永定矿区植被覆盖度变化及其热环境效应研究

Analysis on the change of fractional vegetation cover and its thermal environmental effects in Yongding mining area

遥感技术已成为监测矿区生态地质环境变化的重要方法。以永定矿区为研究区,选择山地植被指数（Normalized Difference Mountain Vegetation Index，NDMVI），利用像元二分模型方法，对矿区山地植被覆盖度进行遥感估算，并利用热红外波段反演地表温度来研究矿区的热环境状况变化。结果表明，从2000-2014年永定矿区植被覆盖度呈显著提升趋势，平均植被覆盖度从68．23％增长到81.45％，但空间变化不均衡，矿区、经济开发区、村镇居民区等局部地区植被覆盖度降低比较明显。植被覆盖度与矿区热环境效应关系密切．回归分析表明植被覆盖度与地表温度之间呈线性负相关关系，尤其2014年的负相关性更为显著，R2达到0．55。据此可预测，植被覆盖度每增加10％，地表温度降低0．3～0．8℃。因此，矿产资源开发将使植被覆盖度降低，并引起一定的热环境效应，导致矿区生态环境质量下降。

It is an important method to monitor the change of ecological geological environment based on remotely sensed imagery in mountainous area and mining area. Yongding mining area was selected as the study area, and the Normalized Difference Mountain Vegetation Index （NDMVI） and dimidiate pixel model were selected to estimate the fraction vegetation cover （FVC）, and the thermal environment changes by thermal infrared band was analyzed, The results showed that during 2000-2014, the FVC was in a significantly increasing trend in the study area, with an increase from 68.23% to 81.45%. But the space changes were uneven, the FVC of the mining area, economic development zone and the village residential area reduced obviously; there is a close relationship between FVC and thermal environment effect in mining areas. By regression analysis, there is a linear negative correlation relationship between the FVC and the land surface temperature （LST）, and the negative correlation in 2014 is especially significant, with R2 being 0.55. According to this, it can be forecasted that, when the FVC increases 10%, the LST can be reduced up to 0.3-0.8℃. Therefore, the exploitation of mineral resources will reduce the FVC, and cause a certain degree of thermal environment effect, and lower the quality of ecological environment in mining areas.