青藏高原人口地域分异规律及“胡焕庸线”思想应用

青藏高原是中国乃至全球典型的人口稀疏区之一,但内部人口地域分异明显。通过构建青藏高原乡镇街道尺度的人口空间数据集,系统核算青藏高原人口数量及其空间密度,从经度、纬度、极向和垂直4个维度解析青藏高原人口地域分异规律,并基于“胡焕庸线”思想,提出青藏高原的“祁吉线”人口地理划分方案。结论包括：① 青藏高原人口空间分布不均衡,具有“东南密、西北疏”的总体空间分布特征,距离“寒旱核心区”近疏远密的极向地域分异明显;② 青藏高原人口地域分异与海拔、土壤、水资源、气候、植被等自然环境本底具有高度耦合关系,自然因素间交互作用加强了人口地域分异;③ 青藏高原人口地域分异可以通过连接祁连县与吉隆县的“祁吉线”体现,两侧地域面积大致相同,但是东南半壁与西北半壁人口比例达到93∶7的悬殊;④ “祁吉线”长期稳定,但是东南半壁人口持续微降,西北半壁人口持续微增,未来时期,东南半壁依然是青藏高原城镇化及人类活动的主要区域,而西北半壁应当重视人口增长与生态环境压力的矛盾。

Regional differentiation of population in Tibetan Plateau: Insight from the "Hu Line"

The Tibetan Plateau is regarded as a typically sparsely populated area both from Chinese and global perspectives. There exists a large difference in population distribution of the Tibetan Plateau. Based on the town-level census data in 2010, we compiled a spatial population database to calculate the population density of the Tibetan Plateau. We found that the population distribution on this plateau was characterized in four dimensions, namely longitude, latitude, polarization and altitude. In addition, similar to the "Hu Line" for Chinese population distribution, we introduce the "Qilian-Gyirong Line" (short for Qi-Ji Line), a spatial division line of population geography in the Tibetan Plateau. Our main results are summarized as follows. (1) There are significant regional differences in the spatial population distribution in the Tibetan Plateau. The population density in the southeast was higher than that in the northwest. Compared to longitude-oriented, latitude-oriented and altitude-oriented regional differences, the polarization-oriented regional difference of population distribution was more prominent. This finding indicates that fewer people live in areas close to the cold-arid core of the Tibetan Plateau. (2) The spatial population distribution is closely related to the natural and environmental factors, including altitude, soil, water resources, climate and vegetation. The interaction between the natural factors has an impact on enhancing the regional difference of population. (3) The "Qiji Line" reveals the spatial differences of population in the Tibetan Plateau. The areas on either side of the line are approximately similar, whereas the population shares in the southeast and northwest halves are 93% and 7%, respectively. (4) In general, the population differences on both sides of the "Qiji Line" were stable over time. During 1982-2010 the population share in the southeast half decreased counterbalanced by an increased share in the northeast half. In the future, the majority of the people are expected to live on the southeast side. This is likely to imply two major policy initiatives. More attention is required on the urbanization development and transportation network construction in the southeast half and the increasing eco-environmental pressures from the growing population in the northwest half.