The structure of the isotherms from stations 

 9568 to 9571 again suggested that the Labrador 

 Current is an edge phenomenon. 



Figures 40 and 41 studied together tend to 

 suggest that the North Atlantic Current may 

 be intrusively moving westward. As noted pre- 

 viously atypical water was found at station 

 9573 and the 7.0° C isotherm was intruding 

 westward of its usual position. The isotherms 

 and isohalines from stations 9576 to 9578 sug- 

 gested a displacement to the west. 



STANDARD SECTION 2 



The occupations of Standard Section 2 will 

 now be considered. Standard Section 2 was 

 occupied prior to, during, and after the 1966 

 International Ice Patrol Season. The first oc- 

 cupation was by the CGC HUMBOLDT on 

 11-12 March 1966. The next two occupations 

 were made by CGC EVERGREEN on 7-8 

 April and 26-27 May 1966. The surface dynamic 

 heights along Standard Section 2 are presented 

 in Figure 15 and Figures 42 and 43. Surface 

 dynamic heights along the 47° parallel of 

 north latitude obtained from the April and 

 May normal charts prepared by Soule (1964) 

 are shown in Figures 44 and 45. The latter 

 very clearly delineate the average spring con- 

 ditions. The average maximum value for April 

 is 971.024 dynamic meters with a correspond- 

 ing minimum value of 970.869 dynamic meters. 

 In May 1966 the maximum dynamic height 

 value had increased to 971.027 dynamic meters 

 and the minimum value had increased to 

 970.882 dynamic meters. 



Figure 15 shows relatively steep gradients 

 with a net southerly transport and a slight 

 northerly flow between the inshore stations. 

 The 7-8 April 1966 occupation found an in- 

 creased northerly transport between the four 

 easternmost stations and a reduced southerly 

 flow. The 26-27 May 1966 occupation showed 

 an increase in maximum dynamic height val- 

 ues for the continental shelf stations from 

 970.99 to 971.05 dynamic meters. The trough 

 values have remained relatively constant dur- 

 ing all three surveys. The actual values were 

 970.85, 970.87, and 970.87 dynamic meters, in- 

 dicating an increase in velocity of the 

 Labrador Current. 



The vertical temperature and salinity struc- 

 tures observed in 1966 along Standard Section 



2 are presented in Figures 12, 13, 21, 22, 46 

 and 47. These figures indicate that the succes- 

 sive occupations were characterized by a de- 

 crease in temperature and salinity in the most 

 rapidly flowing portion of the southerly flow. 

 There was a persistent presence of a steep 

 4.0° C isotherm on each occupation. It was 

 most apparent on the 26-27 May 1966 oc- 

 cupation. 



No water with a temperature less than 

 0.0° C was observed during any 1966 occupa- 

 tion of Standard Section 2, an extremely 

 anomalous condition for a section located so 

 far to the north. These three occupations did 

 not indicate any eastward branching of the 

 Labrador Current, although the northern leg 

 of Standard Section 2 was designed to indi- 

 cate any such branching. 



STANDARD SECTION 4 



The northern part of Standard Section 4 

 corresponds to the historic Ice Patrol Section 

 W. This portion was occupied by the CGC 

 EVERGREEN on 2-3 April 1966 and the en- 

 tire section was occupied on 22-24 May 1966. 

 The 2-3 April 1966 occupation extended across 

 the Labrador Current. The 22-24 May 1966 

 occupation extended from 37°21'N to 43°09'N 

 along 50° W and crossed the Labrador Current 

 and extended well into the North Atlantic Cur- 

 rent. The surface dynamic heights along the 

 northern end of Standard Section 4 are pre- 

 sented as Figures 48 and 49. The normal 

 monthly mean dynamic heights along the 

 northern end of Standard Section 4 obtained 

 from Soule (1964) are presented in Figures 

 50 and 51. The April normal dynamic topog- 

 raphy showed a strong, well defined Labrador 

 Current with a relatively wide trough between 

 it and the vigorous North Atlantic Current. 

 The observed dynamic topography was ex- 

 tremely flat with the swiftest current occur- 

 ring between stations 9511 and 9512, approxi- 

 mately 20 miles south of its usual position. 



The 22-24 May 1966 occupation showed 

 some filling of the trough and an increase of 

 approximately 9 dynamic centimeters in the 

 dynamic height of the northernmost station. 

 The ribbon of rapid surface current remained 

 displaced to the south. 



Standard Section 4 has been occupied 4 

 times previously by the International Ice 



12 



