However, such factors as the temperature, humidity, rate of evaporation and evapotranspiration, and the moisture storage capacity of the ground have a marked effect on the degree of aridity and the plant and animal life that can be sustained. [107] Traditional means of overland transport declined with the advent of motor vehicles, shipping and air freight, but caravans still travel along routes between Agadez and Bilma and between Timbuktu and Taoudenni carrying salt from the interior to desert-edge communities. [17], Based on precipitation alone, hyperarid deserts receive less than 25 mm (1 in) of rainfall a year; they have no annual seasonal cycle of precipitation and experience twelve-month periods with no rainfall at all. A dessert is the sweet course at the end of a meal. Please refer to the appropriate style manual or other sources if you have any questions. Deserts have strong temporal variability in the availability of resources due to the total amount of annual rainfall and the size of individual rainfall events. In this now widely accepted system, extremely arid lands have at least twelve consecutive months without precipitation, arid lands have less than 250 mm (10 in) of annual precipitation, and semiarid lands have a mean annual precipitation of between 250 and 500 mm (10–20 in). [55] The Tassili Plateau in Algeria is an impressive jumble of eroded sandstone outcrops, canyons, blocks, pinnacles, fissures, slabs and ravines. About 40% of people infected with this fungus develop symptoms. The description of manna in the Bible matches what Danin found in the Sinai Desert. This desert also harbours several other plants and animals peculiarly adapted to the arid environment, suggesting that it might have a longer continuous history of arid conditions than most other deserts. Where these are found, oases can occur. It is one of Earth’s major types of ecosystems, supporting a community of distinctive plants and animals specially adapted to the harsh environment. Competitive interactions are weak. The Anza-Borrego Desert State Park in southeastern California is experiencing a "super bloom." It seems probable that with the onset of virtual life, the orientation of people and the very definition of ‘human’ will transform. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. [46] Across the world, around 20% of desert is sand, varying from only 2% in North America to 30% in Australia and over 45% in Central Asia. [27] Former desert areas presently in non-arid environments, such as the Sandhills in Nebraska, are known as paleodeserts. Desert pictures. [9] Other regions of the world have cold deserts, including areas of the Himalayas[10] and other high-altitude areas in other parts of the world. [14] The characteristics of hot deserts include high temperatures in summer; greater evaporation than precipitation, usually exacerbated by high temperatures, strong winds and lack of cloud cover; considerable variation in the occurrence of precipitation, its intensity and distribution; and low humidity. The desert of the real . They are often preceded by severe dust storms and occur when the wind velocity increases to a point where it can lift heavier particles. These include the horned viper of Africa and the sidewinder of North America, evolutionarily distinct but with similar behavioural patterns because of convergent evolution. [2] Phrases such as "desert island"[3] and "Great American Desert", or Shakespeare's "deserts of Bohemia" (The Winter's Tale) in previous centuries did not necessarily imply sand or aridity; their focus was the sparse population. It is the spread of arid areas caused by a variety of factors, such as climate change (particularly the current global warming) and overexploitation of soil as a result of human activity.. According to some definitions, any environment that is almost completely free of plants is considered desert, including regions too cold to support vegetation—i.e., “frigid deserts.” Other definitions use the term to apply only to hot and temperate deserts, a restriction followed in this account. Many mean annual temperatures range from 20-25° C. The extreme maximum ranges from 43.5-49° C. Minimum temperatures sometim… [37] In a really severe steady blow, 2 m (6 ft 7 in) is about as high as the sand stream can rise as the largest sand grains do not become airborne at all. People have struggled to live in deserts and the surrounding semi-arid lands for millennia. Is The Gobi Desert the largest desert in the world? When there are two directions from which winds regularly blow, a series of long, linear dunes known as seif dunes may form. A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. However, a significant degree of commonality exists among the plant families that dominate different desert vegetations. It is the hottest desert in the North American continent with air temperatures consistently rising above 118°F (48°C). One example is the bizarre conifer relative tumboa, or welwitschia, in the Namib Desert of southwestern Africa. In deserts, trees are usually absent, and shrubs or herbaceous plants provide only very incomplete ground cover. Tanks and armoured vehicles were able to travel large distances unimpeded and land mines were laid in large numbers. Wells are dug to extract water from the porous sandstone that lies underneath. [128], The desert is generally thought of as a barren and empty landscape. Desert fever: A disease also called coccidioidomycosis (CM) due to a fungus called Coccidioides immitis. Rounded mounds of sand without a slip face are the rare dome dunes, found on the upwind edges of sand seas. A lake occupied this depression in ancient times and thick deposits of sandy-clay resulted. Even today, there are several roads that go through western deserts like U.S. Route 50 through southern Nevada, and the Mojave Desert that feature … Deserts also probably existed much earlier, during former periods of global arid climate in the lee of mountain ranges that sheltered them from rain or in the centre of extensive continental regions. Generally deserts