Tibet

I

Introduction

Tibet, former independent state and provincial-level administrative area of China, in the south-western part of the country. Officially Tibet (Chinese, Xizang) Autonomous Region, it is bounded on the north by Xinjiang Uygur Autonomous Region and Qinghai Province; on the east by Sichuan and Yunnan provinces; on the south by Myanmar, India, Bhutan, and Nepal; and on the west by India. Tibet is the highest region on Earth, having an average elevation of more than 4,875 m (16,000 ft); for this reason it is sometimes called the Roof of the World. It is also one of the world's most isolated regions, surrounded on three sides by vast mountain systems, namely the Himalaya on the south, the Karakorum Range on the west, and the Kunlun Mountains on the north. Tibet has a total area of about 1,200,000 sq km (463,320 sq mi). The capital and largest city of Tibet is Lhasa.

II

Land and Resources

The southern part of Tibet falls wholly within the Himalaya. Many of the world's highest summits are situated in the main Himalayan chain, extending along the entire southern frontier. Among the principal peaks are Mount Everest (8,850 m/29,035 ft), the world's loftiest mountain; Namzha Parwa (7,756 m/25,445 ft); and Gurla Mandhata (7,728 m/25,355 ft). Another Himalayan chain, commonly known as the Trans-Himalaya, lies parallel to the main chain on the north, and has peaks up to about 7,300 m (24,000 ft) in elevation. Between this chain and the main chain is a river valley region, which extends about 1,000 km (620 mi) from east to west. The Brahmaputra River (known in Tibet as the Yarlung Zangbo) flows from west to east through most of this region. The Trans-Himalaya chain slopes north to the Northern (or Tibetan) Plateau. This is a vast tableland extending to the Karakorum on the west and the Kunlun Mountains on the north. The Northern Plateau is broken by mountain outcroppings and has an average elevation of about 4,570 m (15,000 ft). It slopes gradually to the south and east. The eastern part of Tibet is a rugged region of numerous north-south trending mountain ranges, interspersed with deep valleys.

A

Rivers and Lakes

Tibet is the principal watershed of Asia and the source of many of the continent's major rivers. The Brahmaputra is Tibet's most important river. The Indus, Ganges, and Sutlej rivers have their headwaters in western Tibet. The Salween River (Nu Jiang) rises in central Tibet, and headwaters of the Mekong (Lancang Jiang), Yangzi (Chang Jiang), and Huang He (Huang Ho, or Yellow River) are found in northern Tibet. Many of Tibet's rivers have great potential for hydroelectric development. The Northern Plateau is dotted with numerous brackish lakes, including Ngangla Ringco in the west and Nam Co (Na-mu-ts'o) in the east.

B

Climate

Tibet has a semi-arid climate. The average annual precipitation is only about 381 mm (15 in) and is considerably less in many areas. The south-east has the heaviest precipitation. Temperatures in the mountains and plateaux are generally cold, and strong winds are a common year-round feature. The most equable climates are found in the river valleys. The average annual temperature is about 1.1° C (34° F); sudden drops in temperature after sunset are characteristic.