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On clathrate ice, and some general Antarctic statistics

Posted December 17th, 2008 by celene.carillo@oregonstate.edu

Date: December 17, 2008
Location: WAIS Field Camp (Science Rac Tent)
Time: 11:00pm
Latitude: 79°28’1.2”S
Longitude: 112°5’6.0”W
Elevation: 1,759m
Temperature: -23.9°C
Wind speed: 3 knots
Visibility: Unrestricted
Wind direction: 319°
Relative Humidity: 77%
Precipitation: None
Animals: None
Breakfast: frittata & Finnish coffee cake.
Lunch: Chicken breast, lentil soup, fresh baked bread, wild rice, and
chocolate birthday cake.
Supper: Seafood scampi (mussels & shrimp), orzo pilaf, mixed vegetables,
and crème brûlée.

Today was a very important day which can be summarized with one phrase: Happy birthday Natalie!! For her birthday, the sun came out, the wind died down, we all had yummy chocolate birthday cake, we drilled 3 meters of core, there was another pair of sundogs around the sun, and there was a camp wide softball game after dinner. The core drilling was very exciting because we were testing a drilling technique that is very important for determining how much core we will be able to drill this season. In a certain depth range in the ice sheet the ice changes from bubbly ice (where all of the air in the ice is trapped in bubbles) to clathrate ice (where there are no bubbles and all of the air that used to be in bubbles has been absorbed into the crystal structure of the ice) and in this transition region the ice is very brittle. It is so brittle that if you try to cut it with a saw it will shatter into tons of pieces and will therefore not be very useful to scientists.

To work with ice from the brittle ice region you have to store it in a cold place for awhile while the ice “relaxes” and becomes more supple. Our plan is to store the ice we drill this season on 1 meter trays in the basement of the drilling arch (which is just a huge room dug into the snow beneath the drilling arch) for 1 year and then pack up the ice and ship it back to the U.S. The main goal for this season is to drill all the way through the brittle ice region, which is hundreds of meters thick, and we are just starting to enter into it. Our problem is that it takes about an hour for each drilling run which consists of lowering the drill down the hole (which is currently 580 meters deep) and bringing ice back up to the surface. The drill is capable of drilling ~3 meters of ice at once, but since we can’t cut the ice we were worried that our throughput would only be 1 meter of ice per drilling run (because we have to put the ice on the 1 meter trays). If that was the case we wouldn’t be able to drill very much core this season. The test we tried today was to drill 1 meter of core, break it (as if only drilling one meter), then drill another meter of core and pull up the two sections intact. Nobody has done this before and we weren’t sure if it would work, but it did!! That means (if it continues to work well) that we will be able to get plenty of core this year which makes everyone here very, very happy.

I personally am very happy that we are finally starting to drill some ice. My lodestar has always been “work first play later”, but so far on this expedition I have gotten to play a lot in New Zealand and McMurdo before I got to work. So it feels nice to actually get a chance to finally do what I came here to do: get some good quality ice core that will result in awesome science.

For this blog entry I decided to compile some interesting statisticsabout life here:
- Days since my last shower: 5
- Days since my last sunset, or any kind of “night”: 18
- Relative cost of the fuel we use in camp: ~$15/gallon (this is so
high because the fuel is flown in from McMurdo…)
- Gallons of diesel that the generator that powers the freezer units
in the drilling arch uses every day (Yes, even in Antarctica I work in a
freezer, and its kept at about -25 to -29°C): 300-400 gallons/day
- Price of that diesel: ~$5,000/day
- Percent of meals that I have a second helping: 100%
- Number of jackets I have here: 7
- Number of pairs of boxers: 7
- Amount of jet fuel an LC-130 uses: 700-800 gallons/hour
- Amount of spare fuel we have in camp (if we were isolated and no
more flights came, this is how long our fuel would last): ~4 weeks
- Amount of spare food we have in camp (same deal): ~16 weeks
- Total depth of the ice sheet: ~3,500 meters
- Current depth of drilling: ~584 meters

That’s all for now. Hope everyone is doing well and staying warm back home!

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