2000 年以来中国城市空间扩张的时空平稳性

城市空间扩张一方面表现为建成区的空间扩张，另一方面表现为市辖区面积的不断增加，在当今快速城镇化的中国这两个过程尤为剧烈而显著不平稳。地理学上的平稳性强调时间和空间两个层面的演变过程。引入几何学的方法，以标准化的建成区面积和市辖区面积构建坐标系，绘制2000-2010 年主要地级城市的空间扩张的路径，按照均值对路径进行分类，并引入mov、tor、sd 三个指数作为时空平稳性的测度。研究表明：① 2000 年以来，市辖区扩张主要集中在长三角、珠三角、闽东南以及中西部的省会及其周边城市，而建成区的扩张态势并没有这种显著的极化效应，在各个城市群均有较高的速率。② 从类型上，可以分为稳定型和跨越型两种。稳定型中以稳定在低于均值的LL型最多，而其他偏少；跨越型中，以在HH、HL、LH、LL四者间发生一次置换的为主。③ 三个平稳性系数的计算结果显示，城市等级较高的城市对mov、sd 指数比较敏感，这两个指数主要反映了城市相对于全国的平稳性特征；而处于中游的城市对tor指数比较敏感，这个指数主要反映了城市自身在年际间变动的平稳性特征。

The research on urban spatial expansion and its space-time stability in China since 2000

Municipal district expansion and built-up area expansion are two main forms of urban spatial expansion. They are unstable under high-speed urbanization in China. Geographic stability contains both stability of time and space. With the help of geometric methods, the paper constructs a coordinated system based on standardized values of built-up area and municipal district area. What's more, the paper draws spatial expansion paths of some typical cities from 2000 to 2010 and classifies them based on standardized mean value. Finally, three indexes which are called mov, tor and sd are used to calculate space-time stability. The results show that, (1) In recent years, municipal district expansion can often be found in the Yangtze River Delta region, Pearl River Delta region, southeastern Fujian and the capital cities of central and western China. However, built-up area expansion seems unpolarized and each urban agglomeration has high speed expansion. (2) The space-time paths can be divided into stable type and unstable type. Most of the stable types are LL, which means both municipal district and built-up area are below mean values, while most of the unstable types only have one transformation between HH, HL, LH and LL. (3) The cities with high rank are sensitive to mov & sd, which indicate stability difference between the cities and the whole country. But the cities with medium rank are sensitive to tor, which indicates interannual stability of a city.