Tuesday, June 12, 2007

Summit Camp, Greenland

Last night, the weather was cooler than the night before, but still comfortable. I slept in a bit (8 am), ate breakfast, and took a walk on the ski way. It is the ice runway used by the C-130s. Its length is about three miles. Lucky for me, it was in the process of being groomed, so walking was easy. I have come to like packed snow. Walking a distance, or walking and carrying/dragging anything with weight is tiring when sinking in snow. The snow here does not lend itself to snowballs and snowmen. It is dry and powdery. On the average, it snows about 50 cm/yr in Greenland, and this is considerably more than Antarctica. However, the snowfall's geographic distribution varies greatly. Summit Camp sits very near to the icecap's geographic high point. Snow falling here forms the ice that flows down the slope, and calves into icebergs at the edge of the island. Map courtesy of http://en.wikipedia.org/wiki/Greenland_ice_sheet.

After the morning's walk, and before lunch, I visited with one of the meteorology teams. This group is trying to assess the energy balance above Greenland's ice sheet. Energy arrives to Greenland through sunlight, and through large air masses that are moved around the globe. Some sunlight (light is a form of energy) is reflected back in a process called the albedo effect. Snow and clouds are particularly good reflectors of energy. Some of the energy from sunlight is absorbed, and then reradiated back. This reradiated energy heats the air immediately above the surface. This process creates sensible heat, and it is the heat (another form of energy)humans experience. This heated air rises, and as it rises loses its heat, and sinks. This turnover of air is called convection. Convection occurs in boiling pots of water, and underneath our feet as earth's huge tectonic plates move around on upwelling magma generated deep within earth's core! Also, energy is used to warm water in the air. This process generates latent heat. As they move around the globe, air masses laden with water then are able to distribute latent heat.

If heat is in equilibrium, heat inflow equals heat outflow, then the system is in equilibrium, and temperature remains constant. If heat input is greater than outflow temperature increases, and if heat outflow is less than inflow, temperature decreases. Obviously, global warming is a concern, so examining heat balance is of great concern. The meteorology team's study of the energy dynamics on Greenland will contribute to the our understanding of global energy distribution. One concern on the part of the team was the presence of black carbon resulting from burning of fossil fuel. Black carbon on snow (impossible to see, but measurable) reduces snow's albedo, increases energy absorption, and therefore increases temperatures. The team has ground-based instruments, and data-collecting balloons they launch daily at twelve noon. This dual positioning of instruments gives meteorologic information at ground-level and aloft.

Tuesday night is the guest lecturer night. Typically, a scientist will share aspects of their research, or interest. Tonight was different. Sara Wheeler (author) gave a talk on her biography entitled "A Life of Apsley Cherry-Garrard" published by Random House, Inc. 2003. "Cherry" was the youngest member of British explorer Captain Robert Falcon Scott's tragic 1912 expedition to the South Pole. Captain Scott lost the race to the South Pole to Norwegian Roald Engelbregt Amundsen, as well as losing his life returning from the pole. Cherry survived the expedition, and went on to write what is credited by many as being the best "polar" book written. It is entitled "The Worst Journey in the World", and it is still in print.

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