300 BC-1900 AD无定河流域城镇时空格局演变

通过分析和整理从战国中晚期（约300 BC）至清末（约1900 AD）无定河流域历代县级及以上城址的位置、兴废年代数据,结合行政区划沿革、经济社会发展、政权更迭等资料,分析流域城镇格局的时空演变过程。研究表明：① 受气候周期性波动影响,无定河流域城镇的兴起与衰废具有明显的周期性特征,城镇几何中心的移动轨迹具有明显的“西北—东南”向潮汐性运动特征;② 城址存续年限普遍较短,具有明显的阶段性特征,流域内曾存在过4个阶段性中心城镇,中心城镇移动的方向和过程与城镇几何中心的潮汐性移动过程趋势一致;③ 流域城镇空间格局可分为3种类型,即秦汉与隋唐时期的沿河流谷地分布,宋、明两代的沿边境线与长城分布,以及元、清两代集中于流域下游分布。流域城镇未来的发展布局应重视气候变化对城镇分布的长期影响,关注区域环境的脆弱性,合理安排城镇体系发展规模与布局。

A historical study on the patterns of spatio-temporal evolution of towns in the Wuding River Basin

The Wuding River is one of the main branches in the middle reaches of the Yellow River, flowing through the Loess Plateau in northern Shaanxi. This paper analyzes the positions as well as the beginning and ending dates of the counties in the Wuding River Basin, from 300 BC to 1900 AD. Based on the history of administrative divisions, economic and social developments, and regime changes, three spatio-temporal patterns of towns evolution process in this river basin are found: (1) Influenced by the cyclical fluctuation of climate, the rise and decline of towns in the river basin has obvious periodicity, and the geometric center of the towns in this basin has obvious characteristics of tidal movement in a "northwest- southeast" direction. (2) The life spans of the town sites are generally short, and there were four stages with four different central towns in history. The direction and process of the movement of the central towns were consistent with the trend of the tidal movement of the geometric center of the towns. (3) In the history of the river basin, there were three types of towns spatial patterns: along the river valleys in the Qin-Han and Sui-Tang periods, along the border lines and the Great Wall in the Song and Ming periods, and along the lower reaches of the river basin in the Yuan and Qing periods. Based on the analyses, the authors suggest that to rationally determine the scale and layout of the towns system, the future development plan for the Wuding River Basin should focus on the long-term impact of climate change on towns distribution and the reality of regional environmental vulnerability.