Inside the Arctic Circle
Here at sea aboard the US Coast Guard Cutter Healy we get “pipes”: announcements over the public address system. Last night’s pipe was a first for me, along with lots of other “bluenoses” aboard: the news that we had officially entered the Arctic Circle. Along with the Honorary “polar bears” (who’ve been here before), we had crossed the 66º parallel.
At almost the same time, we came upon our first significant sea ice. The ice comes alongside in hunks and chunks of white, aqua, silver, gray, and brown. (The brown derives from river water, or from the bottom, or walrus poop, I’m told.) Some of the more experienced polar bears among us sniffed, “You ain’t seen nuthin’ yet,” but for me — and lots of others — this sighting was glorious. To see ice floes floating on the surface of the sea is to understand why ice albedo — the percentage of incoming solar radiation reflecting from the surface — is so necessary in maintaining the balance of the Arctic.
Crew members of the US Coast Guard Cutter Healy watch their icebreaker break the first ice. (Credit: Karen Romano Young)
The ocean with ice floating on it seems to glow. Watching it from aboard the Healy, I got that sensation you get sometimes in train stations, in which you think the train next to yours is moving, but yours is actually the one leaving the station. There were walrus in lumpy brown heaps atop the ice floes, and I wanted to call out to ask them where they were going. But really they weren’t going anywhere; the Healy was passing through.
In doing so it made a rumble, pushing into ice floes until they cracked apart, sending chunks alongside the ship’s red sides. It seemed to bode well for the ice stations that are planned for today in Kotzebue Sound, so I went to ask Co-Chief Scientist Don Perovich about them.
Perovich is a principal investigator from the US Army’s Cold Regions Research and Engineering Laboratory in New Hampshire. He’s been studying sea ice for decades, including work on the SHEBA mission I wrote about on the 17th.
“We’ve begun an ice watch, every two hours at the bridge. We look to port and starboard and straight ahead and assess what fraction of the area is ice,” Perovich said. “We also estimate the ice thickness, by looking down at the pieces of ice that the ship breaks up. They get knocked on their sides, and you can tell how thick the ice is. We’ll also look at the fraction of area covered by melt ponds.”
The ice scientists are checking things out to determine whether we’ll be able to make ice stations, but also to learn more about the general condition of the ice.
“Roll back the clock three months ago,” says Perovich. “It was all ice, covered with snow. The albedo reflecting was 85 percent [of incoming solar radiation]. But the ice slowly melts back, and the albedo is around 5 percent today. You’re putting more heat in the water, which melts the ice, and as the ice retreats more heat gets into the water. This is the ice-albedo feedback, of strong interest to the climate system.”
Don Perovich uses a fiber optic probe to measure absolute spectral radiance, in preparation for ice stations where he’ll assess how the sun interacts with sea ice. (Credit: Karen Romano Young)
Once we reach an ice station, scientists will go out on the ice to take a closer look. They’ll measure the thickness of the ice, how much light reaches through the ice to the sea, and how light extends into the water under the ice. They’ll take samples of ice to send home to examine for soot, and take ice cores (long plungers of ice) that biologists will study. They will also study melt ponds that form atop the ice as it melts, measuring their depths. (“The rule is that they’re always an inch deeper than your boot tops,” jokes Perovich.)
ICESCAPE provides Perovich and the other scientists aboard with a unique opportunity to collaborate on an integrated understanding of the Arctic. “We are such a diverse group, and we’re tying in our data with an incredible array of NASA satellites. Here we are! We’ve done 7 stations in the last day and a half,” Perovich said, with the goal of gathering data at about 130 stations. It will be an excellent look, an unprecedented amount of information in this amount of time and space,” he said.
This map showing Arctic sea ice helps the ICESCAPE ship and science crew plan their research stations here in Kotzebue Sound and beyond. The Healy’s track and our science stations are shown in purple.
The combined efforts of ICESCAPE scientists will extend our comprehensive view of the Arctic ice and its effects on Arctic ecosystems. But, will we get to ice that is strong enough to get out and walk around on? “Whether we get on the ice now or not, there is a ten day period in early July dedicated to finding ice and we’ll keep going until we get to it,” says Perovich. And yet, he adds, “I know that there are big changes in ice cover that will have a significant impact on light levels. This is a remarkably poor ice year. At the end of May we had the lowest ice levels in 30 years.”
Even so, he says it’s a great time to be studying sea ice. “So much is going on, with so many significant changes. We have to do three things. We have to make observations, to assess the conditions and the changes in them. Then we have to try to understand what we’re seeing, which is what science is all about. But third, we have to respond, and that’s harder, because as a society we’re going to have to decide how to respond to these changes.”
See the other blogs in this series.
For more on ICESCAPE, see: