The observations made during the second survey indicated a con- 

 tinuation of this mixing at subsurface levels but with some recovery of 

 the Labrador Current temperature minimum and the area in which 

 undiluted Labrador Current water was found more nearly normal. The 

 reestablished temperature minimum in the Labrador Current was shal- 

 lower than normal and, except in the northernmost sections, warmer than 

 normal. Figure 20 shows the highest dynamic heights of the Atlantic 

 Current in the surveyed area to have returned to about normal values. 



A cold water pool with counterclockwise circulation and partly detached 

 from the Labrador Current lay westward of 51° W. south of the Tail of 

 the Banks. The clockwise eddy found in the first survey near 44°30'N. 

 47 °00' W. was still present in the second survey somewhat southwestward 

 of its previous position and connected by a warm salty ridge to the 

 Atlantic Current water in the southern part of the surveyed area. This 

 was accompanied by a cold fresh valley extending southward from the 

 45th parallel to the southern limits of the chart between the ridge and 

 the Atlantic Current to the eastward. This is the reverse of the usual 

 relative positions of a pair of meanders which develop a counterclockwise 

 intertwining as the pattern decays and moves with a translation parallel 

 to the Atlantic Current. 



Figure 21 shows the dynamic topography found at the Bonavista 

 triangle during the postseason cruise. In any comparison of the situation 

 shown here with the topography farther south shown in figures 19 and 20 

 it should be kept in mind that figure 20 was the result of a survey con- 

 ducted 1 to 12 May whereas the Bonavista triangle was occupied 22 to 25 

 July. Our only information as to changes which might have taken 

 place in the current pattern in the Grand Banks area is from berg drifts 

 and these indicate that the current pattern in the western half of the 

 area surveyed in May remained remarkably steady and as shown in 

 figure 20 through June and July. 



There are two features of the dynamic topography shown in figure 21 

 that are especially worthy of note. One is the exceptionally high dynamic 

 heights found near the Cape Bonavista corner and the other is the 

 comparatively small distance from Cape Bonavista to the eastern edge 

 of the water following the western branch of the Labrador Current. 

 The low densities of the inshore stations which produced the large 

 dynamic heights were largely the result of low salinity. In terms of 

 berg movements, the division between eastern and western branches of 

 the Labrador Current meant that any bergs crossing the 49th parallel 

 eastward of about 52°30' W. would follow the eastern branch. Because 

 of the absence of opportunity to make any dynamic topographic surveys 

 of the northeastern slope of the Grand Banks during the 1957 season the 

 significance of this unusually far westward division point cannot be 

 assessed. 



As implied above in the discussion of figures 19 and 20 the temperature- 

 salinity relationships found at each station of the two surveys made in 

 1957 were examined. 



88 



