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تقرير Deserts of the world


Deserts of the world

The Desert Biome
Deserts are places on earth that are characterized by little vegetation and rain. They are made up of sand or rocks and gravel. Deserts cover about one-fifth of all the land in the world. Most deserts lie along the Tropic of Cancer and Tropic of Capricorn, imaginary lines that lie north and south of the equator.

Deserts
The Middle East and North Africa make up the driest region of the earth. Nearly two thirds of the region is desert. A desert is land that receives an average of less than ten inches of rain per year. The Sahara of northern Africa is the largest desert in the world.

World’s Largest Deserts

Factmonster: Principal Deserts of the World

North American Deserts
North American Deserts

Sonora Desert

Sonoran Desert
The Sonoran Desert of Southern Arizona and Northwestern Mexico is well known for its beauty and many spectacular and grand cacti. The abundant cacti and other succulents simply defy the harsh climate with exuberant biodiversity.

Southwest Deserts
A traveler crossing overland from Los Angeles to Big Bend National Park in West Texas encounters three of North America’s four great deserts, each ecologically distinct and strikingly beautiful.

Great Basin Desert
The Great Basin Desert, the largest U. S. desert, covers an arid expanse of about 190,000 square miles and is bordered by the Sierra Nevada Range on the west and the Rocky Mountains on the east, the Columbia Plateau to the north and the Mojave and Sonoran deserts to the south.

Mojave Desert
The transition from the hot Sonoran Desert to the cooler and higher Great Basin is called the Mojave Desert. This arid region of southeastern California and portions of Nevada, Arizona and Utah, occupies more than 25,000 square miles.

The Chihuahuan Desert
Most of the Chihuahuan Desert — the largest desert in North America covering more than 200,000 square miles — lies south of the international border. In the U.S. it extends into parts of New Mexico, Texas and sections of southeastern Arizona. Its minimum elevation is above 1,000 feet, but the vast majority of this desert lies at elevations between 3,500 and 5,000 feet.

The Chihuahuan Desert Region
A desert region can be defined many ways. To a physical scientist such as a meteorologist, a desert can be defined as an area receiving an average annual rainfall of 10" or less.

Welcome to the Chihuahuan Desert
The Chihuahuan Desert is the easternmost and southernmost of the four North American deserts: the Great Basin Desert, the Sonoran Desert, the Mojave Desert, and the Chihuahuan Desert.

The Chihuahuan Desert
The Chihuahuan Desert is the easternmost, southernmost, and largest North American desert. Most of it is located in the states of Chihuahua and Coahuila in Mexico, but fingers of the Chihuahuan reach up into eastern Arizona, southern New Mexico, and Texas, and down to the states of Zacatecas, and San Luis Potosi in Mexico. This desert is quite large – about 175,000 square miles – making it bigger than the entire state of California.

White Sands Desert of New mexico
At the northern end of the Chihuahuan Desert lies a mountain ringed valley called the Tularosa Basin. Rising from the heart of this basin is one of the world’s great natural wonders – the glistening white sands of New Mexico.

Deathe Valley
Although Death Valley is in California, it’s right on the California-Nevada border, closer to Las Vegas than to Los Angeles. Apart from the unexpected snowcapped mountains of winter, it’s a lonely and arid place pockmarked with suspicious looking mounds and crackling salt flats, crisscrossed by crevassed earth and powdered with relentless sand dunes.

Death Valley National Park
Many first time visitors to Death Valley are surprised it is not covered with an endless sea of sand. Less than one percent of the desert is covered with dunes, yet the shadowed ripples and stark, graceful curves define "desert" in our imaginations.

OneWorld Magazine: Deserts of Our World
OneWorld Magazine would like you to experience the diversity and cultural richness of the world’s deserts, if only virtually. Over the next 4 weeks we will bring you a selection of articles, paintings, sculptures, poems and photographs of men and women who have been challenged by the uniqueness of a desert, defeated by its dimensions, rewarded by its remoteness. Our delivery is by no means comprehensive — for every grain of sand there is a desert word, a desert painting, a desert thought.

Asian Deserts
Gobi Desert

Middle Eastern/African Deserts
The Sahara Desert

Sahara Desert
Sahara Desert, is a great desert area, lying in Northern Africa, and the western portion of the broad belt of arid land ,extends from the Atlantic Ocean eastward past the Red Sea to Iraq.

Sahara Desert
Here’s a fact to challenge popular imagination: more people drown in the Sahara than die from exposure or thirst. It may not rain often and it may not rain long but, in the capricious ways of this vast inland plain, when it does rain, it rains with devastating ferocity.

