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Antarctica

Of the seven continents on planet Earth—North America, South America, Europe, Africa, Asia, Australia, and Antarctica—the last lies at the southernmost tip of the world. It is the coldest, driest, and windiest continent. Ice covers 98% of the land, and its 5,100,000 sq mi (13,209,000 sq km) occupy nearly one-tenth of the Earth’s land surface, or the same area as Europe and the United States combined. Despite its barren appearance, Antarctica and its surrounding waters and islands teem with life all their own, and the continent plays a significant role in the climate and health of the entire planet.

Humans have never settled on Antarctica because of its brutal climate, but, since its discovery in the early 1800s, explorers and scientists have traveled across dangerous seas to study the continent’s winds, temperatures, rocks, wildlife, and ice. Scientists treasure the unequaled chance at undisturbed research; as travel to the continent improves, tourists enjoy the opportunity to visit the last “frontier” on the earth; environmentalists focus on Antarctica as the only continent largely unspoiled by human hands; and, in an increasingly resource-hungry world, others look at the continent as a key source of oil and mineral resources. While some countries have tried to claim parts of the continent as their own, Antarctica is an independent continent protected by international treaty from ownership by any one country.

Climate

Antarctica is the coldest and windiest place on Earth. The wind can gust up to 200 MPH (322 km/h), or twice as hard as the average hurricane. Surprisingly, little snow actually falls in Antarctica; because the air is so cold, the snow that does fall turns immediately to ice. Because of the way the Earth tilts on its axis as it rotates around the Sun, both polar regions experience long winter nights and long summer days. At the South Pole itself, the sun shines around the clock during the six months of summer and virtually disappears during the cold winter months. The tilt also affects the angle at which the Sun’s radiation hits the earth. When it is directly overhead at the equator, it strikes the polar regions at more indirect angles. As a result, the Sun’s radiation generates much less heat, even though the polar regions receive as much annual daylight as the rest of the world. Even without the wind chill, the continent’s temperatures can be almost incomprehensible to anyone who has not visited there. In winter, temperatures may fall to -100°F (-73°C). The world’s record for lowest temperature was recorded on Antarctica in 1960, when it fell to -126.9°F (-88.3°C).

The coastal regions are generally warmer than the interior of the continent. The Antarctic Peninsula may get as warm as 50°F (10°C), although average coastal temperatures are generally around 32°F (0°C). During the dark winter months, temperatures drop drastically, however, and the warmest temperatures range from -4 to -22°F (-20 to -30°C). In the colder interior, winter temperatures range from -40 to -94°F (-40 to -70°C). The strong winds that constantly travel over the continent as cold air races over the high ice caps and then flows down to the coastal regions, are called katabatic winds. Winds associated with Antarctica blizzards commonly gust to more than 120 mi (193 km) per hour and are among the strongest winds on Earth. Even at its calmest, the continent’s winds can average 50-90 mi (80-145 km) per hour. Cyclones occur continually from west to east around the continent. Warm, moist ocean air strikes the cold, dry polar air and swirls its way toward the coast, usually losing its force well before it reaches land. These cyclones play a vital role in the exchange of heat and moisture between the tropical and the cold polar air.

While the Antarctic sky can be clear, a white-out blizzard may be occurring at ground level because the strong winds whip up the fallen snow. The wind redesigns the snow into irregularly shaped ridges, called sastrugi, which are difficult to traverse. Blizzards are common on the continent and have hindered several exploration teams from completing their missions.

Surprisingly, with all its ice and snow, Antarctica is the driest continent on Earth based on annual precipitation amounts. The constantly cold temperatures have allowed each year’s annual snowfall to build up over the centuries without melting. Along the polar ice cap, annual snowfall is only 1-2 in (2.5-5 cm). More precipitation falls along the coast and in the coastal mountains, where it may snow 10-20 in (25-51 cm) per year.

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