CARA Education and Outreach:
Cold Facts about Antarctica

So, how cold is it?

Here are some other Cold Facts...

• Is it dry?
  • Although there is lots of snow and ice around, the Pole is really a desert environment, because it averages less than 4 mm of precipitation monthly, about the same as the Sahara Desert.
• Is it windy?
  • Many people think of Antarctica as a windy place. That is true, but only near the edges of the continent. At a coastal location, like Australia's Mawson Base, winds average 40 km per hour, with week-long blizzards bringing winds in excess of 80 km per hour and gusts up to 190 km per hour.
  • The severe coastal winds called the katabatic winds result from cold air flowing down off the interior ice sheet. These winds are further disturbed and strengthened by the low pressure systems that ring the continent. But ...
  • ...high on the plateau, at the South Pole, the average wind speed is typically less than 14 km per hour, with the peak winds rarely over 40 km per hour. There the winds almost always blow from the same direction - the compass quadrant containing Dome A, the highest point on the Antarctic Plateau. At Dome A, typical wind speeds are less than a few km per hour, making it possibly the calmest place on Earth.
• OK, so what kinds of weather do you find at the Pole itself?
  • The South Pole is located within a permanent polar high, making it possibly the most consistently clear place on Earth where there is a scientific station. This air mass is created by the normal Hadley Circulation that causes air to descend at the poles of the Earth.
  • Radiative cooling causes this air mass to become very dense and relatively thin. The troposphere is only 7-8 km thick at the Pole, almost half of its thickness at low latitudes.
  • Forming around this permanent high is the polar vortex, a jet stream of stratospheric winds. This vortex is responsible for isolating the polar stratosphere and thereby enabling the chain of events that leads to the notorious ozone hole.
  • The violent weather that coastal Antarctic inhabitants experience is due to cold, outward flowing air from this high meeting the warm moist air from the circumpolar trough of low pressure cells.
• How thick is the ice sheet?
  • The average thickness of the ice sheet that covers 98% of Antarctica is 2,200 meters (7,200 feet). This amounts to 90% of the ice and 70% of all the fresh water in the world.
  • The thickest ice found is in Wilkes Land, where it reaches a depth of 4,776 meters (15,669 feet). That is about as deep as the highest of the Alps is high.
  • If the ice cap were to melt, the average sea level would rise 67 meters (230 feet). This doesn't seem like much, but it would easily inundate most coastal cities, among them: New York, London, and Hong Kong. Los Angeles, however, would survive.
  • The weight of all this ice is so enormous that the continent buried beneath it would rise to an average altitude of 1,000 meters (3,280 feet) if the ice sheet were removed.
• How many people live there?
  • Not too many decades ago, one could count the number of people on the Antarctic continent on two hands. Today the peak scientist and support personnel population reaches 4,000 during the summer season. Tourist numbers are comparable.
  • The population at the South Pole also peaks when the summer sun is high, reaching 125. The winter is a different story. The number of people at the South Pole during the winter of 1993 was only 28.
  • Unlike the human population, the number of dogs in Antarctica has been declining. In fact, the "1991 Protocol on Environmental Protection to the Antarctic Treaty" bans dogs from the continent entirely starting April 1, 1994. This was done to protect the seal population from distemper.
• What is the altitude of the site?
  
  • The South Pole is a high-altitude site. The elevation of the South Pole is 2,835 meters (9,300 feet), about the same height as mountain top observatories like Kitt Peak, Arizona. Some parts of the Antarctic Plateau are higher than 4,215 meters (13,830 feet), the altitude of Mauna Kea, Hawaii. The total amount of air above the Polar Plateau is reduced an additional 20% or more by the combined effects of the Earth's rotation and the low temperatures.
• How many South Poles are there?
  
  • There are three South Poles. The first is the striped ceremonial pole where people have their pictures taken. The actual geographic pole is about 90 meters away along the 160 west longitude line.
  • The third pole is the south geomagnetic dip pole and is over 2,700 km from the geographic pole. In fact, it is currently not even on the Antarctic continent, but is off the coast near the French Dumont D'Urville station. The last time it was located (1986) it was at 65.30 S and 1400 E.
  • The geomagnetic pole wanders because of the motion of Earth's conducting fluid interior. In 1841, James Ross located this Pole for the first time to be over the continent at 75.50 S and 1540 E.
  • The south geomagnetic pole was not visited until 1909, when Australians Mawson, David, and McKay found that it had wandered 375 km north of Ross' position, heading for the sea at a rate of 5.5 km/yr.