ACCURACY OF AIRBORNE LASER ALTIMETRY OVER THE GREENLAND ICE-SHEET

During September 1991, April 1992 and June/July 1993, a NASA P-3 aircr aft, equipped with a scanning laser altimeter, flew numerous transects of the Greenland ice sheet. The aeroplane location was measured preci sely using differential Global Positioning System (GPS) surveying tech niques, allowing all altimetry data to be converted into measurements of ice-surface elevation relative to the Earth ellipsoid. Results from flight data indicate that ice-surface elevations can be reliably meas ured to an accuracy of similar to 20 cm (and possibly to similar to 10 cm) over baselines of more than seven hundred kilometres.