分形理论支持下的城市土地利用热环境效应研究——以武汉市为例

A study on the thermal environmental effect of urban land use based on fractal theory——a case of Wuhan City

传统的城市土地利用热环境效应研究主要以统计分析方法为主,无法从本质上反映城市土地利用与热环境在空间上的内部关联性.该文引入分形理论方法,构建了半径维数,定量描述从热岛效应中心向四周低温辐射过程中土地利用空间格局的变化特征,并以武汉市为例展开案例研究.从分析结果来看,武汉市农用地、林地、水域、未利用地和建设用地5种土地利用类型的半径维数从大到小分别是2.343,2.333,2.218,2.304和1.715,说明建设用地对城市热环境表现为正效应,林地、农用地及水域表现为负效应,未利用地效应不显著.研究结论表明,半径维数能够有效区分各种土地利用在空间结构上对热环境效应的聚集或缓解的作用效果,可以科学地指导政府部门通过城市土地利用规划手段来降低城市热岛效应影响范围与程度.

Traditionally, the studies on the thermal environment effects of urban land use mainly use statistical analysis, which cannot fundamentally reflect the internal spatial correlation between urban land use and thermal environmental effects. This study introduces the method of fractal theory to this research area and builds a radius dimen- sion to quantitatively describe the characteristics of the spatial pattern of the land use change from the center of the heat island effect to the surrounding low-temperature radi- ation process, taking Wuhan as a case study. The results show that： the radius dimen- sion of cropland, forest, water, bare land and built-up area from large to small is 2. 343,2. 333,2. 218,2. 304 and 1. 715 respectively, indicating that built--up areas has positive effects on urban thermal environment, while forest, cropland and waters have negative effects on urban thermal environment and that of bare land is not obvious. It can be concluded according to our study that the radius dimension can effectively distin- guish the gathering or mitigating effects of various urban land use spatial structure on thermal environmental. Therefore, the results of this study can provide scientific guid- ance for the government to reduce the extant and degree of urban heat island effect by urban land use planning.