Tropical climate

A tropical climate is a climate of the tropics. In the Köppen climate classification it is a non-arid climate in which all twelve months have mean temperatures above 18 °C (64 °F). Unlike the extra-tropics, where there are strong variations in day length, and hence temperature, with season, tropical temperature remains relatively constant throughout the year.

[edit] Subtypes

Within the tropical climate zone there are distinct variations based on precipitation:

• Tropical rainforest climate (Af): All twelve months have average precipitation of at least 60 mm (2.4 in). These climates usually occur within 5–10° latitude of the equator. In some eastern-coast areas, they may extend to as much as 25° away from the equator. This climate is dominated by the Doldrums Low Pressure System all year round, and therefore has no natural seasons.
  • Examples:
    • Kuala Lumpur, Malaysia
    • Belém, Brazil
    • Hilo, Hawaii, United States
    • Georgetown, Guyana

• Tropical monsoon climate (Am): This type of climate, most common in southern Asia and West Africa, results from the monsoon winds which change direction according to the seasons. This climate has a driest month (which nearly always occurs at or soon after the "winter" solstice for that side of the equator) with rainfall less than 60 mm, but more than (100 − [total annual precipitation {mm}/25]).
  • Examples:
    • Conakry, Guinea
    • Chittagong, Bangladesh
    • Miami, Florida, United States
    • Cairns, Australia

• Tropical wet and dry or savanna climate (Aw): These climates have a pronounced dry season, with the driest month having precipitation less than 60 mm and also less than (100 − [total annual precipitation {mm}/25]).
  • Examples:
    • Mumbai, Maharashtra, India
    • Jakarta, Indonesia
    • Rio de Janeiro, Rio de Janeiro, Brazil
    • Veracruz, Veracruz, Mexico
    • Port-au-Prince, Haiti
    • Dar es Salaam, Tanzania
    • Lagos, Lagos State, Nigeria
    • Darwin, Northern Territory, Australia
    • Honolulu, Hawaii, United States

Note that, in this scheme, many places within the tropics do not have a tropical climate: for example, the Sahara desert. Mountaintops within the tropics, e.g. Mount Kenya, can be cold.

[edit] Intertropical Convergence Zone

Because of the effect of sun angle on climate most areas within the tropics are hot year-round, with diurnal variations in temperature exceeding seasonal variations. Seasonal variations in tropical climate are dominated by changes in precipitation, which are in turn largely influenced by the tropical rain belt or Intertropical Convergence Zone (ITCZ), a portion of the Hadley cell. The ITCZ is shown, for July average, in the graphic. Areas of ascending air have heavy rainfall; areas of decending air are dry. The ITCZ somewhat follows the solar equator throughout the year, but with geographical variations, and in some areas (India) is heavily influenced by local large-scale monsoon circulations.

[edit] References

1. ^ McKnight, Tom L; Hess, Darrel (2000). "Climate Zones and Types: The Köppen System". Physical Geography: A Landscape Appreciation. Upper Saddle River, NJ: Prentice Hall. pp. 205–211. ISBN 0-13-020263-0. 
2. "CHAPTER 7: Introduction to the Atmosphere". physicalgeography.net. http://www.physicalgeography.net/fundamentals/7v.html. Retrieved 2008-07-15.