Tropical Desert

1
Tropical Desert

• Characteristics of various spheres
• Opportunities and constraints
• Human activities
• Human impacts
• - Desertification
• - Salinization
• - Change in Microclimate

2
A Scene of Tropical Desert
3
Another scene
4
Spatial Distribution

• Around 30 degrees N and S
• Western coast

5
Spatial Distribution of Tropical Desert

• High temperature
• Large annual range of temperature
• Low rainfall
• great variability
• convectional rain
• Pe gt P

6
Five Reasons to account for the high temperature

• High angle of incidence
• Long sunshine period
• lack of cloud cover
• lack of vegetation cover
• low atmospheric humidity
• (more sensible heat and less latent heat)

7
Limitations to plant growth

• Physical factors
• water deficiency
• marked extremes of temperature
• high soil temperature
• high evaporation rate
• accumulation of excessive amounts of salts, Na,
  Ca, Mg
• lack of soil organic matter and soil
  micro-organisms

8
Limitations to plant growth

• Antropogenic factors (Human)
• complete destruction of natural vegetation due to
  cultivation
• partial destruction (cutting, overgrazing)
• grazing of some ungrazed species in drier years
• increasing soil erosion

9
Soil Problems