On the Distribution of Cyclonic Precipitation in Japan. 



Method of Investigation. 



The " smear " method adopted Ijy Mill and Reed, though very 

 useful and convhicing for its proper purpose, is not convenient for 

 revealing the influence of the physical nature of land, since this 

 effect essentially lies in the peculiar distribution of precipitation 

 determined l)y the momentary position of the given configuration 

 of land and water, or of flat land and mountain range, relative to 

 the centre of depression, and may he quite obliterated if only the 

 smear is compared with the track of the centre. To make the 

 effect apparent, it is necessary to find the probability or the 

 amount of precipitation at different districts for different positions 

 of the depression. If these statistical data be at hand, we may 

 construct the isohyets for the different positions of the depression, 

 or draw for each district a diagram showing the distribution ()f the 

 probability or the amount for the different positions of the centre 

 relative to the district in question. 



As material for the present statistical investigations the daily 

 weather charts and " Kisyôyôran " (a brief monthly weather re- 

 view) of the Central Meteorological Observatory, from January 

 1905 to December 1915 were used. The different districts of which 

 the precipitations were to be investigated were at first classified 

 into three groups : Pacific, Japan Sea and middle regions. Each 

 group was again divided into six subgroups including the meteoro- 

 logical stations mentioned Ijelow : 



Pi Kagosima, Satazaki, Toizaki, Miyazaki. 



P2 Asizuri, Koti, Hinomisaki, Siomisaki. 



P3 Namikiri, Tu, Nagoya, Hamamatu. 



P4 Numadu, Xagaturo, Yokosuka, Yokohama, Tokyo, jNIera, 

 Tyôsi, :\Iito, Tukuba. 



P5 Kanayama, Kinkwazan, Isinomaki, Miyako. 



l\ Tokati, Kusiro, Nemuro, Abasiri. 



^Ii (Jita, Matuyama, Hirosima, Kure. 



]M2 Okaj^ama, Tadotu, Tokusima, Wakayama, Kolje, Osaka, 

 Yagi. 



