Today, the People's Republic of China is divided into 23 provinces, five autonomous regions, four municipalities directly under the Central Government, and two special administrative regions. Tibet is one of the five autonomous regions, featuring autonomy mainly by the Tibetan race.

Location & Area

The Tibet Autonomous Region in southwest China forms the southwestern portion of the Qinghai-Tibet Plateau. It adjoins the Xinjiang Uygur Autonomous Region and thc provinces of Qinghai to the north, Sichuan to the east and Yunnan to the southeast, and the nations of Myanmar, India, Bhutan. Sikkim and Nepal to the south and west along an international border of nearly 4,000 kilometers. The 1.22-million-square-kilometer autonomous region accounts for 12.8 percent of China's total land area.

Topography & Mountain Ranges

Averaging more than 4,000 meters in elevation. Tibet forms the main part of the Qinghai-Tibet Plateau and is known as the "roof of the world". While the topography is complex, the area can be divided into three distinct natural zones:

• The North Tibet Plateau in the north, which, accounting for two-thirds of the region in area, is surrounded by the Kunlun, Tanggula, Kangdese, and Nyainqentanglha mountains;
• The Tibet Valley in the south, where the Yarlung Zangbo River and its tributaries flow;
• High Mountains and Deep Valleys in the east, including part of the Hengduan Mountains, which run east-west and then north-south.

  Geomorphologically, there are six principal forms: polar altitude mountains, alpine mountains, medium-height mountains, low mountains, hills and plains. Volcanic, aeolian, karst and periglacial landforms are found as well.

  The Himalayas are a group of mountain ranges running roughly parallel to one another in an east-west direction on the southern edge of the Tibet Plateau along China's border with India and Nepal. The mountains run for 2,400 kilometers at a width of 200 to 300 kilometers and altitudes averaging over 6,000 meters. Mount Qomolangma, the world's highest peak with an elevation of 8,848.13 meters, rising abruptly on the Sino-Nepalese border midway through the range. Four peaks each with an elevation of over 8,000 meters and 38 peaks each over 7,000 meters can be found in the more than 5,000 square kilometers surrounding Qomolangma.

  Rivers & Lakes

  More than 20 rivers with drainage areas in excess of 10,000 square kilometers and more than 100 with drainage areas of more than 2,000 square kilometers are found in Tibet. Best known are the Jinshajiang, Nujiang, Lancangjiang and Yarlung Zangbo rivers. Tibet has more rivers flowing into foreign countries than any other
  Chinese provinces, municipalities directly under the Central Government and autonomous regions. Great rivers of Asia that find their origin in Tibet include the Ganges, Hindus, Brahmaputra, Mekong, Salween and Irrawaddy. These rivers for the most part arise from rains, melted ice and snow and underground water, hence their water is of excellent quality, their flow rate high and siltage low.

  The Yarlung Zangbo River, the largest of its kind in Tibet, has its source in the Gyimayangzong Glacier at the northern foot of the Himalayas in Zhongba County. After flowing through Lhoyu and entering India it is known as the Brahmaputra. The 2,057- kilometer Chinese portion, with a drainage area of more than 240,000 square kilometers at an approximate average altitude of 4,500 meters high, is the world's highest-altitude river.

  The 370-kilometer Yarlung Zangbo Grand Canyon, with a depth of 5,382 meters, the world's deepest, is only 74 meters wide at the narrowest point along its base and 200 meters at the widest.

  The vast Tibet Plateau is bejeweled with more than 1,500 large and small lakes; the Nam Co, Siling Co and Zhaxi Namco are larger than 1,000 square kilometers and 47 other lakes are larger than 100 square kilometers. All told there are 24,183 square kilometers of lakes, about one-third of China's total. The Tibet Plateau is the area in China with the most dense concentration of lakes; in terms of number, area and altitude of lakes it leads all the world's plateaus. Most of these lakes are saline. Seventeen, all larger than 50 square kilometers, are located about 5,000 meters.

  Climate

  The Tibet Plateau's various complex topographies and landforms engender a distinctive climate. Beyond the general tendency of a cold, dry northwest and a warm, wet southeast, can be found a wide variety of localized climates and distinct vertical climatic belts. Two sayings "different weather five kilometers apart" and "four seasons in one day" well describe this phenomenon.

  Tibet has thinner air, more sunlight, lower temperatures and less precipitation than other areas in China. The air contains only 150 to 170 grams of oxygen per cubic meter, 62 to 65.4 percent the rate found in plains areas. Solar energy is more readily available than elsewhere nationally, with more than one-third to even double that available in plains area at the same latitude. There are also more hours of daylight than elsewhere in China; in Lhasa there are 3,021 hours of daylight annually. Daytime and nighttime temperature vary greatly, despite low average temperatures and low annual temperature differentials. Average temperatures and peak temperatures for the hottest month in Lhasa and Xigaze are 10-15 degrees centigrade lower than in Chongqing, Wuhan and Shanghai at about the same latitude. Annual temperatures in Lhasa, Qamdo, Xigaze and elsewhere in Tibet range 18 to 20 degrees centigrade over the year. At elevations in excess of 5,000 meters in Ngari Prefecture, daytime temperatures in August climb above 10 degrees centigrade, only to fall below zero at night.

  Seasonal precipitation is disproportionately distributed throughout the region. The dry season and the rainy season are clearly demarcated. Rain usually falls at night. Annual precipitation is 5,000 millimeters in the lower elevations to the southeast decreasing gradually to a mere 50 millimeters in the northwest. Precipitation from October to April accounts for only l0 to 20 percent of the yearly total. Rainfall is concentrated in the period between May and September, accounting for about 90 percent of the yearly precipitation.