SOIL AND ATMOSPHERE INFLUENCES ON THE SPECTRA OF PARTIAL CANOPIES

An atmospheric radiant transfer model was used to compare ground-measured radiances over partially vegetated canopies with their simulated responses at the top of a clear (100 km meteorological range) and a turbid (10 km) atmosphere. Radiance mesurements in the first four bands of the Thematic Mapper were taken over incomplete cotton (Gossypium hirsutum L.) and Lehmann lovegrass (Evagrostis lehmanniana Nees) canopies with different soil backgrounds separately inserted underneath. Atmospheric influences on the spectra of partial canopies were found to be significantly dependent on the 'brightness' of the underlying soil. The change in canopy red and near-infrared radiance between the ground and the top of the atmosphere was the such that an increase, decrease, or no change could be observed, depending on the magnitude of the canopy substrate contribution.