NEW YORK, April 4, 2008 –Last month, a large chunk of the Wilkins Ice Shelf collapsed. However, surface snowmelt in Antarctica for 2008 was 40 percent below the average for 1987 – 2007, according to research by Dr. Marco Tedesco, Assistant Professor of Earth and Atmospheric Science at The City College of New York.
Professor Tedesco’s findings were published March 25 in “EOS: Transactions of the American Geophysical Union.”
The surface snowmelt, which was derived from space-borne passive microwave observations at 19.35 GHz, was 3,465,625 square kilometers * day versus the 20-year average value of 8,407,531 square kilometers * day. The extent of the melt area for 2008 was 297,500 square kilometers, a new low, versus an average around 861,812 square kilometers.
“The past season was one of extremely low melting,” noted Professor Tedesco. “However, variations in melting from year to year are affected by more than one factor, so it is not possible to predict whether trends are changing in a relatively simple way and by relying solely on melt data.”
Because the Antarctic ice shelves come in direct contact with the surrounding oceans, they are more sensitive to changes in ocean conditions and ocean temperatures, he explained. “If the ocean warms, the warm water underneath works on the ice shelf from below.”
However, proving that the ocean is warming requires taking measurements that are difficult to obtain because of the thickness of the ice shelf, Professor Tedesco added. “The next step would be to drill below the ice shelf to see what is going on. Several groups are planning to go there to see what they can find.”
In addition, he said the collapse of the Wilkins Ice Shelf points to the need to focus research on specific geographic areas. Because of its vastness, climate conditions are not uniform across Antarctica, a continent that stretches between 2,500 and 3,000 miles and has a surface area 30 percent larger than Europe, he explained. Studies conducted on West Side ice shelves need to be repeated on the East Side to analyze the trends on both sides of the continent.
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