Retrieval of atmospheric parameters from the hyperspectral image data

Interaction of radiation emitted or reflected by the ground with the atmospheric constituents gives rise to trouble when remote sensing of the Earth is attempted. In fact atmospheric gases and aerosols are responsible for radiation absorption and scattering; due to these phenomena the radiation field observed by any remote sensing imaging system holds features originated not only by the ground, but also by the atmospheric constituents themselves. Features introduced by the atmosphere must be removed (atmospheric correction), when the retrieval of ground parameters is the main goal of observations. On the other hand they can also be used for extraction of information concerning those atmospheric constituents which originated them. The authors have tried to carry out atmospheric mapping by using the O₂ band at 0.76 mm and the H₂O band at 0.94 mm. The utilised band parameters have been the central depth normalised to the continuum intensity, the full-width at half maximum and the band area. The effect of the atmospheric scattering on this kind of band measurements has been investigated. The authors have used the computer code MODTRAN in order to evaluate the ground reflected radiance and the path scattered radiance. Images utilised for the paper have been acquired by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) over Cuprite (USA) and over Messina (Italy)