What is the desert?

Deserts are often defined as areas that receive less than 10 inches of average annual rainfall, but a more accurate defining factor is aridity. In addition to low rainfall, deserts are characterized by a high rate of water loss from the ground (evaporation) and through plants (transpiration). read more

In deserts the rate of potntial evapotranspiration exceeds the average annual rainfall by factors ranging from 2:1 to 33:1 or more. In other words, a desert is arid. Another characteristic of a desert environment is the uneven and unpredictable nature of the little precipitation that occurs. read more

A desert is a barren area of landscape where little precipitation occurs and consequently living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to the processes of denudation. read more

Cacti dominate the Sonoran Desert vegetation near Tucson, Arizona. (Photograph by Peter Kresan) Approximately one-third of the Earth's land surface is desert, arid land with meager rainfall that supports only sparse vegetation and a limited population of people and animals. read more