Satellite shows much arctic ice thinning

PASADENA, Calif., July 7 (UPI) -- Data from a U.S. satellite shows arctic sea ice thinned dramatically between the winters of 2004 and 2008, NASA scientists said.

The scientists said the data, for the first time, showed thin seasonal ice replacing thick older ice as the dominant type.

Researchers from NASA and the University of Washington conducted the survey using observations from NASA's Ice, Cloud and Land Elevation Satellite.

The scientists said they found arctic sea ice thinned about 7 inches a year, for a total of 2.2 feet, during four winters. The total area covered by the thicker, older "multi-year" ice that has survived one or more summers shrank by 42 percent.

"Ice volume allows us to calculate annual ice production and gives us an inventory of the freshwater and total ice mass stored in Arctic sea ice," said Ron Kwok of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Our data will help scientists better understand how fast the volume of arctic ice is decreasing and how soon we might see a nearly ice-free Arctic in the summer."

The research team attributes the changes in the overall thickness and volume of Arctic Ocean sea ice to the recent warming and anomalies in patterns of sea ice circulation.

The study appears in the Journal of Geophysical Research-Oceans.