塔里木河中游典型绿洲盐渍化土壤的反射光谱特征

研究盐渍化土壤的光谱特性是利用遥感技术实现在区域尺度上进行土壤盐渍化监测和评价的工作基础, 是建立地面数据和遥感数据关系的桥梁。本文以塔里木河中游典型绿洲--渭干河-库车河三角洲绿洲为研究对象, 采用光谱学技术以及多元统计相结合的方法, 研究干旱区典型绿洲盐渍化土壤的反射光谱特征。首先, 对光谱数据进行预处理(去噪、剔除水分吸收波段), 以便消除仪器本身噪声及外界条件的影响, 并且计算了部分盐渍地样本的光谱吸收特征参数, 说明相同程度的盐渍化土壤具有相似的吸收特征;其次, 研究盐渍化土壤的反射光谱与盐分因子(八大离子、电导率(EC)、含盐量(salt content)、pH、总溶解固体(TDS)等) 之间的关系, 并选择具有代表性的盐分因子与野外实测光谱数据建立定量回归模型, 通过多元线性回归分析得出含盐量、SO₄^2-、TDS、EC与原始光谱数据的相关性分别是0.746、0.908、0.798 和0.933, 达到了理想的效果。本研究对于干旱区典型绿洲盐渍土的光谱特征研究有着重要指示意义, 为发展和完善中国盐渍土理化特征的可见光-近红外反射光谱分析理论奠定科学积累, 并进一步为干旱区土壤盐渍化、沙漠化灾害等环境恶化问题的解决提供新的科学技术手段。

The Study on the Reflectance Spectral Characteristic of Salt-Affected Soil in Typical Oasis of the Middle Reaches of Tarim River

With the economic development and the population increase,unreasonable land development has caused ecological problems such as degradation,while soil salinization becomes a major concern in arid and semi-arid areas.It is a basic work to study the spectrum characteristics of soil salinization by using remote sensing technology to achieve the monitoring and evaluation of soil salinization at regional scale,and to establish the relationship between ground data and remote sensing data.In this paper,the author takes the delta oasis of Weigan and Kuqa rivers located in the middle reaches of Tarim River as study areas by using spectroscopy technology and multivariate analysis technology method.This paper studies the correlations between salt-affected soil chemical properties and reflectance spectrum in the middle reaches of Tarim River.Firstly,ASD spectrometer was used to measure spectral data in surface features.The spectral data should be removed from the equipment itself and the external conditions such as noise.Aiming at this experimental application study,we chose appropriate methods from the existing spectral matching processing technologies such as spectral absorption index.Secondly,the paper focused on retrieving soil chemical characteristic parameters(including ions,electricity conductivity,salt content,pH,TDS) from the hyperspectral data.By using single-correlation analysis,the quantifying regression models between salinized soil reflectance and soil ions,electricity conductivity,salinity,pH,TDS were established.It is shown that the correlation coefficient of salt content is 0.746,of sulfate ion is 0.908,of total dissolved solid is 0.798 and of electricity conductivity is 0.933.The result achieved a good effect.To sum up,the result of this research will produce a significant meaning for the research on the saline-alkali soil in the arid area.Furthermore,since a large part of Xinjiang belongs to the arid area,taking the delta oasis of Weigan and Kuqa rivers as the study areas has realistic meanings to the environmental research in the arid area.