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Why Is The Sahara So Dry?
One of the driest places on Earth
The Sahara is one of the driest regions on the planet. It receives very little rainfall, and the air is often devoid of moisture. Rain falls sparingly, and what moisture does form is often sucked off of the African coast in the form of tropical waves. This leaves the Sahara region hot, dry, and dusty. The Sahara has been known for centuries for its large seas of sand dunes. But why is the Sahara so dry? Why doesn’t rain fall over such a large region? Many deserts are formed by rain shadows caused by towering mountains, but there are no such mountains hemming in the Sahara. So what gives?
The reason that the Sahara is so dry actually has to do with something called Hadley Cells. This is a natural occurrence that takes place in the Earth’s atmosphere. Air around the equator, which is typically always warm, rises upward and then flows outward. When the air flows outward toward the poles, it cools, is caught by the Coriolis Effect, and then begins to sink in the subtropical regions.
Sinking air is known as subsidence, and it creates an extremely stable atmosphere. Stable atmospheres generate very little rainfall due to a lack of dynamics. One example of subsidence closer to home can be seen in the Bermuda High, a block of high pressure that always exists over the Bermuda Triangle and serves as a…
