Atmospheric Effects on Tm Measurements: Characterization And Comparison with the Effects on Mss

The effects of the Earth´s atmosphere on the Thematic Mapper (TM) measurements are studied with two radiative transfer models. A doubling model is used to compute the effective reflectance of the Earth-atmosphere system, as measured by the TM for the reflective bands. An emission-transmission model is used to compute the satellite -received radiance for the thermal band. The influences of the aerosol loading, the amount of water vapor, and the solar illumination angle on the effective reflectance are investigated. The effect of varying atmospheric water vapor on the measurements of the thermal band is studied. The scattering and absorption effects on TM bands are compared with those on Multispectral Scanner System (MSS) bands. While the changes in the aerosol loading introduce comparable variation of the effective reflectance for both sensors, the changes in the water vapor amount give less impact on TM4 than MSS7.