Ice Stations, Everyone!
The Coast Guard Cutter Healy is plowing through the icy Chukchi Sea, which lies between and to the north of both Siberia and Alaska, and scientists aboard are eager to get to work. As Healy threads her way through the ice, seeking cracks and fissures and leads, I climb three narrow ladders to Aloft Con — the high tower that looms above the bridge — and visit with Bosun John Placido. He’s the one doing the threading, at the helm of this massive, 420-foot vessel.
Below, in the bridge, the Ice Watchers, led by Co-Chief Scientist Don Perovich, of the Army’s Cold Regions Research and Engineering Laboratory, take turns reviewing the situation. Every two hours, a watcher enters information about the ice status into a computer, noting the ship’s location and activity (such as transiting toward a station), along with the coverage and appearance of ice. Just as the French have many words for love, ice scientists have many ways of describing ice. If you’re looking at ice that came from a glacier, you might see formations known as growlers, blocky growlers, bergs, bergy bits, and wedged bergy bits, among others. The ice that forms at sea, such as we’re seeing here in the Chukchi, comes in pancakes, ice cakes, belts, strips, and floes ranging in size from small to giant. The computerized form that Don and the other Ice Watchers use was designed for the Antarctic, but was adapted for Arctic use during the International Polar Year, in an effort to create a common language among ice scientists.
ICESCAPE mission scientists look for ice that is solid enough to hold an ice station. (Credit: Luke Trusel)
As the ice concentration moves up the range from 10 percent to 50 and beyond, the crew begins looking for ice that’s solid enough for an ice station. I shiver at the thought, and not just because the air’s getting cooler. This ice looks none too stable — riven with blue cracks, topped with expansive melt ponds. But the ship and science work together to locate what is necessary and possible.
The crew watches from the Healy's deck as scientists set up an ice station. (Credit: Karen Romano Young)
Just when I think the chances are shot for the night, and am heading for “the rack,” I realize the ship has stopped. As I round the curve of the ship, I see something strange: day-glo orange traffic cones on the ice. There’s a bustle of activity in the bow, and a steep gangplank extends onto a small floe of ice. Two Coast Guard stand by, wearing yellow flotation devices and keeping watch in all directions, while four scientists in “mustang suits” guide equipment down the gangplank on a sled. Karen Frey and Luke Trusel of Clark University, Don Perovich and Chris Polashenski, of Dartmouth College, will finish their work in under an hour. They do measurements of the thickness of the ice and its freeboard — the percentage of the thickness that floats above the surface. They take optical measurements of the ice and the water beneath the ice, sample that water, and use an ice auger to tug out a long ice core — a tubular piece of ice that can be sectioned for analysis back in the lab. (While doing all this, Luke took beautiful pictures from the ice.)
The two orange cones mark the location of the ice station. (Credit: Luke Trusel)
“This was kind of a shakedown station for us,” explains Frey. She is impressed with the Healy’s ability not only to break through the ice in passage, but to select a floe and park right next to it for a station. “It was good that we were able to get the brow [the gangplank] down because we have a significant amount of gear.” For this shakedown, Frey and Perovich took along only about half the gear they would require in the full stations we’ll be reaching within days. “We’ve obviously got multiple really important things going on,” she says, “so we have to hang back to get part of the science done, but some of us are getting a little antsy to get moving northward before the ice completely goes out.”
It is, after all, the summer solstice in the Arctic Circle. The sun barely touches the horizon at about 2:30 a.m. before it pops back up again. Last time Frey worked on the ice se was south of here, in the Bering Sea. When we passed through last week, it was free of ice. Her work in the far north extends to Siberia, where she takes undergraduate students each year to study the effects of global warming on rivers and their flows to the Arctic Ocean, and to cruises with Lee Cooper and Jacqueline Grebmeier, whose work as a benthic (sea floor) ecologist includes studying conditions that affect walrus. All of this adds to the sense of the big picture of the Arctic that Frey brings to the ICESCAPE cruise.
“I’m a bit biased, but I would say sea ice decline is one of the most profound, climatic impacts that are changing in our life time. Many of the models that are out there right now say that perennial sea ice will be absolutely gone in 30 years. Thirty years! That’s not your grandkids or your great grandkids. That’s our lifetime! What are the biological ramifications of that? What are the biogeochemical ramifications of that? What are the feedbacks that are going to ensue, and how is the biology going to change?”
Karen Frey’s group of scientists will focus on that question, sharing ice with Don Perovich’s group, studying the physical aspects of the ice.
“There are some really important science questions here. ICESCAPE is at the cusp of biology and chemistry and physics. It’s exciting to be on board with scientists from these different disciplines. Together you come up with different answers and maybe more correct answers than you might on your own or with people that are all your own discipline, so you end up being much more creative about your thinking.”
See the other blogs in this series.
For more on ICESCAPE, see: