SAN FRANCISCO (Reuters) - New satellite data are providing a first glimpse of some important aspects of Antarctica, which include icy tributaries feeding giant, frozen streams that churn icebergs into the sea, researchers said on Monday.
Understanding Antarctica is crucial because of the frozen continent's role in regulating sea level. If the entire Western Antarctic ice sheet flowed into the ocean, global sea levels could rise as much as 20 feet (six meters), said Robert Bindschadler, a glaciologist at NASA Goddard Space Flight Center.
"We have to understand the ice streams in order to predict the future and to know what their contribution will be to sea level change,'' he said at the Fall meeting of the American Geophysical Union in San Francisco.
Scientists have known of the ice streams since the mid-1970s but were unsure why they appeared to start from a near standstill before flowing hundreds of feet per year faster than the surrounding ice sheet.
The ice streams carry accumulated snow from the interior of the Western Antarctic ice sheet, spitting it into the ocean in the form of ice.
When these ice streams begin to flow rapidly, they leave a starting point marked by deep crevasses in the ice between the fast flowing streams and the slower moving ice sheet.
But they do not leave clues on the surface upstream as to where they could have started, Bindschadler said.
Now, new data from the Canadian Radarsat satellite in 1997 have shown researchers that these ice rivers are the product of smaller tributaries flowing from farther into the continent's interior.
The tributaries are not marked by gaping crevasses along their borders because they flow more slowly than the larger ice streams, Bindschadler said.
"It's a huge amount of information that would have taken decades to collect and we never would have made this stunning discovery without Radarsat,'' said Bindschadler.
The Radarsat satellite has also allowed a different team of researchers at the Byrd Polar Research Center at the Ohio State University to produce the first, high-resolution radar map of the entire Antarctic continent, the fifth-largest in the world.
The map is so precise that it allows scientists to outline things as small as a research bungalow but still detail the entire Antarctic coastline, helping researchers to learn how the ice sheet ebbs and flows over time, said Ken Jezek, a glaciologist at Ohio State.
"It is a truly remarkably gauge of what the Antarctic looked like for a brief period,'' Jezek told a news conference at the AGU meeting.
advertisement
