What is a desert and how are they formed

(ORDO NEWS) — The standard used in many textbooks to define a desert is that it is an area that receives less than 10 inches (250 mm) of precipitation per year. But why is there so little water in these areas?

Geographically, most deserts are on the western sides of the continents or, in the case of the Sahara, Arabia, and Gobi deserts and the smaller deserts of Asia, are located far from the coast in the interior of Eurasia.

They tend to be found under the eastern sides of large subtropical high pressure cells. These huge wheels of wind spiral clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere in the subtropics over the oceans; however, their behavior affects nearby continents.

Moist rising air near the equator cools and condenses into clouds and then into rain. When the airflow moves towards the pole, the air releases most of its moisture.

By the time the current turns back towards the equator, the air is sinking. It shrinks and warms, and its relative humidity drops even more. Under these conditions, clouds and rain rarely form.

Add some wind to speed up evaporation at the surface, and the continental regions below become extremely dry due to the lack of available moisture. Thus, the deserts are almost completely dry.

You may think of heat and dunes when you think of the desert, but such areas can also be found in colder areas.

Temperatures in cold deserts such as the Atacama Desert in Chile and some Asian deserts located on the Eurasian steppe (such as the Karakum Desert in Turkmenistan) often drop below freezing during the cold months of the year.

In addition, there is one extremely large desert whose “sands” are actually water. This desert covers the whole of Antarctica, in the coastal regions of which about 200 mm of precipitation falls annually, but in the interior – no more than 50 mm.

For many people, the Sahara, covering an area of ​​about 8.6 million square kilometers, is the largest desert in the world; however, it is safe to say that in fact it is Antarctica with an area of ​​14,


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