Conference 7.286::space

788.0. "NASA to measure Arctic Sea ice and Greenland polar glaciers" by PRAGMA::GRIFFIN (Dave Griffin) Wed Mar 18 1992 12:53

Brian Dunbar
Headquarters, Washington, D.C.                        March 18, 1992

Keith Koehler
Wallops Flight Facility, Wallops Island, Va.

RELEASE:  92-38



     NASA researchers will use airborne instruments to measure
Arctic sea ice and Greenland polar glaciers in April 1992, aiding
scientists in the study of global climate changes.

     Researchers from NASA's Goddard Space Flight Center's Wallops
Flight Facility, Wallops Island, Va., will use laser-ranging
instruments aboard the Wallops P-3B (HL) Orion aircraft to measure
the sea ice above the water and the polar glacier elevations.  The
airborne laser systems are capable of measuring elevations to an
accuracy within 1 to 1-and-a-half inches.

     The data gathered on the sea ice will be compared to previous
studies and used to develop a baseline for future studies, according
to Bill Krabill, Principal Investigator from Wallops.  The Greenland
glacier measurements will be compared to data gathered during a
similar study by Wallops in 1991 and with data from the European
Space Agency's European Earth Resources Satellite.

     Scientists are interested in developing accurate measurements
of sea ice and glaciers because changes in these systems may
indicate trends in world climate.  Appreciable changes in these ice
systems, such as increased melting, could directly affect global
climate.

     The researchers will leave Wallops on April 6 and are expected
to return in late April.  They will base their Arctic sea ice
flights from Eielson Air Force Base near Fairbanks, Alaska, and
Longyearbyen, Vest Spitsbergen, a Norwegian island.  The sea ice
measurements will be taken along flight lines from the bases of
operation toward the North Pole.

     The principal instrument on the P-3B (HL) aircraft is the
Airborne Oceanographic Lidar (AOL).  The AOL measures the time it
takes for a laser pulse to reach the ice and return to the aircraft.
Time variations will occur because of changes in the terrain and the
aircraft's altitude.  Using the Global Positioning System, a Defense
Department satellite system that allows aircraft or ships to
precisely determine their locations, researchers will derive the
elevations of the sea ice relative to the mean sea level and the
elevations of the Greenland glaciers.

     Krabill said that by knowing the thickness of the ice above the
sea, researchers can infer the amount of ice below the sea and
obtain a measurement of the total ice mass.  He noted that the
researchers may conduct reflights over the same flight paths in
future years to gather follow-up data.

     The program is conducted under the Earth Sciences Directorate
of NASA's  Office of Space Science and Applications.