On the Distribution of Cyclonic Precipitation in Japan. 19 



Discussion of the Results, 

 1.) Isohyels. 



A passing glance at the isohyets will reveal tlie undeniable in- 

 fluence of the land and water. Referring to Figs. ], 2, 5, 14, 17, 

 19 and 20, we see that in front of a distant cyclone, the Pacific 

 coast has decidedly greater expectation than the Japan Sea coast, 

 whereas on the rear side the reverse is the case. This fact has al- 

 ready been noticed and explained by one of us in the above cited 

 paper. This relation is not so conspicuous as in the above exam- 

 ple when the cyclone approaches tlie main island, though the same 

 tendency is still suggested by the shape of some isohyets, as in Figs. 

 3, 4, 6, 7, 8, 1], 13, 16 and 18, especially in the regions remote 

 from the centre of depression. In the immediate neighbourhood 

 of the centre, the difference between the Pacific and the Japan Sea 

 coast is not conspicuous, as may be seen from Figs. 3, 4, 6, 7 etc. 

 It is quite evident that the above cited theory requires a modifica- 

 tion in the inner region of a cyclone where the curvature of the 

 isobars and the variation of the gradient could no more be neg- 

 lected, and the ascending air current proper to this region is more 

 conspicuous, so that the effect of the topography does not appear 

 so pronounced as in the external region. 



Comparing Figs. 5, 12, and 15, it may be seen that the dis- 

 trict Mo and probaljly also J3 shows some local irregularities, which 

 may probably be attributed to the peculiar configuration of land 

 and water in this region. Next, referring to Figs. 15, 16 and 18, 

 a tendency is suggested that wlien the centre lies in tlie Japan Sea, 

 M districts often show smaller expectations than the neighbouring 

 P or J districts. This peculiarity is most pronounced in the iso- 

 hyets for the position of the centre, 132.5° E, 42.5° N which were 

 omitted in the above diagrams, since the number of occurence JV 

 in two of the four meshes surrounding this point were less than 5. 

 If we nevertheless calculate the corresponding expectations, we 

 obtain 



Ml M, M3 M, M, Mo Pi P. Pa P4 P5 P6 Ji J2 Ja 'h J5 Jg 



8 8 9 5 7 7 2 16 16 7 13 6 8 13 32 29 20 32 



