The desert or arid climate It is a subtype of climate that is characterized by its dryness caused by the scarcity of annual rainfall; It only has an amount of rainfall that does not exceed 300 mm throughout the year. In this subtype of climate the evapotranspiration process is frequently carried out.
Evapotranspiration is the loss of localized moisture on a surface due to direct evaporation; To this is added the transpiration of the water found in the vegetation. This phenomenon causes the amount of rainfall to remain at 250 mm annually and can occur as a result of different factors..
For example, evapotranspiration can develop due to the arrangement in which the relief of a region is located, although it can also arise from a series of very cold marine currents that limit or prevent evaporation, damaging humidity levels. These factors generate ecosystems known as coastal deserts..
Desert climates are generally located near the tropics, with a latitude that ranges between 35 and 15 degrees. In addition, in these places you can find some particular specimens of flora and fauna, which have been able to develop despite the lack of water because they are species with a high capacity for adaptation..
Usually, when referring to deserts, they are usually associated with a large amount of sand and very hot temperatures; However, an arid climate also develops in Antarctica and the North Arctic since these regions receive very little humidity (this is usually presented in the form of snow).
In contrast to desert regions, there are some places where the opposite occurs. For example, the island of Fiji is one of the tropical areas with the highest amount of rainfall; it receives up to 120 inches of water a year, in contrast to deserts that only receive 10 inches of rain.
Likewise, the rains that fall in desert climates are sporadic and usually manifest in the form of an electrical storm. After precipitation occurs, streams and soils swell with water; however, it only keeps for a few hours as it evaporates easily.
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The regions with a desert or arid climate are considered some of the most inhospitable on planet Earth and have the following main characteristics:
The most outstanding characteristic of this type of climate consists of the lack of humidity or the dryness that develops in these places; therefore, not only is the soil very dry, but so is the air that is breathed there.
In most of these desert regions the percentage of evaporation is higher than that of precipitation, which leads to a net loss of moisture.
Even in some hot deserts the rain evaporates before reaching the ground. However, when certain downpours occur, some bursts of plant and animal life also develop, which allows certain areas to not be completely inhospitable..
Some deserts stay warm all year round; however, other arid areas can have very cold winters and hot summers. For example, the Sahara desert is hot all the time, while the Gobi desert - located in Tibet - does have both seasons..
Despite this, the winter temperatures these places experience do not reach freezing. In fact, even in the deserts of warmer regions they tend to have some cold nights because there is not enough vegetation to maintain the heat received during the day..
Consequently, an unprepared traveler who is exposed to an arid climate may die from heat stroke in the daytime or die of hypothermia at nightfall..
In places with arid climates, evaporation occurs more frequently than precipitation, which means that the soils hardly allow the gestation of plant life.
For example, in arid regions located in the Middle East, only eight inches of rain fall per year, while the amount of evaporation exceeds two hundred centimeters; that is, the amount of evaporation is up to ten times greater than the amount of precipitation.
The average temperature in arid regions is 18 ° C, although temperatures vary greatly 24 hours a day, between 20 and 30 ° C. These oscillations are due to the scarcity of vegetation, which produces a lot of heat on the ground during the day and cold at night..
These calculations only apply to hot deserts, since in arid or cold deserts the temperatures are excessively low: they can reach - 30 ° C.
Precipitation is not only scarce but also occurs irregularly. This scenario is due to the continuous influence of the so-called tropical anticyclones.
In semi-arid areas there are more than seven months of drought, while in deserts all months of the year remain dry.
Generally, rainfall occurs as heavy downpours that nourish desert rivers, known as wadis. However, these waters never reach the sea, since they dry up before the end of the journey. The wadis stay dry most of the time, until the rain returns.
The desert and warm climates can be located in the subtropical ridge, whose ecosystem develops in those low middle latitudes, between 20 and 35 degrees, both north and south of the globe..
In these regions the air steadily descends continuously; In addition, these are areas where high pressures promote arid and hot conditions. This context causes the sun's rays to penetrate very intensely.
When the climates are desert and cold, these are usually located in places that have a notable altitude, such as the Tabernas desert in Almería, located in Spain. Another example may be the climate of Leh, a city located in the Greater Himalayas..
Therefore, the location of desert and cold climates will not depend so much on latitude but rather on altitude. However, these deserts are more likely to manifest themselves in those places that are further from the tropics, distancing themselves from the equator line..
Desert or arid climates can maintain some variations depending on their location and their reliefs. Taking this into account, it can be said that there are the following types of arid climate:
These deserts are usually located in subtropical regions, where the sky is clear most of the year due to anticyclones and currents that descend permanently..
Within this category, the Pacific desert (located in South America), the Sahara, the Syrian desert, the Arabian desert and several regions of Australia stand out. The temperature in these regions is very high, as they reach 45 ° during the course of summer.
It should be noted that all the hot deserts in the world hold the record for the highest temperature recorded on the earth's surface. Likewise, these deserts have the greatest amplitude or daily thermal oscillation recorded..
During winter, hot deserts can reach zero degrees Celsius; however, this does not happen often.
