Science Letters:A modified chlorophyll absorption continuum index for chlorophyll estimation

INTRODUCTION Great advance has been achieved in vegetation characterization with remote sensing techniques. Most spectral vegetation indices (VIs) are usually calculated as the combinations of red and near-in- frared (NIR) reflectance because the information contained in a single spectral band is insufficient for characterizing vegetation status as vegetation exhibits unique reflectance properties in these bands. These VIs can be generally grouped into ratio indices and orthogonal indic…

Science Letters: A modified chlorophyll absorption continuum index for chlorophyll estimation

There is increasing interest in using hyperspectral data for quantitative characterization of vegetation in spatial and temporal scopes. Many spectral indices are being developed to improve vegetation sensitivity by minimizing the background influence. The chlorophyll absorption continuum index (CACI) is such a measure to calculate the spectral continuum on which the analyses are based on the area of the troughs spanned by the spectral continuum. However, different values of CACI were obtained in this method because different positions of continuums were determined by different users. Furthermore, the sensitivity of CACI to agronomic parameters such as green leaf chlorophyll density (GLCD) has been reduced because the fixed positions of con- tinuums are determined when the red edge shifted with the change in GLCD. A modified chlorophyll absorption continuum index (MCACI) is presented in this article. The red edge inflection point (REIP) replaces the maximum reflectance point (MRP) in near-infrared (NIR) shoulder on the CACI continuum. This MCACI has been proved to increase the sensitivity and predictive power of GLCD.