基于Landsat时序数据的高潜水位煤矿区植被扰动分析

Vegetation disturbance analysis in coal mining area with high ground water level based on Landsat time series NDVI data

  • 摘要: 我国东部矿区是重要的煤粮生产复合区,由于境内地势平坦,地下潜水位高,采空区形成的沉陷大多常年积水或季节性积水,所引起的土地、生态、环境问题尤为严重。植被作为矿区生态环境的重要组成部分,因外界干扰和环境要素的变化而具有动态特征。归一化差值植被指数(NDVI)是植被生长状况遥感监测的常用指示因子,基于NDVI时间序列数据的分析可以有效揭示植被的扰动效应。以安徽淮南顾桥矿为研究对象,基于2007—2018年Landsat NDVI时间序列数据的分级统计,以及热点分析、聚类与异常值分析和剖面线分析,研究NDVI值的时空变化特征,探讨煤矿开采沉陷对周围植被的扰动效应。研究表明:2007—2018年间顾桥矿植被生长状况整体良好,但植被覆盖离散程度在增大;NDVI分布具有明显的空间聚集特征,均为“高–高”聚类和“低–低”聚类,无异常出现;受煤炭开采影响,热点区减少,冷点区增加,热点向冷点的转化主要发生在沉陷积水区、德上高速和永幸河附近;沉陷积水区周围一定范围内存在明显的植被扰动,开采初期扰动较小,随着积水区范围的增长和时间的推移,扰动范围逐渐增大,最后趋于稳定,具有时序滞后性和时空累积性。研究成果为采煤沉陷区生态影响范围的确定及生态环境的恢复治理提供了参考。

     

    Abstract: The eastern mining area of China is an important coal and grain composite production area. Due to the flat terrain and high underground diving level, most of the subsidence caused by mining is perennial or seasonal water, which causes serious land, ecological and environmental problems. As an important part of the ecological environment in mining area, vegetation has dynamic characteristics due to the external disturbance and the change of environmental factors. The normalized difference vegetation index(NDVI) is a common indicator for remote sensing monitoring of vegetation growth. The analysis based on NDVI time series data can effectively reveal the disturbance effect of vegetation. Taking Guqiao Coal Mine in Huainan, Anhui Province as the research object, the temporal and spatial variation characteristics of NDVI values were analyzed based on the classification statistics of Landsat NDVI time series data from 2007 to 2018, as well as hot spot analysis, clustering and outlier analysis, and profile analysis, and then the disturbance effect of coal mining subsidence on the surrounding vegetation was discussed. Results showed that from 2007 to 2018, the vegetation growth in Guqiao Mine was generally good, while the dispersion degree of vegetation cover was increasing. The NDVI distribution in Guqiao Mine has obvious spatial clustering characteristics, both are “High-High” Cluster type or “Low-Low” Cluster type, and there is no abnormal appearance. Under the influence of coal mining, hot spots decreased and cold spots increased, and the conversion of hot spots to cold spots mainly occurred in the area of subsidence water, near the Deshang speedway and Yongxing River. Within a certain range around the subsidence water accumulation area, there was an obvious vegetation disturbance effect, and the initial disturbance of mining was small. With the growth of the water accumulation area and the lapse of time, the disturbance range gradually increased and finally tended to be stable, which showed temporal lag and spatio-temporal accumulation. The results would provide a reference for the determination of ecological influence range and the restoration of ecological environment in coal mining subsidence area.

     

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