Warm air, sea-surface temperatures in February limited Arctic sea-ice growth

Arctic sea ice extent for February 2017 averaged 5.51 million square miles (14.28 million square kilometers), the lowest February extent in the 38-year satellite record. February 2017’s sea-ice extent is about 15,400 square miles 40,000 square kilometers) below February 2016’s, which set the previous lowest extent for the month, and 455,600 square miles (1.18 million square kilometers) below the February 1981-2010 long-term average.
(NSIDC)

It’s been a relatively cool and snowy winter here in the Interior, compared with the past couple of winters. But climate experts say the Arctic has been warmer than average. They say that’s why it appears this year’s maximum Arctic sea-ice cover, measured near the end of winter, is likely to set another record for the smallest maximum on record.

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Spring equinox is a week away, which means the time is nigh for the National Snow and Ice Data Center’s annual declaration that Arctic sea-ice cover has grown as much as it’s going to this winter.

“We’re at about the maximum sea-ice extent you’ll see for the year. Usually the maximum happens around mid-March,” Mark Serreze said. He’s a senior research scientist with the Snow and Ice Data Center.

Serreze said the formation of sea ice this past winter was once again sparse, due mainly to above-average air and sea-surface temperatures throughout the winter and again last month.

“We already had a record-low sea-ice extent in February,” Serreze said. “We’re looking at a very, very low sea-ice extent ending the freeze-up season, starting the melt season.”

This may seem contradictory to residents of the Interior after a week during which the mercury dropped to 30-, 40-, even 50-below overnight in many areas around the region. Serreze said this season was cooler than the previous two, which set consecutive records.

Overall, for the Arctic, it’s been a very, very warm winter, and you see that reflected in the very, very low sea-ice levels that we have right now,” he said.

But National Weather Service climate specialist Rick Thoman said it’s been a chilly winter for much of the Alaska.

“For Alaska as a whole, for the 2016-17 mid-winter – say, December-through-February period – Alaska as a whole was actually very close to the long-term normal,” Thoman said.

Except for some parts of the state. Thoman said it was a much milder winter north of the Brook Range, especially along the Arctic Ocean coast.

“As you would expect in Alaska, there (are) regional differences,” Thoman said. “And the North Slope, in particular, was quite warm this winter – about the 12th warmest winter for the North Slope as a whole.”

Serreze said it’s been especially warm on the Atlantic side of the Arctic. And he expects that will be reflected in the sea-ice maximum extent map the Snow and Ice Data Center will post in the next week or so.