武汉市不透水地表时空格局分析

根据植被-不透水地表-土壤（V-I-S）模型,以武汉市2002、2009、2015年3期Landsat影像为数据源,利用线性光谱混合模型进行亚像元分解获取不透水地表比例的空间分布。在此基础上采用梯度分析、景观格局指数等方法对研究区内不透水地表空间格局及变化进行分析。得到以下结论：武汉市2002、2009、2015年的平均不透水地表比例分别是27.53%,34.65%,40.51%,呈不断增长的趋势。主城区的不透水地表比例明显高于新城区,但新城区不透水地表比例增加幅度大于主城区。武汉市不透水地表主要沿长江、汉江两条轴线分布,随着与城市中心距离的增大,不透水地表比例递减后趋于稳定,三环线内4 km和三环外10 km范围是平均不透水地表比例增量最大的圈层。2002~2015年,武汉市由自然地表与极低盖度等级占主导的景观格局逐渐演变为以中高盖度不透水盖度等级占主导。

Spatial and Temporal Patterns Analysis of Impervious Surface in Wuhan City

Impervious surface is considered as an indicator of urban ecological environment and impervious surface area data, which is important to urban planning and environmental and resources management. The reconciliation between the V-I-S model and LSMA provided a continuum field model, which offered an alternative, effective approach for characterizing and quantifying the spatial and temporal changes of impervious surface. In this article, we extracted the impervious surface information from Landsat images of 2002, 2009 and 2015 within the metropolitan area of Wuhan by a fully constrained linear spectral mixture model based on the vegetation-impervious surface-soil (V-I-S) model. Here, gradient analysis was adopted to analyze spatial distribution and four different landscape indicators were chosen to analysis landscape patterns dynamics of impervious surface from 2002 to 2015. Rusults of this study were as follows: The average impervious surface coverage of Wuhan was respectively 27.53% in 2002, 34.65% in 2009 and 40.51% in 2015, which showed a trend of rising. The areas of high impervious surface coverage value of Wuhan are mainly distributed along the Yangtze River and Han River as well as in some secondary centers such as Jiangxia and Hannan and that of low value are mainly distributed in suburban counties. For the period 2002 to 2009, areas of new impervious surfaces mainly formed around existing urban areas and mostly concentrated in circumjacent areas of Wuhan Economy and Technology Development Zone and Donghu New Technology Development Zone as well. After 2009, it was observed that the distribution of new impervious surfaces was scattered. The impervious surface coverage of main urban area is obviously higher than new urban district, but the impervious surface coverage of new urban district increase rapidly. With the increase of the distance to downtown, impervious surface coverage tended to be stable after progressive decrease. The range of 10km outside the third-ring road and 4 km within it was the area of largest increment of average impervious surface coverage. Landscape pattern analysis results showed that natural surface and area of very high density impervious surface had a low degree of fragmentation, strong spatial continuity and a very simple shape. Conversely, low density and medium density impervious surface area had a high degree of fragmentation, weakest spatial continuity and a very complex shape. The patches shape shows that natural surface had a high dominant position in 2002, but after that changed to high density impervious surface after 2015.