Abstract
The vertical distribution of water vapour can be considered to consist of two factors, the one concerning with the distribution of saturated vapour pressure and the other, with that of humidity or degree of nonsaturation. The former can be calculated theoretically if the vertical distribution of temperature is given, but the latter cannot be calculated theoretically at present. If we assume that humidity decreases exponentially with height, admitting some error, we have for the vertical distribution of e in the polytropic atmosphere, where γ is the lapse rate in degree/km, T_??_ surface air temperature in absolute degree, z height in km. The values of e calculated by the formula agree with the observed values of e at Sendai and Hukuoka within the errors of 12% up to 6km high.
