Sahara Flashcards
(21 cards)
How much does the Sahara cover?
8.6 million km2
How many countries does the Sahara cover?
10 countries
Why did the Sahara form there?
Because of the air circulation patterns at this latitude
What are the air patterns like?
Air that rises at the equator usually loses moisture before it reaches the Tropic of Cancer and rainfall is low
What area is the Sahara in?
Area of high pressure - air descends there which prevents cloud formation and rainfall is low
What does the large temperature range in the Sahara affect?
Rocks - more vulnerable to thermal fracture and frost weathering
What does infrequent intense rainstorms mean for the desert?
That the fluvial processes caused by water operate intermittently but are powerful when they occur
What does the high temperatures and low rainfall mean for sediment?
Very mobile and can easily be eroded and transported by strong winds of the Sahara
How much does desert pavements make up of the Sahara?
70%
How much of the Sahara is covered by sand plains and dunes?
1/4
Where is the biggest deflation hollows in the world?
Qattara Depression in NW Egypt
How much does the Depression hollow cover and how below sea level is it?
18,100km2 and 133m below sea level
Why may of the Qattara depression form?
Salt weathering
What happens when rain falls in the Sahara?
Rapid runoff and water runs into ephemeral rivers and wadis
When were many wadis formed in the Sahara?
When it had a wetter climate
Name an example of Yardang in Sahara
Aorounge Impact Crater in Chad
Name some dunes in the Sahara?
Great Sand Sea
What is the Great Sand Sea?
An area of dune fields covering 72,000km2 of Western Egypt and Eastern Libya
How much of the Great Sand Sea is Seif dunes?
2/3
What do seif dunes form?
Parallel lines running roughly north to south because of prevailing winds
Where does the Sahara cover?
Northern Africa
