基于SPAD值的植被“红边位置”确定方法探讨

Determination of the Position of the Red Edge in Accordance with the SPAD Value

以茶树、杨梅树和樟树为研究对象,每种树分3个部位随机采集50个叶片,应用线性内插方法、倒高斯方法、有理函数方法和拉格朗日等4种红边位置估算方法,分别计算了相关叶片的红边位置。同时将3种树叶的SPAD(叶绿素)值分别按照数值大小、树叶在树上的不同生长位置等为基数组成区间,再按照区间数据的不同组合共计分为25个区间段,然后运用SPSS软件,按照不同分划区间将红边位置与树叶的SPAD值进行双变量相关分析与计算。其结果表明无论怎样划分区间,依据SPAD值的红边位置以线性内插方法的吻合度最高,有理函数方法次之。

In this paper, the leaves were collected according to the growth from the canopy of the three tree species including tea, Yang Mei tree and camphor,SPAD values and reflection were measured from 50 leaves of each species, and red edge position was identified by 4 methods including inverted Gaussian methods, rational function, the Lagrange function,and the linear inter- polation. The range of the SPAD data was divided into 25 segments according to the SPAD value and growth state. Using SPSS software,bivariate correlation between the red edge position and the range of the SPAD value from different division were ana- lysed. The results show that no matter how divided interval,the best method to estimate red edge was the linear interpolation, followed by a rational function method.