Leaving Certificate: Desert Biome

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Discuss the characteristics of a biome you have studied.
Biomes are large world regions in which climate, soils, natural vegetation and animal life are all interrelated. The biome that i have studied is the desert biome. Dry Climate
Desert climate is very dry, with a yearly rainfall of between 0 and 250mm. Although deserts are very dry regions, very few deserts are completely dry. Parts of the Atacama Desert in Chile are said to be the driest places on earth. They receive an average of less than 15mm of rain per annum and sometimes receive no rain. Rainfall is as unpredictable as it is rare. When rain does occur it usually comes in the form of short, heavy downpours , which may affect small areas. Very limited precipitation can also occur in the forms of dew or fog. Sudden drops in temperature can cause night dews in parts of the Sahara. Fog sometimes brings limited moisture to narrow coastal areas were cold ocean currents flow offshore. Such fogs occur regularly on the coastal sand dunes of the Namib Desert in Africa. Some hot desert areas lie on the ‘horse latitudes’, high pressure belts that runs across much of the earth about 30° north and south of the equator. Air descends towards the earth along these high pressure belts. As it does so, the air becomes warmer. Warm air holds more water vapour than cooler air, so the descending air absorbs moisture. That is why high pressure brings prolonged dry conditions. Most hot desert regions are in path of the trade winds that blow over much of the earth from 30° latitude towards the Equator. As these winds blow towards the Equator, they become warmer. Warm air holds more water vapour than cold air can. The trade winds therefore absorb rather than emit moisture, and they are therefore dry winds. Occasionally, moisture-laden winds can blow in from the western seas towards the deserts, but these winds must pass over cold ocean currents. As they do so, they are cooled and lose almost all of their moisture – usually in...
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