树基沟矿区铜胁迫落叶松的光谱响应特征研究

Spectral reflected response of Larch to copper stress in Shujigou mining area

为了研究长白落叶松光谱对土壤Cu胁迫的响应特征和变化规律,在辽东树基沟矿区的3条勘测线上布置采样点,进行表层土壤的多种重金属元素含量和长白落叶松针叶的反射光谱测定,并提取了7个特征波段,计算了多个波段区间的光谱角,将其与土壤主要重金属铜的含量进行相关分析,建立了回归模型。结果表明:7个光谱特征波段中,"红谷"参数与表层土壤铜含量的相关系数最大,基于"红谷"反射率建立的回归模型的R^2达到0. 865。光谱角对铜胁迫长白落叶松针叶波段区间[400,716]nm、[400,2 500]nm的光谱变化十分敏感。"红边"位置和反射率与土壤铜含量不相关,不适合区分矿区表层土壤重金属含量间的细微差别。对可见光敏感的"红谷"参数和光谱角均表明反射光谱的差异主要由叶绿素含量控制,小部分受到针叶中水分含量的影响。本研究利用长白落叶松"红谷"和光谱角的"指纹效应",为快速有效反演大面积高植被覆盖区的土壤重金属含量、圈定隐伏矿(化)体提供了理论依据。

In order to study the spectral response and change rule of Larix olgensis Henry to copper stress,sampling points were arranged along three exploratory lines in Shujigou mining area of eastern Liaoning province.Several heavy metal concentrations in the surface soil and reflectance spectra of Larix olgensis Henry needle leaves of each sample point were measured.7 characteristic wavelengths were extracted and spectral anglesof several band regions were also calculated respectively.Then the spectral signatures changes in copper-stressed needle leaves and soil copper concentrations were disposed by bivarite correlations analysis and regression equation were estimated.Results showed that the correlation coefficient of the'Red trough'parameter and soil copper concentration was the largest among them,and that the coefficient of determination(R^2)of regression model based on the reflectance of'Red trough'was 0.865.The spectral angles were very sensitive to spectral changes of copper stressed Larix olgensis Henry needle for wavelength from 400 nm to 716 nm and wavelength from 400 nm to 2 500 nm,which has been proved to be an efficient tool for describing the spectral differences between copper-contaminated leaves and healthy ones.However,the red edge position(REP)and reflectance of REP had little to do with the content of heavy metals in soil and were not suitable for determining copper contamination in soil.The fact that'Red trough'parameter and spectral angles are sensitive to visible light demonstrates that the difference in the reflectance spectrum is mainly controlled by chlorophyll content,and only a small part of the difference is affected by the water content of needles.The fingerprint effects of'Red trough'and spectral angles in this paper can provide new technology to support the diagnosis and monitoring for mine contamination and locate the future mineralization.