Analysis Finds Downward Trend In Arctic Sea Ice

The Arctic Sea ice has experienced a steady declining trend during the past 33 years, according to a new comprehensive analysis of satellite data by experts at the U.S. National Ice Center, a tri-agency team from the National Oceanic & Atmospheric Administration (NOAA), the U.S. Navy and U.S. Coast Guard, based in Suitland, Md.

This new climatology dataset is expected to be a more useful and accurate tool for the research community to use than other datasets, NOAA officials said on Nov. 20. This tool can be applied to improve seasonal and climatological sea-ice-change forecast research in the Arctic.

The dataset, New 30-Year Arctic Sea Ice Climatology, is derived from a 1972 to 2004 chart series that provides a close representation of the sea-ice extent as derived from a combination of satellite observations, measuring instruments on the surface and model output.

"The new datasets show shrinkage in the Arctic Ocean summer-ice cover of more than 8 percent per decade, and gives us concrete information with which to develop improved seasonal and long-term forecasts in the future," said Pablo Clemente-Colón, the ice center's chief scientist.

The new dataset confirms that the overall trend in summer, winter and multi-year total ice extent is down. Both winter (maximum) and summer (minimum) sea ice extents are decreasing, although summer shrinkage is more pronounced. The percentage of multi-year ice in the winter also is decreasing significantly, researchers said.

The NIC's new dataset is available at the Web site of the National Snow and Ice Data Center: http://nsidc.org/data/g02172.html.

Since 1972, the ice center has produced weekly or bi-weekly operational sea-ice charts. These analyses are used primarily for mission planning and safe navigation. They also are incorporated into weather forecasts and serve as a comprehensive global record of sea-ice extent and concentration that can be used for climate monitoring.

This article originally appeared in the 11/01/2006 issue of Environmental Protection.

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