PRECIPITATION ON MOUNTAIN SLOPES POCKELS lOI 



Similarly, we find for winter: 



C x = =380, G x=>l/6 ~770, G._ w -1264; 



the total precipitation is distributed over a strip 9400 meters iong, 

 so that the average precipitation is 0.485 millimeters per hour. 



From the above three values of G (x) we can graphically construct 

 the course of this function approximately by considering that the 

 tangent to the curve for G is horizontal at its initial point and when 

 x = + A/ 4. 



The tangent to the slope of the curve is found by considering its 

 measure W. Thus we recognize in our case that the maximum 

 of the precipitation in summer is attained between x = o and 

 x = — 1, but in winter between x = o and x — + 2 kilometers 

 and amounts to a X 2.2 millimeters, or a X o.75^millimeters per 

 hour, respectively, for a wind velocity of a meters at some very 

 great altitude; furthermore, after passing the summit of the moun- 

 tain the precipitation diminishes more slowly than was found under 

 our previous assumption of a constant thickness of clouds. In 

 reality, on account of the conveyance of the water or ice with the 

 cloud, which we still neglect as before, the maximum of precipita- 

 tion is pushed still more toward the summit of the mountain. More- 

 over, since one part of the cloud floats over the summit and is there 

 dissipated in the sinking or descending currents of air, the precipi- 

 tation will stretch a little beyond the summit, but its total quantity 

 will be less than the computed. 



The results of the preceding analysis, namely, (1) that there exists 

 a zone of maximum precipitation on the windward slope of a moun- 

 tain and (2) that the inclination of the surface of the earth is more 

 important than its absolute elevation, in determining the quantity 

 of precipitation, are confirmed by observations, at least for the 

 higher mountains. 12 



12 See Hann: " Klimatologie," Vol. I, p. 2( 



