Gobi Desert
The Gobi Desert is a large, cold desert and grassland region in southern Mongolia and North China. It is the sixth-largest desert in the world.
The name of the desert comes from the Mongolian word gobi, used to refer to all of the waterless regions in the Mongolian Plateau; in Chinese, gobi is used to refer to rocky, semi-deserts such as the Gobi itself rather than sandy deserts.
Geography
The Gobi measures from southwest to northeast and from north to south. The desert is widest in the west, along the line joining the Lake Bosten and the Lop Nor. Its area is approximately.Gobi includes the long stretch of desert extending from the foot of the Pamirs to the Greater Khingan Mountains, 116–118° east, on the border of Manchuria; and from the foothills of the Altay, Sayan, and Yablonoi mountain ranges on the north to the Kunlun, Altyn-Tagh, and Qilian mountain ranges, which form the northern edges of the Tibetan Plateau, on the south.
A relatively large area on the east side of the Greater Khingan range, between the upper waters of the Songhua and the upper waters of the Liao-ho, is reckoned to belong to the Gobi by conventional usage. Some geographers and ecologists prefer to regard the western area of the Gobi region : the basin of the Tarim in Xinjiang and the desert basin of Lop Nor and Hami, as forming a separate and independent desert, called the Taklamakan Desert.
Much of the Gobi is not sandy, instead resembling exposed bare rock.
Climate
The Gobi is overall a cold desert, with frost and occasionally snow occurring on its dunes. Besides being quite far north, it is also located on a plateau roughly above sea level, which contributes to its low temperatures. An average of about of rain falls annually in the Gobi. Additional moisture reaches parts of the Gobi in winter as snow is blown by the wind from the Siberian Steppes. These winds may cause the Gobi to reach in winter to in summer.However, the climate of the Gobi is one of great extremes, with rapid changes of temperature of as much as in 24-hour spans.
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In southern Mongolia, the temperature has been recorded as low as. In contrast, in Alxa, Inner Mongolia, it rises as high as in July.
Average winter minimums are a frigid, while summertime maximums are a warm. Most of the precipitation falls during the summer.
Although the southeast monsoons reach the southeast parts of the Gobi, the area throughout this region is generally characterized by extreme dryness, especially during the winter, when the Siberian anticyclone is at its strongest. The southern and central parts of the Gobi Desert have variable plant growth due to this monsoon activity. The more northern areas of the Gobi are very cold and dry, making it unable to support much plant growth; this cold and dry weather is attributed to Siberian-Mongolian high pressure cells. Hence, the icy dust and snowstorms of spring and early summer plus early January.
Conservation, ecology, and economy
The Gobi Desert is the source of many important fossil finds, including the first dinosaur eggs, twenty-six of which, averaging in length, were uncovered in 1923.Archeologists and paleontologists have done excavations in the Nemegt Basin in the northwestern part of the Gobi Desert, which is noted for its fossil treasures, including early mammals, dinosaur eggs, and prehistoric stone implements, some 100,000 years old.
Despite the harsh conditions, these deserts and the surrounding regions sustain many animal species. Some are even unique, including black-tailed gazelles, marbled polecats, wild Bactrian camels, Mongolian wild ass and sandplovers. They are occasionally visited by snow leopards, Gobi bears, and wolves. Lizards are especially well-adapted to the climate of the Gobi Desert, with approximately 30 species distributed across its southern Mongolian border. The most common vegetation in the Gobi desert is shrubs adapted to drought. These shrubs included gray sparrow's saltwort, gray sagebrush, and low grasses such as needle grass and bridlegrass. Due to livestock grazing, the amount of shrubs in the desert has decreased. Several large nature reserves have been established in the Gobi, including Gobi Gurvansaikhan National Park, Great Gobi A and Great Gobi B Strictly Protected Area.
The area is vulnerable to trampling by livestock and off-road vehicles. In Mongolia, grasslands have been degraded by goats, which are raised by nomadic herders as a source of cashmere wool.
Desertification
The Gobi Desert is expanding through desertification, most rapidly on the southern edge into China, which is seeing of grassland overtaken every year. Dust storms increased in frequency between 1996 and 2016, causing further damage to China's agriculture economy. However, in some areas desertification has been slowed or reversed.The northern and eastern boundaries between desert and grassland are constantly changing. This is mostly due to the climate conditions before the growing season, which influence the rate of evapotranspiration and subsequent plant growth.
