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3 reasons for the dry conditions in central Antarctic​

User Simontemplar
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The driest place on Earth is in Antarctica in an area called the Dry Valleys, which have seen no rain for nearly 2 million years. ... The reason why this region receives no rain is due to Katabatic winds, winds from the mountains that are so heavy with moisture that gravity pulls them down and away from the Valleys.

The driest place on Earth is in Antarctica in an area called the Dry Valleys, which have seen no rain for nearly 2 million years. ... The reason why this region receives no rain is due to Katabatic winds, winds from the mountains that are so heavy with moisture that gravity pulls them down and away from the Valleys.Antarctica’s climate is also very windy and dry. Wind speeds vary across the continent and are discussed in Regional climate variation and weather; but the idea that Antarctica is a kind of desert requires some explanation here. The relative humidity of air at the South Pole is often as low as 0.03%, and the continent is a polar desert. This may at first seem surprising with 99% of its area being covered by ice; and Antarctica certainly doesn’t conform to the image that most people have of a desert. Yet, most of Antarctica is classed as a desert on the basis of its mean annual precipitation. What little precipitation there is mostly falls as snow, averaging less than 50mm a year (water equivalent) across much of the interior. This is in the ‘hyper arid’ category, shared with the Sahara, Namib, Atacama, and other great deserts of the world. The presence of so much ice despite such low precipitation is simply due to the fact that low temperatures cause even less ablation than accumulation (see Tectonic history: into the deep freeze and Ice sheets and glaciation for an account of the build up of the Antarctic Ice Sheet).

The driest place on Earth is in Antarctica in an area called the Dry Valleys, which have seen no rain for nearly 2 million years. ... The reason why this region receives no rain is due to Katabatic winds, winds from the mountains that are so heavy with moisture that gravity pulls them down and away from the Valleys.Antarctica’s climate is also very windy and dry. Wind speeds vary across the continent and are discussed in Regional climate variation and weather; but the idea that Antarctica is a kind of desert requires some explanation here. The relative humidity of air at the South Pole is often as low as 0.03%, and the continent is a polar desert. This may at first seem surprising with 99% of its area being covered by ice; and Antarctica certainly doesn’t conform to the image that most people have of a desert. Yet, most of Antarctica is classed as a desert on the basis of its mean annual precipitation. What little precipitation there is mostly falls as snow, averaging less than 50mm a year (water equivalent) across much of the interior. This is in the ‘hyper arid’ category, shared with the Sahara, Namib, Atacama, and other great deserts of the world. The presence of so much ice despite such low precipitation is simply due to the fact that low temperatures cause even less ablation than accumulation (see Tectonic history: into the deep freeze and Ice sheets and glaciation for an account of the build up of the Antarctic Ice Sheet).Although related, the terms climate and weather do have distinct meanings. This section focuses on the general climate characteristics of Antarctica as a whole, while the next section looks more specifically at regional differences in Antarctica’s climate and weather across the continent.

User John Ackerman
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