Boeken

Sunday, May 11, 2008

On the ice - Part 2

Tuesday April 29, 2008 (Published on http://ipy-cfl.ca/page11/page34/page34.php)

Yesterday it was decided that the boat will leave it’s present drifting position in the ice on May 1 to sail into Prince of Wales Strait. But any planning on the Amundsen is tricky business, as the behavior of the weather and the sea ice can change plans within an hour. So it happened that yesterday’s plan has already been thrown into the dustbin. The sea ice conditions have changed dramatically in the last day. Blame the wind. It is no longer possible to safely enter Prince of Wales Strait.

We will leave one of these days, but nobody knows when and to which new home in the ice.

Up till now, every day that I have been on the Amundsen, the ice and the sky have looked differently. We have had a foggy day, a sunny day, a very windy day and today was a cloudy day with some wind, but not as much as yesterday. Dark clouds were today hanging above the open water that we can see from the ship. Actually, the sky can tell something about the state of the ice. More open water means a higher chance for cloud formation. The water, the ice, the atmosphere – they all shake hands.

In the morning I have joined John Iacozza on the ice. On a tiny white sledge he was dragging a 1.5 meters long red cylinder over the rough ice, equipped with an ice measuring instrument. By sending electromagnetic waves through the ice and measuring how much comes back, the instrument unravels the thickness of the snow covered ice. It has a built in GPS that gives the geographic position with a one-meter accuracy. The instrument is basically used to check the measurements of a similar type of equipment that John uses in the helicopter to measure ice thickness over a much larger area from the air.

I love the pressure ridges in the ice. The ones I saw today had a bluish color. Small ice mountains that easily make you stumble. I have always had the image in my mind of ice as something flat, but the pressure ridges show the enormous power of colliding ice floes. They are a miniature version of the formation of mountains in the earth’s crust by the colliding tectonic plates. Around the present position of the Amundsen, pressure ridges are up to half a meter. Dwarfs. A few days ago John saw from the helicopter pressure ridges close to Banks Island that were seven meters high.

And the ridges are very photogenic too…

Sea ice hides some funny secrets. First year ice is bluish, whereas multi year ice appears whiter. Multi year ice contains much less brine than first year ice, so it is much less salty. You can even taste the difference. If you would melt several years old sea ice, you can drink a fresh cup of arctic water, naturally cleaned from the salt. Multi year ice also contains more air pockets than first year ice. And if you look at a satellite image, you can also see the difference between one year and multi year ice. Mutli year ice looks much brighter on the image, as it scatters more electromagnetic waves back.

I don’t know whether the Amundsen has been given it’s red color for photographic purposes, but whether it’s sunny, foggy or cloudy, whether the Amundsen surrounded by snow, ice or open water, the red vessel in the background always makes a great photo shot. Just press the button.