森林地表凋落物含水率红外光谱特性分析

NIR Spectral Characteristics of Moisture Content for Forest Litter

为了实现森林地表凋落物含水率的实时测量,研究了森林地表凋落物含水率与红外光谱特性参数之间的关系。选取了四种森林地表凋落物,搭建了含水率红外光谱测量装置,获得了不同含水率所对应的红外吸收光谱图,分析了不同含水率与峰值吸收光强、谷肩连线与谷底连线交点纵坐标、吸收谷面积之间的关系。结果表明,含水率吸收谱线峰值在1 450nm附近;三种光谱参数中,森林地表凋落物含水率与峰值吸收光强线性相关性最好,所得一元回归方程经F检验显著性良好,斜率的相对不确定度均小于1.0%和截距的相对不确定度小于0.51%,相关系数γ>0.95。为含水率实时测量仪的光源选择和标定提供了依据。

In order to develop a real-time measuring instrument based on NIR spectral absorption method for forest surface litter moisture content,the relationship between water content and absorption spectrum of litter in forest was analyzed in this paper.In addition,four kinds of forest surface litter were selected and the infrared absorption spectrum measuring device was constructed.Besides,the infrared absorption spectrum corresponding to different water content were obtained.The relationship between thedifferent moisture content and the peak absorption intensity,the absorption valley areaand the vertical axis of the valley connection and the valley connection are analyzed.The results showed that the peak value of water absorption wasnear 1 450 nm,and the correlation between water content and peak absorption intensity of forest litter was better.The single regression equation was well tested by F-test,and the relative uncertainty of slope was less than 1.0%and the intercept of the relative uncertainty of less than 0.51%,the correlation coefficient r>0.95.It provides the basis for the light source and calibration process of the moisture content real-time measuring instrument.