Arctic sea ice minimum at third-lowest

The National Snow and Ice Data Center said Sept. 15 that Arctic sea ice appeared to have reached its annual minimum extent on Sept. 10. That minimum was the third-lowest in the satellite record after 2007 and 2008.

The sea ice extent dropped to 1.84 million square miles on Sept. 10, the center said, the third-lowest recorded since 1979. The 2010 extent is 93,000 square miles more than 2008 and 240,000 square miles more than 2007.

The 1.84 million square miles recorded this year is 130,000 square miles below 2009, 753,000 square miles below the average minimum for 1979-2000, and 625,000 square miles below the 31-year 1979 to 2009 average minimum.

This is only the third time in the satellite record that ice extent has fallen below 1.93 million square miles and all three occurrences have been in the past four years, the center said. The 2009 minimum, 1.97 million square miles, was the fourth lowest in the satellite record.

The center said that because of the variability of sea ice at this time of year, it determines the minimum using a five-day running mean value. While there have been four days of gains in extent, it is possible that ice extent could fall slightly because of further melting or a contraction in the area of the pack due to the motion of the ice.

When all the data for September are in, the center will confirm the minimum ice extent for the season, and will issue a formal announcement at the beginning of October with a full analysis of the melt season.

—Petroleum News