安太堡露天矿区复垦地植被覆盖度反演估算研究

Remote estimation of vegetation fraction for reclaimed areas of Antaibao opencast mine

长期露天开采造成了植被大面积破坏、土地压占损毁等环境问题。利用遥感技术准确、快速监测矿区植被覆盖度,对植被恢复和土地复垦监管具有重要意义。以山西平朔安太堡露天煤矿为研究对象,利用多时相TM数据结合实地调查数据,采用主成分分析法,从19个植被指数因子中提取主成分,建立植被覆盖度反演模型。结果表明：（1）前两个主成分PC1和PC2的累积贡献率为91.508%,建立复垦植被覆盖度反演模型,经检验R2=0.742,达到显著相关水平。（2）1990~2010年,南、西排土场植被覆盖度分别增加了20.88%和12.89%,西扩排土场和内排土场植被覆盖度分别降低了18.23%和7.59%,南、西排土场植被覆盖度和植被覆盖增加量都大于西扩排土场和内排土场的。（3）南、西排土场植被复垦时间都超过了10年,而西扩排土场和内排土场的复垦时间少于10年,说明复垦周期长有利于植被恢复,进行复垦工程对矿区生态环境的修复具有直接作用和重要意义。

In an area like the Antaibao coal mine, where extensive and rapid opencast mining is going on continuously, long-term reclamation monitoring is important. Accurate information of vegetation fraction is important for assessing how mining activities affect the ecosystem in mining areas. The principal components （PCs） for vegetation indices （VIs） are obtained by principal components analysis （PCA）. A remote sensing method based on vegetation cover monitoring and assessment by using Landsat data sets with the temporal coverage from 1990 to 2010 was presented and applied to the Antaibao opencast mine, Shanxi Province, China. To reduce the impact of phenology on remote sensing based vegetation monitoring, 7 Landsat data were selected during vegetation growing season （June - October）. A total of 33 pixels were selected as the survey fields during vegetation growth season in August 2010. VF of arbores canopy in the selected plots was computed. We monitored reclaimed vegetation variation through analyzing time series data of 19 vegetation indices, which were usually applied to mine area monitoring, such as NDVI, EVI. PCA for the VIs, the accumulative ratio of contribution of the first two PCs is 91.508%, the variance contribution rate of PC1 is 84.656%, and the variance contribution rate of PC2 is 6.852%.The VF model was set up by regression analysis of SPSS based on the PC1 and PC2. T test examination showed that the field VF was correlated significantly to PC 1 and PC2, the correlation coefficient R2 of the model was 0.742. The result confirmed that the PCA in the inversion of vegetation fraction worked effectively, which could be widely used. In addition, we concluded that the vegetation system of South Dump, West Dump and West Enlarged Dump had gradually transformed to the natural ecosystem from 1990 - 2015. The vegetation in Inner Dump and Inner Enlarged Dump should be well restored. Reclamation was a long-time and dynamic project, whose effect is hard to determine in short term, while remote sensing technology is an effective way to monitor the inter-annual variation of vegetation recovery.