Rubber ducks help track melting glacier
Monday, September 22, 2008
TO help figure out what's happening inside the fastest-moving Greenland glacier, a US rocket scientist sent 90 rubber ducks into the ice, hoping someone finds them if they emerge in Baffin Bay.
The common yellow plastic bath toys are one part of a sophisticated experiment to determine why glaciers speed up in the summer in their march to the sea, said Alberto Behar of Nasa's Jet Propulsion Laboratory in California.
The Jakobshavn Glacier is very likely the source of the iceberg that sank the Titanic in 1912 and researchers focus on it because it discharges nearly seven per cent of all the ice coming off Greenland. As the planet warms, its melting ice sheet could make oceans rise this century.
"It's a beautiful place to visit. You can watch these icebergs continuously march across and fall into the ocean," Behar said.
What you can't see is how melting water moves through the ice.
"Right now it's not understood what causes the glaciers themselves to surge in the summer," Behar said. One theory is that the summer sun melts ice on the top glacial surface, creating pools that flow into tubular holes in the glacier called moulins.
The moulins can carry some water all the way to the underside of the glacier, where it acts as a lubricant to speed the movement of ice toward the coast. But because it cannot be seen, no one really knows what occurs.
That's where the rubber ducks come in, along with a probe about the size of a football loaded with a GPS transmitter and instruments that can tell much about the glacier's innards.
In August, Behar flew by helicopter to a place on the glacier where rivers of melted ice flow into moulins. Researchers lowered the probe into one moulin by rope and released it into the water flowing beneath the ice. They also released the flotilla of rubber ducks, each labeled with the words "science experiment" and "reward" in three languages, along with an e-mail address. Reuters
The common yellow plastic bath toys are one part of a sophisticated experiment to determine why glaciers speed up in the summer in their march to the sea, said Alberto Behar of Nasa's Jet Propulsion Laboratory in California.
The Jakobshavn Glacier is very likely the source of the iceberg that sank the Titanic in 1912 and researchers focus on it because it discharges nearly seven per cent of all the ice coming off Greenland. As the planet warms, its melting ice sheet could make oceans rise this century.
"It's a beautiful place to visit. You can watch these icebergs continuously march across and fall into the ocean," Behar said.
What you can't see is how melting water moves through the ice.
"Right now it's not understood what causes the glaciers themselves to surge in the summer," Behar said. One theory is that the summer sun melts ice on the top glacial surface, creating pools that flow into tubular holes in the glacier called moulins.
The moulins can carry some water all the way to the underside of the glacier, where it acts as a lubricant to speed the movement of ice toward the coast. But because it cannot be seen, no one really knows what occurs.
That's where the rubber ducks come in, along with a probe about the size of a football loaded with a GPS transmitter and instruments that can tell much about the glacier's innards.
In August, Behar flew by helicopter to a place on the glacier where rivers of melted ice flow into moulins. Researchers lowered the probe into one moulin by rope and released it into the water flowing beneath the ice. They also released the flotilla of rubber ducks, each labeled with the words "science experiment" and "reward" in three languages, along with an e-mail address. Reuters
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