Pictures showing wind direction in an anti-cylcone (right) in both the southern and nothern hemisphere. Image by Phyical Geography

Pictures showing wind direction in an anti-cylcone (right) in both the southern and nothern hemisphere. Image by Physical Geography

ZIMSEC O Level Geography Notes: Anticyclones.

Features of anticyclones.

  • These are areas of high pressure at the center.
  • Air is sinking in the midst not rising which means no rain or clouds are formed because as the air descends and warms it can hold more moisture thus reducing its humidity.
  • They have small pressure gradients i.e. the pressure from the center decreases gradually.
  • This results in gentle winds.
  • The winds blow away from the center which has the highest pressure in an outward direction i.e. from the High pressure to the lower pressure regions.
  • Wind movement/deflection depends on whether the anticyclone is in the northern or southern hemisphere.
  • In the northern hemisphere-the winds blow in a clockwise direction.
  • In the southern hemisphere-the winds blow in an anti-clockwise direction.

Weather associated with anticyclones.

  • Low/little or no rainfall.
  • Clear skies.
  • Low humidity.
  • Low wind speed because the air will be dense.
  • High pressure.
  • Low temperature.
  • Stratus clouds.
  • Fogs/mist. Fog is found in highland areas and mist in lowland areas.
  • In winter frost may form at night.

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