面向城市热环境格局时空演变的多重分形模式--以郑州市为例  

Spatio-temporal changes of thermal landscape pattern based on a multifractal model: a case study of Zhengzhou City

作　　者：高歆[1] 吴国玺[1] 杜根远[2] 李长坡[1] 申怀飞[1] 

机构地区：[1]许昌学院,城乡规划与园林学院,许昌461000 [2]许昌学院,国际教育学院,许昌461000

出　　处：《生态学报》2015年第20期6774-6787,共14页Acta Ecologica Sinica

基　　金：国家自然科学基金联合基金项目(U1304403);国家自然科学基金青年基金项目(41301405);河南省科技攻关(重点项目)计划(132102210398);河南省基础与前沿技术研究计划(132300410349)

摘　　要：与单分形相比,多重分形模型赋予了更多描述客观世界中复杂现象和事物的参数和手段,为更加准确和精细地刻画自然界中普遍存在的非线性现象和过程提供了一种有效途径。以河南省郑州市为研究对象,选取三期Landsat5-TM影像反演城市地表温度,并采用多重分形的理论与方法定量地探讨和研究城市热环境场纹理结构及其在时空中的分布特征,以及在不同的标度区间内热环境场与NDVI之间的关系。研究结果表明:20年间郑州市热场景观的多重分形谱奇异性指数最大值与最小值之差"α由0.6716减小为0.6419,奇异性指数最小值αmin和最大值αmax分别由1.4644、2.136减小为1.4304和2.0723,背景场奇异值α(fmax)由2.0111减小为2.0083,纹理测度最大值与最小值的分维数f(αmin)和f(αmax)分别由0.2354、1.4877增大为0.3412和1.734,意味着随着近20年经济的发展和城镇化率的提高,研究区域的热场纹理信息量不断减少,结构趋于简单,而纹理测度最大值、最小值和研究区温度有增大的趋势。对于位于郑州市不同位置且由不同景观斑块类型构成的区域,市区区域纹理测度波动幅度最小,而水体区域最大;市区纹理测度最大值和最小值的分维数最大,不同等级纹理像元数量分布比较均匀,空间簇聚程度高,而水体则相反,另从市区样本的多重分形参数来看,新开发的区域比老市区具有更小的αmin值和D2值。区域温度均值与多重分形参数之间呈现较强的线性相关性,而区域标准差与多重分形参数之间的相关性更强,线性变化的顺序依次为水体、农业用地、城郊和市区。另外,还利用C-A(浓度-面积)模型把2011年热场图像纹理结构分割为3个标度不变性区间,在此基础上讨论了奇异性指数α对区域温度与NDVI(归一化植被指数)之间关系的影响,发现斑块边缘的地表温度对NDVI最为敏感,且奇异性指数对不同标度区间的地表�Multifractal analysis has been more commonly used than fractal analysis to give a more precise characterization and a multi-scale analysis of non-linear phenomena. Multifractal analysis can also be used to analyze processes having a greater number of parameters. The objective of this study was to use a multifractal model to quantitatively describe the texture structure, spatio-temporal features, and relationship between regional temperature and Normalized Difference Vegetation Index（ NDVI） at different invariant intervals for the urban thermal environment field in the Zhengzhoumetropolitan area. We used Landsat TM images for three different periods. The results were calculated for the entire area as follows：（ 1） the difference between the maximum value αmaxand minimum value of the singularity index αmindecreased from0.6716 to 0. 6419;（ 2） αmaxand αminof the singularity index decreased from 1. 4644 and 2. 136 to 1. 4304 and 2. 0723,respectively;（ 3） the singularity value of the background α（ fmax） decreased from 2.0111 to 2.0083; and（ 4） the fractal dimension of the maximum and minimum value f（ αmin）,f（ αmax） increased from 0.2354 and 1.4877 to 0.3412 and 1.734,respectively. These results show that with the economic development and progression of urbanization in the past 20 years,the information contained in the texture of the thermal field in the Zhengzhou metropolitan area constantly decreased,and its structure and maximum and minimum texture values became simpler and larger,respectively. For selected locations,we observed that urban areas have fluctuated on a small scale with respect to the amplitude of texture,and the largest fractal dimensions of the maximum and minimum values of texture are well distributed at different scales with high clustering properties. Contrasting results were observed for water areas. Furthermore,there were smaller αminand D2 values for older urban districts than those reported for newly developed areas. The relationship between the multifrac

关 键 词：多重分形 热环境 格局 纹理 浓度-面积模型 

分 类 号：X16[环境科学与工程—环境科学]