ELEMENTARY VIEW OF GREENHOUSE EFFECT OF THE ATMOSPHERES OF VARIOUS PLANETS

The global mean temperatures of the atmosphere and the surface of various planets of the solar system are determined by taking the system as in radiative equilibrium,with the atmosphere taken as transparent to solar radiation but with an albedo α,and composed of N layers each of which absorbs all infrared radiation that falls on it,and a top layer of partial absorptivity a,while the surface is taken as black.It is found that,for the earth's atmosphere with α=0.33, N=0,a=0.83,it gives the current observed mean surface temperature Ts=15℃ and the effective mean radiative temperature of the atmosphere Ta=242.6K.On the other hand;the atmosphere of Venus is characterized by α=0.70 and N=70,which yields a surface temperature of about 700K.It is also found that surface evaporation and absorption of solar radiation by the atmosphere tend to lower the surface temperature.