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Posted at 11:00 AM ET, 01/13/2010

Ann in Antarctica: Stuck at the South Pole

By Ann Posegate

* The warm-up begins: Full Forecast | Canaan Valley snow cover *

Ann Posegate reaches the South Pole. Photo courtesy: Earth Gauge.

CWG's Ann Posegate is part of a group of journalists selected by the National Science Foundation to travel to Antarctica and report on weather, climate and environmental science research going on there. Read more about Ann's trip from previous posts.

There are some experiences in life that you just won't forget. Then they are those that only few humans in our history have had the chance to experience - in fact, those that humans are not supposed to experience. Visiting the South Pole is one of them.

At the South Pole, there are no hurricanes, but there are near-hurricane force winds. There is little snowfall, but you are standing on a two mile-thick ice sheet that covers the continent beneath. Every direction is north and the summer sun never sets. There are no trees and little oxygen, but somehow human life survives.

The South Pole is a three-hour flight away from McMurdo Station, the base of the United States Antarctic Program (USAP). At an elevation of 9,300 feet above sea level (which feels like 11,000-12,000 feet due to a thinner atmosphere and 25 percent less oxygen than at sea level), the Amundsen-Scott South Pole Station is the highest of the three USAP stations. Dedicated in 2008, it is the U.S. Antarctic Program's most recent building, and houses some of the world's most brilliant scientists and important research in air quality, earth science, space physics and cosmology.

The Pole is located on the East Antarctic Ice Sheet - a huge glacier that slowly moves over the land mass beneath. Thus, the geographic Pole marker is moved about 30 feet every year for accuracy.

Technically, every direction is north from the perspective of the Pole. So, the station operates on a directional grid system. Greenwich, England, is toward "grid North," New Zealand "grid South," Cape Town "grid East," the United States "grid Northwest," and so on.

Weather there can change quickly and is difficult to predict, especially given only two satellite passes per day and sparese internet connection. But, in some ways it is much less eventful than weather in the United States: it is either cold and sunny or cold and cloudy, and usually windy. It rarely receives measurable precipitation. Within the 24 hours of our visit, the sun remained at about a 21 degree angle over the horizon as it rotated through the sky - rather, as the Earth rotated - resulting in no sunrise, sunset or diurnal (day-to-night) temperature changes.

In the low pressure systems we are familiar with in the mid-Atlantic, warm air from the surface rises, cools, condenses and forms clouds. But at the Pole, there is typically a temperature inversion, with cooler air near the surface and warmer air aloft. Thus, in a low pressure system there, cool air rises and warms, bringing clear skies. On the contrary, in a South Pole high pressure system, warm air sinks and cools, forming clouds.

The past few days have been a good reminder that, no matter where you are, you can plan for the day's weather, but the atmosphere doesn't always give you what you expect.

By Ann Posegate  | January 13, 2010; 11:00 AM ET
Categories:  International Weather, Posegate  
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Is it really true there's less oxygen at the South Pole? If so is this due to a lack of plant life, or could it be altitude-related?

I always thought that oxygen diffused fairly evenly, at a sea-level figure presently around 20 percent. As for plant life, there's plenty of phytoplankton in the cold Southern Hemisphere ocean surrounding Antarctica, and phytoplankton photosynthesis provides a greater share of the atmosphere's oxygen content than does land-based plant life.

On the other hand the South Pole may have less oxygen due to altitude at a mile above sea level. This would make the oxygen content of the atmosphere there roughly equivalent to that in Denver. Sea-level NFL teams tend to be at some disadvantage when playing on Invesco Field at Mile High, thus giving the Broncos a slightly greater home-field advantage than most NFL teams.

Incidentally, oxygen IS rather scarce at Russia's Vostok Station, site of the world's coldest recorded temperatures [aoa minus 120 Fahrenheit] as Vostok is located at an altitude exceeding 10,000 feet! This may also explain the minus triple-digit temperatures there.

Posted by: Bombo47jea | January 13, 2010 1:40 PM | Report abuse

Correction: I see, by reading your article, that the oxygen issue is definitely altitude-related. In other words, about a mile above sea level PLUS a mile of ice on top of that.

The article poses another question: Since clouds do not form in the rising air of low pressure systems there, doesn't this mean that convective clouds such as cumulus or cumulonimbus CANNOT form at the South Pole, and, hence, thunderstorms are impossible? This would mean that most clouds recorded at the South Pole are either ice fog, stratus or stratocumulus and that precipitation is generally limited to ice needles,; the clouds are generally not deep enough to form nimbostratus layers. The same is not true at the North Pole which sits atop an ice sheet in the middle of the Arctic Ocean. I believe that at least one Arctic expedition has recorded showers at the North Pole during midsummer.

Posted by: Bombo47jea | January 13, 2010 2:06 PM | Report abuse

There are no hurricane force winds at the South Pole - typical MAX winds at any time of the year are in the range of 30-40 mph - average for the year 5-6 mph - highest ever wind speed recorded there perhaps in the low 50's (mph), but that's rare. Hurricane force typically considered to start at 73 mph.

Posted by: save3 | January 13, 2010 3:36 PM | Report abuse

Have you seen any penguins? I caught March of the Penguins on tv last month... pretty amazing.

Posted by: spgass1 | January 13, 2010 3:40 PM | Report abuse

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