NASA, and the world, have a problem. It’s ICESAT-I (Ice, Cloud and Land Elevation Satellite) which provides critical data on rapidly changing ice volume and thickness, is going to go offline this year.
The launch of its replacement, the ICESat-II, isn’t scheduled until 2014-15. This creates a large data gap in laser observations of the Arctic changes. How is NASA going to cover the gap? Introducing “Operation Ice Bridge.”
The Ice Bridge flights will help scientists maintain the record of changes to sea ice and ice sheets that have been collected since 2003 by ICESat. The flights will lack the continent-wide coverage that can be achieved by satellite, so researchers carefully select key target locations. But the flights will also turn up new information not possible from orbit, such as the shape of the terrain below the ice.
Operating from Punta Arenas in the extreme south of Chile, NASA will fly its largest aircraft,—a DC-8, a 157-foot-long airborne laboratory—to study changes in Antarctica’s sea ice, ice sheets and glaciers.
“Space-based instruments like the ICESat lasers are the only way to find out where change is occurring in remote, continent-sized ice sheets like Antarctica,” said Tom Wagner, cryosphere program scientist at NASA Headquarters in Washington, D.C. “But aircraft missions like Ice Bridge allow us to follow up with more detailed studies and make other measurements critical to modeling sea level rise.”
With the DC-8 limited to just a few hours over Antarctica on each flight, mission planners have carefully selected targets of current and potential rapid change.
One such target is West Antarctica’s Pine Island Glacier. “That glacier is one of the great unknowns because its bed — where the glacier contacts rock — is below sea level,” Martin said. “So if there’s a surge or dramatic change, seawater could get under the glacier and we could be looking at very rapid change.”
However remote, Antarctica is an important link in the Earth’s climate system and it is home to 90 percent of the freshwater supplies on Earth and could thus contribute greatly to sea level rise.
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