In August the surface water temperature continues rising and reaches the maximum 



for the year at 23.2 to 25.7 C. The zone with the highest water tennperatures appears 50 



miles off the coast. Within about 100 miles of the coast there is a marked thermocline between 



o ^ o 

 the 25-meter level and the 50-meter level, with temperatures at the former of 19.7 to 21.5 C. 



compared with 7 to 9 C. at the latter. At the 150-mile station the thermocline is deeper, ap- 

 pearing between the 50- meter and the 100-meter levels. 



o 



In September the surface water temperatures have already begun to go down with 19 



to 22.3 C. indicated at the surface. There are some differences between areas, but in general 

 beyond 50 miles from the coast, the thermocline is between the 50-meter and 100-meter level. 



In October the stirring of the sea water by convection is clearly apparent, and water 

 temperatures at all levels above 100 nneters show sinnilar values. Water temperatures are 

 highest at the station 20 miles off the coast, and the temperatures are rather conspicuously lower 

 east of the 100-mile station. 



In November the water temperatures go down even more with 16.8 C. at the 20-nnile 

 station, about 16 C. between 50 and 80 miles off the coast, and a sharp drop farther to the east- 

 ward to 11. 5° to 12° C. 



In December water masses with temperatures above 10 C. are within 50 miles of 



the coast, amd within this area water temperatures gradually drop outward from shore. Water 



temperatures at the station 80 miles of the coast are much lower, 6 to 7 C. , auid at the 100- 



^ o 



mile station they rise somewhat to over 8 C. 



The following table presents some abstracted information for January and August 

 from transverse sectional observationa somewhat farther south off Shioyasaki. 



If this is compared with the data from the Same section, the temperatures in 

 January are generally higher except for the vicinity of 50 miles off the coast, and the difference 

 becomes more marked the farther eastward one goes until in the vicinity of 150 miles off the 

 coast the temperature is up to 19.5 C. The water mass centered around 50 miles off the coast 

 is colder than the water off Same, showing that the main current of the Oyashio is located in this 

 area. 



On the other hand, in August up to 100 miles from shore the temperatures are lower 

 than off Same, and east of 100 miles off the coast there is a zone of remarkably high tempera- 

 tures. Off Same there was a conspicuous thermocline between the 25-meter and 50-meter levels, 

 but in this sea area there is no particularly outstanding discontinuity apparent down to 100 meters. 



Table 77 shows temperature and salinity data for January and August based on 

 sectional observations due east of Inubosaki near the southern extremity of this sea area. 



As the table shows, in January the water temperatures gradually rise the farther one 

 goes off shore, with the maximum water temperatures in the vicinity of the 50-mile station. 

 Farther off the coast from this station the temperatures gradujilly fall. At the 10-mile station 

 the water temperature at the 100-meter level falls rather steeply, but no direct effect of the 

 Oyashio can be seen at the other stations down to 100 naeters. 



In August the highest temperature zone is about 50 miles from the coast, showing that 

 this vicinity is about the center of the Kuroshio. From 10 to 20 miles offshore the water temper- 

 atures axe conspicuously lower than elsewhere, and salinity values are also low in the coastal 

 water zone. 



110 