are defined as areas that receive an average annual precipitation of less than 250 mm (10 inches). Lizards and snakes are the most numerous in arid regions and certain snakes have developed a novel method of locomotion that enables them to move sidewards and navigate high sand-dunes. The Thar Desert near the India/Pakistan border is of this type. [12][13] A non-technical definition is that deserts are those parts of the Earth's surface that have insufficient vegetation cover to support a human population. Updates? Techniques that can be used include drip irrigation, the use of organic residues or animal manures as fertilisers and other traditional agricultural management practices. They then reproduce rapidly while conditions are favorable before returning to dormancy. [102] Other desert minerals are copper from Chile, Peru, and Iran, and iron and uranium in Australia. These larger particles anchor the other particles in place and may also be packed together on the surface so as to form a miniature desert pavement. mirage and Vision Synonym Discussion of mirage. [34], As the mountains are eroded, more and more sand is created. Ground water may be drawn to the surface by evaporation and the formation of salt crystals may dislodge rock particles as sand or disintegrate rocks by exfoliation. Desert plants maximize water uptake by having shallow roots that spread widely, or by developing long taproots that reach down to deep rock strata for ground water. The Sahara receives more sunshine per acre than any part of Europe. Desert farming is possible with the aid of irrigation, and the Imperial Valley in California provides an example of how previously barren land can be made productive by the import of water from an outside source. Erosion and sedimentation are high due to the sparse vegetation cover and the activities of large mammals and people. It can only take place during the day as energy from the sun is required, but during the day, many deserts become very hot. The whirling airborne grains act as a sand blasting mechanism which grinds away solid objects in its path as the kinetic energy of the wind is transferred to the ground. [102] Evaporites are found in the USA's Great Basin Desert, historically exploited by the "20-mule teams" pulling carts of borax from Death Valley to the nearest railway. A scene from one of my all time favorite movies - The Matrix (1999).All rights belong to their respective owners. When it has passed through the gut of a pronghorn it germinates readily, and the little pile of moist dung provides an excellent start to life well away from the parent tree. This is believed to be caused by the stresses put on the rock by repeated thermal expansions and contractions which induces fracturing parallel to the original surface. The Sahara Desert is of this type. [114], The Judean Desert was farmed in the 7th century BC during the Iron Age to supply food for desert forts. Real definition of desert 2 See answers sarveshcpr sarveshcpr Explanation: In geography, a desert is a landscape form or region that receives very little precipitation. By knowing back routes and the locations of oases and by utilizing camels, Muslim Arab forces were able to successfully overcome both Roman and Persian forces in the period 600 to 700 AD during the expansion of the Islamic caliphate. An area with dunes is called a dune system or a dune complex. The lack of vegetation exposes the unprotected surface of the ground to the processes of denudation. Repent definition is - to turn from sin and dedicate oneself to the amendment of one's life. Sand dunes in the Sahara, near Merzouga, Morocco. [105], The desert nomads were also traders. They reduce visibility and can remain in the atmosphere for days on end, conveyed by the trade winds for distances of up to 6,000 km (3,700 mi). The average precipitation in the Chilean region of Antofagasta is just 1 mm (0.039 in) per year. In many environments, the rate of erosion and run off increases dramatically with reduced vegetation cover. Deserts – regions where more water evaporates from the ground than is replaced by precipitation – are generally extremely hot, but some, like the Gobi in Asia, experience very cold winters. [124], Many centuries later, both world wars saw fighting in the desert. [72], Some desert plants produce seed which lies dormant in the soil until sparked into growth by rainfall. Other water from the river is piped to urban communities but all this has been at the expense of the river, which below the extraction sites no longer has any above-ground flow during most of the year. In such cases, of course, the spring or well could not be some mere trickle—it had to be … The River Nile, the Colorado River and the Yellow River do this, losing much of their water through evaporation as they pass through the desert and raising groundwater levels nearby. Real estate notes have been growing in popularity as a new type of investment product on the open real estate market. Leaching by ground water can extract ore minerals and redeposit them, according to the water table, in concentrated form. [51], The shape of the dune depends on the characteristics of the prevailing wind. [129], There is an extensive literature on the subject of deserts. [47] Where sand does occur, it is usually in large quantities in the form of sand sheets or extensive areas of dunes. [52], A large part of the surface area of the world's deserts consists of flat, stone-covered plains dominated by wind erosion. [102], Oil and gas form on the bottom of shallow seas when micro-organisms decompose under anoxic conditions and later become covered with sediment. [20] They usually feature BSh (hot steppe) or BSk (temperate steppe) in the Köppen climate classification. Some mineral extraction also takes place in deserts, and the uninterrupted sunlight gives potential for the capture of large quantities of solar energy. Many trade routes have been forged across deserts, especially across the Sahara Desert, and traditionally were used by caravans of camels carrying salt, gold, ivory and other goods.