A single Antarctic snowflake. Two things have always given me headaches: the number of stars in the universe and the number of these in Antarctica.

Prisoners in time, these frozen gas bubbles give pattern and beauty to the ice.

A different pond and a different pattern.

Ice crystals obey their own rules of pattern formation.

A different place in the ice, these formations did their own thing.

These frozen ice waves remind us, the wind will be heeded.

The large ice structures of Antarctica remind us of the power of this place; the small ones, how fragile it is.

No snowmachines or generators usually means a long, slow walk through the snow pulling a sled piled with gear. This year though, thanks to a group of students at the University of Wisconsin who built a zero-emissions electric snowmobile, we were able to ride to and from our site in style.

The weather was great, and with the help of Tony Cummings, a senior at Georgia Tech here at Summit working with the HOx NOx group (a group of scientists studying the influence of sunlight on snow and atmospheric chemistry,) we were able to dig the big pit, and a smaller “lab” pit that we can work in, in a few short hours. I honestly don’t think that Tony knew what he was in store for, but I also think he enjoyed the good, hard work. Digging is very satisfying, and an excellent way to stay warm.

Let the digging begin.

Elyse peering over the top of the lab pit, with our big research pit in front.

The lab pit is to keep the instruments and scientists out of the wind, and to keep the snow samples cold enough that they don’t melt on warm surfaces or start to change their structure. In the big pit, we are looking at a whole host of physical properties, and how these properties change over time.

Equipment in our lab pit. The grey box on the right is what we call our “permeameter”; it measures how easily air can move through snow. In the white box on the left is a thermal conductivity probe: a needle we push into the snow that heats to a certain temperature then provides us with thermal conductivity readings by measuring the time it takes to heat the snow. The blue box beneath the thermal conductivity probe is a stand for short snow/ice core sections. It isolates samples from the wind– an element that can easily disturb and affect the thermal conductivity measurements.

I had also dug pits here (dragging my gear out in a sled by foot) in the previous two years, and now I can trace the changes in the snow in the intervening time. Last year and the year before, I had put bamboo poles in the snow and tied a brightly colored string across the snow surface. I was able to find both of the strings in the pit, buried by the snow from this year and last. I was relieved and slightly surprised when they both popped up as we were digging.

Kristina stands on one of the pit steps while Maria takes density measurements inside. To take these measurements, we use a tool that cuts out 100 cubic centimeter blocks of snow, then measure the mass of these blocks.

Camp manager Kathy Young and science tech Steve Munsell stopped by our site on the way back to camp after a two hour ski. It was fun to have visitors.

We ended up having to go back out to our site after dinner when things had cooled down a bit. Earlier in the day, we had tried to hand drill a few short cores, but the cores kept getting stuck in the barrel, which was being warmed alarmingly by the sun. Coming out “at night” (it’s 24 hour daylight here now) means colder temperatures, and easier working conditions. Chris, the camp medic, apparently felt sorry for us, and brought out a much needed thermos of cocoa and some after-dinner mints. And then got roped into helping us cover up our pits. A great end to a great day.

Zoe Courville analyzing data at her field camp in Greenland.

Zoe’s Greenland field camp.

In polar areas, snow falls and rarely melts, resulting in layers that build up over time. In Greenland, layers of snow have accumulated over hundreds of thousands of years to a depth of two miles. Snow falling at the surface starts to change almost as soon as it lands on the ground: Smaller snow grains begin to fuse together into larger, more rounded crystals. These changes in the snow occur at the surface, and at depth, until the snow becomes compressed into ice from the weight of the snow above.

A wealth of information about past climate is contained in the snow itself and in the air bubbles trapped in the spaces between the particles of snow. To fully understand this climate record, scientists need to understand the changing snow. Research scientist and engineer Zoe Courville is working in Greenland as part of an ongoing effort to understand how snow layers evolve. She’s studying snow pits—excavations that scientists dig to reveal the different layers in the snowpack.

During the summer of 2008, Zoe’s research took her to Summit Camp, the top of the Greenland ice cap.

In the summer of 2009, Zoe worked at Greenland’s NEEM camp in northwest Greenland. The NEEM project is a large international ice-core drilling project that is part of the International Polar Year (IPY) and is led by Dorthe Dahl-Jensen of the Niels Bohr Institute in Denmark. The goal of the project: to reach ice that is at least as old as the Eemian period, which ended 115,000 years ago. The Eemian is the last interglacial period, a warm period in between the ice ages, before the present one we are experiencing. Understanding the climate of the Eemian might provide clues for our future climate. For example, during the Eemian period, temperatures in Greenland were 3 to 5 degrees Celsius (more than 5° F) warmer than they are now, temperatures that Greenland could once again reach in the not-so-distant future.

Creating the snow pit.