利用高光谱植被指数估测苹果树冠层叶绿素含量

摘要

叶绿素含量是反映植物生长状况的重要参数.利用ASD FieldSpec 3光谱仪,测定春梢停止生长期苹果冠层高光谱反射率,对原始光谱进行微分变换,与苹果叶绿素含量进行相关分析确定敏感波段,通过分析敏感区域400～1 350nm范围内所有两波段组合的植被指数,选择最佳植被指数并建立苹果冠层叶绿素含量估测模型.结果表明:(1)苹果冠层叶绿素含量的敏感波段区域为400～1 350nm.(2)利用筛选得到的植被指数CCI (D794/D763)构建的估测模型能较好的估测苹果冠层叶绿素含量.(3)以CCI (D794/D763)指数为自变量的估测模型CCC=6.409+1.89R3+1.587R2-7.779R预测效果最佳.因此,利用高光谱技术能够较快速、精确的对苹果冠层叶绿素含量进行定量化反演,为苹果长势的遥感监测提供理论依据.%The hyperspectral reflectance of apple tree canopy during spring shoots stopping growth period was measured using ASD FieldSpec3 field spectrometer.Original spectral data were processed in deviation forms,and significant spectrum parameters correlated with chlorophyll content were found out with correlation analysis.The best vegetation indices were chosen and the apple canopy chlorophyll content estimation model was established by analyzing vegetation index of two-band combination in the sensitive region 400～1 350 nm.The result showed that (1) The sensitive band region of apple canopy chlorophyll content is 400 ～ 1 350 rm.(2) The vegetation index CCI(D794/D763)can commendably estimate the apple canopy chlorophyll content.(3) The model with CCI(D794/D763)as the independent variables was determined to be the best for chlorophyll content prediction of apple tree canopy.Therefore,using hyperspectral technology can estimate apple canopy chlorophyll content more rapidly and accurately,and provides a theoretical basis for rapid apple tree canopy nutrition diagnosis and growth monitoring.