A desert is a stretch of land that can be rocky or sandy, might have zero to some vegetation, might be habitable or might not be live-able but most of all a desert is defined on the basis of amount of precipitation it receives. According to national geographic, a desert receives no more than 25 cm of rainfall per year. Now, let us have a look on the distribution of deserts in the whole world and the possible reasons of their occurrence in those places.
There are 5 types of deserts in the whole world-
- Sub tropical deserts- Due to high temperature in the equator, the air gets heated up and absorbs moisture and rise. It reaches high altitudes and the moisture precipitates and comes down as rains. The air cools and the heated air moves away from the equator reaching the tropics. Upon reaching the tropics it cools down and descends where it warms again. Thus it occupies the space meant for moisture laden air and there is no rains in the tropics leading to the formation of deserts in the region. Examples are The Sahara desert in Africa, the Arabian desert, the Syrian desert, the great Victorian desert in Australia, The Thar desert in India. The Sahara desert is the largest sub tropical desert
- Coastal deserts- These type of deserts are formed due to the cold oceanic currents that create low pressure in the surrounding regions and the moisture laden winds that should have travelled from the coasts to the continents ends up travelling away instead. Such deserts are formed in the western coasts of continents in lower and middle latitudes and in the eastern side in the upper latitudes (due to the anticlockwise flow of currents in Southern and the clockwise flow of currents in Northern hemisphere). Examples are the Namib deserts in Africa (formed due to Benguela current) and the Atacama desert in Chile (formed due to Peru current). Atacama desert is the driest desert in the world.
- Cold deserts and polar deserts- The cold and polar deserts are formed in the Temperate and polar region respectively. These regions are very cold and all the moisture immediately freezes to form ice. The cold deserts exist in regions of high altitude where moisture laden winds cannot reach. Examples are the Antarctic desert(the world largest desert), the Arctic desert, The Ladakh desert, Siberian desert
- Interior deserts- Interior deserts are found in the interior of the continents mostly the middle where sufficient moisture laden winds do not reach. Example is the Gobi desert that stretches along both China and Mongolia
- Rain shadow deserts-One another subdivision can be of those deserts where the mountains or any other physical feature act as a barrier for the moisture laden clouds. Example is the Death Valley for which four major mountain ranges(including the Sierra Nevada and Panamint Range, according to Wikipedia) act as a barrier and also The Gobi Desert for which the Himalaya act as a barrier(this river is the reason the yellow river appears yellow).
That’s all in deserts. Hit the like if you found it useful and share it among all those who might want to know something about deserts, after all they do form 1/3rd part (and increasing- desertification)of our earth’s continental mass.