摘要
我国煤炭资源多集中在干旱少雨的北方地区,露天开采和运输等过程极易引起煤粉尘扩散和污染。粉尘扩散后其中一部分在重力作用下沉降覆盖到周边的植被上,导致植被降尘现象普遍。在利用遥感手段进行植被监测时,降尘效应会影响植被光谱的纯净性,使遥感器所获取的信号为植被与降尘的混合光谱信号,从而严重影响植被定量遥感精度。为定量研究植被遥感中煤尘的滞尘效应,开展了叶面滞尘光谱测量实验,探究了光谱和植被指数的变化规律;在此基础上,利用含有红边波段的Sentinel-2A遥感影像,在内蒙古霍林河露天矿区分别选择煤尘影响区与对照区两个区域进行植被指数对比,用来验证地面光谱测量实验结果。结果表明,随着滞尘量(0~36 g·m^(-2))的增加,叶面煤尘会使叶片的反射率整体逐渐降低,叶片光谱波峰处(560,720,860,1 680和2 220 nm)的反射率变化幅度明显高于波谷处(445,681和1 940 nm);随着滞尘量的增加,归一化差异植被指数(NDVI)、简单比值指数(SR_(705))和归一化差异指数(ND_(705))明显下降,而中分辨率成像光谱仪陆地叶绿素指数(MTCI)、改进型简单比值指数mSR_(705)(modified simple ratio)和改进型归一化差异指数(mND_(705))基本保持不变,表现出抗煤尘特性,445 nm处反射率和681 nm处反射率对指数起到了重要作用。利用霍林河露天煤矿区的Sentinel-2A遥感影像计算上述指数,将煤尘影响区与对照区比较,MTCI、 mSR_(705)和mND_(705)等指数表现了抗煤尘特性,验证了地面实验的结果。该研究为煤尘污染区域的植被遥感奠定了一定基础,对保证植被遥感反演精度具有积极意义。
The coal resources in China are mainly concentrated in the arid and rain-less northern areas.Open-pit mining and transportation can easily cause the diffusion and pollution of coal dust.After the dust diffuses,some of them settle and cover the surrounding vegetation under gravity,leading to the common phenomenon of dust falling on vegetation.When remote sensing is used to monitor vegetation growth and health status,the dust fall effect will affect the spectral purity of vegetation so that the signal obtained by remote sensing is the mixed spectral signal of vegetation and dust fall,which seriously affects the quantitative remote sensing accuracy of vegetation.In order to study the dust retention effect of coal dust in vegetation remote sensing,the experiment of spectral measurement for dusty leaf was carried out,and the change of spectrum and vegetation index was studied.On this basis,sentinel-2A remote sensing images with red-edge bands were used to compare vegetation indices in the coal dust affected area and control area in Huolinhe open-pit mining area,the Inner Mongolia Autonomous Region,respectively,to verify the experimental results of ground spectral measurement.In this experiment,vegetation leaves were selected from a coal mining area in Shenyang.The coal dust was evenly sprayed on the leaf surface with a level difference of 2 g·m^(-2) to simulate the effect of dust retention on the actual leaf surface.Spad-502 chlorophyll meter was used to measure the spectrum of dust retention on the leaf surface,and the spectrum and vegetation index variation rules were explored.Since the red edge band was used for the vegetation index in this experiment,sentinel-2A remote sensing images were selected.Huolinhe Open-pit mine in NeiMengGu province and its surrounding areas were selected as the verification area.The coal-dust-affected area,and the control area were selected for vegetation index comparison to verify the experimental results of ground spectral measurement.The results show that,with the increase of dust retention(0~36 g·m^(-2)),coal dust on the surface of the leaves will gradually reduce the overall reflectance of the leaves,and the change amplitude of the reflectance at the peak of the leaf spectrum(560,720,860,1680,2220 nm)is significantly higher than that at the trough(445,681,1940 nm).With the increase in dust retention,NDVI(normalized difference vegetation index),SR705(simple ratio),and ND 705(normalized difference index)decreased significantly.However,MTCI(the medium resolution imaging spectrometer terrestrial chlorophyll index),mSR 705(modified simple ratio)and mND 705(modified normalized difference index)are unchanged,showing the characteristics of coal dust resistance.The reflectivity at 445 and 681 nm in these indices play an important role.By using Sentinel-2A remote sensing image in Huolinhe open pit coal mine area and comparing the coal dust affected area with the control area,MTCI,mSR 705,and mND 705 indices show the characteristics of coal dust resistance,verifying the results of ground experiments.The study would lay a foundation for vegetation remote sensing in the area of coal dust pollution and ensure the accuracy of vegetation remote sensing inversion.
作者
马保东
杨湘儒
蒋紫薇
车德福
MA Bao-dong;YANG Xiang-ru;JIANG Zi-wei;CHE De-fu(School of Resources and Civil Engineering,Northeastern University,Shenyang 110819,China)
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2023年第6期1947-1952,共6页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(41871310,41201359)
中央高校基本科研业务专项资金项目(N2201007)资助。
关键词
煤尘
植被
光谱
植被指数
Coal dust
Vegetation
Spectrum
Vegetation index
