Reflectance measures of grassland biophysical structure

The goal of this study is to develop an efficient method to retrieve vegetation biophysical properties based on ground LAI measurements and satellite data, and thus avoid the labour-intensive and time-consuming process for collecting biomass and canopy height in the future. The field data was conducted in Grasslands National Park (GNP), Saskatchewan, Canada. The two vegetation indices, ATSAVI and RDVI, were derived from SPOT 4 HRV images to estimate LAI and to prepare LAI and biophysical maps for the GNP. The results demonstrated strong relationships between LAI and selected vegetation indices. However, a detailed accuracy assessment indicated that ATSAVI was likely to be better in estimating and mapping LAI than the RDVI. The accuracy of the LAI map was calculated to be 66.7%. The significant relationship between measured LAI and the biophysical data solves the difficulty for mapping biophysical information due to insufficient sampling coverage for GNP.