Mar 24 2006
From The Space Library
Isabella Velicogna and John Wahr, scientists at the University of Colorado, Boulder, who had conducted the first-ever gravity survey of the entire Antarctic ice sheet, reported their findings in the journal Science. Using data from two of NASA’s GRACE (Gravity Recovery and Climate Experiment) satellites, Velicogna and Wahr had determined that the ice sheet’s mass had decreased significantly between April 2002 and August 2005—by 152 cubic kilometers (36 cubic miles) of ice annually, plus or minus 80. The scientists had concluded that the Antarctic melting, an indicator of climate change, was causing the global sea level to rise 0.4 millimeters (0.16 inches) per year. The twin GRACE satellites, which orbit Earth more than a dozen times each day at an altitude of 310 miles (498.9 kilometers), measure variations in Earth’s mass and gravitational pull. Increases or decreases in the Antarctic ice sheet’s mass alter the distance between the satellites as they fly in formation.
Juliet Eilperin, “Antarctic Ice Sheet Is Melting Rapidly,” Washington Post, 3 March 2006; NASA, “NASA Mission Detects Significant Antarctic Ice Mass Loss,” news release 06-085, 2 March 2006, http://www.nasa.gov/home/hqnews/2006/mar/HQ_06085_arctic_ice.html (accessed 14 September 2009); see also Isabella Velicogna and John Wahr, “Measurements of Time-Variable Gravity Show Mass Loss in Antarctica,” Science 311, no. 5768 (24 March 2006): 1754-1756.
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