Most deserts lie between 15° and 35° north and south of the equator. They were created by air that rises over the equator and comes down over the Tropic of Cancer and the Tropic of Capricorn . All over the world many deserts lie in these regions.
• Land over the equator becomes very hot. The hot and wet air rises and it rains a lot in these areas.
• The air cools down and moves north– and southwards. It gets drier.
• The cool air sinks to the ground. It dries out over the Tropic of Cancer in the north and the Tropic of Capricorn in the south.
• Warm air near the surface moves back to the equator. These winds are called trade winds .