Relating satellite multiangular thermal infrared observations to soil and foliage temperature Original Research Article

The anisotropy of thermal infrared (TIR) radiance emitted by terrestrial targets comprising a mixture of soil and foliage is well documented by both ground and space — based radiometric data. Since TIR radiance depends on surface temperature and surface emissivity, observed anisotropy can be interpreted in terms of either anisotropy in emissivity or, for heterogeneous terrestrial targets, of differences in component temperatures. This paper focuses on the latter. A simple linear mixing model is proposed to relate the component temperatures of soil and foliage to the radiance emitted by a soil — foliage mixture. The underlying assumptions are briefly reviewed. It is finally shown that the simple linear model can be used to retrieve soil and foliage component temperatures from radiometric observations at different view angles. This is illustrated with a case — study based on TIR radiometric data collected by the Along Track Scanning Radiometer (ATSR-2) on board the ERS- 2 during the SGPʹ97 and HEIFE experiments.