An adequate band positioning to enhance NDVI contrasts among green vegetation, senescent biomass, and tropical soils

Airborne Visible/InfraRed Imaging Spectrometer (AVIRIS) imagery was used in a quantitative evaluation of the impact of band positioning and bandwidth on values of Normalized Difference Vegetation Index (NDVI) for green vegeta tion (GV), senescent biomass (SB), and soils (S). The results show that the band positioning needed to maximize the NDVI contrast between GV and SE or S should include a narrow or broad red band centred around the chlorophyll absorption band, between 660 and 680 nm, and a narrow near-infrared (NIR) band placed at the shortest wavelength in the 750-1100 nm range. NDVI diffe rences between extreme NIR band positioning can reach values of 0.35 in are as of accentuated phenological contrast. Of the broad-band sensors analysed in this study, Landsat-5 Thematic Mapper (TM) and NOAA-11 Advanced Very Hi gh Resolution Radiometer (AVHRR) presented, respectively, the most favourab le and unfavourable positioning.