Wadi Rum: Jordan
Catch a camel into the Wadi Rum desert and you’ll find yourself in ‘Heroic and Biblical Adventure’ country. You’d be forgiven for thinking that, at any moment, you’ll stumble across a bearded and besandalled Charlton Heston looking square-jawed and self-righteous. It was, after all, in this neck of the woods that seas got parted and the tribes of Israel did some serious wandering.

South American Deserts
Atacama Desert
The Atacama desert in Chile is as parched as a parson’s Sunday sermon. In fact, it’s the driest desert in the world. There are parts of it where rain has never been recorded and the precious little precipitation (1cm/0.3in per year) that does fall comes from fog.

Cold Deserts
Ultima Thule, Greenland
There’s nothing in the law books that says a desert has to be hot, sandy and unpleasant; it’s equally legitimate for a desert to be cold, icy and unpleasant. As long as it’s uncultivated and uninhabitable it makes the grade, desertwise, and Ultima Thule is a shoo-in.

Siberia, Russia
Think Siberia and think cold. Think hoarfrosted faces, howling wolves, frozen mountains, salt mines, human chain gangs and exile. Maxim Gorky once called it a ‘land of chains and ice’ and, until recently, the description still held good. Tsars and Party apparatchiks might have had opposing political ideologies but they were of one mind when it came to Siberia.

يتبع…

Deserts of the world

Desert
****************
Area – sq miles

Africa

Sahara
Northern Africa
3,320,000

Libyan
Libya, Egypt, and Sudan (part of Sahara)

Kalahari
Southwestern Africa
360,000

Namib
Southwestern Africa
52,000

Asia

Arabia
Southwestern Asia
900,000

Rub’al Khali
southern Arabian Peninsula
250,000

Gobi
Mongolia and northeastern China
500,000

Kara-Kum
Turkmenistan
135,000

Kyzyl-Kum
Kazakhstan-Uzbekistan
115,000

Takla Makan
northern China
105,000

Kavir
central Iran
100,000

Syrian
Saudi Arabia, Jordan, Syria, and Iraq
100,000

Thar
India and Pakistan
77,000

Dasht-e-Lut
eastern Iran
20,000

Australia

Great Victoria
Western and South Australia
250,000

Great Sandy
northern Western Australia
150,000

Gibson
Western Australia

Simpson
Northern Territory
56,000

North America

Great Basin
southwestern United States
190,000

Chihuahuan
northern Mexico
175,000

Sonoran
southwestern U.S. and Baja California
120,000

Colorado
California and northern Mexico

Yuma
Arizona and Sonora, Mexico

Mojave
southwestern United States
25,000

South America

Patagonian
southern Argentina
260,000

Atacama
northern Chile
54,000

يتبع …

Deserts of the world

A desert is a landscape form or region that receives very little precipitation

Deserts are defined as areas that receive an average annual precipitation of less than 250
mm (10 in). In the Köppen climate classification system, deserts are classed as (BW).

مقدمه

Geography

A satellite image of the Sahara, the world’s largest hot desert and second largest desert after Antarctica.
Deserts take up one-third of the Earth’s land surface.[1] They usually have a large diurnal and seasonal temperature range, with high daytime temperatures (in summer up to 45 °C or 113 °F), and low night-time temperatures (in winter down to 0 °C; 32 °F) due to extremely low humidity. Water acts to trap infrared radiation from $$$$ the sun and the ground, and dry desert air is incapable of blocking sunlight during the day or trapping heat during the night. Thus during daylight most of the sun’s heat reaches the ground. As soon as the sun sets the desert cools quickly by radiating its heat into space. Urban areas in deserts lack large (more than 25 °F/14 °C) daily temperature ranges, partially due to the urban heat island effect.
Many deserts are formed by rain shadows, mountains blocking the path of precipitation to the desert. Deserts are often composed of sand and rocky surfaces. Sand dunes called ergs and stony surfaces called hamada surfaces compose a minority of desert surfaces. Exposures of rocky terrain are typical, and reflect minimal soil development and sparseness of vegetation.

The snow surface at Dome C Station in Antarctica is a representative of the majority of the continent’s surface.
Bottomlands may be salt-covered flats. Eolian processes are major factors in shaping desert landscapes. Cold deserts (also known as polar deserts) have similar features but the main form of precipitation is snow rather than rain. Antarctica is the world’s largest cold desert (composed of about 98 percent thick continental ice sheet and 2 percent barren rock). The largest hot desert is the Sahara.
Deserts sometimes contain valuable mineral deposits that were formed in the arid environment or that were exposed by erosion. Because deserts are so dry, they are ideal places for artifacts and fossils to be preserved.

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