Ice and Medicine at the end of the earth

Archive for January, 2011

Fata Morgana

Fata Morgana is a type of superior mirage that is seen as a band just above the horizon.  The first time I saw it, I thought I was seeing things.  And I guess I was. . .

The image is distorted, and often unrecognizable, because the mirage is made up of multiple upside down and right side up images stacked on top of each other with alternating stretch and compression zones.  This optical illusion occurs when a ray of light passes through different temperature air layers causing it to bend — usually occurring during a thermal inversion.   Most commonly, Fata Morgana occurs in polar regions over large sheets of ice with uniform low temperatures, which is why we often see it off in the distance.  You can sit and watch the Fata Morgana change over time.  I have not had my camera to capture the phenomenon.  Luckily, on a recent walk, Kressley took a photo for me to share with you all.  It captures the Fata Morgana perfectly!

On a different day, the island to the right looks like a regular island.

Fata Morgana is named for Morgan Le Fey, the half-sister of King Arthur, who was able to change shape at will.

Sleeping at WAIS Divide

We sleep in tents. They are called “Arctic Ovens.” They are very warm when the sun is out, but the sun hasn’t been out much this last week.

Going to sleep can be a bit cold.  I go to sleep at about the coldest part of the day, 2 AM.  The outside temperature is something below zero. The inside temperature is unknown – the “inside” thermometer only goes down to freezing.  Now, every night when I go to bed, it reads LL – which is just as well, I don’t want to know the actual temperature.

The Arctic Ovens are actually quite spacious – 8×8. I have it arranged as sleeping bag on one side, all of my crap covering the rest. 

I have a fair bit of stuff. Warm layers, more warm layers, and of course, a Penguin Onesie. 

Getting into my sleeping bag is actually a bit of complicated affair.  First, I changed into my sleeping clothes – sleeping bag socks and long underwear.  These are normally cold because I leave them in my tent instead of taking them into the heated structures during the day.

Then I climb into my sleeping bag liner, the red fleece thing. This keeps me warm inside my GIANT sleeping bag. I was given a large sleeping bag, good for a 6’6” guy, much too big for me. So I pack extra fleece clothing at the bottom to minimize the air space. I then lay the blanket over the top of the sleeping bag.

I spend the next five minutes trying to figure out how to get both the zipper of the fleece liner and sleeping bag to be up at the same time. Then I put on a hat, lay my head on my pillow, and try to cinch the sleeping bag so that cold air doesn’t sweep in around my neck.  If it’s really cold, I tie a wool sweater around my neck like a scarf. It may feel like I’m being strangled every time I move slightly, but at least I’m warmer.

After falling asleep, I slowly shed layers throughout the night, as the outside and inside temperature warm up.  I sleep a lot here – I’m in my tent at least 10 hours a night.  It’s always warmer in the morning, typically 40 or 50 degrees. Balmy.

And that’s sleeping at WAIS.  Overall, the plushest snow camping I’ve ever done!  

Sleigh Ride to the South Pole!

I had another amazing opportunity — To travel by C-130 to the South Pole.  Since it was a fuel drop mission, we flew to the south pole, had 30 minutes to explore the bottom of the world, and then flew back to McMurdo.  The 6 hour flight was well worth the 30 minutes on the ground.  The flight itself was gorgeous.  There are a couple of windows on the C-130 so we could see and photograph the sites.

The views were phenomenal!  Since my last aerial slide show had good feedback, I will post another slide show from this flight in a couple of days.

We landed on a vast expanse of white.  It was cold and windy.  But the excitement of the experience made the weather not seem so bad.  Unlike McMurdo, the skiway is very close to the South Pole Base.  The main station is pictured below.  It is much smaller than McMurdo!

We walked past the ceremonial pole, located in front of South Pole Station, to see the Geographic South Pole.  Each year the winter over crew designs and creates the pole marker for the geographic pole at 90 degrees south.  On January 1st of each year, there is a ceremony to place the new marker.  The marker has to be placed in a new position every year because it is on an ice sheet!  The ice sheet moves approximately 10 meters per year towards the Weddell sea so the position of the station and marker shifts in relation to the geographic south pole.

This year, they celebrated the 100th anniversary of Amundsen’s arrival at the pole and 100 years of exploration.  It was created in the shape of a sextant – an instrument used for navigation by early explorers.  The 47 degrees on the Sextant represents the 47 winterovers at the pole last winter.

Then we rushed to the more well recognized, Ceremonial South Pole.  The position of this marker never changes in relation to the station.  We walked around the world in less than 30 minutes!

And a self portrait of Christine and I:

And then, our time was up.  I had time to give hugs to friends at the Pole.  Then we boarded the plane back to McMurdo.

WAIS Divide: Ice and Ash

Deep in the ice sheet, the ice is very clear – there are almost no bubbles in it.  By about 1500 meters, the pressure in the ice is so great that air in the bubbles gets forced into the ice matrix into something called clathrates.  It’s really fun to look at such a pure substance. It’s hard (for me at least) to capture it with a camera.

