The dynamic topography found during the three surveys made 

 during the season and during the postseason occupation of the 

 Bonavista triangle is shown in figures 12, 13, 14 and 15 presented 

 in chronological order. It will be seen from figure 12 that during 

 the first survey except at the two northernmost sections the Labra- 

 dor Current was flowing with about normal surface speeds all 

 the way to and westward of the Tail of the Banks. This water 

 continued westward of the Tail beyond the limits of the surveyed 

 area before recurving to the south and east. The temperature 

 structure of the Labrador Current was not normal and the tem- 

 perature minimum was atypically warm and poorly defined except 

 at the northern sections. Here the abnormality seemed to be con- 

 fined to that part of the current which was eastward of the 100- 

 fathom curve. 



Figure 13 shows the considerable northwestward extension of 

 the Labrador Current beyond the Tail of the Banks. The surface 

 speed of the Labrador Current remained strong along the eastern 

 edge of the Banks and in the northwestern part of the surveyed 

 area the pattern of set onto the Banks inside the 100-fathom curve 

 shown in figure 12 was repeated. The temperature minimum of 

 the Labrador Current was about 0.6° C colder than the abnormally 

 warm temperatures found during the first survey. While these 

 colder minimum values showed a recovery to about normal, this 

 recovery was limited to the inshore half of the current. 



During the third survey (figure 14) the abnormally warm mini- 

 mum temperatures in the offshore half of the Labrador Current 

 continued. The only station where negative temperatures were 

 found seaward of the 971.0 dynamic meter contour was station 

 6260 on the southeastern side of the Bonavista triangle and the 

 lowest dynamic height at which a temperature minimum as cold 

 as — 1.0°C was found was 971.05 dynamic meters on the northern 

 side of the triangle. Along the southernmost section of the survey 

 the dynamic topography indicated little change from that found 

 in the northern part of the second survey. 



The current pattern in the Bonavista triangle found during the 

 post-season cruise (figure 15) was much the same as that found 

 during the third survey, the principle change being a seaward 

 shift of the current pattern. From the topography shown in figure 

 15 any bergs crossing the 49th parallel eastward of about longi- 

 tude 51-45° W. Would have followed the eastern branch of the 

 Labrador Current and those crossing westward of that longitude 

 would have followed the western branch. 



Labrador Current water and Atlantic Current water found in 

 the Grand Banks region have temperature-salinity characteristics 

 which identify them as water masses. Here also these parent water 



42 



