The natural and historical development of the Qinghai-Tibet Plateau is extremely young. Influenced by many factors, it has formed the highest and youngest natural geographical unit in the world, with a close combination of horizontal zonality and vertical zonality.
The annual average temperature in the hinterland of the plateau is below 0℃, and the monthly average temperature in the warmest area is also below 10℃. The Qinghai-Tibet Plateau is generally between 3000 and 5000 meters above sea level, with an average elevation of more than 4000 meters. It is the birthplace of many rivers in East Asia, Southeast Asia and South Asia. There are many lakes on the plateau, including Namtso and Qinghai Lake.
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Water system status of Qinghai-Tibet Plateau
The distribution of rivers in Qinghai-Tibet Plateau is mainly influenced by climate and its own topography. Besides abundant precipitation in the southeast, rivers in inland areas mainly rely on the melting of glaciers or snow. Qilian Mountain-Bayankala-Nyainqentanglha Mountain and Gangdise Mountain are the dividing lines between internal and external water systems.
The boundary between the internal and external water systems divides the rivers on the Qinghai-Tibet Plateau into two parts: outflow area and inflow area. The outflow areas are mainly located in the east and southeast of the plateau, such as the Yellow River and the Yangtze River flowing into the Pacific Ocean, and the southwest water systems such as the Yarlung Zangbo River and the Nujiang River flowing into the Indian Ocean.
The internal water system is mostly located in the northwest of the plateau, mainly referring to Qiangtang Plateau, Qaidam Basin and some small closed lake basins. Most of the river water from inland rivers will be injected into these depressions, forming countless salt lakes.
Because the inflow area is blocked by tall mountains, warm and humid air is difficult to reach and precipitation is scarce; Sufficient sunshine makes the evaporation relatively large, so most inland rivers have small runoff and short process; Most inland rivers are mainly supplied by meltwater from ice and snow.
Therefore, the seasonal changes are obvious, summer is the flood season, winter is generally frozen, and water is often cut off, which means there are many intermittent rivers; Because most inland rivers flow into basins or depressions, a large number of salt lakes have been formed, such as the famous Qinghai Lake and Namco.
Baidu encyclopedia-Qinghai-Tibet plateau