Competitive Exams: Climatology Anticyclone Winds

Temperate Cyclone

It is also called ‘Depressions’ It has low pressure at the centre and increasing pressure outward. It has varying shapes such as near circular, elliptical or wedge, therefore, it is also called Low or Troughs or Mid Latitude Depressions.

Secondly, they are formed in the regions extending between 35 degree to 65 degree latitudes in both the hemispheres.

Thirdly, Tropical Cyclone is confined strictly over sea, whereas Temperate Cyclone form over both land and sea.

Fourthly, Tropical cyclone is produced in summer and autumn and Temperate cyclone largely in winter.

Fifthly, Temperate cyclone has low pressure gradient, whereas tropical cyclone has steep pressure gradient; and

finally, rainfall in temperate cyclones is slow and continuous, whereas in tropical cyclone the rainfall is violent and torrential.

Anticyclone

A system of atmospheric pressure in which the isobars on a synoptic chart indicate a relatively, highpressure in the centre and decreasingly low pressures outwards to the periphery of the system. The isobars are generally widely spaced, indicating light winds which may be absent near the centre. Air movement is clockwise in the Northern hemisphere and anticlockwise in the Southern hemisphere. The term anticyclone was coined by Galton in 1861 Anticyclones do notexperience any precipitation and tend to be dry. It is characterized by larger, slow moving and more persistent with a high pressure at the centre but with a weaker pressure gradient and light variable winds diverging from the centre.

  • They are usually circular in shape but sometimes also assume V shape.

  • They are much larger in size and area than temperate cyclones as their diameter is 75% larger than that of the latter.

  • Anticyclones do not have fronts.

  • Winds descend from above at the centre and thus weather becomes clear and rainless.

Fohn Winds

(Latin: Meaning growth) A warm and relatively dry wind which descends on the leeward side of a mountain range. Fohn winds are:

  • Chinook-Andes and Rockies
  • Yamo-Japan
  • Tramontane-C. Europe
  • Samun-Iran
  • Norwester-New Zealand
  • Berg-S. Africa
  • Santa Ana-California
  • Zonda-Argentina

Depression Winds

A moving wind involves air masses originating both on its poleward and equatorward side, therefore, both warm and cold wind result.

Depression winds are:

Warm Winds

  • Sirocco-Italy
  • Leveche-Australia
  • Khamsim-Egypt
  • Gibli-Tunisia
  • Brickfielders-Victoria (Australia)

Cold Winds

  • Southerly Burster-New South Wales
  • Pampero-Argentina
  • Friagem or Surazo-Brazil
  • Papagayo-Mexico
  • Mistral-Rhone Valley (France)
  • Levanter-West Mediterranean
  • Etesian-East Mediterranean
  • Bora-Adriatic Coast
  • Convectional Wind: They are basically desert winds with dusty and gusty surface winds
  • Karaburan-Tarim Basin
  • Haboob-Sudan
  • Harmattah-West Africa

Tornadoes: A rapidly rotating column of air developed around a very intenselow pressure centre. It is associated with a dark funnel shaped cloud and with extremely violent wind blowing in a counterclockwise spiral; but accompanied by violent down draughts. Common in USA.

Zones

There are four principal climate regions:

  1. Tropical (hot)

  2. Subtropical (warm)

  3. Temperate (cool)

  4. Polar Regions (cold)