RESEARCH HIGHLIGHT

Sea Ice Observations

September 17, 2007

Two IARC scientists have sailed on recent missions over the northern seas, each experiencing different aspects of waters that seem to be warming. The summer of 2007 has set a new satellite-era (since 1979) record for the smallest amount of ice covering the Arctic Ocean.

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Research Associate Jenny Hutchings cruised the Beaufort Sea north of Alaska for more than a month from late July to late August. For a second consecutive year, she participated in the Woods Hole Oceanographic Institution’s Beaufort Gyre Exploration Project on the Canada Coast Guard Icebreaker Louis St. Laurent.

“We were seeing unusually thin, rotten ice, all the way to 79 degrees north,” Hutchings said. “That’s where you would expect some of the heaviest ice, and we were having no trouble at all getting through.”

Hutchings was on the cruise to validate satellite observations with data obtained from sea-ice tracking devices, ice samples, and visual observations around the Beaufort Sea, the portion of the Arctic Ocean north of Alaska and northwest of Canada. She said much of the ice they encountered was multi-year ice that has survived from one to three winters. She was surprised to find no first-year ice, from last winter, in the northern regions of the cruise. Young ice can grow to 1.5 meters thick during the winter, but it is also more vulnerable to melting than multi-year ice.

The Louis St. Laurent encountered relatively easy going throughout the entire cruise, Hutchings said, including along the northwestern edge of Canada’s Banks Island.

“There wasn’t much ice around Banks Island,” she said. “Normally, there’s a lot of old, multi-year ice there and it’s more concentrated.”

Hutchings said she would analyze her data this winter in an attempt to find out if the Beaufort Sea ice can recover during the cold season.

“The more I look at the situation this year, the more I realize how unusual it is,” she said.

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Kohei Mizobata sailed the Chukchi Sea from Aug. 5-15, 2007 aboard the Oshoro-maru, a research vessel of the fisheries department at Hokkaido University. An IARC-JAXA researcher with the Arctic Modeling Group and IJIS Research Group, Mizobata and his colleagues measured heat and salt contents in the eastern portion of the Chukchi Sea and looked at how those features affected phytoplankton distribution on the cruise, which was supported by the JAXA Arctic Research Project. They observed very warm waters (warmer than 14 degrees C) along the Alaska coast extending up to Barrow Canyon, which lies under the sea just north of the town of Barrow. Satellite measurements usually show the ocean to be about 10 degrees C in the area. The warm water may have an effect on sea-ice melting in the summer and the delay of sea-ice freezing in the winter, Mizobata said.