^:;j^ 



T'C. 



cOn tT ST ST BT 



=• IT M-> •• IS Ml 



T°C. 



Figure 13.--Vertical distributions of temperature on cruise TO- 

 58-2, parts 2 and 3, along section D-D (see fig. 8); depth scale inm. 



yc. 



Figure 14.--Vertical distributions of temperature on cruise TO- 

 58-2, parts 2 and 3, along section C-C (see fig. 8); depth scale inm. 



Figure 18 shows the following profiles along 

 A-A: (A) and (B), temperature on parts 1 and 2 

 of the cruise; (C-F), salinity, thermosteric 

 anomaly, oxygen, and phosphate on part 1. 



Figure 18A is interpreted as follows: the 

 thermal structure below the 24° isotherm 

 indicates the westward descent of isotherms 

 from the ridge in conformity with the south- 

 ward permanent flow, but the descent appears 

 to be irregular because the western boundary 

 of the ridge is sinuous (figs, 16A, 16B); 

 the structure above the 24° isotherm results 

 from an eastward incursion (fig. 16A) of 

 warm water, partially destratified at about 

 9503O' W. under the influence of the norther 

 that began after station 23. 



Figure 18B shows the westward descent of 

 isotherms in the same region but without the 

 above-mentioned complications, which were 

 probably removed by the Tehuantepecer that 

 occurred between parts 1 and 2 of the cruise; 

 the double thermocline at 96o W. is explained 

 below. The crest of the ridge is at about 94°, 

 as in previous sections, and the area of 

 partial vertical mixing to the west of that. 

 The thermocline top reaches to about 15 m. 

 below the surface, as in thepost-Tehuantepecer 

 section for November (cruise TO-58-2, fig. 

 11 B). 



The remaining parts of figure 18 agree 

 substantially with figure 18A. Figure 18A 

 differs from them in the part of the section 

 between stations 20 and 24, because BT 

 lowerings were available to provide addi- 

 tional temperature information. 



Figure 19 shows the following profiles along 

 the north-south section D-D (not B-B): (A) 

 and (B), temperature on parts' 1 and 2 of the 

 cruise, (C-F), salinity, thermosteric anomaly, 

 oxygen, and phosphate on part 1. Figure 19A 

 is more detailed than the other profiles for 

 part 1 because BT observations were available. 

 In figure 19B, the lower thermocline is 

 identifiable with that at the same latitude in 

 figure 19A, and the upper one is believed to 

 indicate the re-establishment of the charac- 

 teristic post-norther ridging, without the sinu- 

 osity that complicated the ridge structure on 

 part 1 of the cruise (see below). Figures 19 

 (C-F) agree with figure 19A. 



Interpretation 



Both parts of the cruise were made after 

 Tehuantepecers, part 1 beginning about 5 

 days after one and part 2 about 2 days after 

 another. It is therefore not surprising that 



18 



