深圳市不透水表面的遥感监测与时空格局

Quatifying spatiotemporal patterns dynamics of impervious surface in Shenzhen

定量监测城市不透水表面扩展过程,是分析城市景观格局动态,深入剖析城市地区空间镶嵌体内部异质性景观相互转化的重要基础。以深圳市为例,通过定量划分城市不透水表面等级体系,计算不透水表面的转移矩阵与景观格局指数,分析不透水表面的时空动态,结果表明:1990～2005年间,高盖度及极高盖度的不透水表面持续增加,中盖度及低盖度不透水表面先增加后减少,而自然地表及极低盖度的不透水表面则为先减少后恢复,反映了城市化进程对城市地表覆被的结构性影响。景观格局变化显示景观多样性程度较高,且经历了低-高-低-高的变化;斑块在1990年以自然地表为主,1995年以后以中盖度等级为主,高盖度等级显著增加。自然地表和中等盖度的不透水表面变化分别主导着前期和中后期的变化过程。城市建设的迅速扩张,将林地、农田、水体及滩涂等自然地表快速地转变为不同功能的建设用地,主导着不透水表面等级分布的梯度性变化。

Rapid urbanization has changed urban land cover characteristics. Impervious sur- face has been the main land cover categories in urban landscape. How to quantify the spa- tial pattern of impervious surface and its temporal change are necessary for us to under- stand the dynamics of processes and patterns of urban landscape and their relationship be- tween impervious surface and other heterogeneous landscapes. Remote sensing technology has been widely applied in urban impervious surface monitoring and change detection, but the spatial pattern and temporal change of impervious surface is rarely concerned. Taking Shenzhen as a case study area, we quatify the spatiotemporal patterns dynamics of imper- vious surface from 1990 to 2005. In order to analyze the spatial temporal change of imper- vious surface, we used an index of impervious surface area to show the heterogonous of impervious surface by linear spectral mixture method, which can be divided into six cover degrees. We use the matrix change method to explain the changes among four time periods and 3 stages and landscape pattern metrics to indicate the pattern change at three different levels. Results show that there were three changing types in the 15 years, namely, high and full density impervious surface area （HDISA, FDISA respectively）-continued increas- ing, and medium density （MDISA） and low density （LDISA）--first increased and then de- creased, while natural surface （NOISA） and very low density （VLISA） are contrary to MDISA and LDISA. However, the pattern of impervious surface indicates that cover de- grees had a high landscape diversity and the value changed from low to high then decreased and reached a new high level. The landscape aggregation was very low overall in the four time periods, but had a significant fluctuation in classes level. The patches shape shows that natural surface had a high dominant position in 1990, but after that changed to medi- um density impervious surface and high density overtook the second position after 2005. Our research can provide a basis for the orderly development for planning urban impervious surface extension and aggregation; however, we also believe that mitigating the expansion of impervious surface is benefit to the improvement of the urban ecological and environmental quality.