October 1966 to 20 October 1967. The data of 

 these nine patrols, as well as that gathered 

 since January 1964, have been carefully stud- 

 ied in the preparation of this report. With the 

 help of the data collected on the previous pa- 

 trols, the variations of temperature and sa- 

 linity since January 1964 have been included in 

 this report. 



Figures 12-20 show the vertical envelopes 

 of temperature vs. depth for each of the nine 

 patrols. Figure 12 shows the thermocline to be 

 expected during the month of October. During 

 this month the surface temperature varied be- 

 tween 6.14 and 7.09° C. The surface layer ex- 

 tended down to about 50 meters. The main 

 thermocline was limited to the region between 

 50 and 100 meters where an average decrease 

 of 2.40° C/50 meters was found. There was a 

 slight temperature inversion between 100 and 

 150 meters, after which the temperature grad- 

 ually decreased with depth. 



The effects of the start of winter cooling are 

 depicted in figure 13. The surface temperature 

 ranged from 4.85 to 3.99° C. with the excep- 

 tion of one station where the surface tempera- 

 ture of 5.59° C. penetrated to a depth of 50 

 meters. The data for this station have been 

 carefully checked and are considered valid. Al- 

 though not defined in figure 13, there were two 

 inversions in the top 150 meters of the water 

 column on most of the stations taken during 

 this patrol. 



During the January 1967 patrol of the 

 HUMBOLDT the surface temperature ranged 

 from 3.51 to 3.96° C. as shown in figure 14. 

 For the most part, the temperature decreased 

 with depth; however, there was an occasional 

 increase of temperature with depth (six out of 

 20 stations). The maximum temperature in the 

 water column was found between 200 and 250 

 meters during the first part of the month. To- 

 ward the end of the month this maximum temp- 

 erature decreased both in value and in depth as 

 a result of lateral mixing. 



This mixing continued through the patrols 

 of both the USCGC BIBB (figure 15) and the 

 USCGC ESCANABA (figure 16). During the 

 BIBB patrol the temperature experienced a 

 slight increase with depth, the depth of the 

 maximum temperature remaining close to the 

 400 meter level but occasionally shifting down 

 to 600 meters. This maximum temperature 



range was 3.69-3.97° C. compared to a surface 

 temperature range of 3.41-3.52° C. By the 

 start of the April patrol, the temperature in- 

 version had all but disappeared, and by the end 

 of April the surface temperature had de- 

 creased to 3.37° C. As a result there was a 

 gradual increase in temperature with depth 

 throughout the water column. 



Toward the end of May, warming in the 

 upper 100 meters of the water column was no- 

 ticeable (figure 17). Daily fluctuations of up to 

 0.42° C. occurred in the surface temperature, 

 but below the 100 meter level the temperature 

 remained relatively constant. 



By late June the surface temperature had 

 risen to a range of 5.75-8.41° C. There was a 

 large temperature gradient in the upper 100 

 meters and a slight increase in temperature in 

 the 100-200 meter range over the previous 

 month (figure 18). 



The surface temperature continued to in- 

 crease until it reached a maximum in late Au- 

 gust and early September (figure 19). This 

 maximum temperature was in the neighbor- 

 hood of 9.5° C. The maximum temperature 

 gradient was still in the upper 100 meters. 

 However, the effects of summer warming were 

 apparent down to about 450 meters. 



The surface temperature began to drop dur- 

 ing October (figure 20). The maximum temper- 

 ature gradient was still located in the upper 

 100 meters and the effects of warming had pe- 

 netrated to 600 meters. 



Figure 21 represents the variation in tem- 

 perature in the upper 400 meters at Ocean Sta- 

 tion BRAVO. Monthly averages were com- 

 puted from Nansen cast data collected by the 

 Coast Guard since it started monitoring the 

 station in January 1964. 



The most noted feature is the regularity 

 with which the temperature varies at all four 

 levels during each 12 month period. At the sur- 

 face a maximum temperature of about 9.5° C. 

 occurs in late August and early September for 

 all years except 1964, and the minimum usu- 

 ally occurs in March with a temperature 

 range of 3-3.5° C. 



At the 50 meter level the maximum tempera- 

 ture lags the surface maximum by about six 

 weeks, occurring in October. This maximum 

 temperature (6.5° C.) is the same temperature 

 as that at the surface at this time. The tempera- 



