Comparative analysis of IKONOS, SPOT, and ETM+ data for leaf area index estimation in temperate coniferous and deciduous forest stands

摘要: The increasing number of sensor types for terrestrial remote sensing has necessitated supplementary efforts to evaluate and standardize data from the different available sensors. In this study, we assess potential use IKONOS, ETM+, SPOT HRVIR sensors leaf area index (LAI) estimation in forest stands. situ measurements LAI 28 coniferous deciduous stands are compared reflectance visible, near-infrared, shortwave bands, also five spectral vegetation indices (SVIs): Normalised Difference Vegetation Index (NDVI), Simple Ratio (SR), Soil Adjusted (SAVI), Enhanced (EVI), Atmospherically Resistant (ARVI). three show same predictive ability stand LAI, with an uncertainty about 1.0m 2 /m between 0.5 6.9m . For each type, strength empirical relationship NDVI remains same, regardless image processing level considered [digital counts, radiances using calibration coefficients sensor, top atmosphere (TOA), canopy (TOC) reflectances]. On other hand, NDVIs based on radiance, TOA reflectance, TOC determined IKONOS radiometric data, systematically lower than ETM+ data. offset is approximately 0.11 units radiance reflectance-based NDVI, 0.20 after atmospheric corrections. conclusions were observed indices. SVIs always those computed Factors that may explain behavior investigated. Based simulations SAIL bidirectional model coupled PROSPECT optical properties (i.e., PROSAIL), response red band main factor explaining differences two Finally, conclude that, bare soils or very sparse vegetation, acquired by SPOT, similar be used without any correction. surfaces covered dense a negative 10% should considered.