After a long bright night at -24°C (-12°F) we trudged over to breakfast and yet more sessions of knot tying. Soon afterwards the IGERT students gave us a presentation on the properties of albedo before we braved the cold and took our own measurements of the albedo. I learned that the albedo (or reflectivity of a surface) can be affected by a large number of variables including color, density, crystal size and crystal shape. In order to explore these influences on the snow’s reflectivity, we split up into three groups, each sampling undisturbed, compacted and dirty snow. To my group’s (and the IGERT students’) surprise, my group found that the dirty snow at the ‘’pee stick’’ actually had a higher albedo than both of our other measurements! We discussed the possible reasons for these results and came to a general consensus that the yellow snow had been compacted to a flatter and icier surface, reflecting the light more directly at our sensor than the crystals pointing light in many directions. The predictable portion of our data was that where the albedo was higher, the temperature that we measured with temperature guns was lower since the lighter materials should absorb less radiation from the sun.
Next, we switched gears from albedo to glaciers and sat in the aluminum foil like tunnel known as the ‘’Rec Port’’ to watch videos of icebergs (with enough volume of water to provide for Los Angeles for two years) crack off a glacier into the ocean, sending an impact earthquake through the bottom of the fjord. In addition, we learned about the manner in which the ice spreads on land, into water and on top of mountains.
To illustrate this, we mixed our own “flubber” - a combination of glue, water and borax to imitate the properties of ice being able to flow yet being in many respects solid. We placed the flubber into halved PVC pipes that acted like valley walls. We then secured the flubber slides into place with clay, creating slopes down which our miniature glacier (which we named Jimmy) could flow. We experimented with drawing straight, horizontal lines across the surface and watching them stretch into parabola-like curves as the faster flowing center passed the sides slowed by the friction along the PVC walls.
We also added toothpicks to watch the flow slowly flip them over since the top of the glacier moves faster than the bottom, again due to friction. Perhaps the most interesting alteration we made was adding oil as a lubricant beneath Jimmy to exemplify water melt seeping beneath glaciers. This drastically quickened Jimmy’s pace and stretched it even thinner which would lead to more melt on a thinned glacier.
Our next stop was a long walk away from the Big House in heavy Sorel boots and CarHartt coveralls with the slippery snow beneath doing nothing to facilitate the walk. Finally we arrived at the backlit snow pit where we crawled down little snow-carved steps, sliding into a room cramped with the seven of us sitting on foam to keep our behinds from freezing.
The Wall facing us glowed a brilliant, light blue, striped with sections of deeper hues and some bright almost white. The wall was illuminated from behind by the sunlight filling another pit. These beautiful layers each represented a storm or event changing the density of the snow. This breathtaking site was also a time machine two meters deep letting us peer back three years into the past. We could even make out the seasons, visible through darker bands in the winter where the wind blew small snowflakes harshly until the brighter summer bands showed us the soft snowfall and lighter winds.
Most frightening were the melt spots, pure ice layers where the especially warm temperatures of last summer melted the snow and the subsequent water dripped down to refreeze below. We took turns using the Kelly cutter to take perfect blocks of a certain volume, then weighing them so that we could calculate the density. We took a sample every three centimeters, the entire vertical height of the snow pit wall. We plan to compare this with our estimates of the seasons based on the hardness of the snow wall that we poked gently.
Upon returning to the Big House, we found a welcome and wonderful meal (especially considering our cook had the day off) and in our spare time before a lecture, the two of us graduated to our next level in knot tying - the trilobite. The next step will be the evolved trilobite which includes a head. We then listened to a talk given by Dr. David Noone, from the University of Colorado – Boulder, about his research here. He focused on isotopes and how the heavier O-18 which collects in liquids more than O-16. The ratio of this isotope to the rest of the ice can tell us what the climate was like when the snow was formed.
Now that the flags of Greenland, Denmark, and the United States, are flying atop the stairs to the Big House, we all had to pose in our JSEP T-shirts for a group photo there and at the back of the station with the official Summit Station sign. Two of us then geared up and played some 10:00 golf in the snow. Josefine also got to launch an even bigger weather balloon than the one we launched the other morning – it was carrying a polar sonde, which is taking measurements for research that Dr. Murray Hamilton is conducting. He is interested in finding ways to detect supercooled water in clouds which pose icing danger for aircraft.
Everyone in the Big House is beginning to settle down as the guitar and didgeridoo have been put away. We will all gather for a round of Yaniv (an Israeli card-game we learned from Brad). Soon we will all be heading off to bed in the glowing yellow tents, hoping for a warm night.