July 15, 2008
Two low-flying unmanned aircraft are cruising over Greenland this month to closely observe the melting of the Greenland Ice Sheet and its potential contribution to global sea level rise in the coming century. The flights will help scientists determine whether the ice sheet’s melt rate will accelerate in the future.
“We’re seeing the start of a new era in Arctic exploration,” said scientist Betsy Weatherhead, of NOAA’s Earth System Research Laboratory (ESRL) and the Cooperative Institute for Research in Environmental Sciences (CIRES). “With unmanned aircraft systems, we can fly missions too dangerous, dirty, or dull for humans and address questions we couldn’t even think of addressing before.”
Weatherhead is a lead scientist for the Arctic testbed of NOAA’s Unmanned Aircraft Systems program, which is funding the Greenland field experiment. The project is a partnership of ESRL, CIRES, and Advanced Ceramics Research, manufacturer of the unmanned “Manta” vehicles. The two Mantas fly out of Ilulissat, half way up Greenland’s west coast, for three weeks through the end of July.
The Greenland Ice Sheet is shrinking at a rate of 40–50 cubic miles each year, according to NASA satellite measurements, and that rate is accelerating. The total volume of the ice sheet is 700,000 cubic miles. Scientists believe the buildup of heat-trapping gases in Earth’s atmosphere is the main culprit, but the mechanisms are unclear. Better observations will shed light on the role of short-lived surface lakes and why the edges of the ice sheet are melting rapidly.
In summer the sun melts the top layer of the glaciers to form little lakes throughout the region, many of which vanish within a day. Scientists think these lakes may be emptying out through the ice and lubricating the bottom of the glacier with water. The glacier can then slide more quickly down the valleys, eventually breaking off into icebergs at the coastline.
A bird’s-eye view of the region from 500 to 1,000 feet above the ice can provide fine-scale measurements of the water and surface of the glaciers. Low-flying, unmanned Mantas give just that view, cruising at low altitudes over little-known terrain without putting human life at risk.
“We’re concerned that as temperatures rise, more heat will cause more melting, more melting will create bigger lakes, and the rate of ice loss will accelerate,” said NOAA Corps CDR John Adler, the project manager and a CIRES graduate student.
Trained operators from ACR control the crewless vehicles from the ground under the direction of on-site scientists. The eight-foot-wide, 45-pound Mantas take off on airport runways with permission from air traffic authorities. They can carry 15-pound instrument payloads and fly for up to six hours at about 40 knots, or 45 miles per hour, according to the Advanced Ceramics Research Web site.
Advanced Ceramics Research contributed engineering and development to the Greenland field project. CIRES is a partnership of NOAA and the University of Colorado.
The National Oceanic and Atmospheric Administration, an agency of the U.S. Commerce Department, is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and information service delivery for transportation, and by providing environmental stewardship of our nation's coastal and marine resources. Through the emerging Global Earth Observation System of Systems (GEOSS), NOAA is working with its federal partners, more than 70 countries and the European Commission to develop a global monitoring network that is as integrated as the planet it observes, predicts and protects.