Book 16, Question 48
Why Are There So Few Clouds Over Most Deserts?
Many deserts lie where air sinks down from high in the sky! Sinking air warms up and dries out, so clouds rarely form. That is why most deserts have so few clouds.
More fun facts
- Over land, about 30 percent of skies are completely free of clouds.
- Clouds tend to form where air rises, but sinking air makes it hard for clouds to form.
- Huge loops of moving air called Hadley cells rise near the equator and sink near 30 degrees north and south of it.
- Because air sinks between about 15 and 30 degrees north and south of the equator, clouds are rare there and deserts are common.
- Over the oceans, less than 10 percent of the sky is completely clear at any one time.
- Satellites like NASA's Aqua use special instruments to map clouds all over the planet, including over deserts.
Sources: NASA Science
Questions kids ask
What is the most common type of cloud?
Low, lumpy sheets called marine stratocumulus are the most common clouds by area, covering about one fifth of Earth's surface.