* Average Annual Precipitation: The most common definition is less than 10 inches (250 mm) of rainfall per year. However, this is just a general guideline.
* Other Factors: Alongside rainfall, other factors are crucial:
* Evaporation Rate: Deserts often have high temperatures and low humidity, leading to very high evaporation rates. This means even small amounts of rain can quickly evaporate, leaving little moisture for plants and animals.
* Soil Type: Desert soils are often sandy and poorly drained, making it hard for plants to access and retain water.
* Plant Adaptations: Deserts support unique plants that are adapted to extreme dryness and heat. The presence of these adapted species is also a key indicator.
Examples:
* The Atacama Desert in Chile: It receives less than 0.004 inches (0.1 mm) of rain per year, making it the driest place on Earth.
* The Sahara Desert: It receives an average of 4 inches (100 mm) of rain per year, but some areas receive less.
In summary:
While 10 inches of annual rainfall is a good starting point, it's not the sole factor. The combination of low precipitation, high evaporation, poor soil quality, and adapted plant life all contribute to the definition of a desert biome.
