Antarctica: The Frozen Continent
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The towering steamer Koonya as seen from the Nimrod, in a heavy sea storm. This particular wave came aboard the Nimrod and did considerable damage during Shackleton's Antarctic voyage in 1909. (NOAA Corps Collection)

Aurora Australis—surrealistic view of South Pole station with auroral curtain and exhaust emanating in curved line from the station. (NOAA Corps Collection)

 

 

Weather: Antarctica is the coldest place on earth, and the windiest. Why is it so cold? The ground in Antarctica receives much less of the sun’s energy than the tropics where the sun is nearly directly overhead. (See Differential Heating)

From the air, you see the continent is covered in snow and ice. That’s no surprise, since temperatures plunge to -85 and -90°C (-121 to -130°F) in the winter and about 30 degrees higher in the summer months. Ninety-eight percent of the land area is covered by ice sheets that can be up to 2 kilometers (over 6,500 feet) thick.

However, some areas along the coast and on slopes of the mountains have no ice. On warm days, the rock heats up, melting the surrounding ice and snow. As the water seeps down into cracks in the rocks, it freezes again and expands, cracking parts of the rock away. This results in all of the areas with no ice having piles of boulders and rocks.

The average yearly temperature at the South Pole is -48°C (-56°F) while at the scientific research facilities McMurdo or Palmer Stations the temperatures may be warmer. By comparison, the average yearly temperature in New York City is 12°C (55°F) and in Miami it is 24°C (76°F).

This range in temperature difference in Antarctica is primarily due to the fact that the continent is covered by near-darkness during the austral winter (northern hemisphere summer), and near continuous sunlight during the austral summer.

The two research stations are also located along the coast where the ocean waters influence the local climate and temperature.

The wind in Antarctica is also fierce, often at hurricane force for long periods of time. The combination of extremely low temperatures and high winds results in lower ‘effective’ temperatures, and large areas of the continent being devoid of plants or animals.

Classroom Activity from "Classroom Antarctica." Click here for a pdf version to work with yourself!

To estimate effective temperature, draw a line from the appropriate point on the top scale (air temperature) to the appropriate point on the wind-speed scale at the bottom. The effective temperature is the point at which the line crosses the middle scale. In the example, a wind speed of 30 km/h (bottom scale) lowers a temperature of minus 20°C (top scale) to an effective temperature of 31°C (middle scale).