Wednesday, February 13, 2013

Station construction and weather questions

I have received a few questions about the station construction post I made. All of the materials were flown in by four dedicated LC-130’s that made hundreds of flights over a nine year period. The LC-130 (the L designates ski equipped) is the largest cargo plane that can land and take off from the pole ice. The much larger C-17 is too heavy for the ice. The LC-130 has a 22,000 pound capacity and all the construction materials had to engineered to fit inside the cargo hold. All the materials were shipped from Port Hueneme, California (near my home town of Oxnard), which it USAP’s Antarctic shipping depot, to McMurdo, then loaded onto the LC-130’s and then flown on the 6 hours round trip flight to the pole. All of this was accomplished during the pole’s 3 ½ month summer period. At that point flights stop until November.

The South Pole stations throughout the years.

When the ski equipped LC-130 lands it must retract the skis and drop the wheels as the skis will freeze to the ice. Recently one of the skis was not retracted all the way and it took a tractor to break the ski free from the ice. In that same line I was told when using a snowmobile to travel to a work site during the winter two people must go – one to work the required task and the other to keep the snowmobile in motion because it will also freeze to the ice. 

Weather questions:

Why is Antarctica so cold? 
Antarctica is synonymous with cold thanks to its polar location, its high elevation, its lack of a protective water vapor-filled atmosphere, and its permanent ice cover which reflects 80% of the sun's radiation back into space. Angle of incidence also has a lot to do with the temperature in the Antarctic. The highest sun angle here is only 23.5 degrees (currently at 16 degrees), so the South Pole gets a much less concentrated dose of the sun’s rays, versus locations near the equator, which get the highest concentration of the sun’s rays. The South Pole is located within a permanent polar high created by the normal Hadley Circulation. This creates a stable cold air mass, which descends at the poles of the earth. Unlike the Arctic region, Antarctica is a continent surrounded by an ocean which means that interior areas do not benefit from the moderating influence of water. During the winter, the size of Antarctica doubles as the surrounding seawater freezes, blocking heat from the warmer surrounding ocean water.
Does it snow at the Pole?
Actual snowflakes (branched crystals) are pretty rare at the South Pole, and generally are only seen during the warmest periods of the summer. But according to data from snow stake measurements, the annual snow accumulation averages about 9 inches (3.4 inches of water equivalent). Most of this precipitation falls as ice crystals. Ice crystals are very common at the South Pole, often falling out of a clear sky when the air becomes saturated. Since I have been here I have only seen these ice crystals as they fall in the bright sunlight. The precipitation intensity is normally very light, but over the course of a year it adds up. The possibility that some of this “accumulation” is caused by drifting snow complicates the picture. So far there’s no good way to measure or calculate the relative contributions of precipitation and wind deposition. It is interesting to note that the South Pole is dryer than the Sahara Desert.

My first time ever on a snowmobile. One of the antennas was in the wrong position and couldn't be moved remotely so this is a quick way out to reset it.

Snowmobiling at the South Pole!

Replacing test equipment.

The bright sun at 16 degrees elevation doing a 360 every 24 hours. Once the sun is at 16 degrees there is no longer any solar radiation and the cold starts setting in. Unlike McMurdo there are no hills or mountains to block it. Our first sunset will be March 23rd.

The front door of the South Pole Station.

This would be a sturdy hurricane door in Florida. The windows are dual pane and about 5 inches thick.
We have freshies! The last time I was in a line like this I was loading 70 pound 5 inch/54 caliber projectiles and 35 pound shell cases with powder onboard my ship the USS Hoel DDG-13 back in the early 70's.

A call is made for all available personnel to help bring in the cargo. This really is a small community where everyone helps out.
A small portion of the freshies we received as all the other boxes have been moved into the frig. These banana boxes contain an assortment of fruits and vegetables. There were also a few dozen boxes of fresh New Zealand eggs!

No comments:

Post a Comment