The correlation coefficients of all new spectral indices in the original spectra, the reciprocal spectra, logarithmic spectra and square root spectra.

And the top three NSIs significantly correlated with LNC in first-derivative spectra and second-derivative spectra. The correlation coefficient refers to the result of correlation analysis between LNC and NSIs calculated by SWs from different spectral datasets. DSI, RSI and NDSI represent the difference spectra index, ratio spectral index and normalized difference spectral index respectively. R, 1/R, logR, R1/2, R’ and R′′ represent the original spectra, the reciprocal spectra, logarithmic spectra, square root spectra, first-derivative spectra and second-derivative spectra respectively. The NSIs are listed in descending order of the absolute values of the correlation coefficients.

在一阶导数光谱（first-derivative spectra）与二阶导数光谱（second-derivative spectra）中，与叶片氮浓度（Leaf Nitrogen Concentration, LNC）呈显著相关的前三项窄带光谱指数（Narrow-band Spectral Indices, NSIs）：相关系数指通过不同光谱数据集的滑动窗口（Sliding Windows, SWs）计算得到的NSIs与LNC之间的相关分析结果。DSI、RSI与NDSI分别代表差分光谱指数（difference spectra index）、比值光谱指数（ratio spectral index）及归一化差分光谱指数（normalized difference spectral index）。R、1/R、logR、R^(1/2)、R’及R''分别代表原始光谱、倒数光谱、对数光谱、平方根光谱、一阶导数光谱与二阶导数光谱。所述NSIs按相关系数绝对值的降序排列。