Tibet

The Tibetan plateau lies between the Himalayan range to the south and the Taklamakan Desert to the north

The Tibetan Plateau, also known as the Qinghai-Tibetan (Qingzang) Plateau is a vast, elevated plateau in East Asia covering most of the Tibet Autonomous Region and Qinghai Province in the People's Republic of China and Ladakh in Kashmir. It occupies an area of around 1,000 by 2,500 kilometers, and has an average elevation of over 4,500 meters. Called "the roof of the world," it is the highest and biggest plateau in the world, with an area of 2.5 million square kilometers (about four times the size of Texas or France).^[1]

The Tibetan Plateau is surrounded by towering mountain ranges.^[2] It is bordered to the northwest by the Kunlun Range which separates it from the Tarim Basin, and to the northeast by the Qilian Range which separates the plateau from the Gobi Desert. In the south the plateau is delineated by the Yarlung Tsangpo River valley which flows along the base of the Himalayas, and by the vast Indo-Gangetic Plain. To the east and southeast the plateau gives way to the forested gorge and ridge geography of the mountain headwaters of the Salween, Mekong, and Yangtze rivers in western Sichuan. In the west it is embraced by the curve of the rugged Karakoram range of northern Kashmir.

NASA satellite image of the southern area of Tibetan Plateau

Description

The plateau is a high-altitude arid steppe interspersed with mountain ranges and large brackish lakes. Annual precipitation ranges from 100mm to 300mm and falls mainly as hailstorms. The southern and eastern edges of the steppe have grasslands which can sustainably support populations of nomadic herdsmen, although frost occurs for six months of the year. Proceeding to the north and northwest, the plateau becomes progressively higher, colder, and drier, until reaching the remote Kekexili region in the northwestern part of the plateau. Here the average altitude exceeds 5,000 meters (16,500 feet) and year-round temperatures average -4°C, dipping to -40°C in winter. As a result of this extremely inhospitable environment, the Kekexili region is the least populated region in Asia, and the third least populated area in the world after Antarctica and northern Greenland.

The northern part of the plateau is convered with large areas of permafrost, indicating the plateau has not completely emerged from the glacial period.^[3]

Geology

The plateau was formed by the collision of the Indo-Australian and Eurasian tectonic plates near the beginning of the Cenozoic era (approximately 55 million years ago).^[4] The tectonic uplift of the plateau is thought to have had a significant effect on climate change, and it is believed to affect the Asian monsoon. In the Indian monsoon season (June to October) when the winds bring humid, tropical air from the south, the Himalayas create a rain shadow which makes northern India very wet and keeps the Tibetan Plateau very dry. As the winds continue over the plateau, they drop what little moisture remains in the air, becoming drier as they move northwards and creating deserts such as the Taklamakan Desert and the Gobi Desert.^[5]

Several of the world's longest rivers originate on the Tibetan Plateau. Between them, these rivers carry 25% of the world's soil erosion to the sea. These include the Yangtze River (or Chang Jiang), Huang He (or Yellow River), Indus River, Satluj River, Yarlung Tsangpo River ( known as the Brahmaputra in India), Mekong, Irrawaddy River and the Salween River.

Its many brackish lakes include Tso Ngonpo, Nam Tso, Dagze Tso, Lake Yamzho Yumco, Lake Puma Yumco and Lake Paiku.

The Tibetan Plateau has experienced four glacial and three interglacial periods during which the climate warmed.^[6]

See also

• Geography of Tibet
• Taklamakan Desert
• Yunnan-Guizhou Plateau
• Lop Nur

Notes

1. ^ Natural World: Deserts. National Geographicc. Retrieved on 2007-07-23.
2. ^ A Unique Geographical Unit. Retrieved on 2007-08-05.
3. ^ Widespread Glaciers and Frozen Soil. Retrieved on 2007-08-06.
4. ^ The New Largest Canyon in the World --The Great Canyon of Yarlung Tsangpo River (Tibet). Retrieved on 2007-08-29.
5. ^ Leaf morphology and the timing of the rise of the Tibetan Plateau. Retrieved on 2007-07-23.
6. ^ Widespread Glaciers and Frozen Soil. Retrieved on 2007-08-05.

References

• The End of Earth's Summer
• Long Rivers and Distant Sources
• "Roof of the Earth" Offers Clues About How Our Planet Was Shaped

External links

• Tibetan Plateau Perspectives
• Leaf morphology and the timing of the rise of the Tibetan Plateau
• Todays weather in the eastern Chang Tang
• Protected areas of the Tibetan Plateau region
• North Tibetan Plateau-Kunlun Mountains alpine desertzh-classical:青藏高原

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