This type of climate usually develops in Asia, so it is rare to find it in other parts of the world..
Cold deserts are located in temperate zones that face a kind of orographic shadow -that is, a mountainous cluster that prevents the introduction of clouds on the surface-, so rainfall is scarce..
There are several BWk deserts in the world, such as the Great Basin Desert (located in the United States), the Tibet Plateau, and the Gobi Desert in southern Mongolia. These deserts are characterized by having some quite warm days; however they never get as hot as deserts BWh.
In addition, these areas are exceptionally cold, winters are very dry and temperatures are always below zero degrees Celsius. An interesting fact about the BWk deserts is that they are much drier than the warm deserts and are located at a higher altitude..
Similar regions can be found within Antarctica and the Arctic; However, these are not classified as BWk deserts because they are considered phenomena typical of the polar climate.
In general, these climates are located along the western coastal extensions of most continents, maintaining a certain proximity to subtropical and tropical areas. In some cases BWN deserts can be found at high altitudes.
In some locations in South America this type of climate develops, for example in the Atacama desert, located in Chile..
The BWN has also been registered in the city of Lima- capital of Peru-, which makes it one of the driest cities on the globe. On the other hand, this climate is also brewing in North America on the California peninsula..
On the African continent, temperate desert climates develop in the coastal areas of Namibia, with special emphasis on Swakopmund, located on the Atlantic coast..
These climates are characterized by having much more moderate temperatures than those that develop in other deserts, which is due to the cold ocean currents that circulate through these areas..
In addition, the temperate desert climate has a continuous presence of fog and some low clouds, although these places have almost no annual rainfall..
In the first instance, to talk about the economic activities that take place in desert climates, it is necessary to establish what the population that inhabits these territories is like, since they are particularly difficult to inhabit. In this way you can better understand the economy of these places.
In general, the populations of the deserts are very scarce due to the arduous conditions that these natural environments imply..
Usually, this group of people tries to concentrate on the coasts, keeping close to the oases and the valleys produced by the rivers. Some of these desert communities are the Bushmen, the Bedouin -the best known-, the Tuareg, the Zenata and the Sanhaja..
One of the main characteristics of these communities is that they are usually mostly nomadic, since it is difficult to settle permanently in such hostile territories.
For example, the Bedouin support themselves by raising livestock, so they must continually move in search of food and water for their animals..
The main economic activities that occur in arid climates are basically based on grazing and hunting; in some cases, sedentary agriculture is practiced in areas with oases. These are the most traditional economic activities, not counting the influence of modern times.
The peoples of the desert are also dedicated to gathering nuts and water. In addition, they carry out commercial exchanges with other populations located in the oases. This lifestyle has been greatly affected by globalization and modernity..
Today tourism has become one of the most important economic activities in these hostile regions. This is because many travelers are interested in the peculiarities of ecosystems and the charm of oases; Likewise, tourists tend to show curiosity about the traditional customs of the desert.
As mentioned above, the vegetation that develops in arid or desert climates is very particular and scarce, since without water it is impossible for specimens to carry out photosynthesis..
As a consequence of this context, plant life has had to adapt to these arduous climatic conditions, which generates xerophilous specimens (fleshy, spiny and resistant plants).
A fairly common example is that of the cactus, whose ability to store the little water it receives makes it an ideal specimen for this type of climate..
When they are not xerophytic plants, a few weeds can be found along with certain types of short shrubs. In the oases it is possible to find a greater amount of plant life, such as palm trees and some trees that offer nuts such as dates..
In cold deserts it is more difficult to find plant life because they are much drier regions. In certain circumstances it is possible to find some bushes and bushes.
Like vegetation, animals that live in the hot desert have a remarkable capacity to store water and to conserve moisture in their bodies. Consequently, in deserts reptiles abound thanks to their thermal abilities; they are usually lizards or snakes.
You can also find various types of insects such as beetles and ants, along with some species of arachnids such as scorpions..
As for mammals, there are numerous desert rodents; they spend most of their time locked in their burrows to protect themselves from the sun.
These species usually emerge at night, when temperatures have dropped. These small mammals serve as food for scavengers.
The most common desert animals are the so-called camelids, which have two species: dromedaries and camels. These specimens withstand drought extensively and are used as a vehicle by local populations.
As for cold deserts, they are less generous with fauna: they only allow the existence of certain mosses, facilitating bacterial life. In the outermost areas of these deserts it is possible to find polar fauna, made up mainly of mammals whose skin acts as an insulator..
It is one of the most important deserts due to its extension, which makes it the widest hot desert in the entire globe..
Its surface has more than 9 065 000 kmtwo, which implies that it covers almost all of North Africa. As for its dunes, these can reach up to 190 meters in height. In Arabic language "Sahara" means "desert".
It is located in the United States and has an area of 409,000 kmtwo. It is the largest desert in this country since it covers almost the entire state of Nevada, half of Utah, and certain sectors of Oregon and California.
It is a cold desert where no rainfall occurs due to the Sierra Nevada cluster that is located in the west.
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