Page 



19. Salinity profile and salinity-depth curves for the first (B) triplet of hydrocasts at 



front 5 (2Z Apr. 1961). The dashed line on the profile is the corresponding 17° C. 

 isotherm contour (fig. 17), to show the relation of the temperature inversion 

 to the salinity inversion. Note the salinity maximum ( > 34.80%o) of eastern tropical 

 Pacific water at about 125 m. c = cool side; m = middle; w = warm side; « = 

 Nansen bottle depths in profile 26 



20. Salinity profile and salinity-depth curves for the second (E) triplet of hydrocasts at 



front 5 (23 Apr. 1961). The dashed line on the profile is the corresponding 16.5° C. 

 isotherm (figs. 18 and 19). Note the salinity maximum ( >34.80%o) of equatorial 

 Pacific water at about 150 m. c = cool side; m = middle; w = warm side; • = 

 Nansen bottle depths in profile 27 



21. Thermosteric anomaly ( 8 ■p ) profile and 8 ff -depth curves for the first triplet (B) of 



hydrocasts at front 5 (22 Apr. 1961). c "- cool side; m = middle; w = warm side; 



• = Nansen bottle depths in profile 28 



22. Thermosteric anomaly (8^ ) profile and 8 -p -depth curves for the second triplet (E) of 



hydrocasts at front 5 (23 Apr. 1961). c = cool side; m = middle; w = warm side; 



• = Nansen bottle depths in profile 29 



23. T-S curves (on 8 _ field) for the three B-series hydrocasts. Nunnbers against curves 



indicate depths 30 



24. T-S curves (on 8™ field) for the three E-series hydrocasts. Numbers against curves 



indicate depths 31 



25. Temperature, salinity, and thermosteric anomaly distribution across front 5 at the 



surface, as determined on BT pass no. 3 (21 Apr. 1961). (See fig, 15 for corre- 

 sponding vertical temperature distribution.) 32 



26. Oxygen profile and oxygen-depth curves for the first (B) triplet of hydrocasts at front 



5 (22 Apr. 1961). The dashed contour (0.1 ml.l .-1) arbitrarily marks the upper 

 boundary of the extensive oxygen minimum typical of the eastern tropical Pacific 

 water, c = cool side; m = middle; w = warm side; • = Nansen bottle depths in 

 profile 33 



27. Oxygen profile and oxygen-depth curves for the second (E) triplet of hydrocasts at 



front 5 (23 Apr. 1961), c = cool side; m = middle; w = warm side; • = Nansen 

 bottle depths in profile 34 



28. Nitrite-depth curves for the two triplets of hydrocasts made at front 5, B series in 



left panel; E series in right 35 



29. Nitrate-depth curves for the two triplets of hydrocasts made at front 5. B series in left 



panel; E series in right 3^ 



30. Chlorophyll a profile and chlorophyll a-depth curves for a triplet of observations that 



closely corresponded in position to the first (B) triplet of hydrocasts at front 5. 

 Dashed-line contours in the profile are somewhat speculative, c = cool side; m = 

 middle; w = warm side; • = Van Dorn Sampler depths in profile 37 



31. Track of thermograph survey of front 1 (0750-1430 hrs. 7 May 1960), with surface 



isotherms superimposed. Results of four GEK observations are also shown. The 

 track after course reversal (0935) has been displaced for clarity but closely cor- 

 responds to the track between 1928 and 0935 hrs 43 



32. Track at front 2 (10 May 1960), showing positions of hydrocasts, net tows and GEK 



observations. Isotherm contours (where practical to draw) and BT passes are 

 shown separately, offset 44 



33. The temperature profile from BT pass no. 2 across front 2 (10 May 1960). Cross- 



hatching shows water that is practically isothermal vertically 45 



