Friday, July 23, 2010

Antarctica Traced from Space

Antarctica may not be the world's largest landmass it's the fifth largest continent but resting on top of that land is the world's largest ice sheet. That ice holds more than 60 percent of Earth's fresh water and carries the potential to significantly raise sea level. The continent is losing ice to the sea, and scientists want to know how much.

Antarctica's ice generally flows from the middle of the continent toward the edge, dipping toward the sea before lifting back up and floating. The point where ice separates from land is called the "grounding line." For scientists, an accurate map of the grounding line is a first step toward a complete calculation of how much ice the continent is losing.

Such a map is a primary objective of the Antarctic Surface Accumulation and Ice Discharge project. Researchers from NASA's Goddard Space Flight Center in Greenbelt, Md., led a team that used high resolution satellite images, along with newly developed computer software, to trace the most accurate Antarctic grounding line ever compiled.

"This project has been a major achievement to come from the International Polar Year," said Robert Bindschadler, a cryosphere scientist based at Goddard who presented his team's work in June at the International Polar Year Oslo Science Conference. "This project included young scientists, it was an international effort, and it produced freely available data all from satellites."

"Completion of this line was huge, as we connected 3.5 million geographic around the continent," said Goddard's Amy Wichlacz, who popped a cork in celebration after eight months of meticulously connecting the dots.

The next step is to use satellite elevation data from ICESat to determine the ice thickness near the grounding line.