2) subtropical deserts,

3) cold winter deserts, and

4) cool coastal deserts.

The Largest Desert in the world

The two largest deserts on Earth are in the polar areas. The Antarctic Polar Desert covers the continent of Antarctica and has a size of about 5.5 million square miles. The second-largest desert is the Arctic Polar Desert. It extends over parts of Alaska, Canada, Greenland, Iceland, Norway, Sweden, Finland, and Russia. It has a surface area of about 5.4 million square miles.

Non-Polar Deserts

The rest of Earth’s deserts are outside of the polar areas. The largest is the Sahara Desert, a subtropical desert in northern Africa. It covers a surface area of about 3.5 million square miles. A list of more than twenty of the largest non-polar deserts can be found below.

When most people think of a desert, they imagine a landscape covered with sand and sand dunes. Although many deserts are sand-covered, most are not. Many desert landscapes are rocky surfaces. They are rocky because any sand-size or smaller particles on the surface are quickly blown away. Rocky deserts are barren wind-swept landscapes.

Most deserts receive so little precipitation that surface streams usually only flow immediately after rainfall – unless the stream has a source of water outside of the desert. Streams that enter a desert usually suffer major water losses before they exit. Some of the water is lost to evaporation. Some is lost to transpiration (taken up by plants and then released to the atmosphere from the plants). And, some is lost to infiltration (water soaking into the ground through the bottom of the stream channel).