Boeken

Sunday, May 11, 2008

On the ice - Part 3

Thursday May 1, 2008 (Published on http://ipy-cfl.ca/page11/page34/page34.php)

The thermometer reads -8 degrees Celsius as we set foot on the ice at 09.30. The wind makes it feel like -18. Today I am wearing arctic boots for the first time. Thanks to technician Joanne Delaronde, who looked yesterday on the ice a bit worried at my mountain boots and asked whether I did not have cold feet in them. Yes, I did. She managed to find me some size-11 spare boots, which I can use the rest of my stay with the Amundsen.

Experimenting, digging or drilling at one spot on the ice means a lot of standing, little walking, and so even quicker getting cold feet. The cold was cutting in due time through my mountain shoes. And filling them with three pair of thick socks meant that there was no air layer anymore inside to fight the freezing cold. To dam the cold cutting through, arctic boots have a kind of inner sole with air pockets, which use the great insulating properties of still air.

Today we are first going to measure CO2-concentrations in the ice.

A flag in the ice points the way we are heading to by snow scooter. Three days ago technician Keith Johnson from the Department of Fisheries and Oceans – IOS put there four tubes with permeable walls into the ice, at four different depths. Now they are frozen into the ice. “We call them peepers”, Keith says. The ‘peepers’ slowly take in CO2 from the surrounding ice, until the concentration in the tubes is the same as in the ice. Three days should be enough for that slow process, he hopes.

Arriving at the spot with the flag, some small metal pipes stick into the air. Through these little pipes the gas from the tubes is analyzed. PhD-student Nicolas-Xavier Geilfus from the University of Brussels reads the CO2-concentrations and Keith writes them down.

“We know pretty well how much CO2 the oceans absorb”, Keith tells, “but the role of the sea ice in the exchange of CO2-fluxes is much less known. This is what we are trying to find out with our measurements. In the winter, when it’s really cold, the ice works as an insulating cap between the atmosphere and the seawater. Then there is no CO2-flux going through. But in the spring, when the air is getting warmer, the ice gets warmer too. Channels in the ice form, which can transport CO2 from the atmosphere to the seawater and vice versa.”

“Besides this, we also want to know what is the role of the CO2-exchange for the ecological system. In the spring, the algae start to bloom. They can absorb a lot of CO2 through the ice.”

When finished with the measurements, we leave the tubes behind us in the ice. “May be we can use them again later”, says Keith. “When the Amundsen leaves this ice floe, a transponder will be left on the floe. So, even when we leave to somewhere else, we will still be able to tell where this piece of ice is drifting. We can use the helicopter or the Amundsen to come back to do new measurements with the tubes or to take them out of the ice.”

When we are done with the CO2-measurements, we drive by snow scooter to the other side of the boat. It’s much windier over there. At the previous spot, the ship was shielding the wind from us. Still, I love to be outside, though it’s good to know that the Amundsen is always close, in case your body really would start to get cold.

PhD-student Jens Ehn from the University of Manitoba sets his albedo meter up and measures the light reflection. Sea ice with wet snow on top reflects more than seventy percent, sea ice with dry snow even more than eighty. The more ice melts, the more water, and the more light is absorbed. Which means that the ice starts to melt even more.

After two hours working on the ice, we return to the boat. Still, I do not have cold feet. A big hurrah for the arctic boots.

But even the modern, high-tech arctic boots, lose the game against the traditional Inuit shoes, or ‘kamik’, tells my Inuit-roommate Roger Memorana. I ask him how they are made. “The sole consists of three layers”, he tells. “At the bottom: moose skin, in the middle: musk ox wool and on the top: duffle. The rest of the ‘kamik’ is made out of caribou skin, musk ox skin or – if you want them to be complete waterproof – seal skin.”

“The kamik are both warmer and lighter than the shoes you were wearing today”, Roger tells me. All the other experienced arctic researchers whom I ask agree.