semi Desert - a waterless, dry areas of the world where falls no more than 25 cm of rainfall per year.The most important factor in their formation is a breeze.However, not all deserts there is hot weather, some of them, on the contrary, considered the coldest regions on Earth.The representatives of flora and fauna in many ways adapted to the harsh conditions of these areas.
As there are deserts and semi-deserts?
reasons due to which there are deserts, there are many.For example, in the Atacama Desert there is little rain because it is located at the foot of the mountains that its ridges covered her from the rain.
Ice desert formed for other reasons.In Antarctica, the Arctic and the main mass of snow falling on the coast to inland areas virtually snow clouds do not reach.Rainfall generally varies greatly, for a snowfall, for example, the annual rate may fall.These are formed snow drifts hundreds of years.
hot desert differ the most diverse terrain.Only some of them are completely covered with sand.The surface is dotted with most pebbles, stones and other different breeds.Desert almost completely open to weathering.Strong gusts of wind picked up the wreckage of small stone and hit them on the rocks.
a sandy desert wind carries the sand on the territory, creating a wave-like deposits, which are called dunes.The most common type of dunes - dunes.Sometimes, their height can reach 30 meters.The ridge may have a height of sand dunes up to 100 meters and stretches for 100 km.
temperature regime
and semi-desert climate is quite varied.In some regions, daytime temperatures can reach 52 ° C mark.This phenomenon is due to the lack of clouds in the atmosphere, so do not save the surface from direct sunlight.At night the temperature is greatly reduced, which again is due to the absence of clouds, which are able to trap heat emitted from the surface.
in the hot desert rain - a rare phenomenon, but sometimes is the case of strong rains.After rain water is absorbed into the ground, and quickly runs off the surface, washing away particles of soil and pebbles in a dry channels, which are called wadis.
Location deserts and semi
on the mainland, which are located in the northern latitudes, deserts and semi-deserts are subtropical and temperate zones.Sometimes also found, and tropical - in the Indo-Gangetic Plain, in Arabia, in Mexico, in the southwestern United States.In Eurasia, extra-tropical desert areas located in the Caspian depression, on the Central Asian and South-Kazakh plain in a valley in Central Asia and the Persian highlands.Central Asian desert formations peculiar sharply continental climate.
In the southern hemisphere deserts and semi-deserts are less common.Here are some desert and semi-desert formations as Namibia, Atacama desert formation on the coast of Peru and Venezuela, Victoria, Kalahari desert Gibson, Simpson, the Gran Chaco, Patagonia, the Great Sandy Desert and semi-desert Karoo in the south-western Africa.
polar deserts are located on the islands of continental glacier regions of Eurasia, on the islands of the Canadian archipelago, in the north of Greenland.
Pets Pets deserts and semi-deserts in many years, the existence of such places have managed to adapt to the harsh climatic conditions.From cold and heat, they hide in underground burrows and eat mostly underground parts of plants.Among the fauna there are many species of carnivores: fox Fenech, jungle cats, pumas, coyotes and even tigers.The climate is desert and semidesert contributed to the fact that many animals perfectly developed thermoregulatory system.Some residents of the desert can withstand the loss of fluid to a third of their body weight (eg, geckos, camel), and among invertebrates there are species that are able to lose water to two-thirds of its weight.
in North America and Asia found plenty of reptiles, especially lizards lot.Quite common as a snake: ephah, various poisonous snakes, boa.Of the large animals found saiga, Kula camels, pronghorn, recently disappeared Przewalski's horse (in captivity, it can still be found).
Animals deserts and semi-deserts of Russia - it is a great variety of unique fauna.In the desert regions of the country inhabited by rabbits, sandstone, hedgehogs, wild ass, Jamaal, poisonous snakes.In the deserts, which are in Russia, you can also find 2 species of spiders - Black Widow and Tarantula.
In polar deserts inhabited by polar bears, musk ox, arctic fox, and some species of birds.
Vegetation
Speaking of vegetation in deserts and semi-deserts are found various cactus, zhestkolistye grasses, shrubs, psammophytes, ephedra, acacia, Haloxylon, soap tree, the date palm, and other edible lichen.
deserts and semi-deserts: soil
soil, as a rule, poorly developed, its composition is dominated by water-soluble salts.Among the parent rocks is dominated by ancient alluvial and loess deposits that recycled winds.Gray-brown soil is inherent to the elevated plains areas.For deserts and salt flats are characterized, that is the soil, which contain about 1% soluble salts.In addition to the deserts, salt marshes are also found in the steppes and semi-deserts.Groundwater, which contain salts, when reaching the surface of soil deposited in an upper layer, resulting in the salinity of the soil.
Completely different types of soil characteristic of such climatic zones as subtropical deserts and semi-deserts.The soil in these areas has a specific orange and brick red.Honour your shades she received appropriate name - krasnozems and zheltozemy.In the subtropical belt in North Africa and in South and North America have desert where gray soils formed.In some tropical desert formations formed red-yellow soil.
Natural areas of deserts and semi-deserts - is a huge variety of landscapes, climate, flora and fauna.Despite the harsh and cruel nature of deserts, these areas have become home to many species of plants and animals.
