Search results
Results from the WOW.Com Content Network
Low levels of humidity in hot deserts contribute to high daytime temperatures, and extensive night time heat loss. The average annual temperature in hot deserts is approximately 20 to 25 °C, however, extreme weather conditions can lead to temperatures ranging from -18 to 49 °C. Rainfall generally occurs, followed by long periods of dryness.
The average annual precipitation in low latitude deserts is less than 250 mm. Relative humidity is very low – only 10% to 30% in interior locations, and even the dewpoints are typically very low, often being well below the freezing mark. Some deserts do not have rainfall all year round, they are located far from the ocean.
Some desert plants produce seed which lies dormant in the soil until sparked into growth by rainfall. With annuals , such plants grow with great rapidity and may flower and set seed within weeks, aiming to complete their development before the last vestige of water dries up.
Although no part of Earth is known for certain to be rainless, in the Atacama Desert of northern Chile, the average annual rainfall over 17 years was only 5 millimetres (0.20 in). Some locations in the Sahara Desert such as Kufra , Libya , record an even drier 0.86 mm (0.034 in) of rainfall annually.
The climate of the Sahara has undergone enormous variations over the last few hundred thousand years, [49] oscillating between wet (grassland) and dry (desert) every 20,000 years [50] (a phenomenon believed to be caused by long-term changes in the North African climate cycle that alters the path of the North African Monsoon, caused by an ...
Xeric shrublands can experience woody plant encroachment, which is the thickening of bushes and shrubs at the expense of grasses. [5] This process is often caused by unsustainable land management practices, such as overgrazing and fire suppression, but can also be a consequence of climate change.
A satellite image of the Sahara, the world's largest hot desert and third largest desert after Antarctica and the Arctic. Desert greening is the process of afforestation or revegetation of deserts for ecological restoration (biodiversity), sustainable farming and forestry, but also for reclamation of natural water systems and other ecological systems that support life.
Given the Earth's surface area, that means the globally averaged annual precipitation is 990 millimetres (39 in), but over land it is only 715 millimetres (28.1 in). Climate classification systems such as the Köppen climate classification system use average annual rainfall to help differentiate between differing climate regimes.