22 ^^^ ^^^*' Distribution of Cyclonic Precipitation in Japan. 



2.) Centre Loci. 



As already explained, Figs. 21 to 38 sh(3w for eacli of the 18 

 districts, tlie percentage expectation brought about Ijy all possible 

 different positions of the barometric depression. For example, in 

 Fig. 21 the curve marked with 50 shows the trace of the positions 

 of the centre which may bring precipitation t(j the district Pj in 50 

 cases out of 100 on an average. 



From these figures, it will be at once seen that the area with 

 the greatest expectation lies mostly on W, SW or S side of the dis- 

 trict in question. This implies that the expectation is generally 

 greatest on E, NE or N side of a cyclone. On a closer examina- 

 tion, however, we may easily discern the characteristic difference 

 between the Pacific and the Japan Sea coasts. For the P districts, 

 the bO% curves generally pass along the immediate neighbourhoods 

 of the middle point of the districts concerned and the areas with 

 the greater expectations lie entirely on the W to S sides of the dis- 

 tricts. For the J group, however, the districts in question lie 

 decidedly apart from the 50% lines and nearer to the point with 

 the maximum expectation ; moreover, the extent of the belt with 

 10 to 50% expectations in front of the district, is decidedly greater 

 than that in the case of the P districts. Besides, J-., J4 and J5 show 

 a belt with the lesser expectation projecting far in advance of the 

 district, while J3, J4, J,, also suggest another maximum near Sagha- 

 lien. For J« the district in question apparently lies on the rear side 

 of the area with the maximum expectation. For the M districts, 

 the relations are intermediate between P and J as may be 

 expected. 



One interesting relation revealed b}^ this way of graphical re- 

 presentation may be worth a special description. Referring to 

 Figs. 22 to 26, suppose a line drawn along the longer axis of the 

 elongated area with expectations above 30 or 50 %, for each of P,, 

 P2, P3 Pe- The lines seem to turn round clockwise as we pro- 

 ceed successively from Pj to P«. The same tendency is more ap- 

 parent for Ms to Me. The interpretation of this peculiar relation may 

 probably be sought in the influence of the Japan Sea depressions. 



