青藏高原对中国西部自然环境地域分异的效应

近几百万年以来青藏高原的强烈隆升对中国西部地区自然环境地域分异的影响十分明显。它强化了自第三纪以来西北地区的干旱化 ,形成山地湿岛与荒漠绿洲并存 ,导致亚洲干旱核心区域的出现。藏东南水汽通道作用显著 ,横断山区发育着独特的干旱河谷。山地垂直带谱类型的分布模式揭示了青藏高原自然景观的地带性分异规律 ;高原地势格局和大气环流的共同作用 ,制约着高原本身自然地域分异的特点 ,形成独特的自然地域系统格局。

QINGHAI-XIZANG PLATEAU AND ITS EFFECTS ON REGIONAL DIFFERENTIATION OF PHYSICAL ENVIRONMENTS IN WEST CHINA

The uplifting of the Qinghai-Xizang Plateau has exerted great influence on regional differentiation of physical environments in West China. It has strengthened desiccation in Northwest China since the Tertiary, bringing about the coexisting of mountain wet islands and desert oases as well as an arid core in Asia. As a moisture corridor, the Yarlung Zangbo river valley has played a significant role in Southeast Tibet. A number of unique dry valleys occur extensively in the Hengduan Mts. of southwest China. The distribution pattern of various altitudinal belt types reveals the zonal differentiation of natural landscapes of the Qinghai-Xizang Plateau. Under the combined action of its topographic framework and atmospheric circulation, the Qinghai-Xizang Plateau displays in succession the following spatial differentiation of physical environments from SE to NW: montane forest, alpine meadow, alpine/montane steppe and alpine/montane desert. According to temperature, moisture and landforms the Qinghai-Xizang Plateau can be divided into 2 temperature belts, 10 natural zones and 28 physical districts.