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Crackling pretzels

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Editor’s note: Marine geophysicist Robin Bell is leading an expedition to Antarctica to explore a mysterious mountain range beneath the ice sheet. Following is the tenth of her updates on the effort as part of ScientificAmerican.com‘s In-Depth Report on the "Future of the Poles."

McMURDO STATION, ANTARCTICA—I expected to find a piece of machinery snapping away when I rounded the corner. Instead, I encountered a glaciologist systematically snapping one pretzel after another.  Ted Scambos, the glaciologist who was first to observe the Larsen B ice shelf break up, was holding a stiff plastic bag containing a few pretzels and many pretzel fragments. Unable to resist, I asked if getting into the field is really that difficult?  We both started laughing a nervous, knowing laugh.  Both of us are trying to get a major program underway, moving science into East Antarctica.  Sometimes the hurdles seem insurmountable. East Antarctica was criss crossed with traverse vehicles in the 1950s and ’60s, but only a few programs outside of the major bases have occurred since.

Ted will be on the U.S. Norway Traverse, and I will be in the Gamburtsev Mountain program.  His program has been struggling to get the traverse vehicles repaired and in condition to drive across a continent at about 10 miles an hour.  I am trying to get two field camps and two geophysical aircraft operating.  His nightmares are failed transmissions, mine range from flat tires on the ice shelf to insufficient power to plug in the airplanes at the camp. As we move up on to the polar plateau, both of us will struggle with the effects of altitude.

Altitude is a problem for both machines and people, and the altitude on the plateau is even harder on both.  Atmospheric pressure decreases with altitude.  The result is thinner air at high altitudes.  This means that  our bodies must compensate for the reduced oxygen molecules in the air and the machines just do not operate as efficiently.  In the Polar Regions, the problem is compounded by the effect of the spinning earth and the cold temperatures at the poles. Earth’s surface has a bulge.  Here, close to the South Pole, I am about 13 miles closer to the center of the Earth than I would be if I were near the equator in Singapore. 

The rotational forces that have drawn me closer to the center of  Earth also act on the ocean and the atmosphere.  Both the global oceans and the atmosphere have a bulge associated with the rotation of a deformable medium.  The net result is there is more atmosphere at the equator than at the poles.  My barometric watch here at sea level is reading 978 millibars; it reads, on average, 1,015 millibars when I am sitting at on my sailboat at sea level. The fact that the pressure is lower here makes altitude even more of a problem.  Our camp is only 11,482 feet above sea level, similar in elevation to the mid-station of a Colorado ski resort.  The polar low makes the average pressure closer to 14,800 feet – closer to the highest peaks in the Rockies.  Neither people nor machines like to work in this environment. We are being very careful to acclimatize people before the science begins. The generators that will power our camp, however, are unable to adjust and will operate at 40 percent  efficiency.

Some machines are now working at altitude. This afternoon, the U.S. Norway Traverse vehicles came into view from the South Pole, and Ted and his team got the call that they would be on the 8 a.m. flight to join them there. As he stood next to Admiral Byrd’s image, all his worries seemed to have melted away.  When asked how he was feeling about leaving, he bounced in the air with a maneuver that looked more like something from a Broadway show than from a science video.

Just up the hill, the two  temporary 10-kilowatt generators that will run the stoves and keep the airplanes warm at AGAP-S are humming.  Soon I hope to catch one of those early-morning flights to South Pole on my way to AGAP-S.

Photo courtesy of Robin Bell.

Dispatches from the Bottom of the Earth: An Antarctic Expedition in Search of Lost Mountains Encased in Ice





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