OVERVIEW

This chapter focuses on the climates that are found between the tropic of cancer and the tropic of capricorn.

• Low latitude climates:
  • occupy the equatorial zone, much of the tropical zone and some of the subtropical zone.
  • include climates that range from very wet to very dry.
  • are influenced by the intertropical convergence zone, tropical easterly wind systems and the subtropical high-pressure cells.
  • experience travelling low pressure systems such as the easterly wave and tropical cyclones.
• The wet equatorial climate is characterized by:
  • dominance of he intertropical convergence zone (ITC).
  • mE and mT air masses.
  • uniform, very warm temperatures in all seasons.
  • ample precipitation, heaviest when the ITC is nearby.
• Monsoon and trade wind coastal climates are characterized by:
  • heavy rainfall with strong seasonal patterns.
  • a larger temperature range than the wet equatorial climate.
  • dominance of the ITC during the heavy rainfall period and the subtropical high pressure system during the dry season.
  • trade wind coast climates are a result of mT and mE air masses blowing onto coastal areas bringing large amounts of moisture.
  • the monsoon aspect of these climates is a result of the changing position of the ITC and reversing pressure gradients.
  • heavy rainfall is associated with the ITC and an airflow from ocean to land while the dry season is associated with airflow off the Asian continent to the ocean.
• The wet equatorial and monsoon and trade wind coastal climates produce the low-latitude rainforest with dense vegetation, numerous streams and a great diversity of plant and animal life.
  • Products and resources of the rainforest include lumber, drugs, rubber, and foods such as cassava, yams, taro, bananas, plantain and coconuts.
• The wet-dry tropical climate is characterized by:
  • a warm climate but with a more marked temperature range.
  • during the high sun season, proximity to the ITC brings heavy rains.
  • during the cooler period, the subtropical high pressure cell produces very dry conditions.
  • vegetation adapts to the seasonality of rainfall and is described as rain-green as it enters a dormant period during the dry season and leafs out and blooms in the rainy season.
  • dramatic variations in rainfall are reflected in streamflow which varies from very low flows to flood-like conditions.
  • agriculture experiences periodic drought.
• The dry tropical climate:
  • is dominated by the subtropical high-pressure cell.
  • experiences very low precipitation and intense daytime heating under predominantly clear skies.
  • includes many of the world's great deserts.
  • semi-arid areas on the edges of the desert may have a short wet season. These steppe areas are transitional from the desert to the wet-dry tropical climate.

KEY TERMS

wet equatorial     low-latitude       throntree-tall     
climate            rainforest         grass savanna      
intertropical      wet-dry tropical   savanna woodland   
convergence        climate            Sahel              
zone               cT air mass        land degradation   
mE air mass        subtropical        dry tropical       
mT air mass        high-pressure      climate            
monsoon            cell               highland climate   
tradewind coast    raingreen                             
                   vegetation                            

STUDY QUESTIONS

1. Describe the annual temperature and precipitation patterns for the wet equatorial climate.
2. What atmospheric circulation factors dominate the wet equatorial climate?
3. Describe the annual precipitation pattern for the monsoon and trade wind coast climates.
4. How is the trade wind coast climate different from the monsoon climate?
5. Describe the annual temperature pattern of the tropical desert climate.
6. What atmospheric circulation factors dominate the tropical desert climate?
7. How have plants adapted to the tropical desert environment?
8. How does climate impact agriculture and animal life on the savanna?
9. How do temperature and precipitation change as elevation increases?