谈恋爱的三个阶段:撒哈拉沙漠 英文简介

Sahara Desert (ecoregion)
The Sahara Desert is an ecoregion covering part of the Sahara.

The Sahara is the world's second largest desert (Antarctica is the largest) and is located in northern Africa. It stretches from the Red Sea to the highlands of Ethiopia. However, the Sahara encompasses regions significantly different from an ecological perspective. The surface of the desert ranges from large areas of sand dunes (which are called erg), to stone plateaus (hamadas), gravel plains (reg), dry valleys (wadis), and salt flats. The northern and southern margins also receive more rainfall and have greater vegetation than central Sahara. The very scarse rain (less than 25 mm and even less than 5 mm per annum in the east) can fall in any season and in a very irregular way : some areas may receive no rain for years then suffer intense storms. Some areas encompass vast underground aquifers resulting in oases, while other regions severely lack water reserves. Some mountains (Ahaggar, Tassili N’Ajier, Tibesti, Aïr) also rise up in the desert and receive more rainfall and mostly present slightly cooler summer temperatures.

For such reasons, the great Sahara may be divided in several ecoregions and each of them be separately described. Other ecoregions are