REPORT ON OCEANOGRAPHY 55 



As to the possible origin of the Oyashio we have the discussion of 

 N. Watanabe, who found that the most part of the Oyashio originates 

 in the water of the Okhotsk Sea and very little amount of the Bering 

 water is considered to take part in the origin of this cold current (JOSJ, 

 2, 1953). 



A very intensive water mass analysis of the Oyashio Current was 

 made by Yukimasa Saito (JIPOCU, 3, 1952, 79-140). 



Water Mass Analysis 



It is a very important problem in oceanography to separate differ- 

 ent water masses and to establish the boundaries between them. Still 

 we have not had yet any reasonable method for them. M. Nagai has 

 succeeded in classifying into 7 blocks the system of water masses in the 

 East China Sea stochastically, numbering the 18x9 water types having 

 salinity 29Voo, 291/30/00 ■ • •. 35o/oo and temperature 12^ 14M6°, 

 . . ., 30°C. (KK, 5, 1951, 54-61). 



T. Ichiye used monthly TS-diagram for determining the intensity 

 of monthly mass exchange between the coastal and ocean waters. He 

 showed how the ocean water penetrates into the bay due to the dif- 

 fusion by eddies. He also discussed the general types of the TS-dia- 

 gram in the transient region between the ocean and coastal water 

 (KMOM, 10, 1952). 



Recently Michio Miyasaki has been considering the use of T-Oj- 

 diagram in addition to TS-diagram. By doing this, he could classify the 

 so-called deep water in the Japan Sea into a number of water masses. 

 He could point out the existence of several important water types in 

 the deep layers of the Japan Sea (HFLB, 7, 1953, 1-65). 



The intermediate waters of low salinity in the regions south and 

 northeast of Japan have been discussed by J. Masuzawa in their rela- 

 tion to Kuroshio waters. He pointed out the intense turbulence both 

 in horizontal and vertical directions and determined the horizontal dif- 

 fusivity at 106-108 c.g.s. on the isentropic surface (t-26.6-26.8), (OM, 2, 

 1950; KH, 2, 1951, 5-13, 241-245). 



Y. Miyake considers that the boron in sea water behaves as a very 

 good indicator for the water masses and recommends the ratio B/Cl as 

 a useful tool in the water mass analysis (US, 30, 1952, 14-18). 



Ykimasa Saito published a very detailed water mass analysis for 

 the northern seas of Japan, stress being laid on the research on the 

 Oyashio. He could explain the significance of TS-diagram in exactly 

 the same way as W. B. Stockman tried in 1947 (JIPOCU, 3, 1952, 

 79-140). 