The expansion of the Gobi is attributed mostly to human activities, locally driven by deforestation, overgrazing, and depletion of water resources, as well as to climate change.
China has tried various plans to slow the expansion of the desert, which have met with some success. The Three-North Shelter Forest Program is a Chinese government tree-planting project begun in 1978 and set to continue through 2050. The goal of the program is to reverse desertification by planting aspen and other fast-growing trees on some 36.5 million hectares across some 551 counties in 12 provinces of northern China.
Ecoregions
The Gobi, broadly defined, can be divided into five distinct dry ecoregions, based on variations in climate and topography:- Eastern Gobi desert steppe, the easternmost of the Gobi ecoregions, covering an area of. It extends from the Inner Mongolian Plateau in China northward into Mongolia. It includes the Yin Mountains and many low-lying areas with salt pans and small ponds. It is bounded by the Mongolian-Manchurian grassland to the north, the Yellow River Plain to the southeast, and the Alashan Plateau semi-desert to the southwest and west.
- Alashan Plateau semi-desert, lies west and southwest of the Eastern Gobi desert steppe. It consists of the desert basins and low mountains lying between the Gobi Altai range on the north, the Helan Mountains to the southeast, and the Qilian Mountains and northeastern portion of the Tibetan Plateau on the southwest.
- Gobi Lakes Valley desert steppe, ecoregion lies north of Alashan Plateau semi-desert, between the Gobi Altai range to the south and the Khangai Mountains to the north.
- Dzungarian Basin semi-desert, includes the desert basin lying between the Altai mountains on the north and the Tian Shan range on the south. It includes the northern portion of China's Xinjiang province and extends into the southeastern corner of Mongolia. The Alashan Plateau semi-desert lies to the east, and the Emin Valley steppe to the west, on the China-Kazakhstan border.
- Tian Shan range, separates the Dzungarian Basin semi-desert from the Taklamakan Desert, which is a low, sandy desert basin surrounded by the high mountain ranges of the Tibetan Plateau to the south and the Pamirs to the west. The Taklamakan Desert ecoregion includes the Desert of Lop.
Eastern Gobi desert steppe
As the border-range of the Hyangan is approached, the country steadily rises up to and then to. Here small lakes frequently fill the depressions, though the water in them is generally salty or brackish. Both here and for south of Ulaanbaatar, streams are frequent and grass grows more or less abundantly. Through all the central parts, until the bordering mountains are reached, trees and shrubs are utterly absent. Clay and sand are the predominant formations; the watercourses, especially in the north, being frequently excavated deep. In many places in the flat, dry valleys or depressions farther south, beds of loess, thick, are exposed. West of the route from Ulaanbaatar to Kalgan, the country presents approximately the same general features, except that the mountains are not so irregularly scattered in groups but have more strongly defined strikes, mostly east to west, west-north-west to east-south-east, and west-south-west to east-north-east.
The altitudes are higher, those of the lowlands ranging from, and those of the ranges from higher, though in a few cases they reach altitudes of. The elevations do not form continuous chains, but make up a congeries of short ridges and groups rising from a common base and intersected by a labyrinth of ravines, gullies, glens, and basins. But the tablelands, built up of the horizontal red deposits of the Han-gai which are characteristic of the southern parts of eastern Mongolia, are absent here or occur only in one locality, near the Shara-muren river. They are greatly intersected by gullies or dry watercourses. Water is scarce, with no streams, no lakes, no wells, and precipitation falls seldom. The prevailing winds blow from the west and northwest, and the pall of dust overhangs the country as in the Taklamakan and the desert of Lop. Characteristic of the flora are wild garlic, Kalidium gracile, wormwood, saxaul, Nitraria schoberi, Caragana, Ephedra, saltwort and the grass Lasiagrostis splendens. The taana wild onion Allium polyrrhizum is the main browse eaten by many herd animals, and Mongolians claim that this is essential in producing the proper, hazelnut-like notes of camel airag.
The vast desert is crisscrossed by several trade routes, some of which have been in use for thousands of years. Among the most important are those from Kalgan to Ulaanbaatar ; from Jiuquan to Hami ; from Hami to Beijing ; from Hohhot to Hami and Barkul; and from Lanzhou to Hami.