甘草野外地物反射光谱特征研究

为探究不同生长条件下甘草的地物反射光谱特征，为甘草遥感影像定量监测奠定基础。该文利用便携式地物光谱仪，对不同地区和不同生长期的不同甘草品种反射光谱进行测定，研究结果发现：在可见光波段内受冠层叶绿素差异的影响，一年生乌拉尔甘草反射率明显高于两年生；在近红外波段受叶面积指数和叶片含水量变化的影响，一年生乌拉尔甘草反射率明显低于两年生乌拉尔甘草，两年生刺果甘草的反射率高于乌拉尔甘草。在近红外波段通过对红边参数分析发现，一年生甘草的红边光谱比两年生甘草波峰波谷变化大，刺果甘草由于植被覆盖度和叶面积指数大，植被长势较乌拉尔甘草好。对不同地区的甘草光谱数据通过包络线消除法和主成分分析表明，在一定范围内，年平均降水量和年平均蒸发量是造成不同地区甘草光谱数据差异的主要因子，甘草光谱相似性与空间距离有关。

Research on spectral reflectance characteristics for Glycyrrhizae Radix

In order to study the spectral reflectance differences of Glycyrrhizae Radix under different growth conditions and lay the foundation for quantitative monitoring of Glycyrrhizae Radix remote sensing images, spectra of Glycyrrhiza species under different growth period and different varieties and different regions were measured by a portable spectrometer . The results showed that the reflectivity of annual G. uralensis was obviously higher than that of the two years plant in the visible light band own to the contents of crown layer chlorophyll. The reflectivity of two years G. pallidiflora was higher than that of G. uralensis in the near infrared band own to the leaf area index and the content of leaf water. The red edge spectrum of annual plant fluctuated largely than that of two years plant due to vegetation coverage and leaf area index. G. pallidiflora grew well than G. uralensis. Under different regions of the Glycyrrhiza species, spectral data analysis showed that within a certain range, the average annual precipitation and average annual evaporation were the major factors to affect the differences of Glycyrrhiza species spectral data under different regions owe to the leaf water content, the higher leaf water content,the lower spectral reflectance. The principal component analysis and continuum-removed method of the spectral data under different regions found that, within a certain range, the average annual precipitation and average annual evaporation were the major factors caused by the differences of Glycyrrhiza species spectral data under the different regions, Glycyrrhiza species spectral similarity related to the spatial distance.