半干旱山区采矿扰动植被指数时空变化规律

选取潞安矿区7个生产矿井中的8个试验工作面,采用概率积分法预测开采沉陷值；对2004—2007年7个时相(分别为2004年7月8日、11月1日,2005年2月1日、8月26日,2006年5月22日,2007年4月9日和6月1日)的SPOT2/4卫星遥感数据进行大气校正及波段运算,提取工作面开采沉陷前后的NDVI(归一化植被指数)平均值,经离散傅立叶变换得到NDVI时间序列曲线,以研究采矿扰动区植被指数的时空变化规律. 结果表明:①试验工作面地表覆被NDVI变化与采矿扰动区具有空间相关性. 非采矿扰动区(伪不变特征区)森林冠层的NDVI最大值由2004年的0.619451增至2007年的0.739987,平均年净增加6.18%. 在采矿扰动区,虽然开采前地表NDVI最大值呈增加趋势,但开采当年却显著下降,年均降幅达11.91%. ②试验工作面地表NDVI变化与采矿扰动具有时间相关性. NDVI在开采前表现相对稳定,受开采扰动虽出现下降但却滞后4～6个月,并且持续1～2a,其后转入上升期. 常村矿的S1-1#、S3-2#、N1-4#,漳村矿的2101#、2102#、2201#,五阳矿的5100#,王庄矿的5210#等8个试验工作面NDVI最大值年均降幅分别为12.24%、27.81%、15.79%、19.19%、7.19%、21.48%、13.25%和1.66%,平均值为14.83%. 在气候、耕作、采矿扰动等诸多因素影响下,采矿扰动是半干旱山区采矿区地表NDVI变化的主要诱因. 

Spatial-Temporal Variation of Vegetation Index Caused by Mining Subsidence in Semi-Arid Mountain Regions

The ecological environment has been impacted by the coal mining. Vegetation index is often used as an important indicator for monitoring changes of the ecological environment. For the mining disturbance area,the dynamic monitoring of the vegetation index is applied detect the spatial and temporal correlation between mining activities and vegetation biophysical values, by obtaining the change law of green vegetation health status with access to underground mining. The normalized difference vegetation index (NDVI) mean variation before and after the mining subsidence in 8experimental faces of Lu’an mining area were extracted from 2004-2007(i.e. 2004-07-08,2004-11-01,2005-02-01,2005-08-26,2006-05-22,2007-04-09,2007-06-01) by seven temporal remote sensing images (SPOT2/4satellite) after atmospheric correction operation and band calculation. Using the probability integral method, the influenced degrees the mining subsidence to the areas of were assessed. The curve of time series NDVI during the four years was further obtained by Discrete Fourier Transform (DFT). The results showed that spatial connections between NDVI change and surface mining disturbed area were significantly different. The maximum of forest canopy NDVI average in non-mining area (Pseudo-Invariant Feature areas, PIFs) increased year by year(0.619451(2004),0.637263(2005),0.662735(2006), 0.739987(2007)), and its average annual net increased by 6.18%. The maximum of mean NDVI in subsidence areas, however, tended to increase before mining. In mining year, the values decreased with an average annual decrease of 11.91%. In coal faces No. S1-1, S3-2,N1-4at Changcun mine, No. 2101,2, 2201at Zhangcun mine, No. 5100at Wuyang mine and No. 5210at the Wangzhuang mine, an annual NDVI maximum declines 12.24%, 27.81%,15.79%,19.19%,7.19%,21.48%,13.25%,1.66%, respectively after mined. The annual decline of -14.83% of the NDVI maximum was caused by coal mining in the 8experimental faces. This decline lasted about one to two years. This indicated that NDVI change had a temporal correlation with mining activities in the experimental faces, and the damaging of plants growth and the weakening of biomass accumulation in mining disturbed areas was mainly caused by the mining subsidence. The result would be a guide for agriculture and animal husbandry production, land reclamation, environmental protection, ecological restoration and reconstruction in of mine subsidence area.