The Algerian territory is composed of three terrestrial spaces, from the North to the South :
- the tell : discontinuous plain, of variable wide ( 80 km to 190km), with adjoining valleys, and constituted of fertile lands. It represents 4% of the total area of the country.
- The high plateaus : covering 9% of the area, they are announced by two important chains of mountains crossing the country from the east to the west, the Atlas of the tell in the North and the Saharan Atlas with the massif of the Aures in the South. The high plateaus constitute a semi-desert region in form of basin, bringing about in this way the existence of many salted lakes called chotts, which collect superficial waters.
The Sahara in the South of the Saharan Atlas : the biggest desert of the world, it occupies an area of 87% of Algeria and it is composed of rocky plateaus, Tassili N’Adjer and stony plains, Reg Tanezrout, punctuated of beautiful and luxuriant oasis. It contains as well two big groups of dune relieves, the western Grand Erg and the eastern Grand Erg, ending by the Massif of the Hoggar, succession of a very big relieves with indented profile, sculpted in volcanic rock and rising up terraced, to more than 2918 to Tahat, in the North of Tamanrasset.
The climate in Algeria is very diversified and varies from the temperate Mediterranean type to Saharan type, warm and dry. Thus, in the North, summers are mild with moderate temperatures of 25°C and winters are rainy and sometimes very cold, especially in altitude, with 11°c in average and important rains (400 mm to 100 mm of rain per year). In the high plateaus, the climate is arid and dry and records big difference of temperatures, that’s to say 36°C in average during the day and 5°C during the night, irregular and weak rains (from 200 to 400 mm per year), which decrease as fast as we enter in the Saharan South (less than 130 mm par year) where the temperature is about 49°C during the day and less than 10°C during the night. The aridity of the climate is increased by winds of sand.