THE PACIFIC OCEAN 



99 



this conclusion appears to be verified when one compares 

 conditions at stations 104 and 149. 



The deep water is again of a uniform character. The 

 temperature decreases and the salinity increases with 

 increasing depth as far down as observations have been 

 carried out. 



Section IX. --Section IX, comprising stations 107 to 

 120, is actually composed of two different sections, one 

 running southwest from latitude 47° 02' north and longi- 

 tude 166° 20' east to the coast of Japan off Yokohama, 

 and one funning north and south following practically the 

 meridian of 144° east between latitudes 35° and 14° 

 north. We shall discuss the latter part of the section 

 first. 



The convection layer has a thickness of about 50 

 meters at the southern stations of the section, but at the 

 northern stations it has a thickness of less than 40 me- 

 ters. 



Temperatures above 25° are found at the three 

 southern stations only, but the isotherm of 10°, except 

 for some undulations, runs almost horizontally at a 

 level of approximately 500 meters, but between the two 

 most southerly stations it rises distinctly toward the 

 south. In this most westerly section we thus find the 

 greatest accumulation of warm water in the upper layers, 

 but in the deeper layers the temperatures are higher at 

 the southern stations. Between 500 and 1000 meters the 

 isotherms diverge toward the south. 



The surface salinity has values above 35.00 per 

 mille between stations 108 and 109 only. Values above 

 35.1 per mille are found between 150 and 200 meters in 

 the most southern part of the section, indicating a trans- 

 port of water of high salinity from the surface region of 

 high salinity located to the northeast. At a depth of 

 about 500 meters the isohaline of 34.2 per mille runs 

 almost horizontally, undulating up and down, and cor- 

 responding to the course of the isotherm of 10°. A con- 

 spicuous rise toward the south is found between stations 

 107 and 108 corresponding to the rise of the isotherms 

 between these stations. The layer of minimum salinity 

 can be followed at all stations to the south of station 113. 

 Between stations 109 and 113 the axis of the minimum 

 value lies at a level of 650 meters where the tempera- 

 ture is about 6° and rises to 8.°5 at a depth of 450 me- 

 ters at station 107 to the south of station 109. Compar- 

 ing these conditions with the corresponding conditions 

 in Section VII in the same latitude, we find that the layer 

 of minimum salinity probably lies somewhat deeper in 

 the most western part of the ocean. 



In the deep water the temperature, which decreases 

 very slowly toward the north, decreases with increasing 

 depth; and the salinity, which below a level of about 2000 

 meters is slightly above 34.6 per mille, increases with 

 depth. 



In the northeastern part of Section IX we find a 

 quite different stratification. The convection layer is 

 very thin, especially at the northeastern stations where 

 it perhaps has a thickness of 10 meters only. 



The most conspicuous feature of the vertical dis- 

 tribution of temperature is the very rapid change in the 

 character of the temperature distribution between sta- 

 tions 112 and 116. The isotherms rise rapidly toward 

 the north in a manner which reminds one of the rise of 

 the isotherms toward the north on the southern side of 

 the Grand Banks of Newfoundland in the Atlantic. Be- 

 tween stations 115 and 116 we find a "cold wall." The 

 change in the temperature distribution, however, appears 



to be of an irregular character and from the course of 

 the isotherms, it seems that whirls are formed along 

 the boundary between the warm water to the south and 

 the cold water to the north. The great temperature con- 

 trasts are present down to a level of 500 meters. Below 

 this level the contrasts gradually get smaller and at 

 1000 meters the temperature difference has been re- 

 duced to 1°. At 2000 meters practically nothing is left. 



Between stations 112 and 116 the salinity decreases 

 as rapidly as the temperature. The great irregularities 

 in the distribution of the salinity strongly support the 

 opinion that whirls of great dimensions are formed at 

 the boundary between the warm water of high salinity to 

 the south and the cold water of low salinity to the north. 

 The lowest surface salinities are found at the most 

 northeastern stations 119 and 120 where the values are 

 below 33.00 per mille. 



The great contrast between the salinities of the up- 

 per layers can be followed to a depth of about 500 me- 

 ters, but below this level it almost disappears. It is of 

 interest in this connection to note that to the north of 

 station 116 the isoha'ine of 34.00 per m'lle lies at a level 

 of approximately 400 meters where the temperature is 

 somewhat above or somewhat below 4°. It also is of in- 

 terest to note that a downward transport of water, which 

 has the same character as the intermediate water of low 

 salinity in the southern part of the section, apparently 

 takes place only between stations 115 and 116, and that a 

 downward transport of such water can hardly be traced 

 at the northeastern stations. 



The deep water has the same characteristics as in 

 the southern part of the section. Taking the section as a 

 whole, we find a tendency toward decreasing tempera- 

 ture and decreasing salinity as we proceed toward the 

 north at a level of about 2000 meters. 



SectionXVL- -Section XVI (stations 118 to 125) runs 

 west-southwest from latitude 51° 58' north and longitude 

 150° 39' east to 42° 29' north and 155° 24' west. In the 

 eastern part the section bends slightly toward the north. 

 On a short stretch it runs along the Aleutian Islands and 

 continues at last in a southwesterly direction. The con- 

 vection layer is very thin at all stations, especially in 

 the western part of the section where it is of the order 

 of 10 meters only. 



Below the topmost surface layer we find between 

 stations 119 and 123 a layer of minimum temperature at 

 a level of about 100 meters. At stations 119 and 120 the 

 temperature within this layer is below 2° and farther to 

 the east values smaller than 3° are found. This water of 

 very low temperature probably comes from the Bering 

 Sea where it has been formed in the preceding winter 

 and from where it has entered the Pacific Ocean, and 

 partly spread toward the east. At greater depths the 

 temperature decreased regularly as far down as the ob- 

 servations were made 



The salinity is very low at the surface and increases 

 with depth at all stations except at station 118 where 

 some irregularities are found above 200 meters. The 

 increase of the salinity is especially rapid down to the 

 200-meter level. From there the increase continues at 

 a slow rate and the value 34.°6 is reached somewhat be- 

 low the 2000-meter level. 



It should be pointed out especially that in this sec- 

 tion we find no layer of minimum salinity. Furthermore, 

 we find no water masses which have the characteristic 

 temperature and salinity of the intermediate water in the 

 southern sections, namely, 6° and 34 per mille. The 



