Guangzhou Institute of Geography, Guangzhou 510070, China; Key Laboratory of Guangdong for Utilization of Remote Sensing and Geographical Information System, Guangzhou 510070, China; Guangdong Open Laboratory of Geospatial Information Technology and Application, Guangzhou 510070, China.
Guangzhou Institute of Geochemistry, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China; Guangzhou Institute of Geography, Guangzhou 510070, China.
Sci Total Environ. 2018 Jun 15;627:264-281. doi: 10.1016/j.scitotenv.2018.01.155. Epub 2018 Feb 3.
This study evaluated the spatio-temporal change characteristics of urban development at different scales with time-series impervious surface fractions. Landsat-5 Thematic Mapper (TM) and Landsat-8 Operational Land Imager (OLI) images were used to extract impervious surface fractions using a modified linear spectral mixture analysis method in Guangzhou from 1988 to 2015. The results indicated that the impervious surface area has substantially increased, from 70.3 km in 1988 to 580.5 km in 2015. In 2015, the impervious surfaces were distributed almost throughout the whole region of the study area, except in the forest region. Next, impervious surface weighted mean centre (ISWMC) and the standard deviational ellipse (SDE) methods were used to systematically analyse the principle orientation, direction, spatio-temporal expansion trends, and the distribution differences of impervious surfaces at the whole and local region scales from 1988 to 2015. The spatio-temporal dynamics of ISWMC exhibited different expansion directions and intensities of impervious surfaces at the whole and local region scales. On a whole region scale, the principle expansion direction of impervious surfaces was northward. However, the expansion trend of impervious surfaces in the different districts was significantly different from other trends at the local region scale. The parameters of SDE were used to investigate the orientation and the clustering or dispersion degree of impervious surface at different scales. The results from SDE analysis indicated that the impervious surfaces exhibited uncertainty in the expansion direction at the whole region scale; in contrast, they had a distinct preferred orientation and expansion direction at the local region scale. The analysis revealed that urban expansion exhibited different change characteristics in various directions at the local region scale. In summary, the results at the local region scale can better reflect the change trajectory of spatio-temporal dynamics of urban development and its fine spatial structure than at the whole region scale.
本研究利用多时相不透水面分数，评估了不同尺度下城市发展的时空变化特征。利用改进的线性光谱混合分析方法，从 1988 年到 2015 年，从广州市的 Landsat-5 专题制图仪（TM）和 Landsat-8 业务陆地成像仪（OLI）图像中提取不透水面分数。结果表明，不透水面面积显著增加，从 1988 年的 70.3km增加到 2015 年的 580.5km。2015 年，除了森林地区，不透水面几乎分布在研究区域的整个区域。然后，利用不透水面加权均值中心（ISWMC）和标准离差椭圆（SDE）方法，系统地分析了 1988 年至 2015 年整个区域和局部区域尺度上不透水面的主要方向、方向、时空扩展趋势以及分布差异。ISWMC 的时空动态在整个区域和局部区域尺度上表现出不同的扩展方向和不透水面强度。在整个区域尺度上，不透水面的主要扩展方向是向北。然而，不同区域的不透水面扩展趋势与局部区域尺度上的其他趋势明显不同。SDE 的参数用于研究不同尺度上不透水面的方向和聚类或离散程度。SDE 分析的结果表明，不透水面在整个区域尺度上的扩展方向存在不确定性；相比之下，在局部区域尺度上，它们具有明显的优势方向和扩展方向。分析表明，在局部区域尺度上，城市扩展在各个方向上表现出不同的变化特征。总之，局部区域尺度上的结果可以更好地反映城市发展时空动态的变化轨迹及其精细的空间结构，而不是整个区域尺度上的结果。
