Friday, June 20, 2008

Snow Science at Summit

The other day I joined up with Dr. Zoe Courville from the Cold Regions Research and Engineering Lab. and one of her crew members, Elyse Williamson, an undergraduate from Hamilton College. They showed me some interesting research on snow science or more specifically, firn. Firn is snow that is older than a year and has transformed to a much denser medium, but not yet as ice. Zoe studies the thermal conductivity and permeability of the firn in the upper layers at Summit. Below are some pictures of one of her "pits" which is dug with the help of Elsye and others, and this where she collects her data.

Zoe and Elyse in the pit. Notice that it is covered with plywood to keep snow from filling it in overnight.

Zoe demonstrating her instrumentation. The probe measures the thermal conductivity of the snow which is attached to a data recorder(white box). The blue box is used to insulate a core of firn that was collected from the wall of the pit.

Here is another photo of Zoe placing the probe into the pit wall for measuring.

Here, Zoe, indicates different layers in the firn. The dark lines are wind crusts which are a result of wind blown snow that is deposited on the surface and then covered up by more blown snow. Understanding the layering is important because it can impact the permeability of the firn which can reduce airflow through it and modify exchange with the atmosphere. Also note the light blue shading in the snow, that is sunlight that penetrates the surface and can produce chemical reactions within the snowpack.

Here is a photo of the pit entrance from the surface. Below that hole is a frozen laboratory where the temperature is typically -30C!

Ok, now the ski back to camp. Elyse, my guide, is waiting for me to catch up. You can just see Summit Camp in the distance on the left, about 2 Km away.

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