Antarctic Astronomy Diaries 2002/03

   

   
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Tuesday, January 14, 2003

We have ignition

If there's one thing better than a the sound of a two-stroke going flat out, it's the sound of a four-cylinder double-acting Stirling engine purring away, producing over 500 watts of electrical power.

Actually, even better is the sound of two such engines running simultaneously.

During the day, Jon worked like a man inspired - first discovering that both of our spare oxygen sensors have a more sanguine view of the amount of oxygen in the air here, and then exploring the fuel/air ratios needed to get the engines lit and coax them into life. Both Sid and Nancy responded well, with Nancy at one stage producing 580 watts. This is more than enough to run all of our instrumentation. We rang the manufacturer of the engine in Christchurch via Iridium, and they were able to confirm that the problem had arisen simply because the engines are designed mainly to run at sea level. One of the major applications of these Stirling engines is in ocean-going yachts and, largely because of the effect that gravity has on sea water, oceans do not exist at 3,800 metres (at least, not on Earth).

The highlight of today's lunch was having Rich, a research meteorologist from the University of Washington, show us some high-resolution contour maps of the Dome C area. These maps had been generated a few years ago by an Italian and British team, using GPS and airborne radar. From the ground, the surrounding topography looks to be as a flat as pancake, and indeed it is. Surprisingly then, at first sight the maps seem to show that Dome C is a major mountain peak, rising above the surrounding terrain like the Matterhorn. However, the contours are spaced at 1 metre intervals, and you have to travel at least 100 km from here to see the elevation change by 100 metres.

After lunch we took a short break from work to go on a tour of the EPICA "science trench". This is a long laboratory in which the ice cores undergo some preliminary analysis. Piers, a physicist with the British Antarctic Survey, kindly led us through all the various stages of the process, which begins with some electrical measurements, followed by slicing up the 10 cm diameter core into long strips so that different laboratories back in Europe can each have a piece. The sawing is done with bandsaws that look like they belong in a butcher's shop, and Karen was able to show us an impressive scar on her finger, indicating that accidents do occasionally happen. However, she reassured us that you never cut more than halfway through a finger before animal instinct takes over and rescues the situation. She was obviously correct - all of the bandsaw operators still had the standard number of digits on each hand.

Here at Dome C, photos are taken in polarised light to elucidate the crystal structure, electrical measurements are made to determine what was in the air at the time the ice formed, and a thin slice is melted in order to undergo chemical analysis. It is amazing to look at a length of core, perhaps 2 metres long, knowing that it contains within it a precise history of the earth's environment some 800,000 years ago. Within the science trench, the temperature is kept at around -21 C, in order to avoid melting the ice. Warmly dressed, the various scientists were perfectly happy sawing, measuring and recording, while apparently still occasionally finding time to write amusing graffiti of questionable taste on the walls.

Volley Ball at -30C. Photo by: Patrick KaufmannMany of the EPICA team took some time off yesterday to play beach volleyball. Dressed appropriately (swimsuits plus boots) they survived the -30 C temperatures for about 10 minutes before calling it a day.Photos will follow (if I can get hold of them).

Tony has installed the acoustic radar, or SODAR, on the roof of the AASTINO. We will fire it up tomorrow and see if we can detect the turbulence in the lower atmosphere here. In the course of this work Tony suffered yet another injury, slashing a finger on a piece of aluminium tape. It's easy to do, because skin gets so dry that just about anything will cut it. Fortunately Tony was able to raid the AASTINO first aid kit, which proved perfectly suited to the job of restoring him to full functionality.

Our second science instrument, SUMMIT, has been sitting over in the carpentry shop for the last few days, trying hard not to look like a piece of spare timber. After lunch we put it onto a sled and towed it behind a Skidoo to our tent. It will require some minor work before it, too, goes onto the AASTINO roof.

Our little tent is proving to be a very convenient additional work space. We are not heating it, but during the day the sun warms it up enough to make it quite comfortable to work in. We have rolled up the mosquito netting, as the mozzies don't seem to be much of a problem here at this time of year.

-posted by John Story

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