ANALYSIS ON OPTIMAL BANDS FOR RETRIEVAL OF MIXED CANOPY CHLOROPHYLL CONTENT BASED ON REMOTE SENSING

摘要

A large number of spectral indices have been developed for estimation of leaf chlorophyll content. However, in most cases these indices have been tested for only one or at most a few related species and thus it is not clear whether they can be applied across species with varying leaf structure characteristics. The main objective of the study was to find spectral bands that are sensitive to variation in chlorophyll content and are relatively insensitive to species and leaf structure variation, and determine optimal wide bands range for retrieving chlorophyll content of mixed canopies that consist of diverse species, then develop wide bands based approach to retrieve chlorophyll content of mixed canopies. We analyzed the correlation between chlorophyll content and reflectance, the first derivative of reflectance using LOPEX93 database respectively. The results showed: (1) red edge spectral indices provided relatively good correlation with chlorophyll content when applied across a wide range of species; (2) the optimal band for estimation of chlorophyll content was found at 698-715nm range; (3) for the first derivative of reflectance, the optimal bands for estimation of chlorophyll content were at 720-735nm range and 535-550nm range.