The temperature of the Sahara Desert in North Africa reaches up to 50°C, but these regions are not always affected by the heat. For example, the Gobi Desert in Asia and the polar deserts of Antarctica and the Arctic are always cold.
So what else do we need to learn about deserts?
Deserts occur in three different ways.
The sun’s rays are reflected perpendicularly to the Equator, which means that solar energy is concentrated in that region. However, warm air coming from water and land masses rises, and this air has the capacity to hold more moisture compared to cold air that does not have moisture.
Additionally, oceans are abundant around the Equator, and the air carries not only heat but also water vapor. As the hot and humid air in those regions rises, it begins to cool and thus precipitation occurs due to condensation.
The air, which subsequently releases most of its moisture to the Equator, moves around the Equator towards the Tropics of Cancer and Capricorn. When the air reaches these latitudes, it loses much of its moisture and becomes quite dry.
This dryness and lack of rain, combined with complex air circulation patterns, causes deserts. This air circulation is also called Hadley cells.
In addition to Hadley cells, continentality is also the main cause of desert formation.
The concept of continentality refers to the distance of lands from the oceans and their climatic impact. In connection with this, when water evaporates from water bodies, it has a sinking effect on land. Areas close to bodies of water also receive most of this moisture.
Additionally, as the air moves inland, it loses much of its moisture. This causes air currents traveling long distances to lose moisture and dry out, thus causing desert formation in the inner parts of the region. For example, the Gobi and Takla-Makan Deserts are desert regions formed due to continentality.
Another reason is coastal cooling.
In fact, deserts can also form as the air warms or cools. As we mentioned before, cold air carries less moisture than warm air. Air at 30°C carries 30.4 grams of water per cubic meter.
Again, assuming that the air maintains 100% relative humidity and when the air drops from 30°C to 10°C, the existing humidity turns into 9.4 grams of water per cubic meter. In this case, a decrease in humidity to 31% is sufficient for desert formation.
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