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Next Supercontinent will form in Arctic, Geologists Say

Geologists have long predicted that North and South America will eventually fuse together and merge with Asia, forming a new supercontinent along the lines of the ancient Pangea — the precursor to today’s great land masses, which separated about 200 million years ago.

In the past, researchers had guessed that the new continent, often called Amasia, would form either in the same location as Pangea, closing over the Atlantic near present-day Africa, or 180 degrees away, on the other side of the world. But a new study predicts that Amasia will form over the Arctic Ocean.

“The fusion of North and South America together will close the Caribbean Sea and meet Eurasia at the present-day North Pole,” said Ross Nelson Mitchell, a geologist at Yale University, who worked on the study as part of his doctoral research. “And Australia is moving north, and would probably snuggle to join Asia somewhere between India and Japan,” he added.

Mr. Mitchell and colleagues from Yale, who discuss their theory in the current issue of the journal Nature, modeled the movement of supercontinents of the past using paleomagnetic data, a measurement of the force between the earth’s rocks.

Once each supercontinent is assembled, it undergoes back-and-forth rotations about a stable axis on the Equator, Mr. Mitchell said. This motion is called true polar wander. Using this, the researchers determined the center of each of the previous supercontinents — Pangea (often spelled Pangaea), Rodinia and Nuna.

There was a clear pattern. In each case, the centers of the supercontinents were separated by 90 degrees.

…(NY Times)

February 9, 2012 Posted by | Arctic Ice | , , , , , , , | Leave a comment

18-Mile Crack Seen by NASA in Antarctic Glacier

Antarctica is so vast that the pictures give you no sense of scale. The pencil-thin line across the satellite image of Pine Island Glacier (above) is actually more than 18 miles long, 800 feet across in places, and 180 feet deep.

And it’s growing. In the next few months, scientists expect the glacier to create an iceberg about 350 square miles in area. It will probably float northward, melting as it goes.

“Pine Island Glacier is losing ice very quickly, about six meters per year,” said Michael Studinger of NASA’s Goddard Space Flight Center in Maryland, which sent an expedition called Operation Ice Bridge to Antarctica in October in an old DC-8 jetliner, modified for scientific operations. It spotted the break in the ice. Satellites have been watching it since.

“These things happen on a semi-regular basis in both the Arctic and Antarctic, but it’s still a fairly large event,” said John Sonntag, Instrument Team Lead for Operation Ice Bridge, in video recorded on the plane.

“So we wanted to make sure we captured as much of that process as we could.”

“A lot of times when you’re in science, you don’t get to capture the big stories as they happen, because you’re not there at the right place at the right time,” he said, “but this time we were.”

To scientists, this is more than a vast spectacle. Both polar caps are losing ice, and researchers studying the world’s climate say they want to understand the process.

…(Yahoo)

February 5, 2012 Posted by | Arctic Ice, Climate | , , , , | Leave a comment

Arctic Ice News and Analysis

Ice extent for Dec. 2011. Purple line = Median ice edge.

Arctic sea ice extent remained unusually low through December, especially in the Barents and Kara seas.  In sharp contrast to the past two winters, the winter of 2011 has so far seen a generally positive phase of the Arctic Oscillation, a weather pattern that helps to explain low snow cover extent and warmer than average conditions over much of the United States and Eastern Europe.  In Antarctica, where summer is beginning, sea ice is presently above average.

Overview of Conditions
Arctic sea ice extent in December 2011 averaged 12.38 million square kilometers (4.78 million square miles). This is the third lowest December ice extent in the 1979 to 2011 satellite data record, 970,000 square kilometers (375,000 square miles) below the 1979 to 2000 average extent.

Ice extent was particularly low on the Atlantic side of the Arctic, most notably in the Barents and Kara seas. The eastern coast of Hudson Bay did not freeze entirely until late in the month: normally, Hudson Bay has completely frozen over by the beginning of December. In the Bering Sea, ice extent was slightly above average.

2011 year in review
Arctic sea ice extent fell to its seasonal minimum on September 9, 2011, falling just short of the record low set in September 2007, when summer weather conditions were extremely favorable for ice loss. This summer, the weather was not as extreme as 2007, so it was surprising that ice extent dropped so low. The low ice extent, along with data on ice age, suggests that the Arctic ice cover remains thin and vulnerable to summer melt.

Northern Hemisphere snow cover retreated very rapidly last spring, with record and near-record low snow cover extents in May and June despite higher-than-average winter snow extent as of February and March.

Arctic temperatures 
Air temperatures in December were lower than average over much of the Arctic Ocean, but higher than average over the Kara and Barents seas. Higher-than-average temperatures in these regions stemmed from two major factors.

First, where sea ice extent is low, heat can escape from areas of open water, warming the atmosphere. Second, surface winds in the Kara and Barents Sea ice blew persistently from the south, bringing in heat from lower latitudes. This imported heat also helped to keep sea ice extent low in this area. Conditions over Canada were also unusually warm during Dec, but conditions over SE Greenland have been 6 to 8 degrees Celsius (11 to 14 degrees Fahrenheit) colder than average, partly because of northerly winds in the area.

…(NSIDC)

January 25, 2012 Posted by | Arctic Ice | , , , , , , , , , , | Leave a comment