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Amazing Antarctica
Factfile |
 Amazing Antarctica |
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The Driest Continent |
Antarctica is the driest continent in the world and is therefore described by scientists as a `cold desert' as it receives less than the equivalent of 50 mm of rain a year.
Why is Antarctica so dry? As moist air approaches Antarctica, it cools, becomes denser and cannot hold moisture. With decreasing temperatures, this process continues, until there is no moisture left. Once this air reaches the continent, it is forced upwards into the colder atmosphere, due to the topography of the land. Any moisture that does remain in the air at this stage generally falls on the coast and the interior remains dry.
Ice shelf - British Antarctic Survey
Scientists know that Antarctica's great ice sheet has a huge effect on the global climate and for that reason, the stability of the ice sheet is a matter of concern. There are two types of ice to be found In Antarctica and both are scientifically important:
- Continental Ice - This is made of fresh water and has formed as a result of the snow in Antarctica, building up in layers and being compressed under its own weight. Continental ice can reveal to scientists, information about the Earth's climate in the past. By drilling out ice cores, a unique environmental record can be obtained of Antarctica that stretches back more that 200,000 years.
- Sea Ice - This is made each winter when the Southern Ocean around Antarctica freezes. Antarctica's sea ice is important because in the ways that it interacts with the atmosphere. As well as varying between summer and winter the amount of sea ice depends on the weather. The sea ice in its turn influences the weather because there is so much of it in contact with the air.
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