青藏高原的自然环境特征

 本文基于1950年代至今青藏高原综合考察和研究成果，系统总结了青藏高原自然环境的主要特征。青藏高原是中国三大自然阶梯中最高一级，平均海拔超过4000 m，被称为“世界屋脊”。青藏高原土地辽阔，总面积约为250万km²，占中国陆地总面积的1/4。自新近纪以来强烈的隆升，使青藏高原自然环境明显区别于其他地区，形成了自己鲜明的特征，主要表现为海拔高、温度低、辐射强、河湖众多、冰川冻土广布、生物多样性丰富。青藏高原面积广大，高原内部的自然环境差异显著，并具有明显的区域分异特征，根据拟订的原则、方法和指标，青藏高原可划分为10个各具特色的自然区，包括：果洛那曲高原山地高寒灌丛草甸区、青南高原宽谷高寒草甸草原区、羌塘高原湖盆高寒草原区、昆仑高山高原高寒荒漠区、川西藏东高山峡谷针叶林区、青东祁连高山盆地针叶林草原区、藏南高山谷地灌丛草原区、柴达木盆地荒漠区、昆仑山北翼山地荒漠区、阿里山地荒漠区。

Characteristics of natural environment of the Tibetan Plateau

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.