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Thursday, October 04, 2007

I asked; now the answer

Obligatory disclaimer...

A while ago, I asked if anyone could explain the report that Arctic ice the size of Florida "melted" away in just 6 days, since it's physically impossible for an ice mass that large can melt in so short a time, especially in a region where temperatures are so low, even in the warmest times of the year (Sept. and August, when large ice free areas are the norm in Canada's Arctic regions).

Shortly after, I realized I'd been somewhat led astray in my assumption of the accuracy of the article. This assumption was reinforced by the graphic manipulation showing a Florida shaped cutout in an ice sheet. That assumption was that all this ice "melted" away in one big solid chunk. This isn't how things work, of course. For that much mass of ice to disappear in such a short time, it would have to be a combination of many smaller masses breaking up and melting. That realization alone gave me an inkling of what the answer was - the ice didn't "melt" away, but was broken up by wind and currents, which in turn would allow more smaller pieces of ice to actually melt in a climate otherwise too cold for significant seasonal melting. With the Arctic ice cap floating on water the way it is, it would be greatly affected by any changes in winds or currents.

It turns out my supposition was correct.

Here's a response at the new Watt's Up With That site to NASA's quietly released article.

From the NASA article...

Nghiem said the rapid decline in winter perennial ice the past two years was caused by unusual winds. "Unusual atmospheric conditions set up wind patterns that compressed the sea ice, loaded it into the Transpolar Drift Stream and then sped its flow out of the Arctic," he said. When that sea ice reached lower latitudes, it rapidly melted in the warmer waters.

"The winds causing this trend in ice reduction were set up by an unusual pattern of atmospheric pressure that began at the beginning of this century," Nghiem said.

Meanwhile, take a look at this graphical representation of the Arctic ice cap from 1979 to 2006.

This is what we're being told is an ice cap melting away to nothingness.


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