Arctic Trek to ‘Break the Ice’ on New NASA Airborne Radars
Scientists from NASA’s Jet Propulsion Laboratory,
One of the radars, the L-band wavelength Unmanned Aerial Vehicle Synthetic Aperture Radar, or UAVSAR, calibrates and supplements satellite data; the other is a proof-of-concept Ka-band radar called the Glacier and Land Ice Surface Topography Interferometer, or GLISTIN.
Both radars use pulses of microwave energy to produce images of Earth’s surface topography and the deformations in it. UAVSAR detects and measures the flow of glaciers and ice sheets, as well as subtle changes caused by earthquakes, volcanoes, landslides and other dynamic phenomena. GLISTIN will create high-resolution maps of ice surface topography, key to understanding the stresses that drive changes in glacial regions.
During this expedition, UAVSAR will study the flow of
“We hope to better characterize how Arctic ice is changing and how climate change is affecting the Arctic, while gathering data that will be useful for designing future radar satellites,” said UAVSAR Principal Investigator
The UAVSAR collects data over areas of interest while the aircraft flies at 41,000 feet (12,500 meters) altitude. The G-III then flies over the same areas again, minutes to months later, using precision navigation to fly within 15 feet (4.6 meters) of its original flight path. By comparing the data from multiple passes, scientists can detect subtle changes in Earth’s surface.
L-band Principal Investigator
To better predict how glaciers and ice sheets will evolve, scientists need to know what they’re doing now, how fast they’re changing, what processes drive the changes and how to represent them in models. Accurate measurements of ice sheet elevation derived from laser altimeters (lidars) on aircraft or satellites are critical to these efforts. But high-frequency microwave radars can also do the job, with greater coverage and the ability to operate in a wider range of weather conditions. Until now, however, microwave radars operating at wavelengths longer than those of GLISTIN have penetrated snow and ice more deeply than lidars, making interpretation of their data more complex.
Enter GLISTIN, the first demonstration of millimeter-wave interferometry, which was developed to support International Polar Year studies. Principal Investigator
Scientists expect GLISTIN to penetrate the snow and ice by just centimeters, rather than by meters, as current microwave radars do. A multi-institutional team will conduct coordinated lidar and ground measurements to help quantify how deeply GLISTIN’s Ka-band radar penetrates the snow and ice and to verify model predictions.
GLISTIN data will aid in designing future Earth ice topography missions and even missions to map ice on other celestial bodies. Scientists will also apply its data to designing missions to map Earth’s surface water and ocean topography.
A joint partnership of JPL and Dryden, UAVSAR evolved from JPL’s airborne synthetic aperture radar (AIRSAR) system that flew on NASA’s DC-8 aircraft in the 1990s. In 2004, NASA’s Earth Science Technology Office funded development of a more compact version of AIRSAR to be flown on uninhabited aerial vehicles. UAVSAR made its first operational flight in
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PHOTO EDITORS: Publication-quality photos of the Gulfstream III carrying the UAVSAR pod are available on-line at: