AK: Studying Sea Ice
Everyone’s heard about the rapidly retreating sea ice in the Arctic. But if you’re a scientist, how do you actually study what is happening out on a frozen, moving ice cover?
The next generation of sea ice scientists learned the basics in Barrow last month. They worked with top polar scientists and an Inupiat whaling captain to learn both cutting edge and traditional techniques for measuring sea ice. One student, Oliver Dammann, is bringing the two together.
It’s a nice spring day in Barrow, 25 degrees with a brisk wind. In an old theater next to the Chukchi Sea, 22 grad students from a University of Alaska Fairbanks class are huddled around Inupiat whaling captain Joe Leavitt.
“We’re going to take you out on the ice today. This year the ice is all different. We have no multi-year ice out there. It’s just been formed this winter. The problem we had with the ice this year is all winter we had only east winds, hardly any west winds to push the ice back this way. So all winter, maybe until March, we had open water,” Leavitt said.
There’s a lot more movement and cracks in the ice than usual. A couple miles offshore, Leavitt showed students how to check cracks using an ice tester, a sturdy 6-foot pole with a thick nail on the end.
“If my ice tester didn’t go through I could walk across it. But it went through – I can’t walk across it,” Leavitt said.
If the ice breaks, he says to land on the flat side of the pole to spread your weight.
“And you can actually crawl to safer ice,” Leavitt said. “The way they learned that one is, on the young ice we watch a lot of polar bear falling and the polar bear will actually get on his belly and crawl away from it.”
The Inupiat have been hunting whales from the edge of the ice for centuries.
Scientists are tapping into this huge knowledge base to learn about the behavior of sea ice and how it’s changing—freezing later in the fall, breaking up earlier in spring, and less stable in between.
UAF grad student Oliver Dammann is studying whaling trails around Barrow and the knowledge that goes into building them.
“These locals are not geophysicists but they are what you can clearly refer to as sea ice experts,” Dammann said. “These people have learned from the ice since they were kids.”
Each March, whaling crews build seasonal trails from the beach to the edge of the shore-fast ice, as far as 10 miles out, through a maze of ice rubble and tidal cracks. They hack through ridges with ice picks and patch the trail with ice boulders, like road builders but with only their hands. Then they camp out and wait for a lead to open and a whale to come up to breathe.
“They have boats out there, and they’re trying to get that whale,” Dammann said. “Once they get it, it’s crucial that this point that they find, this ice edge, is thick enough so they can haul this massive whale up on the trail.”
Dammann is measuring the thickness of these trails. With a GPS in hand, he tows an electromagnetic conductivity meter in a sled behind the snowmachine. It looks like a car battery and shoots electric current into the ice to measure its depth.
A color-coded map shows most of the trails are between 5-10 feet thick. He also wants to know why they go where they go. Whalers can spot thin ice by the color of the sky and the wind direction. Leavitt says they rely on lower-tech, more intuitive methods.
“’Cause it’s a darker color it’s gonna turn black very quick here, you know, get a lot of sunshine,” Dammann said. “This is a lot of thin ice that’s just been pushed out under and under. That’s why the color is different over here.”
Beginning at freeze up, they constantly monitor weather, storms, and tons of other factors. One good sign they look for is pressure ridges, mini mountain ranges of ice formed when floating ice smashes into shore-fast ice and anchors it to the sea floor.
“What we’re seeing out here is there’s very little ridging,” Dammann said. “It’s very smooth ice.”
“What that does is the ice gets smoother, so it’s easier to access the ice edge, but it’s not stabilized as good.”
What whalers and scientists learn from one another will be shared with governments, companies, wildlife managers, and the many other groups with a stake in sea ice.