I am working to estimate Above Ground Biomass (AGB) using ground sample data and then intending to work out its potential relationship between different vegetation indices like NDVI, RVI, DVI, SAVI, MSAVI etc. This relationship will be ascertained using regression equation. Resultantly, I will be able to predict AGB of earlier date after choosing suitable index to proceed with. I am using images from two different sensors, Landsat 8 OLI (January 2017) and ETM+ (January 2007) to derive above noted vegetation indices and to see change in AGB over the period. All of the said indices involve RED and NIR band to scale vegetation density and intensity. I have noticed the difference in wavelengths of both sensors’ required bands as follows; Wavelength (micrometers) Landsat 7 ETM+ Band 3 – Red : 0.63-0.69 Band 4 – Near Infrared (NIR) : 0.77-0.90 Landsat 8 OLI Band 4 – Red : 0.64-0.67 Band 5 – Near Infrared (NIR) : 0.85-0.88 See Reference https://landsat.usgs.gov/what-are-ban... Keeping in view this wavelength difference of both sensors' RED & NIR Bands, I am interested to know whether this difference will affect my intended results? As such I am estimating increase or decrease of AGB over time by comparing both images with suitable Vegetation Index involving RED & NIR bands of both sensors.