FLUVIAL EROSION NAME DESCRIPTION DIAGRAM EXAMPLE Pediments Pediments are desert plains - gently sloping areas of rock (usually covered in a thin layer of debris). They're formed by the erosion of rock by sediment carried in sheet floods or small streams. ...
Introduction: Northern Africa across tropic of Cancer 6km2 across 10 countries Characteristics: Climate: Air circulation causing little moisture over tropics & high pressure of descending air Rainfall: Less than 100mm annual rainfall - mainly via...
The degradation of land in arid areas by which fertile land becomes desert like 75 billion tonnes of soil eroded annually Human Causes: Overgrazing Reduces vegetation > soil erosion (due to lack of plant roots) Trampling by animals > compressed &...
Introduction: Desert margins are most vulnerable to desertification E.g Sahel Region of Sub Saharan Africa Causes: 80% of Burkino Faso live on water fed agriculture leading to over cultivation Irregular rainfall: 200-600mmpa with several droughts Fragile aridsols-...
: Deserts are open systems- generally in dynamic equilibrium Inputs: Water enters the system through infrequent rainstorms. Sediment can be carried into a desert system by wind or water. Energy: Insolation = the solar radiation that reaches the Earth Insolation is...
Aridity Index: Water balance = relationship between mean annual precipitaion (P) and potential evapotranspiration (PET). If P>PET = water surplus, vice versa = water deficit. In deserts, P<PET (water deficit). The size of the deficit (difference between P and...
Mechanical weathering: Rock is physically broken into smaller pieces in situ. Thermal fracture: Extreme temperatures in deserts (0-50OC desert air can't block sunlight or trap heat) During the day (when it's hot) rock expand and at night (when it's cold) they...