Arid areas - Factors effecting aridity

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  • Created by: hamishc
  • Created on: 11-04-16 17:58
How does latitude affect aridity?
Sub-tropical high pressure cells found 30 degrees N & S of the equator causes air to fall, compress and dry out. Subsiding air also prevents convection.
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How do offshore winds affect aridity?
Prevailing winds blow from land to sea, carrying little moisture
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How does continentality affect aridity?
Areas in the centre of land masses are dry as they are remote from rain bearing winds which carry moisture from the sea
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How does relief affect aridity?
Mountain ranges force rain bearing winds to rise on the windward side, air cools and condeses causing precipitation. Leeward side is dry as most moisture has been lost to foehn affect.
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How do cold offshore currents affect aridity?
Air above the cold current is chilled drying the air as cold air holds less moisture, limiting rainfall. However cold air causes advection fog (which is trapped under and inversion layer), fog travels inland but quickly dissipates.
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Explain the Hadley cell process
At the equator (ITCZ), intense heating occurs due to overhead sun, air rises, cools, condenses and spreads outwards at the tropopause, at 30 degrees N &S of the equator, air begins to sink and compress, making it warmer and dryer (high pressure).
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What is the polar front?
50 - 60 degrees N &S of the equator, cool air from the poles meets warm air from sub-tropical high pressure cells causing precipitation
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How do seasons occur in arid areas?
The Hadley cell shift seasonally with the migration of overhead sun between the tropics, thus the ITCZ moves seasonally to semi-arid areas, bringing convectional rainfall and flooding
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Other cards in this set

Card 2

Front

How do offshore winds affect aridity?

Back

Prevailing winds blow from land to sea, carrying little moisture

Card 3

Front

How does continentality affect aridity?

Back

Preview of the front of card 3

Card 4

Front

How does relief affect aridity?

Back

Preview of the front of card 4

Card 5

Front

How do cold offshore currents affect aridity?

Back

Preview of the front of card 5
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