New satellites help measure thickness of the ice
By Summit Voice
SUMMIT COUNTY — Arctic sea ice extent reached a record low level in July before recovering at the end of the month. As of July 31, the sea ice extent was at 2.62 million square miles.
During the northern hemisphere summer, the ice shrinks through September, then starts to expand again through the winter. Accurate sea ice extent measurements date back to 1979, when satellites first started delivering reliable data and photographic images.
This July, the sea ice extent was 81,000 square miles less than the previous low, set in 2007, and 842,000 square miles less than the average for 1979 to 2000, according to the monthly update from the National Snow and Ice Data Center’s Arctic Sea Ice News & Analysis web page. Based on the data gathered since 1979, Arctic sea ice is disappearing at a rate of about 6.8 percent each decade.
Signalling the trend of vanishing sea ice, new data shows that more of the Arctic’s store of old and thick ice is melting. The ice melted quickly in early July, but the melting slowed down the second half of the month as a high pressure system over the Beaufort Sea, north of Alaska, broke down, bringing stormier and cooler weather to the region. The Arctic ice researchers say the weather change probably pushed the ice apart, forming a thinner but more extensive ice cover.
Between late March and late July, younger sea ice declined by as much as 30 percent, while the oldest ice (older than five year) declined by 18 percent. Researchers are gathering more data on ice age and thickness because it will provide clues as to the overall trend of sea ice loss. The young, thinner ice is more vulnerable to summer melting.
With the meting this summer, the ice has retreated from the shores of Siberia and Eurasia, potentially opening a trans-Arctic shipping route from Murmansk through the Bering Strait. A Russian tanker set sail from Murmansk on June 29, and helped by two icebreakers, completed the passage July 14. The shipping company plans to send several more ships along the northern sea route this summer.
Information compiled from the National Snow and Ice Data Center.
Filed under: climate and weather, Environment, global warming, Summit County news Tagged: | Arctic, Arctic sea ice record low, Beaufort Sea, Bering Strait, climate change, Environment, global warming, National Snow and Ice Data Center, Polar ice packs, Sea ice, sea ice extent 2011