Estimating LAI using EVI based on canopy radiative transfer model

摘要

Leaf area index (LAI) is an important biophysical parameter of vegetation canopy. LAI can be estimated from canopy or image spectra by vegetation indices or by inversion of canopy radiative transfer model. Because of the BRDF effect of vegetation indices, the estimation precision of LAI from vegetation indices depends on observation or illumination angles, soil background, leaf angle distribution etc. In this study, an atmospherically corrected vegetation index, enhanced vegetation index (EVI), is selected to estimate LAI. The effects of chlorophyll content, LAI, leaf angle distribution, observation/illumination angle, soil background on EVI are simulated by PROSAIL canopy radiative transfer model, and the sensitive factors and variances ranges are also analyzed. Then, LAI was estimated using EVI from field spectra, which are corrected by PROSAIL.