107杨叶片叶绿素含量高光谱反演的研究
Inversion of Populus×euramericana cv. “74/76” Chlorophyll Concentration Based on the Hyper-Spectrum

利用Field-Spec Pro测定107杨叶片光谱特征参数，研究不同叶绿素含量的107杨叶片的光谱特性、叶绿素含量与11种植被指数之间的关系以及107杨叶片叶绿素含量的光谱反演模式。结果表明：1）光谱反射率呈现典型的植物光谱特征，蓝紫谷位于350~500 nm之间，其中多集中在350 nm处；绿峰位于500~600 nm之间，其中大部分集中在552 nm处；红谷位于600~700 nm之间，多集中在672 nm处。700 nm后进入近红外高反射平台，以762 nm居多；2）107杨叶片叶绿素含量与11种植被指数之间均具有很强的相关性，其中mND705植被指数与叶片叶绿素含量相关性最强，R2为0.69；3）基于植被指数建立叶绿素反演模型，结果显示mND705植被指数的高光谱反演模型y=0.09x1.621 7反演精度较高，拟合R2和预测R2均达到最大，分别为0.812 4、0.703 5；均方根误差最小，为0.007 0，说明可以利用测量107杨叶片光谱的方法来监测叶片叶绿素含量。
Parameters of Populus×euramericana cv. “74/76” leaves determined by Field-Spec Pro were adopted to study spectral characteristics of the leaves which contained different chlorophyll contents, to examine the relationships of chlorophyll content and 11 vegetation spectral inversion models, as well as the spectral inversion model of leaf chlorophyll content. The spectral reflectance presented typical plant spectral characteristics. The blue valley appeared in 350-500 nm and centered at 350 nm. The green peak appeared in 500-600 nm and centered at 552 nm. The red valley located in 600-700 nm and centered at 672 nm. Infrared ray，wave length longger than 700 nm, entering the near infrared reflectance platform, and centered at 762 nm. The chlorophyll content of P. × euramericana cv. “74/76” leaves and 11 vegetation indices were highly correlated. The correlation of mND705 vegetation index and chlorophyll content in the leaves was the most significant with a R2 of 0.69. The established chlorophyll retrieval model based on vegetation index showed that inversion precision of inversion model y=0.09x1.621 7 of mND705 vegetation index of high-spectrum was the highest, the fitting R2 and predicted R2 which all reached maximum, were 0.812 4 and 0.703 5, respectively. RMSE was 0.007 0, indicating that the method of monitor the Populus × euramericana cv. “74/76” leaves spectral can be used to the measurement of leaf chlorophyll content