The accurate determination of atmospheric temperatures from outgoing l
ongwave radiation depends upon the effective atmospheric emissivity us
ed in Stefan-Boltzmann's law. We reviewed the literature dealing with
the atmospheric emissivity equations for clear sky and studied their e
ffects on the clear sky atmospheric temperatures. The clear sky outgoi
ng longwave radiation data were taken by the National Aeronautics and
Space Administration's (NASA) Earth Radiation Budget Satellite (ERBS)
scanning radiometers. The five years (1985-1989) of global annual-mean
of clear sky atmospheric temperatures with different emissivity value
s are presented and discussed in this paper. The effect of emissivity
on the retrieval of clear sky atmospheric temperatures are found to va
ry by 7-8 K (Kelvin).