ZHENG Du, ZHAO Dongsheng
Based on integrated scientific expeditions to the Tibetan Plateau since the 1950s, this study analyzes the basic characteristics of the natural environment of the Tibetan Plateau (TP). It is shown that the TP is the highest in the three major landform ladders of China, with an average elevation of more than 4000 m above the sea level. Therefore, the TP is called the "roof of the world". The TP covers a vast land with a total area of 2.5×106 km2, accounting for a quarter of the total territory of China. Because of strong uplifting since the Neogene, the TP has unique natural environmental characteristics distinctive from other regions in the world, including the high landform, the cold climate, the strong solar radiation, numerous rivers and lakes, the extensive glacier and permafrost and the abundant biodiversity. Owing to its gigantic area, the TP also enjoys a great variety of the natural environment in its interior, with a certain regional differentiation regulation. According to the principle and the methodology of the physio-geographical regionalization of the plateau, the TP could be divided into 10 physio-geographical regions of similar terrains, climates, and vegetation types, which are the Guoluo-Naqu Plateau mountain alpine shrub-meadow region, the Southern Qinghai Plateau and wide valley alpine meadow-steppe region, the Qiangtang Plateau lake basin alpine steppe region, the Kunlun high mountain and plateau alpine desert region, the Western Sichuan and Eastern Xizang high mountain and deep valley coniferous forest region, the Qilian mountains of eastern Qinghai high mountain and basin coniferous forest and steppe region, the Southern Xizang high mountain and valley shrub-steppe region, the Qaidam Basin desert region, the North Kunlun mountain desert region, and the Ngali mountain desert region.
