Hot Desert Environment- Case Study


  • Northern Africa across tropic of Cancer
  • 6km2 across 10 countries



  • Climate: Air circulation causing little moisture over tropics & high pressure of descending air
  • Rainfall: Less than 100mm annual rainfall – mainly via thunderstorms after long periods of drought
    • Fluvial processes are intermittent but powerful
  • Temperature: More than 30oC annual temperature average,
    • Over 50oC in summer, 0oC freezing in winter, huge diurnal variations
    • High variation causes thermal fracture and freeze-thaw weathering
  • Winds: Prevailing winds from NE carry large amounts of dust
    • Chergui wind carries wind from S to N in Tunisia- hot & dry wind coming from Sahara Desert
  • Soil: Dry, little organic matter causing saline landforms
    • Sediment is very mobile due to erosion so can easily be transported and used for processes
  • Vegetation: Sparse with low diversity- Concentrations along wadis & depressions after rainfall – plants grow rapidly creating a temporary cover


Desert Landforms:

Name Process Example
Deflation Hollows Deflation- Aeolian Qattara Depression in Egypt is the biggest in world at 18100km2 and 133m below sea level at lowest point. Could have been started from a past stream valley and deepened by deflation and salt weathering


Wadis Erosion


Wadi Howar is 1100km long, created from the old Yellow Nile from 9500 to 4500 years ago and runs through Chad and Sudan
Yardangs Erosion


Yardans in the Aorounga Impact crater in Chad are formed from northeasterly prevailing winds
Dunes Deposition


The Great Sand Sea covers a 72000km2 area across Libya and Egypt. 2/3 are seif dunes running north to south from prevailing winds