Seeing Which Way the Wind Blows: New Doppler Radar Takes Flight on This Summer's HS3 Mission

The High-altitude Imaging Wind and Rain Profiler or HIWRAP dual frequency Doppler radar will hang under the Global Hawk.
The HIWRAP dual frequency Doppler radar will hang under the Global Hawk. On the left, the golden disc is the antenna and on the right, the two small white discs are the radar beam transmitters, one for each of two frequencies. The whole apparatus spins while flying.
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Most aircraft carrying Doppler radar look like they’ve grown a tail, developed a dorsal fin, or sprouted a giant pancake on their backs. But when the unmanned Global Hawk carries a radar system this summer, its cargo will be hard to see. The autonomous and compact High-altitude Imaging Wind and Rain Profiler, or HIWRAP, a dual-frequency conical-scanning Doppler radar, will hang under the aircraft’s belly as it flies above hurricanes to measure wind and rain and to test a new method for retrieving wind data.

HIWRAP is one of the instruments that will fly in this summer's mission to explore Atlantic Ocean hurricanes. NASA's Hurricane and Severe Storm Sentinel, or HS3, airborne mission will investigate tropical cyclones using a number of instruments and two Global Hawks. The HS3 mission will operate between Aug. 20 and Sept. 23.

"Radar is an important remote sensor for atmospheric research," said Lihua Li, an engineer who helped develop HIWRAP at NASA's Goddard Space Flight Center in Greenbelt, Md. "Radar signals penetrate clouds and precipitation, allowing scientists to detect information on raindrops or ice particles." That information, he said, is one piece of the puzzle toward improving scientists' understanding of weather events.

This past year, Li and his colleagues further improved their radar technology to make it more effective at high altitudes. The ultimate goal is using radar to measure weather events from space.

Goddard's High Altitude Radar Group.
Goddard's High Altitude Radar Group. Top (left to right): Gerry McIntire, Michael Coon, Matthew McLinden, Gerry Heymsfield. Bottom (left to right): Lihua Li, Martin Perrine.
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