at the National Center for Atmospheric Research.

NOAA already releases dropsondes into hurricanes from manned research and operational airplanes, Wick said, to better understand the wind and thermal structure of the storms and their environment – key information for better storm intensity and track predictions.

But the range of those piloted airplanes is limited, usually to fewer than nine hours, Wick said. Those airplanes typically drop up to 30 sondes, while the Global Hawk may be able to remain in hurricane regions for up to 20 hours at a time, releasing more than 90. On a map, conventional dropsonde locations look “like a few drops,” Wick said; Global Hawk’s releases look like “a pincushion.”

It’s not yet clear if the Global Hawk will be able to fly safely above hurricanes, Wick said. But even if the craft can only soar in close, the aircraft should be able to probe storm structure from several angles, characterize the environment in front of the storm, and track its evolution. “That’s what’s new here,” Wick said. “The fact that we will be able to follow the evolution of a storm.” 

“It’s kind of an exciting time in hurricane research,” said Michael Black, with NOAA’s Atlantic Oceaographic and Meteorological Laboratory, who is working closely with Wick and other colleagues this summer. “A platform like this Global Hawk…could be really tremendous for us.”