Satellites discover new Arctic islands. (Earth Science).
Danish researchers did just that when they analyzed a series of radar observations of the area that includes Tobias Island, located about 75 kilometers off the northeastern coast of Greenland. The islet was discovered in 1993 by German scientists conducting research on Greenland's continental shelf. The island hadn't been found before that time because of its remote location, an unwelcoming girdle of permanent sea ice, and a frequent cloak of fog and clouds, says Rene Forsberg of the Danish National Survey in Copenhagen.
By taking precise altitude readings from satellites passing over the area and combining those measurements into an image--a technique known as interferometry--the Danish scientists looked for areas that didn't move. Even though the ocean around Tobias Island was frozen solid, the satellite could distinguish between land and water because sea ice rises and falls with the tides. It was Tobias Island's stillness that gave it away. Forsberg and Johan J. Mohr found that the land mass is about 2 km long--much larger than originally reported--and rises above the ice about 35 meters. They report their findings in the March 7 Nature.
The same interferometry images revealed a group of smaller islands about 10 km to the southeast of Tobias Island. These islets appear to be about 1 km across, but the radar data didn't have the resolution to determine how many islands there are in the group, says Forsberg. This May, scientists will fly to the region to conduct an aerial survey of the newfound islands. On that trip, no doubt, they'll need gloves and warm clothing. --S.P.
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|Article Type:||Brief Article|
|Date:||Apr 6, 2002|
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