There’s only a limited window to see the ice this clear because once the ice is at the surface, the pressure has been relieved, and the bubbles start to reappear. When I see this ice again in Denver this summer, it will not be nearly as clear.

Most of the ice cores are perfectly clear except for the breaks that occur every three meters. However, we have gotten to see a lot of ash layers. West Antarctica is volcanically active – Ross Island, where McMurdo is, is a volcanic island with the very active Mt. Erebus just a few miles away.  That volcanism leaves beautiful layers in the ice.

This layer is from a little over 3000 meters deep. The ash is about ~45,000 years old and is still amazingly preserved.  We jokingly call it “skua poop.”  It was probably a very thick ash layer at one point because the ice has thinned ~20x (that is, a layer that started 20 cm thick is now 1 cm thick).

We just got a new ash layer, so I’m adding photos of it too! It’s probably around 60,000 years old.

WAIS Divide: The Drill

** We have set a US Ice Core Drilling Depth Record. The previous record was 3053.6 m in Greenland. We past that depth at 1 AM on Jan. 18! **

I answered a question about the drill a couple of days ago, and I thought it deserved a more complete post along with some pictures.

We are using the DISC Drill – Deep Ice Sheet Coring Drill. It was designed about 10 years ago for this project.  The drill is about 15 meters long.

It’s hard to get the entire drill in one photo, so I needed two.  Something  you need to know about drilling ice cores is that the boreholes (that the drill travels through) are fluid filled starting about 100 meters below the surface. The fluid is necessary to keep the borehole from closing in on itself. If the hole were left dry, the ice would flow to the borehole (an area of low pressure) causing it to close.

There are four main sections to the drill from bottom to top:

Core Barrel – The core barrel is the part of the drill on the bottom which does the cutting and collects the core.  You can see the ice core inside the core barrel. For scale, the ice core has the same diameter as a CD. There are four cutters on the bottom of the drill barrel which spin around, shaving away the ice between the core and ice sheet. The core barrel can fit about 3 meters of ice per run.

To get the core back up to the surface, the bottom has to be broken away from the ice below it. To do this, four “core dogs” are pushed into the core at the bottom. These are the four metal pieces that you can see sticking into the core. These hold the ice core as the drill is raised, causing it to break off from the ice below.

This is the longest section of the drill. The chip screens collect the ice that gets shaved away by the cutter head. That ice has to be removed so that you don’t keep drilling the same chips over and over again. The DISC drill gets the chips up and away from the cutter heads by pumping the drilling fluid through the chips screens. The chips are moved with the fluid and get trapped. 

The pump is the curved part just above the chip screen. This is what pumps the chip-filled fluid up through the screens. Above that is the motor which turns the drill. And further above is the instrument section, which has all of the electronics to control the drill.  Most of the electronics are actually in the drill itself rather than being up in the control room.  The core barrel, chips screens, and the motor, pump and instrument section all spin.

The anti-torque is the fancy name for what keeps the drill in place in the borehole. If you look closely, you can see three pieces of bowed metal (the fourth is hidden). These press against the borehole wall, holding the top of the drill in place and allowing the cutter head to cut rather than just spin in circles.

So there are the main portions of the drill. One last part I need to mention is the cable.

The cable is not only what lowers and raises the drill, but it also runs the power and communication channels down to the drill.  You can see the cable is not wrapped cleanly in this photo. This caused about an hour delay, all because one little screw on the winch became loose.

In about 20 minutes, WAIS Divide will be the second deepest ice core ever drilled.  I’m about to head down to the arch to see it come through.  Pretty exciting – 3271.2 m

More on ice cores in a future post!

WAIS Divide: Going to the Bathroom

I thought some of you might be interested in how we go to the bathroom here on the West Antarctic Ice Sheet.  Well, here you go. If you’re about to eat, you may want to wait.

We have three “bathrooms” – one in each of the three main parts of camps – Town, Tent City, and the Arch.

Each bathroom has two parts: pee flags and outhouses.

The pee flag has a snow block wall built around it. This is party for privacy, but also for wind. A strong wind in negative temperatures can cause real problems!

As you can see, there is a large piece of plywood surrounding the hole. It prevents the snow from crumbling in and creating a pee pit.

This is really pretty similar to any other outhouse, except the seats are made of foam so you don’t freeze to it (and so it doesn’t hold much cold).

There is artwork and poetry in the outhouses.

The poetry might get its own post later, but much of it isn’t appropriate for a general audience. 

There are two major differences between these outhouses and your typical National Forest Campground ones. First, they don’t smell much because everything stays frozen. Second, you have to watch out for “pinnacles of poo.” You can imagine what those are – I’ll spare you the photo.

Flying Over The Transantarctic Mountains

Earlier this week, I had an amazing opportunity to fly in a twin otter plane over the Royal Society range of the Transantarctic mountains.  The glaciers, mountains and rock formations were gorgeous — the best views I have ever seen!!  I thought I would share the photos I took on the flight with you.  I have placed them in time order so you can see the constantly changing landscape.

The slideshow can be slowed down by moving your cursor over the picture, pushing stop and using the arrows to navigate.  Enjoy!

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