Use of multiple scattering fraction to estimate leaf area index of grass canopies

Multiple scattering intensity is mainly determined by the total area of scatterers and their scattering coefficients. In a vegetation canopy, it is more directly correlated to leaf area index (LAI) than to other structure parameters. In this study, multiple scattering fraction (MSF) of the total canopy reflectance is used as an index to derive LAI. The method is evaluated by both field measurement data and BRDF model simulations. Results in this study show that, compared to NDVI, MSF is less influenced by other factors such as spatial heterogeneity of canopy structure, Sun and view geometries, and soil background brightness, and is not saturated with increasing LAI as quickly as NDVI does. Therefore, MSF is a good replacement for NDVI for LAI estimation, especially for cases when LAI is high.