THE EFFECTS OF SURFICIAL VEGETATION COVER ON MINERAL ABSORPTION FEATURE PARAMETERS

The effects of surficial vegetation cover on the efficacy of automated absorption feature extraction and parameterisation of short-wave infra-red (SWIR) mineral absorption features is investigated. Synthetic spectral mixtures were generated from laboratory spectra of five SWIR absorbing minerals and live/dead vegetation. After convolution to the bandpasses of the Airborne Visible/Infra-Red Imaging Spectrometer the deepest absorption feature in each spectral mixture was extracted and parameterised in terms of wavelength position, depth, full width at half maximum depth, area and asymmetry. Live vegetation was found not to influence the wavelength position of mineral absorption features, conversely, dead vegetation induced abrupt and large shifts in wavelength position. Both live and dead vegetation reduce the depth of mineral absorption features, however, dead vegetation has the greatest impact on absorption features located at or near 2200 nm. Dead vegetation was found to have a significant impact on the width, area and asymmetry of mineral absorption features.