大米草室内叶片光谱特征参数与叶绿素浓度关系研究

本文通过分析大米草叶片反射光谱特征,并提取红边位置、红边斜率和红边面积三个红边参数以及叶面叶绿素指数(LCI)、水分指数(WI)、三角植被指数(TVI)、结构相关色素指数(SIPI)四个高光谱植被指数,利用线性、对数、倒数、二次函数和三次函数曲线模拟算法得到大米草叶片叶绿素a浓度的高光谱估算模型。研究结果表明:叶绿素a浓度与红边斜率和红边面积在0.01水平上显著负相关,与LCI、WI和TVI在0.01水平上显著正相关。基于红边斜率、红边面积、TVI三个参数,选用倒数法构建叶绿素a浓度的估算模型精度明显高于其他算法。基于LCI和WI参数,应用三次函数法构建的叶绿素a浓度的高光谱检测模型精度明显高于其他算法。比较R2和模型估算误差,利用WI水分指数应用三次函数构建叶绿素a浓度的高光谱检测模型精度在所有模型中最高。因此,利用叶片光谱技术可以较高精度地估算叶绿素a浓度。

Relationship between spectral characteristics parameters at leaf level of spartina anglica and chlorophyll concentration

On this basis,three red edge parameters such as red edge position,red well position,and area of red edge and four hyperspectral vegetation indices such as leaf chlorophyll index (LCI),water index (WI),triangle vegetation index (TVI),and structure-independent pigment index (SIPI) were extracted.Then,chlorophyll a concentration estimation models were constructed by applying linear,logarithm,inverse,quadratic,and cubic function curve simulation methods.Research results were indicated that high negative correlation between chlorophyll a concentration and red well position and area of red edge were founded at the 0.01 significance level.While high positive correlation between chlorophyll a concentration and LCI,WI,and TVI at the 0.01 significance level were mined.Based on the correlation analysis results,chlorophyll a concentration estimation models were established by typical curve simulation methods.Results showed that when red well postion,area of red edge,and TVI were taken as independent variables,the precision of estimation model by using inverse function was higher than that by other functions.On the other hand,when LCI and WI were chosen as independent variables,the precision of estimation model by applying cubic function was higher than that by applying other curve simulation methods.Comparing the adjusted R 2 and standard errors of the estimate of all estimation models,the author found that the precision of estimation model based on WI by using cubic function method was the highest.To sum up,chlorophyll a concentration could be highly estimated by reflectance spectra at leaf level.