Sahara the biggest Desert
 |
Posted by Mark Bond in Strange World section |
|
Sahara is with a size of 9 million km?, the world's largest desert. Its maximum length is 5,000 km, running from west to east. Sahara is covering Mauritania, Morocco, Algeria, Tunisia, Libya, Egypt, Sudan, Chad, Niger and Mali.
1,5 million people live in Sahara, most of these in Mauritania, Morocco and Algeria. Dominant groups of people are Sahrawis, Tuareg and Negroids. The largest city is Nouakchott, Mauritania's capital. Other important cities are Tamanrasset, Algeria and Ghat, Libya.
What makes the Sahara a desert?
The Sahara is one of the hottest places on Earth. Even though temperatures there may rise to 136 F (57.7 C), its dryness, not heat, that makes a place like the Sahara a desert. The frozen continent of Antarctica is so dry that some scientists consider it a desert, too.
As the world’s largest desert, the Sahara receives less than three inches (7.6 cm) of rain a year. Even in its wettest areas, rain may arrive twice in one week, then not return for years.
Wind has name
Many of the Sahara’s winds have names from ancient times:
Haboob is the Arabic name for a wild, sand-laden wind.
Khamsin, also Arabic, means “50 days.” This wind sweeps across the desert from March through May, filling the air with sand.
The name of the desert wind harmattan comes from a word in the West African language Twi that means “to tear your breath apart.”
Sahara is more than sand dunes
Sand dunes make up only about 15 percent of the Sahara, but the desert is so huge (about three and a half million square miles or 5.63 million sq km) that even a single dune may be enormous. The sand dune known as the Libyan Erg is as big as France.
About 70 percent of the Sahara consists of rocky plains covered with stones and gravel. Shale and limestone plateaus or mountain ranges make up the rest.
Just to remember....
Only 200,000 km? of Sahara are fertile oases, where dates, corn and fruits are grown. The spread of Sahara is part of a process starting at least 8,000 years ago, when this region was still fertile. The few fertile regions today are fed by underground rivers and underground basins. Oases are in almost all cases depressions (areas under sea level) where water pops up from underground.
|
