26 December, 2002
Latitude: 86° 30’ 08.99” S
Longitude: 107° 59’ 24.64” W
Time of Observations: 11:00 PM local time
Temperature: -27 C / -16 F
Wind speed: 1 knot
Wind Chill: -28 C/ -17 F
Wind direction: Westerly
Meters of ice collected: 506 m
By Gordon Hamilton
The day after Christmas, what some us from other parts of the world call Boxing Day. Quite appropriate really, because a large part of the day was spent moving boxes around in preparation for our departure to our final site tomorrow morning. Site 4, or Hercules Dome, has been good to us but it will be good to be moving farther into East Antarctica and nearer the end of our adventure.
Hercules Dome sits a few hundred feet above the surrounding East Antarctic Ice Sheet. Notwithstanding its impressive sounding name, it is actually almost impossible to tell that we are close to the summit of the dome. Such is the scale and topography of the Antarctic Ice Sheet. The dome itself is about 100 km long and 60 km wide. It is one of a number of domes in East Antarctica others include Titan Dome, Talos Dome, Dome Concordia, Dome Argus and Dome Fuji.
These domes probably represent the former high elevations of the Ice Age ice sheet. If that is the case, we might expect them to be relaxing to a new equilibrium surface (or flattening out). The same thing happens if you upturn your bowl of oatmeal on the table very quickly it will change from a rounded standing-up lump to a flattened mess covering a larger part of the table (and your parents might be mad, but tell them it’s a science experiment!). Ice sheets do the same thing when their supply of new snow decreases or their flow speeds increase only they relax, or flatten out, much more slowly than upturned bowls of oatmeal. The experiments that Blue and Gordon are doing will tell us if Hercules Dome is getting flatter with time. Their GPS measurements allow them to calculate the rate that the ice sheet is changing thickness. Today, they finished their survey measurements and drilled a shallow 20-meter ice core that they will use to determine the snow accumulation rate. A year from now they will revisit this site by airplane and conduct repeat GPS surveys to allow them to complete the calculations.
The other drill team of Mark, Dan, Paul and Susan persevered through a few drill problems to complete their ice core at a depth of 72 meters. The fact that we are having extremely pleasant weather (cold, but relatively warm in the absence of any wind) undoubtedly made Mark’s mechanical repair work a little less harsh on his bare fingers.
Markus and Betsy performed a full day of science at their atmospheric chemistry tent. One of their experiments was sucking air out of the surface snow to compare its chemistry with the air above the results will be useful for understanding the chemical signatures that are recorded in ice cores. The calm conditions also allowed for several ozone sounding balloon launches.
Brian and Lynn went on a mini-traverse to study the subglacial controls on the location of Hercules Dome. For example, does the dome sit on an elevated region of subglacial mountains? Brian’s radar looks through about 3000 meters of ice to map the shape of the underlying rocks. Today, they collected over 75 km of data together with yesterday’s mini-traverse in the opposite direction they have over 120 km of radar profile data across Hercules Dome.
Around camp, Carl and Andrea were busy as usual taking care of the essential details of field life that we tend to overlook when we are busy with science. Carl organized the fuel for our next traverse leg and performed some preventive maintenance on one of the tractors. Andrea worked her magic in the kitchen, almost outdoing her efforts on Christmas Day with a fabulous meal of stir-fried meats and vegetables. With a little extra hot sauce, it was just the right kind of meal to warm up the hungry bunch coming in from a day in the cold.
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