Satellite makes 3-D maps of ice sheets

Satellite makes 3-D maps of ice sheets

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After less than a year of work, an Earth-orbiting satellite has churned out the most detailed, three-dimensional maps ever of the ice sheets blanketing Greenland and Antarctica. The baseline measurements collected by the Ice, Cloud and Land Elevation Satellite, or Icesat, should allow scientists to track the growth and shrinkage of the ice sheets, and to gauge the effect that might have on global sea levels.

The satellite, launched in January, took less than two months to produce the first topographic maps, said Jay Zwally, project scientist of the nearly $300 million mission at NASA’s Goddard Space Flight Center in Greenbelt, Md. On Tuesday, scientists attending the fall meeting of the American Geophysical Union updated reporters on the mission’s progress.

The satellite can measure the elevation of any one spot on the ice sheets twice each year, allowing scientists to watch for even minute changes in the vast frigid expanses over the projected two- to three-year life of the mission, Zwally said. Eventually, the spacecraft should be able to detect changes in ice levels as small as 0.4 of an inch a year over large swaths of Antarctica and Greenland, scientists said. “It’s unprecedented the accuracy we’re getting,” said Bob Schutz, of the University of Texas at Austin.

Icesat bounces a laser beam off the Earth’s surface 40 times a second as it passes 360 miles
overhead at 16,000 mph to make its measurements. The satellite’s laser also can be bounced off the clouds to provide unprecedented views of their heights and structure. So far it’s successfully tracked the movement of pollutants in the atmosphere as well, including the large plumes of smoke produced in the destructive wildfires that struck Southern California this fall.

3-D graphic view of the Earth as shown in this enhanced undated satellite photo released by NASA. The scientific data and photos are helping scientists understand how life on Earth is affected by changing climate. After less than a year of work, the Earth-orbiting satellite has churned out the most detailed, three-dimensional maps ever of the ice sheets blanketing Greenland and Antarctica. The baseline measurements collected by theIce, Cloud and Land Elevation Satellite, or Icesat, should allow scientists to track the growth and shrinkage of the ice sheets, and to gauge the effect that might have on global sea levels.